Otoacoustic emissions as a screening test for hearing impairment in children

Transient evoked otoacoustic emissions (TEOAEs) are low amplitude sound waves produced by the healthy cochlea. They can be recorded with a microphone in the external ear. TEOAEs are abolished by hearing losses of 30 dB or more. The feasibility of using TEOAEs as a screening test for hearing loss in children was studied. TEOAE recordings were attempted in 56 children attending an audiology clinic. Recordings were possible from both ears in 52 children; of these 104 ears, 32 had hearing deficits of 30 dB or more. Hearing status was compared with the results of six TEOAE screening criteria. All criteria had a sensitivity of 1.00. Four standard TEOAE criteria yielded specificities of 0.46-0.58. Two new criteria derived from analysis of limited frequencies from the TEOAE waveform gave specificities of 0.76 and 0.82. It can be concluded that, when appropriate pass/fail criteria are employed, TEOAEs are a feasible screening test in children.     

Displacement amplitude of ultrasonic scaler inserts

OBJECTIVES: Scanning laser vibrometry is a noninvasive method of measuring the velocity, displacement amplitude and oscillation frequency of vibrating objects. The purpose of this study was to assess, using a scanning laser vibrometer (SLV), the performance of different designs of commercially available ultrasonic scaler generators by measuring the oscillatory characteristics of various scaler tips. METHODS: Four ultrasonic generators were tested (Cavitron SPS and Cavitron Select (Dentsply, York, PA, USA) and Piezon Master 400 and Mini Piezon (Electro-Medical Systems, Switzerland)) with various designs of scaler tip. The tips were positioned with their anterior surface perpendicular to the direction of the laser. A graduated scale, placed over the manufacturer's power dial, enabled incremental power setting selection. For each power setting, the laser beam from the SLV was scanned over the surface of the oscillating tip. RESULTS: The ranges of longitudinal displacement amplitudes (in micrometres) were as follows: Mini Piezon (P-tip): 12.90+/-1.44 to 44.03+/-7.80; Piezon Master 400 (P-tip): 16.02+/-2.66 to 35.85+/-5.29; Cavitron SPS (TFI-10 tip): 7.81+/-0.51 to 29.70+/-1.12; Cavitron Select (TFI-10 tip): 13.13+/-1.44 to 33.77+/-4.27; Cavitron SPS (TFI-3 tip): 5.50+/-0.46 to 31.35+/-3.62. CONCLUSIONS: This study shows that there are differences between commercially available generators and that tip movement varies between tips of the same style as well as between the generator and tip design. Users of ultrasonic scalers should be made aware of this inherent variability that may influence clinical procedures.     

The incidence of Cytomegalovirus (CMV) antigenemia and CMV disease is reduced by highly active antiretroviral therapy

Cytomegalovirus (CMV) infection was one of the most common opportunistic infections in AIDS patients, leading to blindness or life-threatening disease in about 40% of patients in the later stages of AIDS before highly active antiretroviral therapy (HAART). In a retrospective multicenter study we investigated the incidence of CMV retinitis and organ involvement in Northern Italy before (1995 and 1996) and after the introduction of HAART (1997 and 1998) as well as the data regarding CMV antigenemia. We found a sharp drop in the incidence of CMV disease in AIDS patients as well as a decline in the incidence of relapses of CMV-disease after the widespread introduction of HAART.c Moreover, there was a decrease in the incidence of antigenemia-positive cases in AIDS patients in the era of HAART and the median CMV viral load was significantly higher in patients who didn't receive HAART than in patients who received HAART (p= 0.001, ttest).     

Substances with antiviral activity. XIII. Synthesis and in vitro activity of thiosemicarbazones of 1-benzoyl- and 1-benzyl-2-chloro-3-formylindoles

A series of 1-benzoyl- and 1-benzyl-2-chloro-3-formylindole thiosemicarbazones was synthesized and investigated for antiviral activity against vaccinia virus IHD strain and parainfluenza virus type 3, HA-I/CR-8 strain. The results confirmed the previously observed high activity against vaccinia virus of m-substituted benzoyl derivatives. On the contrary, the analogous benzyl derivatives showed marginal activity; the compound (V c), however, was the most active against the parainfluenza virus.     

Attenuation measurements in atherosclerotic tissues: problems with phase-cancellation artefacts

The study was designed to establish whether changes in arterial wall structure due to atherosclerosis may be reflected in the increase of ultrasonic attenuation. Accordingly, fresh aortic wall specimens were analysed by an attenuation technique and pathologically classified into three groups: normal, fibrofatty and calcific. Analysis was performed by using a single broadband transducer acting as transmitter and receiver of the echo produced by a specular reflector positioned behind the specimen under study. Two indices were derived from the transfer function H_(f) of the specimen: the slope of the best-fit straight line to In |H_(f)| and the absolute value of In |H_(f)| at 9MHz. The index based on the slope of In |H_(f)| is able to distinguish normal wall from atherosclerotic lesions. The absolute value of In |H_(f)| is able to differentiate normal, fibrofatty and calcific groups. However, such an index is strongly influenced by specular reflections at water/specimen interfaces. Acquisition of ultrasonic echoes was improved with the use of a small-diameter transducer, which is presumed to reduce distortion in the transfer function due to phase-cancellation effects. According to a statistical test based on the evaluation of the goodness of the straight-line fit to In |H_(f)|, the results of the two sets of measurements were compared. The importance of a small-diameter transducer for the further reduction of phase-cancellation artefacts was assessed.     

Congenital cytomegalovirus infection in twin pregnancies: viral load in the amniotic fluid and pregnancy outcome

Human cytomegalovirus (CMV) is the most common cause of viral intrauterine infection and fetal damage largely attributable to maternal primary infection. Most cases of congenital CMV infection in twins reported in the literature involved only 1 twin. We assessed the validity of polymerase chain reaction (PCR) and quantitative PCR on amniotic fluid (AF), at 21 to 22 weeks' gestation and at least 6 to 8 weeks after seroconversion, to predict the outcome of newborns in twin pregnancies. Two pregnant women with twin pregnancies and 1 woman with a triple pregnancy with primary CMV infection defined by the presence of immunoglobulin (Ig) M and low IgG avidity and/or by the presence of clinical symptoms and abnormal liver enzyme values were evaluated. CMV infection was found in 6 fetuses/newborns, 3 of whom were symptomatic. In the first twin pregnancy with diamniotic-dichorionic separate placentas, CMV symptomatic infection of the female twin was demonstrated by positive virus isolation and high viral load in AF. The male fetus was not infected as demonstrated by negative CMV culture and DNA detection in AF. In the triple pregnancy, the woman had a placenta with 2 monozygotic twins (females) and a separate placenta with a heterozygotic twin (male). The quantitative PCR results were 10(3) genome equivalents (GE)/mL of females AF and 1.9 x 10(5) GE/mL of male AF. Both female twins were asymptomatic at birth, whereas the male presented petechiae, thrombocytopenia, and cerebral ventriculomegaly. In the last twin pregnancy with fused dichorionic placentas, congenital CMV infection of both twins was diagnosed at birth in contrast with prenatal diagnosis. At time of amniocentesis, the left side twin was not infected as shown by negative results of CMV culture and DNA detection in the AF. CMV infection of the right side twin was demonstrated by positive CMV DNA detection with a CMV DNA load of 4.9 x 10(4) GE/mL and positive virus isolation in the AF. The morphologic and histologic examinations of the placentas strongly supported a prenatal horizontal acquisition of CMV infection. These twin pregnancies showed a marked difference in the quantity of virus load documented by the prenatal diagnosis suggesting that twin fetuses may react differently to primary maternal infection despite being exposed to the same maternal influences. A high viral load is correlated with congenital CMV infections symptomatic at birth. In such cases, with fetal infection of only 1 twin (at amniocentesis) and fusion of placentas, fetal outcome of both twins needs to be evaluated for the possibility of viral transfer from one fetus to the other.