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Prevalence of genotypic and phenotypic HIV-1 drug-resistant strains among patients who have rebound in viral load while receiving antiretroviral therapy in the UNAIDS-Drug Access Initiative in Abidjan, Côte d'Ivoire.

OBJECTIVE: To determine the prevalence of genotypic and phenotypic antiretroviral (ARV) drug-resistant HIV-1 strains among patients with viral load rebound while receiving ARV therapy in Abidjan, Côte d'Ivoire. METHODS: Between August 1998 and April 2000, we selected all patients (n = 241) who had received ARV drug therapy for at least 6 months in the UNAIDS-Drug Access Initiative (DAI), in Abidjan. We analyzed for genotypic and phenotypic drug resistance among 97 (40%) of the 241 patients who had a rebound in plasma viral load, defined as an initial decrease of > 0.5 log10 copies/ml followed by a subsequent increase of > 0.25 log10 copies/ml. RESULTS: Of the viruses isolated from the 97 patients, 86 (88.7%) had usable sequences and 68 (79%) of the 86 patients had genotypic resistance to at least one reverse transcriptase inhibitor (RTI) or protease inhibitor (PI). Resistant mutations were found for zidovudine in 50 (78%) of 64 patients who had received the drug, 11 (68.7%) of 16 patients on lamivudine, for nevirapine in two (2%), for indinavir in one (1%), and for ritonavir in one (1%). Phenotypic resistance to at least one nucleoside RTI was seen in 45 (56%) of the 80 patients tested, to non-nucleoside RTIs in eight (10%), and to PIs in one (1.3%). Multivariate regression analysis showed factors associated with resistance to be initial treatment with dual therapy (P = 0.04) compared with highly active antiretroviral therapy, and maximal initial viral load response (P = 0.006). CONCLUSION: Our results demonstrate a high prevalence of ARV drug resistance associated with dual ARV therapy. These results indicate the limited role for dual ARV therapy.

Adult↗

Reliability and intersubject variability of the real ear unaided response.

Intratester test-retest reliability of the real ear unaided response (REUR) was determined on 49 ears using the Frye 6500 real ear analyzer. Results revealed mean differences of less than 1 dB for repeat measurements at seven test frequencies between 250 and 4000 Hz. The average peak resonant frequency of the repeated measure was within 16 Hz of the initial measure. In addition, the intersubject variability of the amplitude of REUR was quite large. A range of 7 dB was found at 250 to 500 Hz with the range expanding to 15 to 20 dB at 2000 to 4000 Hz. Also, the peak resonant frequency varied between 2100-4800 Hz. These results are discussed in terms of those dispensers who use the REUR to "custom" order hearing aids.

Acoustics↗

Probe-tube microphone measures with very young infants: real ear to coupler differences and longitudinal changes in real ear unaided response.

OBJECTIVE: The feasibility and practicalities of performing probe-tube microphone measures with infants is addressed, as well as two aspects of acoustic functioning of infant ears: the real ear unaided response (REUR) and the real ear to coupler difference (RECD). DESIGN: Part 1 is a longitudinal study involving 12 infants. Serial measures of REUR were obtained over an 18-mo period. Infants were < or = 3 mo for the first test and < or = 21 mo at the last test visit. Practicalities of probe-tube microphone testing of unsedated infants and changes in the position (i.e., frequency) of the primary REUR peak were addressed. For part 2 of the project, 33 infants under 12 mo of age took part. A comparison of real ear hearing aid gain versus coupler gain was made. Test-retest differences for real ear aided response were estimated. RESULTS: Part 1 results indicate that probe-tube microphone measures in unsedated infants are feasible and show good within-subject repeatability. REUR measures for the more alert and mobile older subjects, as for the younger infants, showed an acceptably small degree of intersubject variability. The frequency of the primary REUR peak decreased during the first year of life, with a group mean of 2932 Hz reached at the end of the first year. However, thereafter, instead of stabilizing at around this value there was considerable fluctuation in the frequency of REUR peak. For Part 2, results a) confirmed the large RECD value for infants in the first year of life and b) showed a high degree of intersubject variability. Test retest measures of real ear aided response (REAR) gave values small enough to indicate the clear potential of probe-microphone use with infants during the hearing aid selection and fitting process. CONCLUSION: These findings should encourage attempts to carry out individual probe-tube microphone measurements with very young infants. They point to the need for infant hearing aid fitting procedures which involve such measurements to secure appropriate amplification.

Amplifiers, Electronic↗

The performance-perceptual test and its relationship to unaided reported handicap.

OBJECTIVE: Measurement of hearing aid outcomes is necessary for demonstration of treatment efficacy, third-party payment, and cost-benefit analysis. Outcomes are usually measured with hearing-related questionnaires and/or tests of speech recognition. However, results from these two types of test often conflict. In this paper, we provide data from a new test measure, known as the Performance-Perceptual Test (PPT), in which subjective and performance aspects of hearing in noise are measured using the same test materials and procedures. A Performance Speech Reception Threshold (SRTN) and a Perceptual SRTN are measured using the Hearing In Noise Test materials and adaptive procedure. A third variable, the discrepancy between these two SRTNs, is also computed. It measures the accuracy with which subjects assess their own hearing ability and is referred to as the Performance-Perceptual Discrepancy (PPDIS). DESIGN: One hundred seven subjects between 24 and 83 yr of age took part. Thirty-three subjects had normal hearing, while the remaining seventy-four had symmetrical sensorineural hearing loss. Of the subjects with impaired hearing, 24 wore hearing aids and 50 did not. All subjects underwent routine audiological examination and completed the PPT and the Hearing Handicap Inventory for the Elderly/Adults on two occasions, between 1 and 2 wk apart. The PPT was conducted for unaided listening with the masker level set to 50, 65, and 80 dB SPL. RESULTS: PPT data show that the subjects with normal hearing have significantly better Performance and Perceptual SRTNs at each test level than the subjects with impaired hearing but that PPDIS values do not differ between the groups. Test-retest reliability for the PPT is excellent (r-values > 0.93 for all conditions). Stepwise multiple regression analysis showed that the Performance SRTN, the PPDIS, and age explain 40% of the variance in reported handicap (Hearing Handicap Inventory for the Elderly/Adults scores). More specifically, poorer performance, underestimation of hearing ability and younger age result in greater reported handicap, and vice versa. CONCLUSION: Reported handicap consists of a performance component and a (mis)perception component, as measured by the Performance SRTN and the PPDIS respectively. The PPT should thus prove to be a valuable tool for better understanding why some individuals complain of hearing difficulties but have only a mild hearing loss or conversely report few difficulties in the presence of substantial impairment. The measure would thus seem to provide both an explanation and a counseling tool for patients for whom there is a mismatch between reported and measured hearing difficulties.

Adult↗

Human immunodeficiency virus type 1 subtypes defined by env show high frequency of recombinant gag genes. The UNAIDS Network for HIV Isolation and Characterization.

Genetic subtypes of human immunodeficiency virus type 1 can be distinguished on the basis of phylogenetic analysis of their envelope (env) gene. A significant proportion of human immunodeficiency virus type 1 strains was retrospectively shown to result from recombination events between viruses belonging genetically to distinct subtypes (D. L. Robertson, P. M. Sharp, F. E. McCutchan, and B. H. Hahn, Nature [London] 374:124-126, 1995). To establish the frequency of natural infections with recombinant viruses and to exclude tissue culture artifacts, we analyzed plasma samples from the UNAIDS sample collection. The collection includes samples from 53 individuals infected with subtype A (n = 9), subtype B (n = 15), subtype C (n = 1), subtype D (n = 13), and subtype E (n = 15) on the basis of V3 region analysis. Phylogenetic analysis of the gag gene fragment showed intersubtype recombinant genomes in 23 cases: 3 of 9 (33%) of subtype A, 2 of 15 (13%) of subtype B, 3 of 13 (23%) of subtype D, and all of subtype E. Of the 23 recombinant viruses, 19 had a gag gene from one subtype and env from another (B(env)/C(gag), A(env)/C(gag), D(env)/A(gag), and E(env)/A(gag)). Phylogenetic analysis clustered the A(gag) of subtype E viruses as an outgroup of subtype A, suggesting that these viruses may belong to a distinct A' cluster. The remaining four recombinant viruses (B(env)/B(p17)F(p24), A(env)/A(p17)D(p24), A(env)/A(p17)C(p24), and D(env)/ D(p17)A(p24)) had breakpoint crossover sites in the proximity of the p17-p24 protein processing site. We conclude that recombination in the gag gene is highly frequent among the major env subtypes and that selection of recombinants is apparently based on particularly beneficial combinations of gag and env gene products.

Gene Frequency↗

Optimal postoperative refraction for good unaided near and distance vision with monofocal intraocular lenses.

Forty five eyes with up to 2 dioptres of myopic astigmatism and up to 1 dioptre sphere either plus or minus following cataract extraction and implantation of a monofocal intraocular lens were examined to assess their unaided visual acuities. Forty three percent were able to see 6/12 and N8, and 60% were able to see 6/12 and N10. Subjects with between 1 and 2 dioptres of myopic astigmatism and virtually no sphere were able to see 6/12 and N10 in 82% of cases. This study confirms the benefits to both distance and near vision of myopic astigmatism as an alternative to multifocal intraocular lenses.

Adult↗

Probe-tube microphone measures in patients with open-mastoid surgery: real-ear-to-coupler differences and real-ear unaided responses.

Real-ear-to-coupler differences (RECDs) and real-ear unaided responses (REURs) were measured using a probe-tube microphone system in 15 patients who underwent open mastoid surgery. The results show that RECDs are significantly smaller at higher frequencies (1.5, 2.0, 3.0, 4.0 and 6.0 kHz) in mastoid ears. The intrasubject variability of RECDs measures in these patients is on average 2.6 dB larger than for controls. For REURs, mastoid surgery significantly reduced the mean peak resonant frequency without affecting the amplitude and bandwidth. In operated ears, mean resonant frequency is by a factor of 1.4 lower than that for normal ears. Reduced responses (negative gains) at frequencies above the resonance peak occurred in 7 out of the 15 patients. These reduced responses corresponded to the smaller RECD at the middle and high frequencies. The results support the need for individual RECD measures to be made in operated ears instead of using average values from normal subjects. Otherwise, real-ear measures of the aided response should be made for each patient with open-mastoid cavity and the fitting should be done in terms of the target response at the eardrum rather than by defining a target insertion gain.

Adolescent↗

Usability of a computer-assisted interview system for the unaided self-entry of patient data in an urban rheumatology clinic.

OBJECTIVE: This study quantified the ease of use for patients and providers of a microcomputer-based, computer-assisted interview (CAI) system for the serial collection of the American College of Rheumatology Patient Assessment (ACRPA) questionnaire in routine outpatient clinical care in an urban rheumatology clinic. DESIGN: A cross-sectional survey was used. MEASUREMENTS: The answers of 93 respondents to a computer use questionnaire mailed to the 130 participants of a previous validation study of the CAI system were analyzed. For a 30-month period, the percentage of patient visits during which complete ACRPA questionnaire data were obtained with the system was determined. RESULTS: The computer system provided cost and labor savings in the collection of 2,476 questionnaires for 2,964 patients visits over 30 months for a capture rate of 83.5%. In the last 12 of those months, 1,035 questionnaires were collected for 1,062 patient visits (97.5% capture). There were no missing data. The prestudy capture rate was 13.5%, with 33% of surveys having complete data. Patients rated the overall usability of the system as good (mean = 1.34, standard deviation = 0.61) on a scale of 0-2, where 2 = good, but expressed difficulty with mouse manipulation and concerns about the privacy of the data entry environment. CONCLUSION The system proved easy to use and cost-effective for the (mostly) unaided self-entry of self-report data for each patient for each visit in routine outpatient clinical care in an urban rheumatology clinic.

Attitude to Computers↗

Comparison of unaided MCLs and use-gain of hearing aids.

Unaided MCLs for narrow bands of noise centered at 1 000, 2 000, 3 000 and 4 000 Hz were compared with the use-gain of hearing aids worn by 10 subjects with sensorineural hearing loss. In addition, for eight subjects, MCLs measured at the time of the hearing aid evaluation were compared with MCLs observed at the time of hearing aid follow-up. Results of the study suggest that (1) hearing aid use-gain can be accurately predicted on the basis of the MCLs for the narrow bands of noise, and (2) the hearing-impaired subjects were highly consistent in their MCL judgments for narrow-band noise.

Consumer Behavior↗

The effects of speech and speechlike maskers on unaided and aided speech recognition in persons with hearing loss.

Speech understanding in noise is affected by both the energetic and informational masking components of the background noise. In addition, when the background noise is everyday speech, the relative contributions of the energetic and informational masking components to the overall difficulties in understanding speech are unclear. This study estimated informational masking effects, in conversational speech settings, on the speech understanding of persons with and without hearing loss. The benefits and limitations of amplification in settings containing both informational and energetic masking components were also explored. Speech recognition was assessed in the presence of two types of maskers (speech and noise) that varied in the amount of informational masking they were expected to produce. Persons with hearing loss were tested both unaided and aided. Study results suggest that background noise, consisting of individual talkers, results in both informational and energetic masking. In addition, the benefits of amplification are limited when the background noise contains both informational and energetic masking components.

Adult↗

[The joint work of NGOs and UNAIDS in realizing a project for the prevention of HIV/AIDS among people using narcotics by injection in a region with relatively low rates of HIV infection spread].

In recent years the Ukraine has become the epicenter of AIDS in Eastern Europe, though there are still regions with a relatively low number of HIV-infected persons, such as Vinnitsa Province. After the comprehensive study of the factors contributing to the spread of HIV infection in groups of risk the realistic evaluation of the epidemiological danger could be made and the preventive work could be carried out with the help of collaboration between a non-governmental organization (NGO) and the UN Theme Group on the Problems of HIV/AIDS. The successful work of the Public Congress "Stalist" one of such NGO, in Vinnitsa in 1998-1999, carried out with the financial and methodological support of UNAIDS in the Ukraine, created conditions for the introduction of such components of the strategy of harm reduction as information and educational work, as well as the exchange of syringes and needles, which showed a high degree of efficiency in controlling the spread of HIV/AIDS.

Adolescent↗

MTCT programs work in a variety of ways. UNAIDS, others working to help pregnant women.

While mother-to-child transmission (MTCT) of HIV has been reduced to very small numbers in the United States and Europe, there still are more than 1,600 children infected with HIV each day, mostly in sub-Saharan Africa. Besides free drug programs to prevent MTCT, there have been efforts made by UNAIDS of Geneva, Switzerland, the Elizabeth Glaser Pediatric AIDS Foundation in Washington, DC, and others to combat this problem.

Anti-HIV Agents↗

Scientific considerations for the regulation and clinical evaluation of HIV/AIDS preventive vaccines: report from a WHO-UNAIDS Consultation 13-15 March 2001, Geneva, Switzerland.

The consultation was jointly organized by the WHO-UNAIDS HIV Vaccine Initiative and the Quality Assurance and Safety of Biologicals Team of the World Health Organization (WHO). Thirty-four experts from 16 developed and developing countries attended the meeting, bringing together expertise from academic institutions, clinical trial centres, national and international regulatory authorities. Representatives of major pharmaceutical companies were also invited. The primary objective of the meeting was to identify gaps that need to be addressed from regulatory perspective to ensure appropriate progress of HIV vaccine development from basic research to human trials, licensing and future application, with a special focus on needs of developing countries. As a result of discussions, the following priority needs were identified and recommendations were made in order to establish an appropriate regulatory framework for the development and evaluation of preventive HIV/AIDS vaccines, which were divided in two main areas: (a) standardization and control of candidate HIV/AIDS vaccines, and (b) approaches to the conduct of clinical trials of candidate HIV/AIDS vaccines.

AIDS Vaccines↗

Audiometric correlates of the unaided APHAB.

The Abbreviated Profile of Hearing Aid Benefit (APHAB) is a self-report questionnaire that is used to quantify the impact of a hearing problem on an individual's daily life. In this investigation, the relationships were explored between typical clinical audiometric data and the four subscale scores of the APHAB administered in the unaided (without-amplification) condition. Sixty subjects provided APHAB scores, audiograms, and speech recognition data. Analyses revealed significant relationships between audiometric data and each of the three APHAB subscales that reflect speech communication (EC, RV, and BN). None of these subscales was significantly more strongly related to any specific audiological variable. However, the pattern of associations between audiometric variables and subscale scores was consistent with predictions based on item content for subscales EC and RV, but not for BN. As predicted, no relationship was found between audiometric data and scores for the Aversiveness subscale (AV). Even for the subscales with the strongest associations, differences in audiometric data could be used to explain half or less of the variance in self-report data.

Adult↗

Real ear unaided responses in ears with tympanic membrane perforations.

This study evaluated 13 adult patients with tympanic membrane (TM) perforations in one or both ears. Probe microphone real ear unaided responses (REURs) for mean peak frequency and peak dB gain showed no substantial differences among patients, across ears with intact TMs, ears with TM perforations (regardless of size), or between measures taken before and after closure of the perforations. Inspection of individual differences in the patients' REURs, however, produced an interesting finding. The REURs of ears having small TM perforations did not differ from those with intact TMs, but the REURs for ears having larger perforations consistently revealed bimodal responses (two prominent peaks separated by a valley of at least 10 dB lower gain). Thus, size of the perforation affected the REURs.

Acoustics↗

Aided and unaided narrow band noise thresholds in listeners with sensorineural hearing impairment.

This study explored the relationship between narrow band noise thresholds obtained under aided and unaided conditions with normal listeners and with subjects demonstrating sensorineural hearing impairment. Pure-tone and narrow band noise thresholds obtained under earphone conditions were found to approximate each other within 3 dB. Mean noise thresholds obtained in sound field required less sound pressure than thresholds obtained under earphone conditions. In comparing the predicted aided noise thresholds with the observed thresholds, a 4-dB mean difference was found. The close relationship between hearing aid acoustic gain and changes in aided narrow band noise thresholds suggests the use of narrow band noise audiometry in hearing-aid selection when traditional measures cannot be used.

Adult↗