Lung function, airway responsiveness, and respiratory symptoms before and after bronchiolitis

Acute viral respiratory illness during infancy has been implicated as a precursor for subsequent lower respiratory morbidity in childhood. A prospective, longitudinal study of respiratory function, airway responsiveness, and lower respiratory illness during early childhood was performed in a cohort of 253 healthy infants to characterise those who experienced bronchiolitis. Seventeen infants (7% of the cohort), were given a diagnosis of bronchiolitis during the first two years of life with two (1%) requiring hospital admission. Seventy one per cent of those infants with bronchiolitis had a family history of atopy, 53% of asthma, and 29% had a mother who smoked cigarettes. These family history characteristics in this group with bronchiolitis were not different from the rest of the cohort. There were also no differences in the number of older siblings, the number breast fed, the duration of breast feeding, or socioeconomic status of the families between those that did and did not get bronchiolitis. Respiratory function was assessed at 1, 6, and 12 months of age. Maximum flow at functional residual capacity (VmaxFRC) was measured using the rapid thoracic compression technique. Resistance (Rrs) and size corrected compliance (Crs/kg) were obtained from a single brief occlusion at end inspiration. Airway responsiveness was assessed by histamine inhalation challenge and the provocation concentration of histamine resulting in a 40% fall on VmaxFRC from baseline (PC40) was determined. Respiratory measurements were ranked into terciles to assess the distribution of infants who developed bronchiolitis through the cohort. Cough and wheeze were noted to be frequent before the episode of bronchiolitis. This study has demonstrated that infants who develop bronchiolitis have evidence of pre-existing reduced respiratory function and lower respiratory symptoms. It is proposed that bronchiolitis, although potentially contributory, is not usually causative of subsequent lower respiratory morbidity.     

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.     

Trichomonas vaginalis among HIV-Infected women: are immune status or protease inhibitor use associated with subsequent T. vaginalis positivity?

BACKGROUND AND OBJECTIVES: Trichomonas vaginalis (Tv) is a common sexually transmitted disease (STD) among HIV-infected populations. The relationship between Tv and immune status and HIV viral load as affected by protease inhibitor (PI) use has not been well examined. GOAL: The goals were to evaluate the association between Tv and both immune status and PI use among HIV-infected women, and to characterize factors associated with Tv among HIV-infected women. STUDY DESIGN: We used a retrospective cohort study conducted between 1990 and 2000. RESULTS: Of 1578 women, the majority was under 35 years, black (AA), and infected heterosexually or with unidentified risk. Thirty percent (30.2%) had Tv at least once, and 36.9% had at least one subsequent positive test; Tv was more common than chlamydia, gonorrhea, genital warts, or syphilis. After adjusting for follow-up time, young age, AA race, substance use, and other sexually transmitted diseases (STDs) were associated with initial Tv infection, but pregnancy, immune status, and PI use were not associated. After adjusting for follow-up time, having other STDs was associated with and pregnancy was protective of subsequent Tv positivity, but immune status and PI use were not associated; neither were age, race, or substance use. CONCLUSION: Tv is a common STD among HIV-infected women and does not appear to be associated with immune status or PI use. Aggressive screening might represent a means of reducing the incidence and prevalence of Tv.     

Renal arteries: navigator-gated balanced fast field-echo projection MR angiography with aortic spin labeling: initial experience

A cardiac-triggered free-breathing three-dimensional balanced fast field-echo projection magnetic resonance (MR) angiographic sequence with a two-dimensional pencil-beam aortic labeling pulse was developed for the renal arteries. For data acquisition during free breathing in eight healthy adults and seven consecutive patients with renal artery disease, real-time navigator technology was implemented. This technique allows high-spatial-resolution and high-contrast renal MR angiography and visualization of renal artery stenosis without exogenous contrast agent or breath hold. Initial promising results warrant larger clinical studies.     

Direct comparison of 3D spiral vs. Cartesian gradient-echo coronary magnetic resonance angiography.

While 3D thin-slab coronary magnetic resonance angiography (MRA) has traditionally been performed using a Cartesian acquisition scheme, spiral k-space data acquisition offers several potential advantages. However, these strategies have not been directly compared in the same subjects using similar methodologies. Thus, in the present study a comparison was made between 3D coronary MRA using Cartesian segmented k-space gradient-echo and spiral k-space data acquisition schemes. In both approaches the same spatial resolution was used and data were acquired during free breathing using navigator gating and prospective slice tracking. Magnetization preparation (T(2) preparation and fat suppression) was applied to increase the contrast. For spiral imaging two different examinations were performed, using one or two spiral interleaves, during each R-R interval. Spiral acquisitions were found to be superior to the Cartesian scheme with respect to the signal-to-noise ratio (SNR) and contrast-to-noise-ratio (CNR) (both P < 0.001) and image quality. The single spiral per R-R interval acquisition had the same total scan duration as the Cartesian acquisition, but the single spiral had the best image quality and a 2.6-fold increase in SNR. The double-interleaf spiral approach showed a 50% reduction in scanning time, a 1.8-fold increase in SNR, and similar image quality when compared to the standard Cartesian approach. Spiral 3D coronary MRA appears to be preferable to the Cartesian scheme. The increase in SNR may be "traded" for either shorter scanning times using multiple consecutive spiral interleaves, or for enhanced spatial resolution.     

Sexual behavior, smoking, and HIV-1 infection in Haitian Women.

OBJECTIVE--To determine whether a previously observed association between human immunodeficiency virus type 1 (HIV-1) infection and smoking in Haitian women could be explained by confounding high-risk behaviors. DESIGN AND SETTING--A nested case-control study at a primary care health clinic in Cité Soleil, Haiti. PARTICIPANTS--Women who reported having smoked (n = 89) and randomly selected nonsmokers (n = 329) who had participated in a survey 1 to 12 months earlier evaluating risk factors for HIV-1 infection. MAIN OUTCOME MEASURES--Lifetime sexual practices, smoking, health beliefs and practices, and other factors potentially confounding the relationship between smoking and HIV-1 infection. RESULTS--Compared with nonsmokers, smokers reported higher rates of high-risk behaviors, including more lifetime sex partners (P less than .001), being less likely to be married (P less than .01), and being more likely to have visited folk healers (P less than .01). No intravenous drug use was reported, and no significant differences were noted between smokers and nonsmokers in numbers of past surgical or dental procedures or injections. Adjustment for all factors associated with HIV-1 infection and smoking in regression analyses revealed an independent association between smoking and HIV-1 infection (odds ratio [OR], 3.4; 95% confidence interval [Cl], 1.6 to 7.5). Other factors associated with HIV-1 infection included having more than two life-time sex partners (OR, 3.4; 95% Cl, 1.7 to 6.8) and lower socioeconomic status as reflected by a dirt floor in the home (OR, 8.6; 95% Cl, 3.3 to 22.0). CONCLUSIONS--Smoking is a marker for high-risk sexual behavior and is associated with an increased risk of HIV-1 infection in this population. The persistent association between smoking and HIV-1 infection after adjustment for all known risk factors suggests the possibility of a biologic effect of smoking that warrants further evaluation in other populations.     

Selective dorsal rhizotomy: efficacy and safety in an investigator-masked randomized clinical trial

The objective of this single-center investigator-masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty-three children with spastic diplegia were randomly assigned on an intention-to-treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty-eight children completed follow-up through 24 months. Twenty-one children received SDR (SDR+PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiological monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (spasticity measurement system [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, 6, 12, and 24 months by evaluators masked to treatment.
At 24 months, the SDR+PT group exceeded the PT Only group in mean reduction of spasticity by SMS measurement (-8.2 versus +5.1 newton meters/radian, P=0.02). The SDR+PT group and the PT Only group demonstrated similar improvements in independent mobility on the GMFM (7.0 versus 7.2 total percent score, P=0.94). Outcomes on secondary variables were consistent with primary outcomes. There were no serious adverse events. We conclude that SDR is safe and reduces spasticity-in children with spastic diplegia. SDR plus PT and equivalent PT without SDR result in equal improvements in independent mobility at 24 months. SDR may not be an efficacious treatment for children with mild spastic diplegia.     

Colorimetric, enzymatic, and liquid-chromatographic methods for serum uric acid compared.

We describe high-performance liquid chromatography in conjunction with electrochemical detection as a possible reference method for serum uric acid. Separation was effected on a column packed with "Vydac" strong anion-exchange resin, with use of a detection potential of +0.80 V vs. an Ag/AgCl reference electrode. Results were linearly related to concentration up to 1.0 g/liter, and no interferences were seen. Assay of human sera gave within-run and day-to-day coefficients of variation of 0.83% and 1.1%, respectively; analytical recoveries averaged 100%. Comparison of the new procedure (x) with the phosphotungstate and uricase methods (y) showed the following linear regression and correlation coefficients for results: y equal 0.963x + 0.219 (r = 0.995), and y = 0.991x + 0.165 (r = 0.999), respectively. As compared to these methods, the procedure we describe is more accurate, because of the selective detection system based on retention time and redox potential. Samples can be analyzed at the rate of 20/h. No deproteinization is required.