Age-related changes in upper airway muscles morphological and oxidative properties

Obstructive sleep apnea (OSA) is a common disorder of the middle aged and elderly. It results from the decrease in upper airway muscle (UAM) tone that occurs during sleep. It is unclear whether age-related changes in UAM could constitute a contributory mechanism to the increased prevalence of OSA with increasing age, and previous papers evaluating the effects of aging on UAM in rats reported conflicting results. In the present study, we compared, in four age groups of Wistar rats (6–24 months), fiber-type distribution, mean cross-sectional fiber area and succinate dehydrogenase optical density of dilating and non-dilating UAM, and the diaphragm. Succinate dehydrogenase optical density, a marker of oxidative capacity, decreased significantly after the age of 6 months in all muscles (except for the sternohyoid), particularly in the genioglossus, the main tongue protrudor. In this muscle, we also found a significant decrease in type IIa and an increase in IIb fibers after the age of 18 months. Age-related changes in fiber-type distribution in other muscles were mostly insignificant. Dilating UAM could not be distinguished from their non-dilating neighboring muscles by their histochemical properties or aging-related changes. The aging-related changes observed in the present study may decrease UAM endurance, particularly that of the main tongue protrudor, the genioglossus.     

CLINICAL ASSISTED REPRODUCTION: Improvement of IVF Outcome in Poor Responders by Discontinuation of GnRH Analogue During the Gonadotropin Stimulation Phase—A Function of Improved Embryo Quality

Purpose: To assess the efficacy of a protocol involving the discontinuation of the GnRH analogue at the mid-phase of ovarian stimulation for IVF in patients with a previous poor response.Methods: Prospective case-control evaluation compared with same patient's previous performance. Thirty-six patients enrolled in an IVF program were treated in two consecutive cycles. The first with a standardized protocol utilizing mid-luteal administration of Nafarelin (N) 600 mcg/d continued throughout the stimulation phase with human menopausal gonadotropin (hMG) until follicles of 20 mm were identified by transvaginal ultrasound (Standard group). Patients with a poor response in the Standard cycle were treated in the subsequent cycle with N and hMG initially in a similar manner, then N was stopped after 5 days of hMG stimulation (N-stop group). All clinical and laboratory aspects of treatment were done in a similar fashion in both cycles, each patient acting as her own control.Results: Results were analyzed by paired t test. The change in each parameter in the N-stop cycle was expressed as the percent change as compared with the standard protocol cycle for each patient. Peak estradiol (E2) and number of aspirated oocytes were increased in the N-stop cycle (+16.9% and +28%, respectively), but insignificantly so. The percent of cleaving embryos was significantly increased by 27.9% (p = 0.03) in the N-stop cycle, as embryo morphology was improved by 22% (p = 0.02). The efficacy of gonadotropin treatment was enhanced in the N-stop cycle, as expressed by a 32.5% increase in oocytes retrieved per hMG ampoule administered (p = 0.04). Three cycles of 36 were cancelled during the N-stop cycle, whereas only one was cancelled in the standard protocol cycle. Of the 36 patients, 7 conceived in the N-stop protocol and 5 are ongoing pregnancies.Conclusion: Discontinuation of GnRH-a during ovarian stimulation for IVF has a beneficial, but not statistically significant, effect on both E2 and oocyte production. Embryo cleavage rates and morphology were significantly improved, this may be due to improved oocyte quality, which may have been responsible for achieving pregnancies. The efficacy of gonadotropin treatment was enhanced when GnRH-a was discontinued. These results hint that GnRH-a may have a direct negative effect on folliculogenesis and oocytes, which is apparent especially in poor responder patients.     

Acute respiratory distress syndrome in children with malignancy—Can we predict outcome?

Purpose: The purpose of this study was to delineate early respiratory predictors of mortality in children with hemato-oncology malignancy who developed acute respiratory distress syndrome (ARDS). Materials and Methods: We conducted a retrospective chart review of children with malignant and ARDS who needed mechanical ventilation and were admitted to a pediatric intensive care unit from January 1987 to January 1997. Results: Seventeen children with ARDS and malignancy aged 10.5 ± 5.1 years were identified. Six of the 17 children (35.3%) survived. Sepsis syndrome was present in 70.6% of all the children. Peak inspiratory pressure, positive end-expiratory pressure (PEEP), and ventilation index values could distinguish outcome by day 3. A significant relationship between respiratory data and outcome related to efficiency of oxygenation, as determined by PaO₂/FIO₂ and P(A-a)O₂, was present from day 8 after onset of mechanical ventilation. Conclusions: Peak inspiratory pressure, PEEP, and ventilation index values could distinguish survivors from nonsurvivors by day 3. This may assist in early application of supportive nonconventional therapies in children with malignancy and ARDS. Copyright © 2001 by W.B. Saunders Company     

Outcomes of combined penetrating keratoplasty and cataract extraction compared with penetrating keratoplasty alone

PURPOSE: To compare the rejection rates, graft failure rates, mean visual, keratometric and refractive outcomes of combined penetrating keratoplasty and cataract extraction with penetrating keratoplasty alone. METHODS: A retrospective study of all patients who had combined keratoplasty and cataract extraction/intraocular lens insertion (49 eyes; mean age 65.3 years; mean follow up 17 months) compared with all patients who had keratoplasty only (58 eyes; mean age 64.0 years; mean follow up 14 months). RESULTS: One hundred and seven eyes in 99 patients had keratoplasty in the period and were included in the study. The most common indication for keratoplasty in patients who had triple procedures was Fuchs' endothelial dystrophy (24.5%). During the study seven (6.5%) grafts failed and four (3.7%) had allogenic rejection without failure during this period. There was no statistical difference between the graft survival rates of the two study groups. The mean postoperative logMAR visual acuity (VA) was 0.42 and postoperative VA of 6/12 or better was seen in 71% of patients. Mean postoperative corneal curvature was 44.6 dioptres (D), mean corneal astigmatism was -4.0 D and was >or=5 D in 38%. Mean double-angle Cartesian coordinates for corneal astigmatism were x-0.87 D and y-0.29 D. Mean best sphere of postoperative refractions was -0.61 D and mean absolute refractive error was 2.2 D. There was no statistically significant difference in VA, keratometric or refractive outcome measures between the two study groups. CONCLUSION: Over a short follow up, keratoplasty combined with cataract extraction/intraocular lens insertion showed a similar risk of graft failure or allogenic graft rejection when compared with keratoplasty alone and we recommend the triple procedure for quicker visual recovery and less operative procedures.