[The morphology and resilience change of upper airway in patients with OSAHS: A MSCT study]

Objective:To analyse the morphology and resilience of upper airway in patients with OSAHS using 128-slice MSCT. Method:CT imaging of the upper airway in 49 patients with OSAHS was acquired in two respiratory status (quiet respiration and Müller maneuver). The two-dimensional measurements of retropalatal and retroglossal regions, airway volume, and airway resilience were measured in patients with severe OSAHS and non-severe OSAHS. And the results were compared between those two groups. Result:① The following measurements during Müller maneuver were smaller than those during quiet respiration: the smallest cross section area of retropalatal and retroglossal region, the anteroposterior diameters(AP) and lateral diameters(L) of retropalatal region, L of retroglossal region, volume and average volume of upper airway and retropalatal area（P<0.01）.②The pharyngeal wall resilience of retropalata region was larger than those of retroglossal region in patients with severe OSAHS. The total resilience of retropalatal was larger than that of retroglossal region in patients with non-severe OSAHS. The pharyngeal wall resilience between severe and non-severe OSAHS had no significant difference. ③ L of retropalatal and retroglossal region, and average area of retropalatal region, were smaller in patients with severe OSAHS than those with non-severe OSAHS during Müller maneuver（P<0.05）.④ The cross-section of upper airway tend to be horizontal oval in retropalatal regions, and vertical oval in retroglossal regions. Conclusion:128-slice MSCT scan can achieve both positioning and quantitative analysis of the morphology and resilience changes of the upper airway in patients with OSAHS.

[Analysis on possibilities of multi-spectral data for quantitative retrieving soil nutrition element contents]

Models for predicting soil nutrition elements content were established by regression methods. The data source was simulated multi-spectral data from reflectance spectra measured under laboratory condition. First, the reflectance spectra were resampled to the corresponding bands of multi-spectral sensors (TM and ASTER) according to their reflectance response functions. Then, the experiential models were established between measured spectra, simulated reflectance spectra (TM and ASTER) and soil nutrition element contents by stepwise multiple linear regression (SMLR) and partial least square regression (PLSR) methods. Precision of these models was tested by validation soil samples. Compared with models established by measured spectra, precision of simulated spectra models is slightly affected by spectral resolution. Simulated spectra models give good results for nitrogen (R = 0.89), phosphor (R = 0.79), and potassium (R = 0.68). The selected band range of SMLR models for soil N, P, and K are 2 000 to 2 300 nm, 1 650 to 1 800 nm and 600 to 800 nm respectively. The coefficients of PLSR models show that near infrared (NIR) band is more sensitive to nitrogen and phosphor than visible (VIS) band, while VIS is better for potassium. Good prediction performance indicates theoretically the future possibilities of multivariate calibration for soil nutrition element concentrations by multi-spectral remotely sensed images and bands character of sensors should be considered well because different element has different response.

Management of descending necrotizing mediastinitis

BACKGROUND

Descending necrotizing mediastinitis (DNM) is uncommon, and may be lethal if not treated adequately and promptly. Delayed diagnosis of the disease is sometimes encountered in clinical practice.

METHODS

Eight consecutive patients with acute DNM were identified between 1991 and 1995, including five men and three women. The mean age was 45.8 years (range, 22-71 years). The infectious sources consisted of six esophageal perforations, one cervical cutting injury and one tonsillitis. The clinical presentations were evaluated. Diagnostic procedures including chest radiograph, sonogram and computerized tomography scans of the chest and neck were examined. Diagnosis and treatment, including culture results from drained fluids and debrided tissues, and antibiotic and supportive therapies were reviewed.

RESULTS

Six patients who underwent aggressive surgical treatment recovered well. Two patients who received supportive treatment died of sepsis alone. The cultured bacteria included: Klebsiella oxytoca, Staphylococcus aureus, Trichosporum and other mixed oral cavity flora.

CONCLUSIONS

Early diagnosis and adequate antibiotic and support therapies are essential to achieve good patient outcomes in acute descending mediastinitis. Adequate drainage and debridement, appropriate antibiotic therapy, and sufficient nutritional and respiratory support are the main treatment elements.