ABSTRACT
Let ß = [formula: see text] be a sequence of positive numbers with ß0 = 1, 0 < ß(n)/ß(n+1) ≤ 1 when n ≥ 0 and 0 < ß(n)/ß(n-1) ≤ 1 when n ≤ 0. A kth-order slant weighted Toeplitz operator on L(2)(ß) is given by U(φ) = W(k)M(φ), where M(φ) is the multiplication on L(2)(ß) and W(k) is an operator on L(2)(ß) given by W(k)e(nk)(z) = (ß(n)/ß(nk))e(n)(z), [formula: see text] being the orthonormal basis for L(2)(ß). In this paper, we define a kth-order slant weighted Toeplitz matrix and characterise U(φ) in terms of this matrix. We further prove some properties of U(φ) using this characterisation.
Subject(s)
Models, TheoreticalABSTRACT
Azithromycin Dihydrate (Poorly water soluble drug), when prepared as solid dispersion showed improved solubility and dissolution. So the main purpose of this investigation was to increase the solubility and dissolution rate of Azithromycin Dihydrate by the preparation of its solid dispersion with urea using solvent evaporation method. Physical mixtures and solid dispersions of Azithromycin Dihydrate were prepared by using urea as water-soluble carrier in various proportions (1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 by weight), by employing solvent evaporation method. The drug release profile was studied and it was found that the dissolution rate and the dissolution parameters of the drug from the physical mixture as well as solid dispersion were higher than those of the intact drug. FT- IR spectra revealed no chemical incompatibility between drug and urea. Drug-polymer interactions were investigated using differential scanning calorimetry (DSC) and Powder X-Ray Diffraction (PXRD).
ABSTRACT
Cefuroxime Axetil (Poorly water soluble drug), when prepared as solid dispersion showed improved solubility and dissolution. Therefore, the main purpose of this investigation was to increase the solubility and dissolution rate of Cefuroxime Axetil by the preparation of its solid dispersion with urea, using the solvent evaporation method. Physical mixtures and solid dispersions of Cefuroxime Axetil were prepared by using urea as a water-soluble carrier in various proportions (1:1, 1:2, 1:3, 1:4, 1:5, 1:6, and 1:7 by weight), by employing the solvent evaporation method. The drug release profile was studied and it was found that the dissolution rate and the dissolution parameters of the drug from the physical mixture as well as solid dispersion were higher than those of the intact drug. The Fourier Transform Infrared (FTIR) spectra revealed no chemical incompatibility between the drug and urea. Drug-polymer interactions were investigated using differential scanning calorimetry (DSC) and Powder X-Ray Diffraction (PXRD).
ABSTRACT
A prospective study comparing standardized non-bronchoscopic bronchoalveolar lavage (sNB-BAL) and non-specific endotracheal aspirate (NsETA) in the microbiological diagnosis of pneumonia in mechanically ventilated patients is described. One hundred episodes in 82 mechanically ventilated patients with or without radiological and clinical diagnostic criteria of pneumonia were studied. NsETA and sNB-BAL was performed on the day of study. Fifty-one patients had pneumonia (21 ventilator-associated, 12 hospital-acquired, 18 community-acquired) and 49 had no pneumonia as defined by widely accepted clinico-radiological criteria. The sNB-BAL was found to be significantly more specific (0. 73) compared to NsETA (0.35) for the microbiological diagnosis of pneumonia. Colonization rates with NsETA were significantly higher compared to sNB-BAL (P value <0.0001). No patient had complications attributable to the sNB-BAL procedure. We conlude that sNB-BAL is a safe, effective, sensitive, specific and inexpensive procedure for the serial evaluation of pneumonia in mechanically ventilated patients.
Subject(s)
Bronchoalveolar Lavage/methods , Community-Acquired Infections/diagnosis , Cross Infection/diagnosis , Pneumonia, Bacterial/diagnosis , Respiration, Artificial/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Community-Acquired Infections/etiology , Cross Infection/etiology , Female , Humans , Male , Middle Aged , New South Wales , Pneumonia, Bacterial/etiology , Prospective Studies , Trachea/microbiologyABSTRACT
Subacute sclerosing panencephalitis is characterized by the insidious onset of diffuse cerebral dysfunction associated later with myoclonus and typical electroencephalographic changes. The disease progresses relentlessly to coma and death within 2 years. We report a case of acute onset and rapid course associated with atypical CSF, EEG and MRI features simulating acute disseminated encephalomyelitis. Brief review of relevant literature is presented.
Subject(s)
Encephalomyelitis, Acute Disseminated/etiology , Subacute Sclerosing Panencephalitis/diagnosis , Adolescent , Electroencephalography , Encephalomyelitis, Acute Disseminated/physiopathology , Humans , Magnetic Resonance Imaging , Male , Subacute Sclerosing Panencephalitis/complications , Subacute Sclerosing Panencephalitis/physiopathology , Tomography, X-Ray ComputedABSTRACT
We studied retrospectively 80 elderly patients who had been admitted to hospital with tuberculosis (TB) between January 1988 and June 1993. There were 64 with pulmonary TB and 16 with miliary tuberculosis (MTB). The mean age was 70+/-7.5 years (range 60-88 years) with 56% over 70 years of age. Underlying disease preceding TB was present in 86.3% patients. In the majority of patients clinical manifestations were subtle. Chest X-ray showed involvement of lower lung fields and miliary shadowing in 71.2% (33/80) and 20% (16/80) patients, respectively. The organism was detected in expectorated sputum specimens in 62.5% (50/80). Of the specimens obtained by flexible fibreoptic bronchoscopy (FOB), 61% were positive for acid-fast bacilli (AFB) by films and culture. Drug-induced adverse effects were observed in 17.6% (6/34). In 18 patients (22.5%), the diagnosis of TB was delayed or missed. The overall mortality of 21% (9/43) included seven patients with MTB and two with pulmonary TB. TB was the direct cause of death in the former and a significant contributory cause in the latter.
Subject(s)
Tuberculosis, Miliary/epidemiology , Tuberculosis, Pulmonary/epidemiology , Aged , Aged, 80 and over , Bronchoalveolar Lavage Fluid/microbiology , Bronchoscopy/methods , Female , Hospitals, University , Humans , Lung/diagnostic imaging , Male , Middle Aged , Pleural Effusion/microbiology , Radiography , Retrospective Studies , Saudi Arabia/epidemiology , Sputum/microbiology , Tuberculosis, Miliary/diagnosis , Tuberculosis, Pulmonary/diagnosisABSTRACT
During a one-year period 105 patients suffering a total of 134 infectious episodes were studied prospectively in the medical intensive care unit (MICU). These patients included 54 male and 51 female patients, age ranging from 14 to 100 years (median = 54 years). The overall incidence of infection was 46.7%. Infections acquired in medical wards accounted for 47.8% of the total, followed by community-acquired infections in 27.0%, and MICU-acquired infections in 25.2% of the cases. The most frequent infections were pneumonia and septicaemia accounting for 88% of the total, whereas urinary tract (4.4%), gastrointestinal tract (5.0%), skin and wound infections (2.5%) constituted only 11.5%. The pathogens mainly involved were gram-negative rods, Staphylococcus spp. and Streptococcus pneumoniae. However, in community-acquired pneumonia, the major pathogens were gram-negative rods. In addition, Mycobacterium tuberculosis was an important cause of pneumonia in these patients. The majority of patients had a monoinfection; multiple pathogens were isolated in 11.9% of the episodes. The overall mortality was 46.7%. Several factors that influenced the mortality in these patients were analyzed. Early recognition of these factors may reduce morbidity and mortality.