Effects of bronchial vascular engorgement on airway dimensions

Airway vascular engorgement has been suggested to cause luminal narrowing and airflow obstruction. To determine the extent to which changes in bronchial vascular volume could influence airway dimensions, we studied the effects of left atrial pressure elevation on airway morphometry in sheep (n = 17). The bronchial branch of the bronchoesophageal artery was cannulated and perfused with autologous blood (0.6 ml.min-1.kg-1). A balloon-tipped catheter was inserted into the left atrial appendage to elevate left atrial pressure by 10 mmHg, and papaverine was infused into the bronchial artery to eliminate airway smooth muscle tone. Morphological measurements were made from rapidly frozen lungs excised in vivo. Left atrial pressure elevation caused a 79% increase in total vascular area (P = 0.0002). Average airway luminal area was significantly decreased from 86 to 71% of the airway maximal area (P < 0.0001). Noteworthy were the prominent bronchial vessels located within mucosal folds. However, when papaverine was infused during left atrial pressure elevation, despite a comparable total vascular area, luminal narrowing did not occur and remained at 87% of the maximal area (P = 0.6267). In conclusion, we found that engorgement of the bronchial vasculature leads to an increase in the vascular area in regions inside and outside the smooth muscle layer. The associated decrease in luminal area only occurs in the presence of airway smooth muscle tone. This suggests a reflex effect on the airway caused by the vascular engorgement. We conclude that vascular engorgement of the airway wall per se has a negligible effect on airway obstruction.     

Quantitative bone histology in children with chronic renal failure

Quantitative bone histology (on undecalcified sections following double tetracycline labeling), radiographs, and biochemistry were studied in 47 children, ages 1 to 17 years, with glomerular filtration rates (GFR) below 80 ml/min/1.73m2. The earliest histologic change was an increased osteoid surface accompanied by increased osteoblast and tetracycline surfaces. However, significant bone disease (increased osteoclastic surface, fibrosis, increased osteoid area, increased mineralization lag time, and reduced tetracycline uptake at osteoid surfaces) occurred only at GFR below 30 ml/min/1.73m2. Radiographs and alkaline phosphatase were normal in 25% of children with significant bone disease; parathyroid hormone was increased in 48% of children without bone disease. Thus, these noninvasive investigations were poor predictors of disease presence. GFR was the most sensitive indicator because bone disease occurred only at GFR below 30 ml/min/1.73m2 and was present in all children with GFR below 20 ml/min/1.73m2. It was concluded that bone histology is required for early detection of bone disease and is an essential tool in experimental studies of renal osteodystrophy. However, because the level of GFR will indicate the presence or absence of bone disease in most children, bone biopsy can be avoided generally in clinical practice.     

Secretory immunoglobulin A in the blood sera of healthy and ill persons

Sera of healthy and sick persons were tested for the presence of secretory IgA (SIgA) and free secretory component (SC) SIgA was present in the blood of healthy persons in low concentrations (1.07 mg/100 mg), and free SC was absent. Infectious and somatic diseases, in which damage of the epithelial covering of the gastrointestinal and respriatory tracts was possible, were accompanied by increased blood SIgA content. There was also noted a distinct relationship between the blood SIgA concentration and the severity of infectious diseases and pneumonia supervention. In these cases the SIgA level proved to rise.     

Naming in dementia secondary to Parkinson's, Huntington's, and Alzheimer's diseases

Confrontation naming problems have been found in patients with dementia secondary to Alzheimer's (AD), Huntington's (HD), and in a subset of Parkinson's disease (PD) patients with dementia. The source of the naming deficit has not been established. The "Perception" and the "Semantic Feature" theories have been proposed to explain this naming dysfunction. Subjects with dementia secondary to AD, HD, and PD were given three tasks to determine which theory best explained the source of confrontation naming problems. The three tasks including picture matching, visual recognition, and confrontation naming were given to 42 subjects with dementia secondary to AD, HD, and PD controlled for severity of dementia, and to age-matched controls. Subjects with dementia did not have significantly more difficulty matching pictures but did have more difficulty associating pictures through semantic features. Subjects with mild dementia secondary to AD and HD had significantly more confrontation naming errors than subjects with mild dementia secondary to PD and normal controls. All subjects with moderate dementia had significantly more confrontation naming errors than normal controls. Statistical power may have been limited due to the small number of subjects in each group. The source of the reduction in confrontation naming performance in subjects with dementia secondary to AD, HD, and PD originated in the deterioration of semantic fields. The perception theory was rejected as findings were consistent with the semantic feature theory.     

Ba(ZnTi)_xFe_(12-2x)O_(19)铁氧体的磁特性

采用标准陶瓷工艺 ,并进行湿压磁场成型和氧气氛烧结 ,制备了高取向度、低介电损耗的各向异性 Ba(Zn Ti) x Fe12 - 2 x O19多晶六角铁氧体。根据分析 ,我们认为 M型六角钡铁氧体的六面体位 2 b位是一个特殊的四面体位 ,Zn2 +取代了 4f1和 2 b位上的 Fe3+,而 Ti4 +取代了1 2 k和 2 a位上的 Fe3+。