Pulmonary function tests and the diagnosis of bronchial asthma

A simple, heuristic model of a photographic emulsion is described for the purpose of illustrating the fundamental physical processes and emulsion properties which determine the characteristics of an x-ray film (viz., the shape of the H - D curve, film gamma, and film speed). By means of this model, it is shown that the contrast multiplication afforded by an x-ray film (i.e., a film gamma greater than unity) is a direct result of the exponential attenuation of the viewing light by the developed film, and that film gamma is proportional to grain size, grain density, and emulsion thickness. The difference in the H - D curve that is observed when the same film is exposed to light from an intensifying screen or directly to x rays is also predicted by the model.     

Physiologic variations in lower extremity venous valvular function

We conducted this study to investigate the physiologic variations in venous valvular function and calf muscle pump function that occur in normal limbs after prolonged stationary standing. Twenty-two limbs from 11 healthy volunteers were studied after a brief period of activity and after 4 to 6 hours of stationary standing. Vein diameter, peak reflux flow velocity (PRFV), and valve closure time (VCT) were measured with duplex scanning in the standing position in the common femoral vein (CFV), superficial femoral vein (SFV), popliteal vein (POP), proximal greater saphenous vein (GSV), and greater saphenous vein at the knee (kGSV). Pneumatic rapid inflation-deflation cuffs were used to elicit reflux. Vein cross-sectional area (VA) and peak reflux volume (PRVol) were calculated. Venous volume (VV), venous filling index (VFI), ejection fraction (EF), residual volume fraction (RVF), and outflow fraction (OF) were measured with air plethysmography in all limbs. After stationary standing, there was no significant change or trend toward an increase in diameter or VA in any of the deep veins and there was no change in the PRFV or VCT. In the proximal GSV there was a significant increase in diameter (p = 0.0001) and VCT (p = 0.048) without a change in PRFV. No significant changes were noted in the kGSV. In the GSV the PRFV was significantly lower (p < 0.05) and the VCT significantly shorter (p < 0.05) compared with the SFV and POP but values were no different from those in the CFV. The PRFV was significantly higher in the SFV (p < 0.0001) and the POP (p < 0.002) compared with that in the CFV.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bronchial epithelium: morphology, function and pathophysiology in asthma

Human bronchial epithelium has a number of mechanical functions, including mucociliary clearance and protection against noxious agents. Bronchial epithelial cells are also able to release a variety of mediators, including cytokines, chemokines, growth factors, and arachidonic acid metabolites, which are able to regulate the recruitment, activation, and differentiation of inflammatory cells. They also modulate the function of the underlying smooth muscle cells by the release or metabolism of bronchoactive mediators. Finally, bronchial epithelial cells may control inflammatory reactions by the release of anti-inflammatory mediators or by the inactivation of pro-inflammatory mediators. Morphological or functional abnormalities of the bronchial epithelium may contribute to the initiation, perpetuation and prolongation of inflammatory processes and thereby to the pathogenesis of asthma. In this review, the morphology of the bronchial epithelium, its function with regard to host defense, and its immunological potential will be reviewed. Alterations associated with asthma will be emphasized.     

An undetected burden of asthma in Italy: the relationship between clinical and epidemiological diagnosis of asthma

OBJECTIVE: The purpose of this study was to analyze the anatomic relationship between the superior labrum, the superior glenoid rim, the superior glenohumeral ligament, and the long head of the biceps tendon. MATERIALS AND METHODS: Seventeen cadaveric shoulder specimens underwent axial, oblique coronal, and oblique sagittal MR imaging on a 1.5-T imager. Unenhanced proton density- and T2-weighted spin-echo images with and without fat suppression, and T1-weighted fat-suppressed spin-echo images after intraarticular injection of gadolinium, were obtained of each specimen. The shoulders were then frozen and sectioned into 4-mm-thick slices, either transversely or oblique coronally. After gross anatomic correlation, histologic analysis was performed on 32 sections. RESULTS: A sublabral recess was present in 12 (71%) of 17 shoulders. MR arthrography was significantly better at showing the sublabral recess than was unenhanced MR imaging. Histologically, the synovial recess in all cases was covered by synovial lining cells. Intralabral altered histologic patterns were found in 20 (63%) of 32 labral sections. In addition to signs of degeneration, five sections of two specimens showed proliferating fibroblasts and vessels, as well as fibrosis, suggesting trauma. The presence or absence of altered intralabral histologic patterns was better assessed with T1-weighted fat-suppressed arthrograms than with unenhanced MR images. We found a close association grossly and histologically between the superior labrum and the biceps tendon. CONCLUSION: The attachment of the superior glenoid labrum to the glenoid rim shows great variability. In MR imaging, an overlap appears to exist between physiologic recesses of the superior labrum and a type 2 superior labrum anterior-posterior lesion. T1-weighted fat-suppressed MR arthrograms provided the best view of the superior labrum and the labral-bicipital complex.     

Occupational asthma. Practical points for diagnosis and management

Asthma is a common chronic illness characterized by episodes of reversible airflow obstruction. A cornerstone of asthma management is identifying and avoiding agents that cause bronchospasm. The workplace is an important potential source of respirable exposures that can cause or trigger asthma. Identification of an occupational factor in asthma is important: early diagnosis and removal of the worker from the exposure is associated with improved prognosis; the diagnosis of occupational asthma may lead to compensation for work-related impairment and disability; and the diagnosis of occupational asthma is a Sentinel Health Event with implications for public health and prevention. In this article, we review specific causes of occupational asthma and general settings in which an occupational factor should be suspected and explored as part of the management of the worker with asthma. We also review specific and simple elements of history and pulmonary function testing that can be easily assessed by most health care practitioners and may be sufficient to establish a diagnosis of occupational asthma. Finally, we review the medical-legal implications of occupational asthma.     

Moderate asthma in adults: diagnosis and management in general medical practice

Moderate asthma is a frequent disorder in general medicine. In 1990, the British Thoracic Society published their first guidelines on the management of asthma. Three years later, we have studied, using a questionnaire, the diagnosis and therapeutic criteria of moderate asthma used by general physicians, and comparing these to the guideline recommendations. Out of 46 physicians questioned in Bordeaux, 40 (87 per cent) agreed to participate in the study. Thirty two physicians (80 per cent) described as moderate an asthma which was mild according to the guidelines; eight physicians (20 per cent) described a moderate asthma according to the guidelines; twenty five (63 per cent) considered as severe a moderate asthma according to the recommendations, although eleven (28 per cent) considered it as moderate and four (10 per cent) did not give an opinion. In total, four (10 per cent) judged asthma severity according to the guidelines (Group R), twenty one (52 per cent) over-estimated the severity of moderate asthma (Group S), and fifteen (37 per cent) gave an inconsistent assessment (Group 1). Twenty six (65 per cent) prescribed an association of beta-2-agonists and inhaled corticosteroids for moderate asthma. Although most of the questioned physicians gave an appropriate treatment for moderate asthma treatment adapted to the severity of the situation, their therapeutic approach did not seem to be based upon the same criteria than that recommended in the guidelines.     

The specific bronchial provocation test in the diagnosis of occupational asthma

Specific bronchial challenge (SBC) testing is a key technique for diagnosing the origin of occupational asthma (OA). SBC is indicated in specific circumstances, including whenever several agents present in the work environment may be the cause of OA, when new or unusual occupational agents need to be identified, when evidence for legal action is required, or when research is conducted. SBC procedures are not standardized, because of the great diversity of occupational agents and the variety of physical and chemical properties involved. Thus, SBC testing with agents found in fumes, gases or vapors can be administered in special cabins or in closed circuits with continuous monitoring of sub-irritant concentrations. Agents found in dust, most but not all of which have high molecular weights, may be appropriate for routine SBC testing in an allergy laboratory. This paper will treat only these cases. SBC must be formed in specialized centers by experienced personnel, as it is a sophisticated and potentially dangerous technique. We describe a series of 20 patients diagnosed of OA in our unit over the past two years in whom SBC provided an etiologic diagnosis. All were exposed to dust or aerosols at work. The cause was a substance of high molecular weight in 17 cases, and low molecular weight in 3. The procedure used is described and models of bronchial response are discussed.     

Larva migrans syndrome: a rare differential asthma diagnosis

PURPOSE: The aim of the study is to demonstrate the changes in visual evoked potentials (VEP) in treatment of amblyopia. MATERIAL AND METHODS: Pattern reversal VEP of 28 children treated because of amblyopia and 16 healthy persons were analysed. Before treatment and after treatment the results of the interocular amplitude difference ratio and interocular latency difference ratio were compared with standards. RESULTS: After treatment of amblyopia the percentage of normal interocular amplitude and latency difference ratios increased. CONCLUSION: Study of pattern VEP enables monitoring of amblyopia treatment.     

Role of the CTLA-4 receptor in T cell activation and immunity. Physiologic function of the CTLA-4 receptor

Near-death experience (NDE) was studied in a series of 48 consecutive patients who were admitted to hospital in a deep coma (level III on the III-3 coma scale) due to cardiac arrest, pulmonary failure, cerebrovascular accident, and/or other life-threatening disease. When the patients recovered from coma without complications such as aphasia, dementia or mental disturbance, they were interviewed by the same physician following the same protocol consisting of 25 questions about their experience during the period of deep coma. Of 48 patients interviewed, 14 (37%) had a vivid and undeniably personal experience during their unconscious state. Factors attributable to the NDE were assessed by the following three methods. First, the frequency and odds ratio were examined in terms of gender, age, underlying disease, occupation, religion, education, site of accident, duration of comatose state, drugs and treatment for resuscitation, and drugs being taken at the time of interview. There were no specific factors significantly related to the NDE. Next, background factors were compared between the NDE positive and negative groups to detect a particular factor related to the NDE. However, there were no factors that showed significant frequency in the NDE-positive group. Finally, discriminatory analysis was performed to detect discriminatory factors in the occurrence of NDE by selecting NDE as an objective variable and background factors as explanatory variables. However, the discriminatory equation gained was not significant. Thus, there were no background factors that could explain the occurrence of NDE. Among the NDE reported, there were such elements as flying in a dark void space with dim light ahead, encountering dead relatives or friends, standing at the boundary of brook, river or pond, and returning to the world in response to a voice calling from behind. These elements are common to those reported by investigators abroad, except for the lack of a tunnel experience. As for the influence of the NDE on life subsequent to the experience, the majority of patients who had had a NDE stated that they became more sincere to towards every aspect of life and held spiritual values in high esteem than before. This was quite a contrast to the attitudes in the non-NDE patients who looked upon the comatose episode as arising from an underlying disease and considered it a health problem only. Most of the NDE patients considered that death was neither fearful nor difficult, but calm and peaceful if it occurs in a manner similar to that in their NDE. From this study, a picture can be down of the dying process, based on empirical information, it can also be seen that a NDE causes the individual to develop a sincere introspective depth. It is possible that these findings may be applicable to elderly patients in terminal care.     

Bronchial asthma: update on the revised guidelines for diagnosis and management

Bronchial asthma is a chronic disease with variable airway narrowing, respiratory distress, hyper-responsiveness and inflammation. The morbidity and mortality are increasing despite availability of newer diagnostic and therapeutic strategies. The National Institutes of Health recently issued revised guidelines for disease management. The keys to improved care include earlier recognition of the illness, reduced exposure to triggers, careful monitoring, greater use of long-term control medications and improved patient education.