Design of double-coated optical fibers to minimize long-term hydrostatic-pressure-induced microbending losses.

The design of double-coated optical fibers to minimize long-term hydrostatic-pressure-induced microbending losses is investigated. Microbending loss in these fibers is dominated by compressive radial stress at the interface between the glass fiber and the primary coating, which is a function of the material properties of the polymeric coatings and their thickness. To minimize long-term hydrostatic-pressure-induced microbending losses, one should decrease the Young's modulus and Poisson ratio of the primary coating but increase the radius, Young's modulus, Poisson ratio, and relaxation time of the secondary coating. Alternatively, the radius and relaxation time of the primary coating have their optimum values.

Effect of corticosteroid therapy on the acute injury and recovery stage of oleic acid induced lung injury in the rat.

In the rat model of lung injury induced by oleic acid (OA), we studied the effect of corticosteroid therapy on pulmonary inflammation and compliance at acute (1 day post OA) and recovery (3 and 7 days post OA) stages. Methylprednisolone (MP) and dexamethasone (DM) were examined for therapeutic benefit in this model. Histologic examination, lung compliance, and analysis of bronchoalveolar lavage (BAL) fluid were used to assess lung injury. Our results demonstrated that, at 1 day post OA, both steroids effectively reduced pulmonary inflammation and restored lung compliance when compared to animals that received only OA. In comparison to DM, MP was more effective in inhibiting the pulmonary inflammation induced by OA, but was less effective in restoring lung compliance. However, at 3 and 7 days post OA, cell and/or protein levels in BAL fluid from both MP- and DM-treated OA animals were significantly higher than levels observed in animals that received only OA. Lung compliance returned to normal by 3 days in animals that received only OA. This effect, however, was blocked in OA animals that were treated with either steroid, MP, or DM. Our data suggest that steroid therapy can be beneficial in the acute stage of OA-induced lung injury, but appears to be detrimental during the early recovery stage, perhaps by inhibiting the repair process.

Recognition of distinctive patterns of gallium-67 distribution in sarcoidosis.

Assessment of gallium-67 (67Ga) uptake in the salivary and lacrimal glands and intrathoracic lymph nodes was made in 605 consecutive patients including 65 with sarcoidosis. A distinctive intrathoracic lymph node 67Ga uptake pattern, resembling the Greek letter lambda, was observed only in sarcoidosis (72%). Symmetrical lacrimal gland and parotid gland 67Ga uptake (panda appearance) was noted in 79% of sarcoidosis patients. A simultaneous lambda and panda pattern (62%) or a panda appearance with radiographic bilateral, symmetrical, hilar lymphadenopathy (6%) was present only in sarcoidosis patients. The presence of either of these patterns was particularly prevalent in roentgen Stages I (80%) or II (74%). We conclude that simultaneous (a) lambda and panda images, or (b) a panda image with bilateral symmetrical hilar lymphadenopathy on chest X-ray represent distinctive patterns which are highly specific for sarcoidosis, and may obviate the need for invasive diagnostic procedures.

Identification of human immunodeficiency virus in the heart of a patient with acquired immunodeficiency syndrome.

A 35-year-old homosexual white male diagnosed as having human immunodeficiency virus (HIV) infection presented with recurrent pericardial effusion, and HIV was isolated from the pericardial fluid. Autopsy revealed an extensive gross infiltrative lesion in the left ventricle of the heart. Microscopic examination of the myocardium demonstrated multifocal atypical lymphoid cell infiltrations associated with scattered foci of myocardial necrosis. The atypical lymphoid cells were immunoreactive to UCHL-1, a T cell antigen antibody. HIV was immunocytochemically identified in the cardiac lymphocytic infiltrate with anti-p24 monoclonal antibodies. This finding was supported by ultrastructural examination and in situ hybridization study.

Effect of inhaled triamcinolone on bronchial hyperreactivity and airways obstruction in asthma.

We measured changes in methacholine bronchial hyperreactivity and airways obstruction in 37 asthmatics treated with inhaled triamcinolone for 6 weeks. All received regular bronchodilator therapy but not steroids or cromolyn. Initial studies included spirometry and the provocative concentration of methacholine required to decrease the FEV1 by 20% (PC20). Patients were randomized into two groups: those given inhaled triamcinolone, 200 micrograms four times daily (T) by metered dose inhaler, and those given a placebo inhaler (P). Daily AM and PM peak flow measurements were recorded, while PC20 and pulmonary function tests were obtained at 3 and 6 weeks. Change in canister weight was used to determine treatment compliance. The PC20 of T increased from a baseline 1.00 mg/mL to 2.90 mg/mL at 6 weeks, whereas in P it decreased from 1.15 mg/mL to 1.05 mg/mL. Percent change in PC20 (delta PC20) for each patient was defined as: [(PC20(week 6)--PC20(baseline]/PC20 (baseline)] X 100. At 6 weeks, this was 290% in T versus 65% in P (P less than .05). Likewise, at 6 weeks T was significantly greater than P with respect to: delta FEV1 (4.1% versus -3.8%, P less than .05) and delta FEF25-75% (20.3% versus -5.6%, P less than .01). Patients were further separated into higher and lower complier subgroups. In T, higher compliers showed more improvement at 6 weeks than lower compliers in: delta PC20 (533.3 versus 67.8%, P less than .05), delta FEV1 (8.7 versus -1.7%, P less than .01), and delta FEF25-75% (31.9 versus 1.1%, P less than .01). These data suggest that triamcinolone improves bronchial hyperreactivity as well as airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of helium-oxygen mixtures in the support of patients with status asthmaticus and respiratory acidosis.

Ten patients with status asthmaticus and respiratory or combined respiratory and metabolic acidosis were treated with a mixture of helium-oxygen (He-O2) in addition to the usual bronchodilator therapy and corticosteroids. A significant reversal of the acidosis was noted within the first 20 minutes, and no patient required subsequent intubation. The He-O2 mixture was started after the aerosolized and subcutaneous bronchodilators, but before intravenous corticosteroids and aminophylline had reached their peak effects. There were no untoward reactions and most of the patients sensed an immediate reduction in their dyspnea with the onset of He-O2 therapy. We conclude that He-O2 may be a useful adjunct to the usual medications employed in the treatment of status asthmaticus and may allow some patients to avoid intubation and mechanical ventilation.

Pulmonary hypertension from prominent vascular involvement in diffuse amyloidosis.

Pulmonary arterial hypertension was found in a patient with myeloma who had a diffuse lung lesion. Echocardiographic and hemodynamic data from pulmonary arterial catheterization demonstrated relatively well-preserved left ventricular function. The diagnosis of diffuse pulmonary amyloidosis was established by open lung biopsy, which revealed severe diffuse vascular deposition of amyloid with mild involvement of the alveolar septa. Pulmonary arterial hypertension secondary to vascular deposition of amyloid in the lungs is rare. This case corroborates the clinicopathologic relationship.