In vitro effects of Nd:YAG laser radiation on blood: A quantitative and morphologic analysis

Use of the Neodymium: yttrium -aluminum -garnet (Nd:YAG) laser to recanalize stenosed arteries may require delivery of the beam through blood. To assess the degree of hemolysis and debris formation, 54 samples of citrated whole blood were exposed to Nd:YAG laser radiation of varying powers (10, 20 and 30 watts) and duration (1, 2.5 and 5 seconds). Compared to control samples which were not subjected to laser light, there was no significant decrease in hematocrit (41 to 40.5 +/- 5%), hemoglobin concentration (13.8 to 13.8 +/- .06 g/1OO ml), or increase in "free" hemoglobin concentration. Debris weight (from .45 +/- .002 to .45 +/- .002 mg), as well as the white blood cell count, was also not significantly changed (from 5,400 to 5,200 +/- 240 WBC/cm). Light microscopy examination of debris from samples of whole blood, washed erythrocytes, and platelet-rich plasma subjected to the laser at 30 watts for five seconds failed to demonstrate the presence of membrane denaturation of blood elements, as compared with the morphologic changes observed in whole blood samples exposed to a "hot tip" rather than Nd:YAG laser radiation. Nd:YAG laser can be used intravascularly without fear of hemolysis or debris "micro-embolization" up to a power of 30 watts for five seconds.     

Epidemiological findings of seasonal changes in mood and behavior. A telephone survey of Montgomery County, Maryland

Patterns of seasonal changes in mood and behavior in Montgomery County, Maryland, were evaluated in randomly selected household samples by lay interviewers using a telephone version of the Seasonal Pattern Assessment Questionnaire. The method for selecting the sample unit was random-digit dialing. We found that 92% of the survey subjects noticed seasonal changes of mood and behavior to varying degrees. For 27% of the sample seasonal changes were a problem and 4.3% to 10% of subjects, depending on the case-finding definition, rated a degree of seasonal impairment equivalent to that of patients with seasonal affective disorder. The seasonal pattern of "feeling worst" exhibited a bimodal distribution with a greater winter and a substantially lower summer peak (ratio, 4.5:1). Younger women who have a problem with seasonal changes and who feel worse on short days tended to exhibit the highest seasonality scores. It is apparent from our study that seasonal affective disorder represents the extreme end of the spectrum of seasonality that affects a large percentage of the general population. The influence of environmental factors on mood disorders and mood changes in the general population might provide valuable insight into pathogenesis, treatment, and prevention of affective illness.     

"Single-exposure" dual energy digital radiography in the detection of pulmonary nodules and calcifications

We studied the detectability of mineralized and non-mineralized simulated pulmonary nodules with dual energy digital radiography. "Soft tissue" and "bone" images (pixel size = 0.2 mm, 10 bits deep) were obtained with subtraction image processing after a single simultaneous exposure (100 kVp, 8 mAs, 17 mR skin exposure dose) of two storage phosphors with an interleaved 0.9 mm copper wafer. Three classes of paraffin-based nodules (0.5 to 3.0 cm) of varying mineral concentration (0, 120 and 190 mg/cm3 K2HPO4) were randomly positioned on the chest wall of two healthy volunteers to simulate calcified and non-calcified nodules. The average receiver operating characteristics (ROC) area of six readers (n = 2880 observations) showed that digital "bone" images (ROC area: 0.77 +/- 0.03) were significantly better (P less than 0.04) than conventional radiographs (OC Film, Lanex medium screens, 141 kVp, 19 mR skin exposure dose) (ROC area: 0.71 +/- 0.05) in detecting calcification in nodules. The unsubtracted digital images of lower kilovoltage were not superior to the 141 kVp conventional radiographs in a subgroup of two readers (ROC area: 0.73 +/- 0.02). Digital "soft tissue" images were equivalent to conventional chest radiographs in detecting soft tissue pulmonary nodules (ROC areas: 0.92 +/- 0.04 and 0.92 +/- 0.05, respectively.     

Massive pulmonary embolism: triple-armed therapy

Many patients who suffer a massive pulmonary embolus die despite emergent therapy. In these desperately ill patients an aggressive, combined method of management was initiated to improve their chances and quality of survival. During a 5-year period 10 patients were treated with (1) low-dose topical, intrapulmonary thrombolytic therapy to dissolve thrombus, (streptokinase or urokinase); (2) anticoagulation to prevent thrombus propagation (heparin); and (3) the simultaneous insertion of a Greenfield filter to prevent the early, recurrent, and therefore potentially fatal pulmonary embolus--"triple-armed therapy." Thrombolytic therapy was administered through a Swan-Ganz catheter wedged against the pulmonary embolus. During the same interval 10 other patients also sustained massive pulmonary emboli but were treated only with systemic heparin. Serial pulmonary arteriography was performed daily. The patients treated by triple-armed therapy responded favorably with a rapid (less than 6 hours), significant improvement in PaO2, pulmonary artery pressure, cardiac output, pulmonary vascular resistance, and blood pressure, compared with patients treated with continuous heparin alone. Nine patients in the triple-armed therapy group survived whereas only six in the heparin group survived. Two additional patients were treated by triple-armed therapy and had thrombolysis with triple-armed therapy with tissue plasminogen activator; these patients demonstrated the most rapid improvement in cardiorespiratory dynamics and arteriographic clearance of emboli. This management protocol shows promise for patients who sustain a massive pulmonary embolus, because it reduces the morbidity associated with pulmonary embolectomy while avoiding the hazards associated with systemic thrombolytic therapy.     

Renal Biopsy Pathology in Wegener''s Granulomatosis

Eighteen renal biopsies from 10 patients with active generalized Wegener's granulomatosis (GWG), with GWG in remission on therapy, and with active localized Wegener's granulomatosis (LWG) have been examined by light and electron microscopy. In all 9 patients with active GWG, light microscopy revealed focal and segmental glomerulonephritis. Electron microscopy revealed subepithelial basement membrane densities resembling immune complex deposits in two biopsies from patients with active GWG. In biopsies from patients on cytotoxic therapy, there was no active inflammatory process, but focal glomercular obsolescence and segmental tuft sclerosis provided evidence of prior focal and segmental glomercular disease. Discrete zones of basement membrane crimping and increased mesangial material along the capillary wall were observed in some patients with apparent LWG, as well as proven GWG, possibly representing foci of previous glomerular injury. The appearance of dense deposits on the epithelial side of the basement membrane suggests that immune complex deposition in the glomeruli may be at least partially responsible for the renal injury in Wegener's granulomatosis.