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Background: It is hitherto still questionable which of the physical properties of the bile fluid influence the outcome of extracorporeal shock wave lithotripsy (ESWL)., Methods: In this study the influence of the density and viscosity of bile simulating fluid on ESWL was tested in vitro by applying CsCl solutions of densities 1.0, 1.3, 1. 5, 1.7 and 1.9 g/ml. Five almost identical "sister" stones from one patient were fragmented in these five fluids. The number of shock waves required for adequate fragmentation (fragments < 4 mm) was measured for comparison. This was repeated on a further seven patients (five "sister" stones per patient). Subsequently, the influence of the viscosity of the fluid on ESWL was tested using polyethylene glycol (PEG) solutions of the viscosities 1, 5, 17, 30 and 59 mPa.s. Analogous to the first part of this investigation, 40 gallstones from an additional eight patients (again five almost identical sister stones) were fragmented, registering the number of shock waves required for adequate fragmentation., Results and Conclusions: The density of the fluid did not reveal any monotone correlation to the number of shock waves required. In contrast to the density of the fluid there was a distinct correlation (r subsets = 0.84; p < 0.001) between its viscosity and the number of shock waves required. On average, the number of shock waves required in a fluid with a viscosity of 59 mPa . s must be more than three times that required in water, which has a viscosity of 1 mPa.s.

Estimations of the prevalence of central nervous system involvement in patients with systemic lupus erythematosus (SLE) vary from 25 to 75%. In order to assess possible deficits in memory, attention, and/or reaction time, a battery of neuropsychological tests was administered to 15 patients with SLE and to two matched groups of control subjects; eight patients on corticosteroids and 15 healthy controls. The test battery included the Multiple Choice Word Fluency Test (MWT-B), Benton Visual Memory Scale, Syndrome Short Test (SKT; attention and memory), Attention and Concentration Test (d2), Wechsler Adult Intelligence Scale (WAIS) subtests for Comprehension, Digit Span, Block Design, a Computer Controlled Reaction Time task (CCRT), and a Learning and Memory Test (LGT-3). Results revealed a statistically significant short-term memory deficit (for all six relevant subtests used) and a marked delayed simple reaction time in SLE patients as compared with scores in healthy subjects. An attention deficit as well as the expected difference between the estimated premorbid and actual level of intelligence could not be demonstrated. With three exceptions (SKT-9 figural recognition, Benton Visual Memory, and LGT-3 figural recognition), patients treated with corticosteroids did not differ from healthy controls. They also did not differ from SLE patients in any of the parameters tested. It therefore appears that the demonstrated deficit in short-term memory and reaction time in SLE patients may not only be due to the neuropsychiatric manifestation of SLE but possibly also result from medication side-effects.

The influence of a 1-hour neuropsychological stress test on the distribution of lymphocyte subpopulations and on plasma catecholamine levels was investigated in 18 patients with rheumatoid arthritis (RA) and 14 sex- and age-matched controls. Despite significant increases in lymphocyte counts in both groups, lymphocyte subsets did not change accordingly. A wide scattering of catecholamine levels in plasma before and after stress was observed. Plasma levels of lymphokines such as interleukin (IL)-1 beta and IL-6 could not be detected in RA patients. Enzyme immunoassay of markers of lymphocyte activation such as HLA-DR and cell-bound IL-2 receptor showed only a significant elevation of HLA-DR marked cells in RA patients at baseline. Significantly higher amounts of the soluble IL-2 receptor were detected in patients with RA before the stress test, but stress testing did not alter this parameter. In conclusion, lymphocyte activation in RA and a defect in the expression of IL-2 receptor on the cell surface of lymphocytes were confirmed in the present study.

Physical and psychological stress in healthy subjects leads to characteristic alterations of plasma hormone concentrations and the lymphocyte subset distribution. After short-term bicycle ergometry or acoustic stress, and after a 2-h-long neuropsychological examination, a rise in B- and T-suppressor/cytotoxic lymphocytes and a decrease in T-helper lymphocytes has been shown to occur. This cell mobilization was accompanied by an elevation in plasma catecholamines. Although the rise in catecholamine levels was similar in patients with systemic lupus erythematosus (SLE) and in healthy subjects, the alterations in the lymphocyte subsets were less pronounced in SLE patients after bicycle ergometry as well as after psychological testing than in healthy subjects, patients with sarcoidosis, and patients without collagenosis under treatment with corticosteroids. Differences between short-term physical exercise and the acoustic stress test on the one hand, and the 2-h-long neuropsychological test on the other, were observed only for the absolute lymphocyte count. After short-term stress, a rise in the leukocyte and lymphocyte count was noted, whereas after long-term testing, only an increase in leukocytes and a decrease in lymphocytes could be found. In conclusion, sympathomimetic stimulation by bicycle ergometry or by psychological stress led to a characteristic cell mobilization in all the groups investigated. The extent of cell mobilization was attenuated in SLE patients despite the fact that comparable increases of plasma catecholamines were observed.

In a randomized, placebo-controlled, double-blind study, 12 patients with congestive heart failure (New York Heart Association class II) were successively treated for 1 week each with placebo, 40 mg famotidine, and 1000 mg quinidine. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiography, and Doppler ultrasound were measured. Heart rate and blood pressure were not markedly altered by either drug. By contrast, quinidine and famotidine significantly decreased stroke volume and cardiac output in impedance cardiography and Doppler ultrasound (p less than 0.05). A high correlation between both noninvasive methods was found for cardiac output and stroke volume (r = 0.93 and r = 0.97 for stroke volume 1 1/2 hours after quinidine and placebo administration, respectively). In addition, the mechanocardiographic ratio of the preejection period to the left ventricular ejection time in systolic time intervals increased significantly 1 1/2 and 3 hours after administration of quinidine and famotidine (p less than 0.05). In conclusion, both quinidine and famotidine exert similar negative effects on cardiac performance, with no significant differences in hemodynamic parameters emerging between the antiarrhythmic agent and the H2-receptor antagonist.

In a randomized, placebo-controlled, double-blind study, 10 healthy volunteers were treated orally once a day for 1 week each with placebo, 800 mg cimetidine, 300 mg ranitidine, and 40 mg famotidine. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, and impedance cardiography were measured before the morning dose and at 2, 6, 12, and 24 hours after the morning dose. Heart rate and blood pressure were not markedly altered by any of the H2-receptor antagonists compared with the findings for placebo. Cimetidine and ranitidine did not markedly alter parameters of systolic time interval and impedance cardiography compared with placebo in contrast to famotidine, which significantly decreased stroke volume, cardiac output, and the Heather Index in impedance cardiography (p less than 0.05) and also significantly increased the ratio of the preejection period to the left ventricular ejection time in systolic time interval (p less than 0.05) 2 hours after the morning dose. Six hours after administration, most of these alterations could no longer be detected. The observed changes in hemodynamic parameters confirm that famotidine exerts negative effects on cardiac performance, whereas such influences could not be shown for cimetidine and ranitidine.

14 patients with systemic lupus erythematosus (SLE), 12 with sarcoidosis and two age- and sex-matched groups of healthy subjects were exposed to a 10-minute acoustic stress test. Healthy subjects and patients with sarcoidosis showed significant increases in leukocyte and lymphocyte counts (p less than 0.01), relative elevations of B and Tsc lymphocytes (p less than 0.01) and a relative reduction of Th lymphocytes (p less than 0.01). Patients with SLE showed the same characteristic alterations (p less than 0.01) but the degree of this cell mobilization was significantly less pronounced as compared with the healthy subjects (p less than 0.01). No dependence was found between corticosteroid therapy or disease activity and the cellular reaction in SLE patients. In SLE patients there thus seemed to be an attenuated immune response due to stress which may play an etiopathogenetic role in this disease.