Methotrexate therapy for autoimmune hearing loss: a preliminary report.

The management of autoimmune sensorineural hearing loss (SNHL) continues to challenge the otologist. Steroids and cyclophosphamide, the two traditional medications for this malady, are often associated with serious adverse reactions. In an effort to use a less toxic medication, the authors treated five autoimmune SNHL patients with low-dose oral methotrexate. Methotrexate has been found to be very effective in rheumatoid arthritis patients with acceptable adverse reactions. Preliminary results from this study indicate that methotrexate has the potential of being effective for autoimmune SNHL and associated otologic symptoms. Tolerance has been very good and side effects have been minimal.

The heart as a target organ of immune injury.

Over the last 10 years, our knowledge of immunologically mediated processes involving the myocardium appears to have made quantum leaps. New and important disease entities such as AIDS have appeared and the cardiologist now becomes an important member of the "AIDS team." Our understanding of "older diseases" such as sarcoidosis, Lyme disease, systemic lupus and other connective tissue syndromes has significantly increased. The concept of high-dose steroid therapy for these processes may, in fact, turn out to be futile and more selective, as less dangerous immunosuppression is being introduced. This concept has significantly advanced in the field of cardiac transplantation where immunosuppression has now been usurped by specific immunotherapy aimed at selective aspects of the immune sequence. New and exciting concepts will emerge from the molecular biology laboratory that will have direct bearing on the management of patients with cardiovascular disorders. This information explosion will force the cardiovascular physician to become more in tune with the world of immunology and molecular biology. Many obvious, significant problems remain, such as accelerated atherosclerosis in the transplant patient and the role of myocarditis in the patient with heart failure. However, it will truly be an exciting decade in which to work and watch the unraveling of these mysteries and hopefully, the study of today's problems will give way to solutions and a clearer understanding of the heart as a target of immune injury.

Pertussis toxin inhibits human neutrophil responses mediated by the 42-kilodalton IgG Fc receptor.

The effects of pertussis toxin (PT) on human neutrophil responses mediated by the 42-kDa IgG Fc R (Fc gamma R42) were compared with its effects on responses mediated by the FMLP receptor. Pre-treatment of neutrophils with PT completely inhibited FMLP stimulation of superoxide production and blocked over 95% of FMLP-stimulated degranulation. PT inhibited superoxide production stimulated by Fc gamma R42 cross-linking by 92%. In contrast, degranulation stimulated by Fc gamma R42 was only partially inhibited, with beta-glucuronidase release inhibited by 54%, lysozyme by 33%, and lactoferrin by 78%. With either stimulus, PT inhibition was maximal in the range from 1.8 to 2 micrograms/ml. Responses to both stimuli declined in a parallel fashion with increasing time of exposure to PT with maximal inhibition occurring after 2 h of exposure. Inhibition of FMLP responses and Fc gamma R42-mediated superoxide production, but not degranulation, correlated with ADP-ribosylation of a 45-kDa membrane protein. Inhibition by PT of Fc gamma R42-mediated responses was not due to a change in receptor number. These data suggest that activation of polymorphonuclear neutrophils via Fc gamma R42 proceeds through two pathways, only one of which is regulated by a PT-sensitive G protein.

Pharmacokinetic and taste evaluation of ibuprofen (Motrin) 800 mg tablets in extemporaneous solution.

A 4-way crossover study was done to determine the pharmacokinetic and palatability characteristics of ibuprofen 800 mg tablets when given as a solution in various beverages. When compared to the tablet itself, no significant difference was noted for any variable measured for an orange juice solution. A delay in time-to-peak concentration (Tmax) was noted for a dilute cherry syrup solution. Changes in Tmax, peak concentration achieved and area-under-the-curve were noted with a Coca-Cola solution. The authors conclude Coca-Cola to be clearly inappropriate for this method, a dilute cherry syrup solution slightly better and orange juice to be the preferred option.

Monoclonal antibody to human IgG Fc receptors. Cross-linking of receptors induces lysosomal enzyme release and superoxide generation by neutrophils.

The monoclonal antibody KuFc79 binds to a determinant on the Fc receptors (Fc gamma R) of human leukocytes. We examined the biologic effects of the interaction of this antibody with Fc gamma R on human neutrophils (PMNL). The univalent Fab fragment of KuFc79 inhibits the formation of rosettes with IgG-sensitized sheep erythrocytes by as much as 91.7%. In other experiments in which PMNL were washed after exposure to Fab of KuFc79, phagocytosis of IgG-sensitized sheep erythrocytes was inhibited by 36%. Fab fragments of other mouse IgG2b monoclonal proteins did not have these effects. When PMNL are exposed to coverslips coated with univalent Fab fragments of this antibody, the Fc gamma R are removed from the surface of the PMNL. Under these conditions, rosetting could be inhibited by 85.4%. We examined cross-linking of receptor bound monoclonal antibody or its Fab fragment by either Protein A or F(ab')2 of an anti-mouse Ig. As much as 31.7% of beta-glucuronidase, a marker for lysosomal enzymes, is specifically released by cross-linking the Fc gamma R on PMNL. The generation of O2- is also induced by specifically cross-linking Fc gamma R with Fab and anti-Fab. The data constitute the first formal demonstration that cross-linking of Fc gamma R on PMNL leads to enzyme release and superoxide generation.

Effect of antacid suspension on the pharmacokinetics of ibuprofen.

The effect of antacid administration on the pharmacokinetics of ibuprofen was evaluated in a randomized, crossover study of eight healthy volunteers. Doses of 62 mL of aluminum and magnesium hydroxide suspension and single doses of ibuprofen 400 mg were used. Subjects received each of the following treatments at one-week intervals: ibuprofen alone; ibuprofen administered concurrently with one dose of antacid; antacid administered one hour after the ibuprofen dose; and antacid administered concurrently with the ibuprofen dose, plus three more antacid doses given every five hours. Blood samples were taken at various time intervals up to 24 hours after the ibuprofen dose. Serum samples were assayed for ibuprofen content using high-performance liquid chromatography. Values for AUC, Cmax, tmax, and k were not significantly different among treatment groups. The ranges of mean (+/- S.D.) values were 113.97 +/- 21.5 to 127.53 +/- 29.3 micrograms.hr/mL for AUC, 35.30 +/- 6.40 to 41.00 +/- 10.00 micrograms/mL for Cmax, 0.95 +/- 0.30 to 1.28 +/- 0.54 hr for tmax, and 0.346 +/- 0.026 to 0.388 +/- 0.040 hr-1 for k. For the doses used, concurrent administration of aluminum and magnesium hydroxide suspension and ibuprofen does not alter ibuprofen pharmacokinetics.

Effects of cimetidine or ranitidine on the pharmacokinetics of flurbiprofen.

The effect of oral cimetidine or ranitidine on the pharmacokinetics of the nonsteroidal anti-inflammatory agent flurbiprofen was studied. Nine healthy volunteers participated in the study. The subjects were divided into three groups, and each group alternated therapy with each of the following treatments: flurbiprofen 200 mg (two 100-mg tablets), flurbiprofen 200 mg plus ranitidine 150 mg two times daily for seven days before and for two days after receiving flurbiprofen, and flurbiprofen 200 mg plus cimetidine 300 mg four times a day for seven days before and for two days after receiving flurbiprofen. Blood samples were collected at time zero and at various intervals during a 48-hour period. Serum flurbiprofen concentrations were determined by high-performance liquid chromatography. No significant differences in elimination rate constant, peak concentration, time to peak concentration, volume of distribution, or elimination half-life were noted among treatments. The difference in area under the curve (AUC) in subjects treated with flurbiprofen alone and in those treated with flurbiprofen plus cimetidine was significant. Two subjects experienced gastric upset; one case was apparently caused by cimetidine, and the other was likely caused by flurbiprofen. Although a significant increase in AUC was observed in subjects receiving flurbiprofen plus cimetidine, the interaction is probably not clinically important.

Effect of sucralfate on ibuprofen absorption in normal volunteers.

The effect of the concurrent administration of sucralfate on the absorption of a single dose of ibuprofen was studied in nine normal volunteers using a random crossover design. Each participant received a single 600-mg dose of ibuprofen for the control phase, and a 600-mg dose of ibuprofen following 5 g of sucralfate given in 1-g divided doses for the treatment phase. Blood samples were obtained at regular intervals for 12 hours following the administration of ibuprofen, and pharmacokinetic and statistical analyses were performed. Analysis of time to peak serum concentration, maximum serum concentration, elimination rate constant, and half-life showed no significant difference between the control and treatment phases. Mean total area under the curve for ibuprofen decreased by 11.8% in the treatment phase, but this decrease was not statistically significant. The concurrent administration of sucralfate did not significantly alter the absorption of a single 600-mg dose of ibuprofen in healthy subjects.