RB 101, a purported pro drug inhibitor of enkephalin metabolism, is antinociceptive in pregnant mice.

In an earlier study, we demonstrated the enhancement of pregnancy-induced analgesia with an inhibitor of endogenous enkephalin metabolism. The purpose of the present study was to evaluate the antinociceptive effect of another inhibitor of enkephalin metabolism, RB 101, on pregnant mice. Further, since other studies have shown RB 101 to be free of opioid side effects, we examined its effect on respiratory rate. Analgesia was assessed using the hot plate test, and respiratory rate was measured by recording the output from an end-tidal carbon dioxide detector. In pregnant mice, experiments were conducted on Day 17 or Day 18 of pregnancy; mice usually deliver on Day 19. For the hot plate test, animals were tested in the following groups: Group 1, RB 101 150 mg/kg (n = 15); Group 2, RB 101 50 mg/kg (n = 15); Group 3, RB 101 vehicle (n = 15); Group 4, morphine 5 mg/kg (n = 14); and Group 5, RB 101 150 mg/kg + naloxone 5 mg/kg (n = 10). The test was repeated on the second day after delivery in animals in Groups 1 and 3 (given RB 101 150 mg/kg and RB 101 vehicle, respectively). RB 101 150 mg/kg and morphine 5 mg/kg were significantly different (mean percentage of maximum possible effect 30.0 and 37.7, respectively, at 30 min and 41.6 and 32.6, respectively, at 60 min) in their antinociceptive effect in pregnant animals from all other groups. Naloxone, when coadministered with RB 101, prevented the development of antinociception. RB 101 150 mg/kg was not antinociceptive after delivery. Depression of respiratory rate was tested in a separate set of animals in the following groups: Group 1, RB 101 150 mg/kg (n = 16); Group 2, morphine 5 mg/kg (n = 16); Group 3, RB 101 vehicle (n = 15). Morphine 5 mg/kg produced significant depression of respiratory rate at 30 min postinjection when compared with RB 101 150 mg/kg and RB 101 vehicle (mean percent change in respiratory rate was 78.5% compared with 87.7% and 92.4%, respectively, where 100% = no change). These results suggest that drugs such as RB 101 may produce antinociception with minimal effects on respiration.

Ischemic, hemodynamic, and neurohormonal responses to mental and exercise stress. Experience from the Psychophysiological Investigations of Myocardial Ischemia Study (PIMI).

BACKGROUND: The pathophysiology of mental stress-induced myocardial ischemia, which occurs at lower heart rates than during physical stress, is not well understood. METHODS AND RESULTS: The Psychophysiological Investigations of Myocardial Ischemia Study (PIMI) evaluated the physiological and neuroendocrine functioning in unmedicated patients with stable coronary artery disease and exercise-induced ischemia. Hemodynamic and neurohormonal responses to bicycle exercise, public speaking, and the Stroop test were measured by radionuclide ventriculography, ECG, and blood pressure and catecholamine monitoring. With mental stress, there were increases in heart rate, systolic blood pressure, cardiac output, and systemic vascular resistance that were correlated with increases in plasma epinephrine. During exercise, systemic vascular resistance fell, and there was no relationship between the hemodynamic changes and epinephrine levels. The fall in ejection fraction was greater with mental stress than exercise. During mental stress, the changes in ejection fraction were inversely correlated with the changes in systemic vascular resistance. Evidence for myocardial ischemia was present in 92% of patients during bicycle exercise and in 58% of patients during mental stress. Greater increases in plasma epinephrine and norepinephrine occurred with ischemia during exercise, and greater increases in systemic vascular resistance occurred with ischemia during mental stress. CONCLUSIONS: Mental stress-induced myocardial ischemia is associated with a significant increase in systemic vascular resistance and a relatively minor increase in heart rate and rate-pressure product compared with ischemia induced by exercise. These hemodynamic responses to mental stress can be mediated by the adrenal secretion of epinephrine. The pathophysiological mechanism involved are important in the understanding of the etiology of myocardial ischemia and perhaps in the selection of appropriate anti-ischemic therapy.

Utility of posttransplantation panel-reactive antibody measurements for the prediction of rejection frequency and survival of heart transplant recipients.

BACKGROUND AND METHODS: Seventy-six heart transplants in 73 patients were studied for the formation of lymphocytotoxic panel-reactive antibodies after transplantation. Treatment of patient serum with dithioerythritol was used to discriminate between antibodies of the immunoglobulin M and immunoglobulin G isotypes. Human leukocyte antigen specificities of immunoglobulin G panel reactive antibodies were determined by the pattern of reactivity with the cell panel used in the panel-reactive antibodies determinations. A total of 465 panel-reactive antibodies determinations were made during the first year after transplantation. RESULTS: Mean panel-reactive antibodies values were highest during the first posttransplantation month. Positive dithioerythritol-treated panel-reactive antibodies values were rare after the first month after transplantation. Multivariable analysis indicated that previous pregnancy and positive cytomegalovirus serologic analysis predicted a higher dithioerythritol-treated panel-reactive antibodies within the first 3 months. No decrease in actuarial survival, increase in cumulative rejection episodes, or increase in the incidence of coronary artery disease at 1 year was seen in patients with a standard panel-reactive antibodies greater than 10% or among patients with dithioerythritol-treated panel-reactive antibodies greater than 0%. A significant and major increase in rejection-related death or retransplantation occurred among 11 patients in whom donor human leukocyte antigen specific antibodies of the immunoglobulin G isotype were detected during the first posttransplantation year (p = 0.02). Two of the 11 patients died of refractory rejection and 3 and 6 months after transplantation, whereas one patient underwent retransplantation for refractory rejection at 13 months and subsequently died. CONCLUSIONS: (1) Posttransplantation serial standard panel-reactive antibodies or dithioerythritol-treated panel-reactive antibodies are not predictive of rejection-related mortality unless the specificity is determined to be antidonor HLA; (2) routine dithioerythritol-treated panel-reactive antibodies studies are advisable during the first month after transplantation, and, if positive (> 10%), antidonor human leukocyte antigen specificity should be determined; (3) detection of recipient immunoglobulin G anti-donor human leukocyte antigen antibodies after heart transplantation identifies a group at high risk for serious allograft rejection and should prompt more intensive rejection surveillance and consideration for additional immunotherapy.

Dilated cardiomyopathy as an early and rapidly progressive presentation in a woman with acquired immunodeficiency syndrome.

Cardiac disease associated with AIDS is common and is manifested by a variety of lesions. With the advances in therapy for common opportunistic infections, AIDS-associated cardiac abnormalities will play a prominent role in morbidity and mortality. This case illustrates a rapidly progressive and fetal course of AIDS-associated dilated cardiomyopathy in an HIV-infected young woman in relatively stable condition. It is important to be aware of the cardiac manifestations of AIDS so that one can undertake a rational diagnostic and therapeutic approach.

Organ donation: a university hospital experience.

To define the size of the donor pool among nontrauma patients and the role of physicians in the limited supply of organs available for transplantation, we reviewed the 1293 nontrauma deaths that occurred in Vanderbilt University Medical Center during a 31-month period. Computerized discharge abstracts showed that 111 adults died without contraindications to organ donation. Manual review of these 111 medical records yielded 68 records suitable for review by Tennessee Donor Services. From this group 10 eligible donors were identified. Physicians failed to ask the families of three patients, families of three patients refused organ donation, and one patient had cardiovascular collapse before the donation process could be completed. Organs were successfully donated from three patients. All eligible donors died of intracerebral hemorrhage or drug overdose. Failure of physicians to approach families for donation was not based on medical criteria, and it resulted in organ wastage. As a result of this study, we have developed a simplified audit process for hospitals to use in evaluating compliance with required request legislation.

Recurrent bacterial endocarditis in a man with tetralogy of Fallot: earliest recurrence on record.

Enterococcal endocarditis occurred in a young man with tetralogy of Fallot who had just completed therapy for staphylococcal endocarditis. The patient had a transient reversal of flow through the ventricular septal defect during staphylococcal endocarditis with lung abscesses and had persistently elevated teichoic acid antibody titers during the second episode caused by enterococcus. Our review of the literature on recurrent infective endocarditis indicates that our case represents one of the shortest intervals of recurrence with a second organism.