Confirmation that magnesium lithospermate B has a hydroxyl radical-scavenging action

Male LWH: Wistar rats were given creatinine (Cr) intraperitoneally at a dose of 1.00 g/kg body weight, and the urine was collected for 3 h after administration. Magnesium lithospermate B, a compound newly isolated from Salviae Miltiorrhizae Radix, was administered intraperitoneally 30 min before and 30 min after Cr administration. The excretion of urinary creatol and methylguanidine induced by Cr decreased in a dose-dependent manner. Since we have already shown that the main contributor to the Cr-->creatol oxidation step is the hydroxyl radical, magnesium lithospermate B may act as a radical scavenger.

[Effects of the combination of aspirin and nifedipine on platelet aggregation and thrombogenesis]

The effects of nifedipine (Nif), aspirin (ASA) and ASA + Nif on platelet aggregation and generation of thrombosis were studied. Both ASA and Nif inhibited rabbit platelet aggregation in vitro and rat platelet aggregation in vivo induced by ADP, also prolonged the occlusion time of thrombosis induced electrically in the carotid artery of the rat and reduced the death rate resulting from pulmonary thrombosis induced by i.v collagen and epinephrine in mice. The above effects were markedly increased when Nif and ASA were used in combination. All the above effects were dose-dependent.

Adenosine triphosphatase located on unstimulated human small lymphocyte cell membranes

This study was undertaken to localize the enzyme sodium-potassium dependent adenosine triphosphatase in unstimulated human small lymphocytes using the histochemical technique of McClurkin [1964]. The substrate adenosine 5' triphosphate is hydrolyzed by the ATPase resulting in a lead phosphate precipitate at the site of enzyme action, subsequently visualized as lead sulphide. The enzyme was demonstrated in three different patterns, and for each donor the pattern was constant both on all four of the test slides, and on different occasions. The patterns observed were: clusters of granules related to the cell membrane; positive staining localized to portions of the cell membrane, and, less commonly, the whole cell circumference. The significance of this distribution may relate to areas with large numbers of antigen recognition sites on the lymphocyte membrane.

Lymphocyte tissue culture studies on human heart transplant recipients. III. Prediction of outcome of transplantation based on immunologic studies

Using in vitro lymphocyte tissue culture screening tests human heart transplant recipients during the academic year 1973/1974 were evaluated and an attempt made to predict their post-operative rejection course. The tests involved screening for serum depressive factors and screening for the recipient's lymphocyte reactivity. A scoring system was devised whereby the laboratory results could be converted to a predicted rejection score. Of the nine patients studied, eight are still doing well. Three recipient's who had a high postoperative rejection score as determined by an independent clinical team, were correctly identified pre-operatively and one of them had to be retransplanted. These screening tests may be helpful in the future in the selection of recipients.

Immunodepressive serum treatment of acute heart transplant rejection

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The status of cardiac transplantation, 1975

Since December 1967, 263 human cardiac transplant operations have been performed throughout the world. Eighty-two of these were performed at Stanford University Medical Center, In 1974, 27 such operations were performed, 15 at Stanford Survival rates for the entire Standford series are 48% at one year and 25% at three years; survival rates at one and three years for patients surviving the first three critical months after transplantation are 77% and 42%, respectively. Recipients under the age of 55 years, with New York Heart Association Class IV cardiac disability, are selected for transplant procedures according to criteria dictated by experience over the past seven years. A routine immunsuppressive regimen for organ transplantation, incorporating prednisone, azathioprine, and antithymocyte globulin is employed early postoperatively, and prednisone and azathioprine are used for indefinite maintenance therapy. Acute cardiac graft rejection in nearly all recipients is diagnosed by clinical signs, electrocardiographic changes, and percutaneous transvenous endomyocardial biopsy. Ninety-five percent of acute rejection episodes are reversible with appropriate immunosuppressive treatment, but infectious complications are common and have accounted for 56% of all postoperative deaths. The Stanford experience in cardiac transplantation has demonstrated the potential therapeutic value of this procedure. Maximum survival now extends beyond five years. Satisfactory graft function has been documented in long-term surviving patients, the majority of whom have enjoyed a high degree of social and physical rehabilitation.

Lymphocyte tissue culture studies on human heart transplant recipients. I. Screening recipients for serum factors which inhibit the mixed lymphocyte reaction

The sera of 20 random human heart transplant recipients, drawn before the administration of immunosuppressive medications, were screened for the presence of factors that might inhibit the mixed lymphocyte reaction. The donors for the lymphocyte cultures were unrelated both to one another and to the heart donor and recipient. Inhibition was defined as a reduction of the number of transformed cells produced in vitro to less than one-third of that produced in autologous serum. It appears that patients who have had previous heart surgery on bypass fare better with heart transplants than those who have not had surgery. This may indicate some change in the overall physiology of the former class of patients resulting in better acceptance of the transplant. In turn, this could be due to the development of a serum factor or an impairment in the patients' cellular immune systems. In the series of recipients studied, the majority possessed serum inhibitory factors possibly non-specific by-products of their heart failure. The precise nature of these factors has yet to be determined. Future research is planned to determine whether bypass surgery is responsible for the stimulation of new immuno-depressive factors or if in some way it boosts the titer of pre-existing factors.

The effects of atrial pacing on the synergy and hemodynamics of the orthotopically transplanted canine heart

Instantaneous left ventricular dynamics were measured from cineradiographs utilizing implanted tantalum coils as myocardial site markers in the orthotopically transplanted canine heart. Four parameters of myocardial synergy were obtained: mean shortening, anisotropy of contraction, mean time to half shortening, and asynchrony of contraction. Estimates of end diastolic volume, end systolic volume, stroke volume, ejection fraction, and cardiac output were obtained. Heart rate was altered by pacing the left atrium of the donor heart. Of the nine parameters, only cardiac output was significantly changed by alterations in heart rate. The invariance of stroke volume with rate resulted in a proportional increase in cardiac output with cardioacceleration.

Hemodynamic observations one and two years after cardiac transplantation in man

Cardiac catheterization studies were performed in eight patients 1 year after cardiac transplantation and in two of these again at 2 years. Intracardiac pressures at rest were normal in all patients, both 1 and 2 years postoperatively. Average cardiac index at rest at 1 year was 2.3 liters/min/m 2 and average heart rate was 90 beats/min. Responses to amyl nitrite, atropine, and tyramine failed to demonstrate efferent autonomic reinnervation of the donor hearts. Findings associated with a 10-min period of submaximal supine bicycle exercise 1 year after transplantation included: (1) a gradual rise in heart rate throughout most of the exercise period; (2) prompt elevation of left ventricular end-diastolic pressure by an average increment of 10 mm Hg, followed by a decrease during late exercise in some patients; (3) a progressive increase in LV systolic pressure throughout the first half of the exercise period; (4) a continuously positive change in LV rate of pressure change (dp/dt) throughout exercise; (5) an average 44% increase in stroke volume; and (6) an average 92% increase in cardiac output. The slope of the regression of cardiac output on oxygen uptake during exercise was within the range of normal. Cardiac output, however, was lower than normal both at rest and during exercise, and the arteriovenous oxygen diflerence was accordingly widened.

In one patient studied 1 and 2 years after transplantation, hemodynamic findings were comparable on both occasions. In the other, however, the cardiac output response to exercise was distinctly diminished at 2 years as compared to 1 year, due almost entirely to failure of the stroke volume to increase. Coronary arteriography in this recipient revealed evidence of occlusive coronary disease compatible with graft atherosclerosis.

These studies demonstrate the sustained capacity of the transplanted human heart to support normal physical activity late in the postoperative period. Although utilizing atypical adaptive mechanisms characteristic of the denervated heart, the transplanted heart responds in a directionally appropriate manner to the metabolic demands of exercise.

The Bainbridge reflex in canine cardiac autotransplants

The effects of volume infusion were examined in cardiac autotransplants to determine the role of cardiac innervation in the Bainbridge reflex. In autotransplantation the atria are transected ventral to the vena cavae and pulmonary veins. The remaining atria ("host") are innervated. The autotransplanted atria and ventricles ("donor") are extrinsically denervated. Host and donor heart rate, arterial pressure, aortic flow, and, in several experiments, venous pressure were monitored. Sixteen volume infusions (saline or 6% dextran) of 300 to 800 cc were given to five unanesthetized animals. In three additional experiments infusions were given after atropine, 2 mg, and propranolol, 1 mg/kg.

In all of these animals, volume infusion was accompanied by a small change in donor rate and a consistent increase in the host rate. The venous pressure, when measured, increased 7 cm H 2 O, the aortic pressure mean change was +3 mm Hg, and the cardiac output increased 0.2 L/min. Atropine and propranolol both attenuated the host rate response to infusion.

A venous pressure rise distributed equally to innervated and denervated portions of the same heart resulted in an increase only in the innervated portion. It is concluded that local stretch does not appear to be responsible for the tachycardia in the intact animal.