Early-phase myocardial infarction: evaluation by MR imaging

In vivo gated magnetic resonance (MR) imaging was performed in 12 dogs immediately after occlusion of the left anterior descending coronary artery and serially up to 5 hours and again between 4 and 14 days. This was done to evaluate the appearance of acute myocardial infarcts and to determine how soon after coronary artery occlusion MR imaging can demonstrate the site of acute myocardial ischemia. In nine dogs with postmortem evidence of myocardial infarction, regional increase of signal intensity of the myocardium was present by 3 hours after coronary artery occlusion and conformed to the site of myocardial infarct found at autopsy. The signal intensity on T2-weighted images of the infarcted myocardium was significantly greater than that of normal myocardium at 3, 4, and 5 hours after occlusion. The T2 (spin-spin) relaxation time was significantly prolonged in the region of myocardial infarct at 3, 4, and 5 hours postocclusion compared with normal myocardium. Myocardial wall thinning and increased intracavitary flow signal were found in six dogs with comparable pre- and postocclusion images in late systole.     

Maternal Blood Donation for Intrauterine Transfusion

Pregnancy affected by erythrocyte alloimmunization often requires intrauterine transfusion for fetal survival. Because blood donated by a random donor has been associated with an increased risk of disease transmission, maternal blood donation has been advocated as an alternative blood source for intrauterine transfusion. Collaboration between medical, nursing, laboratory, and nutrition personnel optimizes the safety and success of the procedure. This article describes the collaborative care of the woman participating in maternal blood donation for intrauterine transfusion.     

MAGNOLOL DECREASES BODY TEMPERATURE BY REDUCING 5 HYDROXYTRYPTAMINE RELEASE IN THE RAT HYPOTHALAMUS

1. The effects of magnolol, isolated and purified from the cortex of Magnolia officinalis Rehd. et Wils, on thermoregulation and hypothalamic release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were assessed in normothermic rats and in febrile rats treated with interleukin-1β. 2. Intraperitoneal administration of magnolol (25–100 mg/kg) produced a decrease in colon temperature, an increase in foot skin temperature, a decrease in metabolic rate and a decrease in the endogenous release of 5-HT in the rat hypothalamus. 3. Depletion of rat brain 5-HT, produced by intracerebro-ventricular pretreatment with 5,7-dihydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneous vasodilation and decreased metabolism. 4. Intracerebroventricular administration of (±)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT₂ receptor agonist; 5–10 μg/5 μL) increased basal colon temperature and reversed the magnolol-induced hypothermia. 5. The increases in both colon temperature and hypothalamic 5-HT release produced by interleukin-1β injection were attenuated by treatment with magnolol. 6. The data suggest that magnolol decreases body temperature (due to increased heat loss and decreased heat production) by reducing 5-HT release in rat hypothalamus.     

Evidence for adaptation of the entire PTH-calcium curve to sustained changes in the serum calcium in haemodialysis patients

BACKGROUND: Based on in vitro studies, the set point of calcium has often been considered to represent an intrinsic property of parathyroid gland function. However, in the dialysis patient, the serum calcium does not consistently reflect the magnitude of hyperparathyroidism; in addition, little information is available on whether the PTH-calcium curve is modified by sustained changes in the serum calcium. The present study in haemodialysis patients was designed to evaluate whether the set point of calcium and the dynamics of PTH secretion were modified by sustained changes in the serum calcium. METHODS: To accomplish the goal of the study and obtain a wide range of changes in the serum calcium, haemodialysis patients were dialysed with either a 1.75 mM (group I) or a 1.25 mM (group II) calcium dialysate for 2 weeks, and were then changed to a 1.25 mM (group I) or a 1.75 mM (group II) calcium dialysate for an additional 2 weeks. At the end of the first and second 2-week periods, low and high calcium studies were performed to obtain PTH-calcium curves. RESULTS: In group I, the serum ionized calcium decreased with the lower calcium dialysate (P < 0.02) and the set point of calcium was reduced (P < 0.02); in group II, the serum calcium did not change and the set point of calcium was not modified. When both groups were evaluated together, the delta serum calcium correlated directly with the delta set point of calcium (r = 0.87, P < 0.001) and inversely with the delta PTH (r = -0.73, P < 0.005); at the same time, an inverse correlation was observed between the delta PTH and the delta set point of calcium (r = -0.67, P < 0.01). Moreover, the delta serum calcium correlated with both the delta ratio of basal/maximal PTH (r = -0.71, P < 0.005) and the change in predialysis serum calcium necessary to maximally stimulate PTH (r = 0.84, P < 0.001); these latter two are indicators of the position of PTH along the PTH-calcium curve. Finally, in group I the entire PTH- calcium curve shifted to the left on the 1.25 mM calcium dialysate as compared with the 1.75 mM calcium dialysate. CONCLUSION: The findings of the present study indicate that: (1) the set point of calcium followed sustained changes in the serum calcium independently of PTH secretion, and (2) the parathyroid gland was able both to adjust the position of PTH secretion on the PTH-calcium curve and to adapt PTH secretion to the existing serum calcium concentration.      

A comparison between fluconazole tablets and clotrimazole troches for the treatment of thrush in HIV infection

Fluconazole, a newly available triazole, has been evaluated extensively as a treatment for thrush. It has been effective in the treatment of this condition in patients with HIV infection. Clotrimazole troches have been a common treatment for thrush in patients with HIV infection for several years. This study compared the efficacy and safety of fluconazole 100 mg tablets once per day versus clotrimazole 10 mg troches five times per day in the treatment of thrush in patients with HIV infection. Patients were evaluated at baseline, day 7, 14, 28, and 42. The following parameters were evaluated: clinical cure, colonization at the end of treatment, relapse at day 28, and relapse at day 42. Side effects including liver enzyme values were also monitored. Clinical cure was superior with fluconazole tablets than with clotrimazole troches. Also, rates of colonization at the end of therapy and relapse at days 28 and 42 were less with fluconazole tablets than with clotrimazole troches. However, these differences were not statistically significant. Patient compliance with fluconazole was superior to that of clotrimazole. This difference was statistically significant. Both fluconazole tablets and clotrimazole troches are effective in treating thrush in patients with HIV infection. The avoidance of multiple-per-day dosing would appear to favor fluconazole.     

High human T-cell lymphotropic virus type I proviral DNA load with polyclonal integration in peripheral blood mononuclear cells of French West Indian, Guianese, and African patients with tropical spastic paraparesis

Human T-cell lymphotropic virus type I (HTLV-I) proviral integration status was examined by Southern blot analysis in peripheral blood mononuclear cell (PBMC) DNA from patients presenting a tropical spastic paraparesis (TSP) and serological evidence of HTLV-I infection. Surface phenotype and morphological aspects of PBMC were also studied. A polyclonal HTLV-I proviral integration was found in the PBMC of the 10 patients studied irrespective of their geographical origin (French West Indies, French Guiana, and Africa), the duration of their clinical illness, or the HTLV-I antibody titer. Furthermore, by dilution experiments and hypothesizing that only one copy of HTLV-I proviral DNA is present in one cell, we estimated that this HTLV-I integration is present in 3% to 15% of their PBMC. All 10 TSP/HTLV-I patients studied had an average of 10% of their lymphocytes abnormal, presenting either a misshapen nucleus or an adult T-cell leukemia/lymphoma (ATL)-like feature. Moreover, an elevated CD4/CD8 ratio associated with the presence of activated T cells with a high level of DR expression was observed in most patients. The significant frequency of viral-positive PBMC and the important load of HTLV-I proviral DNA that we observed in TSP/HTLV-I patients might play an important role in the pathogenesis of this recently identified clinico-virological entity.     

The influence of hemorrhagic shock on the pharmacokinetics and the analgesic effect of morphine in the rat

Summary— The influence of hemorrhagic shock (removal of 30% of the blood volume) on the pharmacokinetics and the analgesic effect of morphine was investigated in conscious rats. Plasma concentrations of morphine after a bolus injection (5 mg/kg) are higher in the shock animals, which is attributed to a small decrease in clearance (-22%; P > 0.05) and a significant decrease in distribution volume (-33%; P < 0.05) of the drug. The areas under the plasma concentration-time curve of the metabolite morphine-3-glucuronide (M3G) are significantly higher (+237%; P < 0.01) in the shock rats, which is probably explained by a decreased distribution and renal excretion. The analgesic effect of morphine was evaluated using the tail-flick test during a continuous infusion (10 mg/kg/h) with measurement of the plasma concentrations of morphine and M3G. Data from these experiments show higher plasma concentrations of morphine (+33%; P < 0.05) and M3G (+66%; P > 0.05) during shock, and a significantly increased analgesic effect (+43%; P < 0.05). Our data suggest that the increased analgesic effect of morphine during hemorrhagic shock can most likely be explained by pharmacokinetic changes resulting in higher morphine concentrations.