Retention, distribution, and excretion of lead by the rat after intravenous injection.

The distribution and excretion of lead was studied during a period of about a week after a single intravenous injection of 203Pb as chloride accompanied by less than 1 microng of lead carrier. The peak concentration in venous blood was reached after about an hour when it contained 35 to 40% of the administered activity. The subsequent decline in concentration was much more rapid than is observed in man. The main storage organs were the kidneys and bone. Initially, 20% of the dose could be accounted for in the kidney and the biological half-life was about 100 hours. The level in bone built up rapidly at first and then more slowly. After a week, between 25 and 30% of the dose was present in bone.     

The value of maintenance therapy following treatment of central nervous system leukemia.

The efficacy of intrathecal (IT) maintenance chemotherapy following central nervous system (CNS) leukemia was demonstrated in a retrospective study of 77 such episodes. The median durations of CNS and bone marrow (BM) remissions were significantly longer for the 41 maintained episodes (10+ and 9.5 months, respectively) compared with the 36 unmaintained episodes (4 and 2 months, respectively). Patients were comparable in each of these two groups. For those patients receiving maintenance therapy, there appeared to be an advantage in using four or more doses of IT medications for treatment of CNS leukemia, regardless of the number of doses necessary to clear the cerebrospinal fluid (CSF).     

Facial injuries associated with cervical fractures: recognition, patterns, and management

Publications in both the orthopedic and maxillofacial literature have noted the association of cervical spine and facial injuries. However, because the incidence of spinal injury is low, we found no study which documented the relationship between maxillofacial and cervical spine injuries. The present study reviewed 982 cervical spine injuries in two major trauma centers, finding a 19.3% incidence of facial injury. Fourteen per cent of patients had soft-tissue injuries and 8.6%, facial fractures. Important relationships were noted between fractures of the mandible and upper cervical spine, and soft-tissue injuries of the upper face and fractures of the lower cervical spine. Methods of care adapted to the combined injuries are described. The study concludes that examination of the face for soft-tissue and bony injuries may give important clues on the direction and intensity of the force injuring the cervical spine.     

Effect of mercuric chloride on the rat mesenteric vascular bed: Relevance to the mechanism of mercury toxicity

The effects of mercuric chloride on the vasculature were studied in the perfused rat mesenteric vascular bed. Mercuric chloride inhibited the vascular response to bolus injections of norepinephrine (100 ng) and potassium chloride (2 mg) even at a low concentration (3.7 × 10^?8m) and the inhibition increased in a dose-dependent manner. Mercuric chloride at concentrations of 3.7 × 10^?7m or more significantly increased the baseline perfusion pressure, an effect which was rapidly reversed probably as a result of severe damage to the vascular wall. This rise of baseline was in proportion to the calcium concentration of the perfusing buffer. In calcium-free buffer, mercuric chloride, even in high concentration (3.7 × 10^?5m), had no effect on baseline pressure but the vascular responses to both pressor agents were inhibited almost in the same manner as in the case of normal calcium buffer. Prepefusing the preparation with 10^?5m lanthanum chloride in calcium-containing buffer and then adding mercuric chloride to this buffer, with lanthanum still present, also prevented the rise of baseline pressure by mercury. Heavy metal antagonists (d-penicillamine, N-acetyl-dl-penicillamine, dimercaprol) were effective in the treatment of early stage damage and in its prophylaxis. These results indicate that circulatory disturbances may play an important role in mercury toxicity and that the effects are in part related to modulation of calcium movements.     

Reduction of Antibody Plaque-Forming Cells by Allogeneic Antilymphocyte Serum

Allogeneic mouse antilymphocyte serum effectively reduced the number of antibody plaque-forming cells after the natural antilytic property had been eliminated by dilution.