Pharmacological assessment of ARTCEREB irrigation and perfusion solution for cerebrospinal surgery using primary cultures of rat brain cells.

ARTCEREB irrigation and perfusion solution (Artcereb), an ethical pharmaceutical, is typically applied inside the skull and spinal cavity as artificial fluid. Artcereb is composed of glucose and electrolytes (Na+, K+, Mg2+, Ca2+, Cl-, HCO3- and P) and has a pH of 7.3. An in vitro assessment of the effects of Artcereb on cell culture of rat fetal astrocytes or rat fetal brain cells was performed in comparison with normal saline and lactated Ringer's solutions. Furthermore, the effects of Artcereb on cell culture of rat fetal brain cells were also assessed in comparison with Krebs bicarbonate solution. Cell function after exposure to Artcereb was assessed based on 3H-thymidine incorporation activity. Cell function after exposure to Artcereb and lactated Ringer's solution in primary cultures of rat fetal astrocytes remained unaffected when compared to that after exposure to normal saline. Cell function after exposure to Artcereb in a primary culture of rat brain cells remained unaffected as compared to that after exposure to normal saline and lactated Ringer's solution. However, function decreased after exposure to a modified Artcereb formulation lacking bicarbonate, thus confirming that the presence of bicarbonate is essential for the Artcereb formulation.

Effect of whole blood clotting time in rats with ionized hypocalcemia induced by rapid intravenous citrate infusion.

Although the toxic effects of citrate including hemodynamic and cardiovascular changes result from a decrease in ionized calcium levels in serum due to chelating action, these effects of citrate on blood coagulation have not yet been fully clarified. The present study examines whether serum citrate and ionized calcium levels affect whole blood clotting time in rats using the test tube method in which citrate is administered by rapid intravenous infusion. Citrate was infused via the tail vein into 10 rats at 3, 4 or 5 mmol/kg/hr for 1 hr, and then whole blood clotting time, serum citrate and ionized calcium levels were determined. Whole blood clotting time did not significantly change at citrate infusion rates of 3 and 4 mmol/kg/hr. However, at 5 mmol/kg/hr, whole blood clotting time was significantly prolonged by a factor of 2.1 relative to the untreated group, when the serum citrate level was 10.03 +/- 1.39 mmol/l (59.0-fold higher than that in the untreated group) and the serum-ionized calcium level was 0.29 +/- 0.02 mmol/l (0.2-fold lower than that in the untreated group). These results suggest that whole blood clotting time is significantly prolonged in rats with severe ionized hypocalcemia.

Tolerable infusion rate of citrate based on clinical signs and the electrocardiogram in conscious dogs.

BACKGROUND & AIMS: The possible clinical significance of the toxic effects of citrate has not yet been fully clarified. This study was therefore conducted to confirm the toxicity and determine the tolerable infusion rate of citrate administered by rapid intravenous infusion to conscious dogs. METHODS: Citrate solutions were infused via the cephalic vein of 4 conscious dogs at 0.33, 0.67, or 1.33mmol/kg/h up to 1.33mmol/kg. Clinical signs and the electrocardiogram were observed during and after infusion. Serum citrate and ionized calcium levels were also measured. RESULTS: Although the mean citrate level increased in accordance with the infusion rate, the calcium level decreased. No significant changes in clinical signs or the electrocardiogram were observed during infusion at 0.33mmol/kg/h despite an increase in the serum citrate level to 1.22+/-0.11mmol/l (pre-infusion value: 0.38+/-0.01mmol/l) and a decrease in the serum calcium level to 1.28+/-0.03mmol/l (pre-infusion value: 1.50+/-0.05mmol/l). Vomiting and QTc prolongation were observed at 0.67mmol/kg/h or higher. Salivation and tachycardia were observed at 1.33mmol/kg/h. CONCLUSIONS: Based on clinical signs and the electrocardiogram, the tolerable infusion rate of citrate in conscious dogs is concluded to be 0.33mmol/kg/h.

Four-week intravenous repeated dose toxicity study of L-cysteine in male rats.

A 4-week intravenous repeated dose toxicity study of L-cysteine (L-Cys) was conducted in male Sprague-Dawley rats to investigate in detail the toxic effects of this compound and to determine the dose level at which these toxic effects are observed following repeated intravenous administration. Male rats were randomly allocated to 4 groups to receive L-Cys by intravenous administration at dosages of 0, 100, 300, and 1,000 mg/kg body weight/day. Body weight gain was significantly suppressed throughout the study period in the 1,000-mg/kg group, although food consumption was reduced only on study day 3. A decrease in spontaneous activity, salivation, stereotypy, ptosis, and tremor were observed in the 1,000-mg/kg group. Mild anemia characterized by decreases in hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and an increase in the reticulocyte count was also noted in the 1,000-mg/kg group. Histopathological examination showed sperm granulomas in the epididymis and necrosis of the Purkinje cells and granular layer in the cerebellum in the 1,000-mg/kg group. Slight tubular basophilia with blood or hyaline casts was observed in the kidney in the 300-mg/kg and 1,000-mg/kg groups, associated with proteinuria or occult blood in urinalysis. Additional studies are needed to clarify the causes for these toxicological findings by excess of L-Cys.