Uptake of AMP, ADP, and ATP in Escherichia coli W.

The uptake activity ratio for AMP, ADP, and ATP in mutant (T-1) cells of Escherichia coli W, deficient in de novo purine biosynthesis at a point between IMP and 5-aminoimidazole-4-carboxiamide-1-ß-D-ribofuranoside (AICAR), was 1:0.43:0.19. This ratio was approximately equal to the 5'-nucleotidase activity ratio in E. coli W cells. The order of inhibitory effect on [2-³H]ADP uptake by T-1 cells was adenine > adenosine > AMP > ATP. About 2-fold more radioactive purine bases than purine nucleosides were detected in the cytoplasm after 5 min in an experiment with [8-¹4C]AMP and T-1 cells. Uptake of [2-³H]adenosine in T-1 cells was inhibited by inosine, but not in mutant (Ad-3) cells of E. coli W, which lacked adenosine deaminase and adenylosuccinate lyase. These experiments suggest that AMP, ADP, and ATP are converted mainly to adenine and hypoxanthine via adenosine and inosine before uptake into the cytoplasm by E. coli W cells.

Chronic liver disease increases the risk of linezolid-related thrombocytopenia in methicillin-resistant Staphylococcus aureus-infected patients after digestive surgery.

Linezolid is an effective antibiotic for treatment of infections caused by resistant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). However, thrombocytopenia has been reported in a certain proportion of patients receiving linezolid treatment. We investigated the risk factors for linezolid-related thrombocytopenia in MRSA-infected patients after digestive surgery. Forty-three patients who were treated with linezolid for postoperative MRSA infection were enrolled. We compared the characteristics of the patients who developed thrombocytopenia during linezolid therapy with those of the patients who did not. Thrombocytopenia was defined as a platelet ratio (post/pre-treatment with linezolid) of < 0.7. Twenty-one (48.8%) patients developed thrombocytopenia. In univariate analysis, long treatment duration, high pre-treatment levels of total-bilirubin and transaminases, and the coexistence of chronic liver disease (CLD) were found to be significant risk factors for development of thrombocytopenia. Other factors, for example pre-treatment platelet count, serum creatinine and albumin levels, and previous hepatic resection were not associated with thrombocytopenia. In the multivariate regression analysis, only CLD remained as an independent factor associated with thrombocytopenia. In addition, thrombocytopenia was more common among patients with indocyanine green retention at 15 min (ICG-R15) of more than 10% than in those with an ICG-R15 of 10% or less. Our results suggest that patients with CLD are at high risk of developing linezolid-related thrombocytopenia. Therefore, they should be targeted for more intense platelet count monitoring during linezolid therapy.

[Effective made of octreotide intravenous administration for malignant gastrointestinal obstruction in terminal cancer patients].

Continuous subcutaneous administration of octreotide acetate (SMS201-995: SMS) has not been done in Meiwa Hospital for malignant gastrointestinal obstruction in terminal patients for the following reasons: First, patients and families refuse an indwelling needle on the abdominal wall; second, an additional route limits daily activity; third, the needle site becomes inflamed or sclerosed; and fourth, an infusion pump is required. Hence, the effectiveness of three types of intravenous administration was investigated retrospectively in 15 patients in our hospital: 7 cases received intermittent IV drip infusion; 4 continuous IV drip infusion; and 4 bolus IV injection. As a result, 6 cases (86%), 2 cases (50%), and 1 case (25%), respectively, were successfully treated. These results suggested that intermittent IV administration of SMS is efficient, safe, and very convenient, while continuous IV administration is also efficient as long as the SMS potency is not reduced by mixed drugs.