Investigation of the prediction accuracy of vancomycin concentrations determined by patient-specific parameters as estimated by Bayesian analysis.

BACKGROUND/OBJECTIVE: There have been many studies of therapeutic drug monitoring (TDM) of vancomycin (VCM) based on Bayesian analysis, but there have been no reports of the accuracy of prediction based on Bayesian-estimated patient-specific parameters. This study was conducted to compare the accuracy of prediction based on the population pharmacokinetic (PPK) method and Bayesian-estimated parameters. METHOD: The subjects were 22 patients who were treated with VCM for MRSA infection and whose blood was sampled twice or more during the administration period. The concentrations between the blood samples were predicted based on the concentrations in the first blood samples based on the PPK method using mean parameters for the Japanese population and Bayesian-estimated patient-specific pharmacokinetic parameters. The mean prediction error (ME), mean absolute error (MAE) and root mean squared error (RMSE) were compared to examine the accuracy of prediction based on Bayesian-estimated patient-specific parameters. RESULTS AND DISCUSSION: The mean measured VCM concentration was 10·43±5·19 µg/mL, whereas the mean concentration predicted based on the PPK method was 8·52±4·34 µg/mL, with an ME of -1·91, MAE of 2·93 and RMSE of 3·21. The mean concentration predicted based on patient-specific parameters was 9·62±4·95 µg/mL with ME of -0·81, MAE of 1·38 and RMSE of 1·74. The ME and MAE for the concentrations predicted using patient-specific parameters were smaller compared with those predicted using the PPK method (P=0·0471 and 0·0003, respectively), indicating superior prediction with a significant difference between approaches. CONCLUSION: Prediction using Bayesian estimates of patient-specific parameters was better than by the PPK method. However, when using patient-specific parameters it is still necessary to fully understand the clinical status of the patient and frequently determine VCM concentrations.

Use of hydroxyapatite to fill cavities after excision of benign bone tumours. Clinical results.

We treated 75 patients with benign bone tumours by curettage and filling the defect with calcium hydroxyapatite (HA). There were 28 women and 47 men with a mean age of 27.7 years (3 to 80). The mean follow-up was for 41.3 months. Postoperative radiological assessment revealed that the implanted HA was well incorporated into the surrounding host bone in all patients. Two patients suffered fractures in the postoperative period. Two patients complained of pain associated with HA in the soft tissues, but this diminished within six months. No patient had local pain at the final follow-up. Recurrence of the tumour was seen in three cases. Histopathological study of the implanted area showed removal of the HA by histiocytes and multinucleated giant cells, and the formation of much appositional bone. We conclude that HA is an excellent bone-graft substitute in surgery for benign bone tumours.

Effect of prostaglandin E2 on nitric oxide synthesis in articular chondrocytes.

Both nitric oxide (NO) and prostaglandin E2 (PGE2) are known to play an important role in cartilage metabolism. The present study investigated the novel intercellular mechanism of inducible NO synthase (iNOS) induction mediated by PGE2 in articular chondrocytes. Bovine articular chondrocytes were stimulated by cyclic adenosine monophosphate (cAMP) elevating agents like PGE2 in the presence of interleukin-1 alpha (IL-1 alpha). NO generation was measured by using the Griess reaction. Inducible NOS mRNA was semi-quantitated by reverse transcription-polymerase chain reaction (RT-PCR). While little NO was released from articular chondrocytes in the presence of PGE2 or direct adenylate cyclase activator such as forskolin, synergistic augmentation of NO generation was observed when chondrocytes were stimulated by PGE2 or forskolin in combination with IL-1 alpha. Further expression of iNOS mRNA by stimulation of PGE2 in the presence of IL-1 alpha simultaneously was also detected by RT-PCR in comparison with the mRNA induction by IL-1 alpha stimulation alone. These results indicated that PGE2 might modulate the articular cartilage metabolism by augmentation of chondrocyte NO synthesis in inflammatory process through cAMP-protein kinase A system.

[Disseminated carcinomatosis of the bone marrow occurring 11 years after subtotal gastrectomy for gastric cancer].

A 44-year-old man was admitted to our hospital because of purpura, increased serum alkaline phosphatase, and thrombocytopenia. He had undergone subtotal gastrectomy for gastric cancer 11 years earlier. A biopsy specimen of the bone marrow revealed metastatic mucin-forming, moderately differentiated adenocarcinoma. Because the primary tumor was not detected in any other organ, the gastric cancer the patient was treated for 11 years earlier was suspected as the primary tumor. Microangiopathic hemolytic anemia and disseminated intravascular coagulation developed during the clinical course, and the patient deteriorated despite treatment with anticoagulants. Finally, he died of pulmonary carcinomatous lymphangitis. Autopsy revealed a small number of adenocarcinomatous cells in the lymphoduct of the remaining stomach in spite of its mucosa being intact. We concluded that the bone marrow was infiltrated by cancer cells which originated in the stomach 11 years before. It is unclear why adenocarcinoma cells remained dormant for as long as 11 years in the gastric lymphoduct and bone marrow.

Induction of D2 and D3 cyclin-encoding genes during promotion of the G1/S transition by prolactin in rat Nb2 cells.

Prolactin has been demonstrated to induce the expression of the genes encoding cyclin D2 and D3 during promotion of the G1/S transition in rat Nb2 pre-T-lymphoma cells. cDNA clones encoding these rat cyclins D2 and D3 were isolated and analyzed.