Predictive performance of three practical approaches for grapefruit juice-induced 2-fold or greater increases in AUC of concomitantly administered drugs.

WHAT IS KNOWN AND OBJECTIVE: Clinical pharmacists have a challenging task when answering patients' question about whether they can take specific drugs with grapefruit juice (GFJ) without risk of drug interaction. To identify the most practicable method for predicting clinically relevant changes in plasma concentrations of orally administered drugs caused by the ingestion of GFJ, we compared the predictive performance of three methods using data obtained from the literature. METHODS: We undertook a systematic search of drug interactions associated with GFJ using MEDLINE and the Metabolism & Transport Drug Interaction Database (DIDB version 4.0). We considered an elevation of the area under the plasma concentration-time curve (AUC) of 2 or greater relative to the control value [AUC ratio (AUCR) ≥ 2.0] as a clinically significant interaction. RESULTS AND DISCUSSION: The data from 74 drugs (194 data sets) were analysed. When the reported information of CYP3A involvement in the metabolism of a drug of interest was adopted as a predictive criterion for GFJ-drug interaction, the performance assessed by positive predictive value (PPV) was low (0.26), but that assessed by negative predictive value (NPV) and sensitivity was high (1.00 for both). When the reported oral bioavailability of ≤ 0.1 was used as a criterion, the PPV improved to 0.50 with an acceptable NPV of 0.81, but sensitivity was reduced to 0.21. When the reported AUCR was ≥ 10 after co-administration of a typical CYP3A inhibitor, the corresponding values were 0.64, 0.79 and 0.19, respectively. WHAT IS NEW AND CONCLUSION: We consider that an oral bioavailability of ≤ 0.1 or an AUCR of ≥ 10 caused by a CYP3A inhibitor of a drug of interest may be a practical prediction criterion for avoiding significant interactions with GFJ. Information about the involvement of CYP3A in their metabolism should also be taken into account for drugs with narrow therapeutic ranges.

Glue embolization for gastroduodenal ulcer bleeding: contribution to hemodynamics and healing process.

BACKGROUND: Although the morbidity of bowel ischemic events after glue embolization has been suggested, a causal relationship between glue and ischemia has not been clearly established. PURPOSE: To evaluate the efficiency and safety of transcatheter arterial embolization with n-butyl cyanoacrylate (NBCA-TAE) for upper gastrointestinal hemorrhage (GIH). MATERIAL AND METHODS: Between October 2006 and October 2012, 21 patients with upper GIH underwent NBCA-TAE, and endoscopic data were obtained within 30 days of follow-up. Shock index prior to and immediately after NBCA-TAE were compared to determine changes in hemodynamics. Days to Forrest type III, as assessed by follow-up endoscopy, was used as an indicator of the healing process. Other clinical outcomes included days for starting ingestion and for hospital discharge. RESULTS: Sixteen gastric and five duodenal ulcers, classified into Forrest type I, were treated. Immediate hemostasis was achieved in all the patients, and no re-bleeding occurred within the follow-up period. Shock index significantly (P < 0.001) improved from before (0.99 ± 0.076) to immediately after NBCA-TAE (0.67 ± 0.038). Sequential mucosal healing processes were observed in all the patients, and the number of days to Forrest type III was 9.6 ± 7.1. The number of days for starting ingestion and hospital discharge was 9.0 ± 4.5 and 15 ± 7.7 days, respectively. CONCLUSION: NBCA-TAE is an effective and safe method for the control of nonvariceal upper GIH, in terms of contribution to hemodynamics and healing process of the gastroduodenal mucosa.

Effects of protein kinase inhibitors and protein phosphatase inhibitors on cyclic AMP-dependent down-regulation of vesicular monoamine transport in pheochromocytoma PC12 cells.

Cyclic AMP down-regulates vesicular monoamine transport in PC12 cells and thereby decreased catecholamine reuptake from the extracellular fluid. We examined the effects of protein kinase inhibitors and protein phosphatase inhibitors on this cAMP action. Treatment of cells with a protein kinase inhibitor, K252a, increased vesicular amine transport and cellular amine uptake, thereby antagonizing the regulatory action of cAMP. In contrast, a protein phosphatase inhibitor, okadaic acid, had the opposite effect on the amine transport, i.e. it enhanced the cAMP action. These results suggest the involvement of a protein phosphorylation process in the cAMP-dependent modulation of vesicular monoamine transport.

Vesicular monoamine uptake by digitonin-permeabilized PC12 cells: inhibitory effect of neuromodulators and drugs on the amine transport.

Vesicular amine transport is crucial for activity of monoaminergic neurons since translocation of cytosolic amine to storage vesicles is required for both exocytotic release and reuptake of the neurotransmitter. We developed a convenient assay system for vesicular amine transport based on permeabilizing the plasma membrane of pheochromocytoma PC12 cells with digitonin at concentrations of 100 to 150 microM. Serotonin (5HT) is a better substrate than either epinephrine or norepinephrine in this assay system. In the presence of 2 mM ATP, 5HT uptake by the permeabilized cells increased linearly for at least 30 min at 25 degrees C, whereas without addition of exogenous ATP, 5HT uptake reached an apparent plateau after 20 min incubation. Reserpine (500 nM) completely blocked the ATP-dependent 5HT uptake in this system whereas nomifensine (10 microM) had no effect, indicating specificity for vesicular transport. Treatment of intact PC12 cells with AMP dose-dependently decreased 5HT uptake with an EC50 of 20-30 microM as measured after cell permeabilization. Treatment of the intact PC12 cells with forskolin and phorbol 12-myristate 13-acetate prior to permeabilization also down-regulated vesicular 5HT transport, whereas the addition of either of these agents into the reaction mixture for the amine uptake by already permeabilized cells did not alter the vesicular uptake activity. Thus, the system can be applied to studies on regulation of the vesicular amine transport by physiological signaling molecules, intracellular messengers, and drugs.

Cyclic AMP-dependent modulation of vesicular monoamine transport in pheochromocytoma cells.

Cyclic AMP (cAMP) is well known to enhance tyrosine hydroxylase activity in PC12 cells. We were able to demonstrate, however, that the cellular dopamine level in PC12 was lowered by dibutyryl cAMP. Furthermore, the decrease in the cellular level of dopamine was accompanied by about a 10-fold increase in the medium. The aim of this work was to elucidate the effect of cAMP on catecholamine transport. Dibutyryl cAMP did not induce exocytotic release of norepinephrine but rather inhibited its uptake. As with forskolin and cholera toxin, physiological signaling molecules such as vasoactive intestinal polypeptide (VIP) and AMP, for which PC12 cells are known to have receptors linked to activation of adenylate cyclase, also inhibited norepinephrine uptake. The inhibitory effects of dibutyryl cAMP, VIP, and AMP were dose dependent, and EC50 values were estimated to be 100 microM, 10 nM, and 1.0 microM, respectively. The inhibition profile of dibutyryl cAMP over the time course of norepinephrine uptake was biphasic: inhibition became clearly detectable after the cytosolic pool of norepinephrine had been saturated. This profile is similar to that of reserpine. Nomifensine, however, inhibited uptake at a rather constant rate throughout the entire time course. The ATP-dependent serotonin uptake by digitonin-permeabilized cells was lowered to approximately 50% that of the control by dibutyryl cAMP treatment before permeabilization, indicating inhibition of vesicular monoamine transport. This effect was also dependent on a dibutyryl cAMP concentration with an EC50 of < or = 100 microM.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyclonal B cell chronic lymphoproliferative disease with hairy cell morphology: a case report and clonal studies.

We describe a patient who has a chronic polyclonal B lymphocyte proliferation with a hairy-cell appearance. A 48-year-old Japanese woman with marked splenomegaly, systemic lymphadenopathy, and leukocytosis was referred to out hospital. Laboratory examination revealed marked polyclonal IgG hypergammaglobulinemia. Morphologic examination of the patient's peripheral blood, including May-Giemsa staining and scanning electron microscopy, showed a monotonous proliferation of hairy-appearing mature lymphocytes. An immunophenotypic study revealed an expansion of cells with mature B cell antigens positive for CD11c; however, light-chain restriction was not seen. The lack of both immuno-globulin heavy-chain and T cell receptor gene rearrangements by Southern blot analysis indicated the polyclonal nature of the proliferating B cells. This was confirmed further by a clonal analysis of the patient's lymphocytes using an X-chromosome-linked restriction fragment polymorphism within the X-linked phosphoglycerate kinase (PGK) gene. Since chronic B cell lymphoproliferation with a hairy cell appearance has not been described previously, this case might be extremely rare, and has important implication for the pathogenesis of mature B cell lymphoproliferative diseases, including hairy cell leukemia.