Improving adherence to medications in pediatric liver transplant recipients.

We describe results from a clinical program, which aimed at improving adherence to medications in children who had a liver transplant. We followed the medical outcomes of 23 children and adolescents who participated in a clinical adherence-improvement protocol during the years 2001-2002. The protocol included identification of non-adherent patients by examining tacrolimus blood levels and intervention by increasing the frequency of clinic visits for non-adherent patients. In the two-yr preintervention (1999-2000), there was no improvement in any of the outcomes. After the intervention, the number of patients with high alanine aminotransferase levels (100 and above) decreased significantly, from eight before the intervention to four afterwards. Other outcomes, including the number of rejection episodes (three before, none after) and the degree of adherence to tacrolimus, also improved, but the improvement did not reach statistical significance. Although non-adherent patients were called to clinic more often under the protocol, the intervention did not lead to increased outpatient costs. This adherence--improvement intervention appears to be promising in improving outcomes in pediatric liver transplant recipients. Larger, controlled studies are needed to establish the efficacy of this or other approaches.

Use of a glucocorticoid-inducible promoter for expression of herpes simplex virus type 1 glycoprotein gC1, a cytotoxic protein in mammalian cells.

Abundant expression of herpes simplex virus type 1 glycoprotein gC (gC1) in transfected mammalian cells has not previously been achieved, possibly because gC1 protein is toxic to cells. To approach this problem, the gC1 coding sequence was placed under the control of the weak but inducible glucocorticoid-responsive promoter from the mouse mammary tumor virus (MMTV) long terminal repeat (LTR). As controls to evaluate for gC1 cytotoxicity, the MMTV LTR promoter was used to express glycoprotein gD1, and a strong, constitutive promoter from the Moloney murine sarcoma virus LTR was used to express gC1. L cells were transfected with these constructs, and a clone expressing gC1 from the inducible MMTV LTR promoter was analyzed. In the absence of glucocorticoid (dexamethasone) stimulation, only a low level of gC1 mRNA expression was detected; after overnight stimulation with dexamethasone, transcription increased approximately 200-fold. Abundant gC1 protein that was functionally active in that it bound complement component C3b, was produced. From passages 5 through 26 (70 cell population doublings), the gC1-producing clone became less responsive to overnight dexamethasone stimulation. The block to gC1 expression occurred at the level of transcription and was associated with hypermethylation of the MMTV LTR DNA. Treatment of the clone with 5-aza-2'-deoxycytidine partially reversed the block in gC1 protein production. Late-passage cells assumed a gC1-negative phenotype that appeared to offer a selective growth advantage, which suggested that gC1 was cytotoxic. Several findings support this view: (i) some cells expressing gC1 after overnight stimulation with dexamethasone assumed bizarre, syncytial shapes; (ii) continuous stimulation with dexamethasone for 5 weeks resulted in death of most cells; (iii) cells transfected with gC1 under the control of the strong Moloney murine sarcoma virus promoter assumed bizarre shapes, and stable gC1-expressing clones could not be established; and (iv) cells induced to express gD1 retained a normal appearance after overnight stimulation or 15 weeks of continuous stimulation with dexamethasone. The inducible MMTV LTR promoter is useful for expressing gC1 and may have applications for expressing other cytotoxic proteins.