Psychiatric Manifestations in Patients with Biopterin Defects.

Psychiatric manifestations in patients with tetrahydrobiopterin (BH4) defects are common, and may occur even with treatment of the underlying disorder. The neurobiological background of these conditions has been linked to abnormalities of neurotransmitters, such as dopamine, serotonin, norepinephrine, and gamma-aminobutyric acid. Here, we review the psychiatric profile of all patients with BH4 defects followed in the pediatric and adult metabolic clinics at our center. Three patients with autosomal recessive (AR) guanosine triphosphate cyclohydrolase (GTPCH) deficiency and three patients with 6-pyruvoyl tetrahydropterin synthase (PTPS) deficiency were reviewed.All patients had behavioral disturbances and two had significant psychiatric comorbidities. These included attention deficit/hyperactivity disorder, anxiety, depression, aggression, or oppositional defiant disorder. One patient with PTPS deficiency had a severe psychiatric presentation, requiring inpatient admission and temporary placement into foster care for intensive behavioral therapy. Another with AR GTPCH deficiency was diagnosed with aggressive behavioral dysregulation requiring intensive psychiatric treatment. Management of the psychiatric manifestations of BH4 defects can be challenging, due to lack of information and studies of interactions between psychiatric medications on the deficient neurotransmitters and their receptors in these conditions. Further studies are needed to establish safety and efficacy of these treatments.

The functional roles of poly(ethylene glycol)-lipid and lysolipid in the drug retention and release from lysolipid-containing thermosensitive liposomes in vitro and in vivo.

Triggered release of liposomal contents following tumor accumulation and mild local heating is pursued as a means of improving the therapeutic index of chemotherapeutic drugs. Lysolipid-containing thermosensitive liposomes (LTSLs) are composed of dipalmitoylphosphatidylcholine (DPPC), the lysolipid monostearoylphosphatidylcholine (MSPC), and poly(ethylene glycol)-conjugated distearoylphosphatidylethanolamine (DSPE-PEG(2000)). We investigated the roles of DSPE-PEG(2000) and lysolipid in the functional performance of the LTSL-doxorubicin formulation. Varying PEG-lipid concentration (0-5 mol%) or bilayer orientation did not affect the release; however, lysolipid (0-10 mol%) had a concentration-dependent effect on drug release at 42 degrees C in vitro. Pharmacokinetics of various LTSL formulations were compared in mice with body temperature controlled at 37 degrees C. As expected, incorporation of the PEG-lipid increased doxorubicin plasma half-life; however, PEG-lipid orientation (bilayer vs. external leaflet) did not significantly improve circulation lifetime or drug retention in LTSL. Approximately 70% of lysolipid was lost within 1 h postinjection of LTSL, which could be due to interactions with the large membrane pool of the biological milieu. Considering that the present LTSL-doxorubicin formulation exhibits significant therapeutic activity when used in conjunction with mild heating, our current study provided critical insights into how the physicochemical properties of LTSL can be tailored to achieve better therapeutic activity.

Development and characterization of oral lipid-based amphotericin B formulations with enhanced drug solubility, stability and antifungal activity in rats infected with Aspergillus fumigatus or Candida albicans.

OBJECTIVE: To develop an oral formulation of Amphotericin B (AmpB) with: (A) medium chain triglycerides, fatty acids and nonionic surfactants as a self-emulsifying drug delivery system (SEDDS); or (B) glyceryl mono-oleate (Peceol) with poly(ethylene glycol) (PEG)-phospholipids. METHODS: SEDDS formulations were prepared by simple mixing at 40 degrees C. Peceol/DSPE-PEG-lipid formulations were prepared by solvent evaporation. Parameters evaluated included: miscibility, solubility and emulsion droplet size after incubation in simulated gastric fluid (SGF) or simulated intestinal fluid (SIF) via dynamic light scattering. The stability of AmpB in Peceol/DSPE-PEG was evaluated in SGF and SIF. Phase stability of AmpB in Peceol+/-DSPE-PEG following thermal cycling was evaluated by atomic force microscopy (AFM). Aspergillus fumigatus (2.9-3.45 x 10(7) colony forming units per mL [CFU]) or Candida albicans (3-3.65 x 10(6) CFU per mL) were injected via the jugular vein; 48 h later male albino Sprague-Dawley rats (350-400 g) were administered either a single oral gavage of a Peceol-DSPE/PEG2000-based AmpB (10 mg AmpB/kg and 5 mg AmpB/kg for the Candida albicans study only) twice daily for 2 consecutive days, a single intravenous (i.v.) dose of Abelcet (5mg AmpB/kg), or physiologic saline (non-treated controls; n=9) once daily for 2 consecutive days. Antifungal activity was assessed by organ CFU concentrations and plasma galactomannan levels in the case of A. fumigatus and organ CFU concentrations in the case of Candida albicans. Plasma samples were taken from each animal prior to infection, 48 h after initiation of infection but prior to drug treatment and at the end of the study for plasma creatinine determinations as a measure of renal toxicity. RESULTS: Mean diameter of SEDDS after 30 min in 150 mM NaCl at 37 degrees C was 200-400 nm. However, the Peceol/DSPE-PEG, where PEG MW was 350, 550, 750 or 2000, showed a greater solubilization of AmpB (5 mg/mL) compared to SEDDS formulations (100-500 microg/mL). Upon dispersion in SIF, Peceol/DSPE-PEG formulations generated submicron emulsion particle sizes varying slightly with PEG MW. Stability of the AmpB in Peceol/DSPE-PEG formulations in SGF or SIF was >80% after 2 h, and best for formulations containing DSPE-PEG 750 or 2000 compared to 350, 550 or Peceol only. Monoglyceride-Peceol-DSPE/PEG2000-based oral AmpB treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by >80% compared to non-treated controls without significant changes in plasma creatinine levels in the A. fumigatus infected rats. In addition, this formulation significantly decreased kidney fungal CFU concentrations by >75% at the 5 mg/kg dose and by >95% at the 10 mg/kg dose compared to non-treated controls without significant changes in the plasma creatinine levels in the Candida albicans-infected rats. CONCLUSIONS: Novel lipid-based AmpB oral formulations were prepared that provide excellent drug solubilization, drug stability in simulated gastric and intestinal fluids and antifungal activity without renal toxicity in rats infected with A. fumigatus and C. albicans.

Tracking monolignols during wood development in lodgepole pine.

Secondary xylem (wood) formation in gymnosperms requires that the tracheid protoplasts first build an elaborate secondary cell wall from an array of polysaccharides and then reinforce it with lignin, an amorphous, three-dimensional product of the random radical coupling of monolignols. The objective of this study was to track the spatial distribution of monolignols during development as they move from symplasm to apoplasm. This was done by feeding [(3)H]phenylalanine ([(3)H]Phe) to dissected cambium/developing wood from lodgepole pine (Pinus contorta var latifolia) seedlings, allowing uptake and metabolism, then rapidly freezing the cells and performing autoradiography to detect the locations of the monolignols responsible for lignification. Parallel experiments showed that radioactivity was incorporated into polymeric lignin and a methanol-soluble pool that was characterized by high-performance liquid chromatography. [(3)H]Phe was incorporated into expected lignin precursors, such as coniferyl alcohol and p-coumaryl alcohol, as well as pinoresinol. Coniferin, the glucoside of coniferyl alcohol, was detected by high-performance liquid chromatography but was not radioactively labeled. With light microscopy, radiolabeled phenylpropanoids were detected in the rays as well as the tracheids, with the two cell types showing differential sensitivity to inhibitors of protein translation and phenylpropanoid metabolism. Secondary cell walls of developing tracheids were heavily labeled when incubated with [(3)H]Phe. Inside the cell, cytoplasm was most strongly labeled followed by Golgi and low-vacuole label. Inhibitor studies suggest that the Golgi signal could be attributed to protein, rather than phenylpropanoid, origins. These data, produced with the best microscopy tools that are available today, support a model in which unknown membrane transporters, rather than Golgi vesicles, export monolignols.