Physiologically Based Pharmacokinetic Modeling To Guide Management of Drug Interactions between Elexacaftor-Tezacaftor-Ivacaftor and Antibiotics for the Treatment of Nontuberculous Mycobacteria.

Nontuberculous mycobacteria (NTM) are the pathogens of concern in people with cystic fibrosis (pwCF) due to their association with deterioration of lung function. Treatment requires the use of a multidrug combination regimen, creating the potential for drug-drug interactions (DDIs) with cystic fibrosis transmembrane conductance regulator (CFTR)-modulating therapies, including elexacaftor, tezacaftor, and ivacaftor (ETI), which are eliminated mainly through cytochrome P450 (CYP) 3A-mediated metabolism. An assessment of the DDI risk for ETI coadministered with NTM treatments, including rifabutin, clofazimine, and clarithromycin, is needed to provide appropriate guidance on dosing. The CYP3A-mediated DDIs between ETI and the NTM therapies rifabutin, clarithromycin, and clofazimine were evaluated using physiologically based pharmacokinetic (PBPK) modeling by incorporating demographic and physiological "system" data with drug physicochemical and in vitro parameters. Models were verified and then applied to predict untested scenarios to guide continuation of ETI during antibiotic treatment, using ivacaftor as the most sensitive CYP3A4 substrate. The predicted area under the concentration-time curve (AUC) ratios of ivacaftor when coadministered with rifabutin, clofazimine, or clarithromycin were 0.31, 2.98, and 9.64, respectively, suggesting moderate and strong interactions. The simulation predicted adjusted dosing regimens of ETI administered concomitantly with NTM treatments, which required delayed resumption of the standard dose of ETI once the NTM treatments were completed. The dosing transitions were determined based on the characteristics of the perpetrator drugs, including the mechanism of CYP3A modulation and their elimination half-lives. This study suggests increased doses of elexacaftor/tezacaftor/ivacaftor 200/100/450 mg in the morning and 100/50/375 mg in the evening when ETI is coadministered with rifabutin and reduced doses of elexacaftor/tezacaftor 200/100 mg every 48 h (q48h) and ivacaftor 150 mg daily or a dose of elexacaftor/tezacaftor/ivacaftor 200/100/150 mg q72h when coadministered with clofazimine or clarithromycin, respectively. Importantly, the PBPK simulations provide evidence in support of the use of treatments for NTM in pwCF receiving concomitant dose-adjusted ETI therapy.

Intralymphatic treatment of flagellin-ovalbumin mixture reduced allergic inflammation in murine model of allergic rhinitis.

BACKGROUND: Bacterial flagellin, a Toll-like receptor 5 agonist, is used as an adjuvant for immunomodulation. In this study, we aimed to evaluate the effect and its mechanism following intralymphatic administration of OVA-flagellin (FlaB) mixture in the mouse model of allergic rhinitis. MATERIALS AND METHODS: BALB/c mice were sensitized with OVA and treated with an OVA-FlaB mixture via intranasal, sublingual, and intralymphatic routes to evaluate the effect of each treatment. Several parameters for allergic inflammation and its underlying mechanisms were then evaluated. RESULTS: Intralymphatic injection of the OVA-FlaB mixture reduced symptom scores, eosinophil infiltration in the nasal mucosa, and total and OVA-specific IgE levels more significantly than intranasal and sublingual administration. Systemic cytokine (IL-4, IL-5, IL-6, IL-17, and IFN-γ) production and local cytokine (IL-4 and IL-5) production were also reduced significantly after intralymphatic injection with OVA-FlaB. Double intralymphatic injection of the mixture was more effective than single injection. Moreover, the expression of innate cytokines such as IL-25 and IL-33 in nasal epithelial cells was reduced, and the expression of chemokines such as CCL24 (eotaxin-2), CXCL1, and CXCL2 was decreased in the nasal mucosa, suggesting the underlying mechanism for intralymphatic administration of the OVA-FlaB mixture. CONCLUSION: Intralymphatic administration of an OVA-FlaB mixture was more effective in alleviating allergic inflammation than intranasal and sublingual administration in a mouse model of allergic rhinitis. This effect may be attributed to the reduced expression of innate cytokines and chemokines. This treatment modality can be considered as a new therapeutic method and agent.

Polymer planar waveguide device using inverted channel structure with upper liquid crystal cladding.

We propose a composite waveguide configuration based on an inverted polymer channel structure with upper nematic liquid crystal cladding. This configuration can achieve a more homogenous liquid crystal molecular alignment between the core and the liquid crystal material by minimizing the rubbing damage during preparation of the alignment layer. We demonstrated our idea with a variable optical attenuator which exhibited a 24 dB of attenuation range over a tuning peak voltage of 10 V at 1550 nm.

Intratumoral hypericin and KTP laser therapy for transplanted squamous cell carcinoma.

OBJECTIVES/HYPOTHESIS: To test intratumoral photodynamic therapy (IPDT) as a new treatment for squamous cell carcinoma in a preclinical tumor model. STUDY DESIGN AND METHODS: Human P3 squamous carcinoma cells were transplanted subcutaneously in athymic nude mice and allowed to grow into 300- to 500-mm3 tumors. Hypericin dye at 1 microg/gm of body weight was injected intratumorally (IT) or intravenously (IV). After 4 hours hypericin biodistribution was assessed in ethanol extracts from tissues by fluorescence spectroscopy. IPDT also was tested by KTP laser fiberoptic insertion in tumors 4 hours after IT dye injection compared to KTP532 laser therapy alone (532 nm, 1W, 40-60 J, 0.6-mm fiber). RESULTS: Hypericin concentration in tissues was as follows: (IT vs. IV) for tumors (3660 vs. 135 ng dye/gm tissue), lung (760 vs. 6345), liver (75 vs. 935), blood (65 vs. 480) compared to skin (465 vs. 110) or muscle (335 vs. 80) adjacent to the squamous cell tumors. Four hours after dye injection, the tumor exhibited bright orange fluorescence when excited by KTP 532-nm green laser light. The IPDT-treated tumors had a 3.32+/-0.32-mm radius of cell destruction when H&E-stained sections were examined compared with 2.5+/-0.38 mm for the laser only control group (n = 10, P = .003). CONCLUSIONS: This pilot study indicates laser IPDT with hypericin induces a significant increase in tumor necrosis compared with laser alone and may be useful as a less invasive adjuvant treatment for recurrent or inoperable human squamous cell cancers of the head and neck.

Effect of platelet activating factor and its antagonist on the mucociliary clearance of the eustachian tube in guinea pigs.

The purpose of this study was to test whether platelet activating factor (PAF) impairs the mucociliary clearance function of the eustachian tube (ET) in a dose-dependent manner and whether PAF antagonist can prevent the impairment of mucociliary function of the ET induced by PAF. Coomassie brilliant blue dye transport time (DTT) in normal guinea pigs was 69 seconds. The DTTs after the application of normal saline and PAF at I and 2 microg/mL into bullae were 66, 74, and 157 seconds. The time was over 15 minutes when 4, 8, and 16 microg/mL of PAF were applied. The DTT was 62 seconds when the animals were pretreated with PAF antagonist (WEB 2170). There were significant delays of the DTTs after treatment with 2, 4, 8, and 16 microg/mL of PAF. Histopathologic examination of ETs from groups with a significant delay in DTTs showed intact cilia, mucous plugs, increased inflammatory cells, and exfoliation of cells. This study demonstrated that PAF impaired the mucociliary clearance function of the ET in a dose-dependent manner. This impairment of mucociliary clearance function was prevented by pretreatment with PAF antagonist. The findings of the study suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by impairing the ET clearance function.

Laser photochemotherapy with anthracyclines on cultured human squamous carcinoma cells.

A new treatment for cancer has been tested in vitro using light-sensitive anthracyclines followed by laser photoactivation, as described by several investigators. We previously reported 10-fold enhanced laser killing after 2 hours of incubation with daunomycin by cultured human carcinoma cells. This short-term uptake leads to drug localization in cytoplasmic and membrane sites prior to nuclear accumulation and topoisomerase inhibition. In the present study, daunomycin was incubated for 2 or 24 hours with P3 squamous carcinoma cells to directly compare cytoplasmic vs. nuclear drug targeting before and after KTP-532 laser activation. Monolayer cultures of the P3 cells sensitized with daunomycin for 2 hours, then chilled (4 degree C), and exposed to the KTP laser (532 nm, 94.2 J/cm2) had a 2- to 10-fold increased therapeutic response compared with drug or laser alone when measured by MTT tetrazolium assays. After 24 hours of incubation with daunomycin, the chemotherapeutic response of P3 tumor cells was amplified 2-fold by laser exposure. The results suggest that daunomycin and laser treatment can be combined for improved therapy of human cancer.

Interstitial laser photochemotherapy with new anthrapyrazole drugs for the treatment of xenograft tumors.

Photodynamic therapy (PDT) with lasers and new dyes has gained popularity in recent years as a minimally invasive technique with high tumoricidal effects in vitro and in some cancer patients. However, because new laser dyes are not FDA approved at present, the clinical evaluation of PDT may be years away. During the past 6 years we have used laser alone for photothermal ablation in both preclinical studies and in a large number of patients with an observed 60% tumor response rate. The 40% treatment failure led us to explore the possibility of combined therapy with lasers and standard chemotherapeutic drugs. We have recently tested a promising preclinical alternative using implantation of a bare 600-microns KTP 532 laser fiberoptic in multiple tumor sites 30 min after intratumor injection of the anthrapyrazole DUP-941. As a control, this drug was injected in 3 sites of P3 human squamous cell tumor transplants in nude mice, which led to tumor stasis without regression. Similar 400-600 mm3 tumors exposed to laser illumination alone (0.8 W for 5 sec) at multiple sites resulted in tumor regrowth after 10 weeks in 80% of the animals. However, combining interstitial laser illumination with intratumor DUP-941 injections led to complete tumor regression in 85% of the mice. We propose that intratumor drug injection followed by interstitial laser fiberoptic treatment represents a potentially useful new method for tumor ablation in advanced cancer patients.

Extended IWKB method for determination of the refractive=index profile in optical waveguides.

A simple method is outlined for the calculation of the refractive-index profiles of both multimode and monomode planar optical waveguides. The method is an extension of the well-established IWKB method. The parameters required are the dispersion relation of the surface index changes and the effective indices at different wavelengths. As an example, the refractive-index profile of a monomode z-cut KTiOPO(4) planar waveguide fabricated by Rb(+):K(+) exchange is computed. Close agreement is obtained, indicating the practicality of this method. The method is also applicable to optical waveguides in other materials, such as LiNbO(3), LiTaO(3), and glass.

Hypericin uptake in rabbits and nude mice transplanted with human squamous cell carcinomas: study of a new sensitizer for laser phototherapy.

Tissue uptake and biodistribution of hypericin was measured in rabbits and in nu/nu mice xenografted with P3 human squamous cell carcinoma to assess the value of this dye as an in vivo sensitizer for laser photoinactivation of solid tumors. Hypericin has absorption maxima at 545 and 590 nm with a fluorescence emission peak at 640 nm in ethanol. Dye uptake after intravenous injection was tested at 4 and 24 hours in rabbit tissues by ethanol extraction and quantitative fluorescence spectrophotometry. Maximum dye levels were seen at 4 hours in most vascular organs with lung having fivefold higher uptake than spleen followed by liver, blood, and kidney. Mice were examined after 2, 4, 6, 8, and 24 hours and after 3 and 7 days for dye uptake. The peak concentration of hypericin in murine organs was reached at 4 hours with uptake per gram of tissue as follows: lung > spleen > liver > blood > kidney > heart > gut > tumor > stomach > skin > muscle > brain. Elimination of hypericin was rapid in most murine organs with residual dye under 10% of maximum by 7 days compared to 25% to 30% retention for the squamous cell tumors and several normal tissues. These results suggest that hypericin may be a useful photosensitizer for KTP/532 laser interstitial therapy of human cancer.

The manifestation of proliferating cell nuclear antigen in adenoid cystic carcinoma.

OBJECTIVE: This study was conducted to evaluate the prognostic value of immunostaining with a genetically engineered monoclonal antibody (PC10) to proliferating cell nuclear antigen in patients with adenoid cystic carcinoma (ACC). DESIGN: Formalin-fixed, paraffin-embedded tissue blocks from patients with ACC were stained with PC10, and an index (percentage of positively staining cells per tumor cells) was calculated. The patients' clinical course was compared with the PC10 index. Follow-up ranged from 12 to 177 months (mean, 64 months). SETTING: Patient selection and immunohistochemical studies were done at Seoul (Korea) National University Hospital. PATIENTS: Twenty-eight cases of ACC were retrieved from our files between January 1979 and December 1992. MAIN OUTCOME MEASURE: All of the cases expressed the PC10 antibody. The PC10 index ranged from 1.0% to 44% (mean, 14.5%). We divided the 28 cases into two groups: group 1 (PC10 index, less than 15%) and group 2 (PC10 index, greater than 15%). RESULTS: The PC10 index (groups 1 and 2) did not correlate with established pathologic grades, tumor staging, local recurrences, or survival rates. However, those with higher PC10 indexes (group 2) exhibited significantly increased distant metastases compared with those with lower indexes (group 1). CONCLUSION: We conclude that the proliferating cell nuclear antigen in ACC may be used as an indicator in the prediction of distant metastasis.

Adenoid cystic carcinoma of the head and neck.

Adenoid cystic carcinoma of the head and neck is relatively rare and is characterized by slow evolution, multiple recurrences, protracted clinical course, and late distant metastasis. This article presents its peculiar clinical course, response to therapy, and long-term treatment results by analyzing 67 cases treated from 1979 to 1991 at the Seoul (Korea) National University Hospital. The most common primary site was the parotid gland in the major salivary glands and the nose and paranasal sinuses in the minor salivary glands. The local control rate was 71.1% at 5 years and 44.3% at 8 years. Late-occurring distant metastases did not allow a plateau in survival curves, even after 8 years. Our study also revealed that surgery combined with postoperative radiotherapy could yield better local control.

Minimally invasive palliative tumor therapy guided by imaging techniques: the UCLA experience.

Imaging-guided palliative therapy of recurrent and/or inaccessible head and neck tumors may soon become clinically practical since sensitive and noninvasive monitoring techniques of energy deposition in tissues are now available. Interstitial tumor therapy (ITT) is a technique whereby a source of energy (laser, radiofrequency, ultrasonic, cryoenergy, etc.) is directly applied into tumors at various depths. Recent studies have demonstrated the efficiency of ultrasound (UTZ) and magnetic resonance imaging (MRI) for real and/or "near" real time tumor and vessel identification as well as monitoring and quantifying energy-induced tissue damage. We now report our initial clinical experience with patients in which UTZ and/or MRI-guided ITT techniques were successfully applied for the treatment of recurrent, nonresectable, local, and/or metastatic head and neck carcinomas. Patients were treated on an outpatient basis either in the operating room or in an upgraded specially equipped SIGNA 1.5T MR suite. Most patients tolerated these procedures well and were successfully palliated for periods ranging from 3 months to 5 years posttreatment. The upgrades introduced in a standard MRI suite, the clinical experience, and future perspectives will be reviewed.

Influence of surface roughness on the propagation of x rays through capillaries.

Calculations have been performed to determine the effect of surface roughness on the propagation of x rays through hollow capillaries. The analysis is based upon assuming an expression for the form of the power reflected from a single bounce of the light and then on obtaining the power in a waveguide by repeated application of this expression. Data from single reflection measurements on highly polished surfaces have been used to show that surface roughness should have little effect on wave propagation.