The treatment of primary and metastatic renal cell carcinoma (RCC) with stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS)

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Background: RCC is often regarded as a radio-resistant tumor. However, brain metastases from RCC have been successful treated with SRS. Therefore, metastases to extra-cranial sites may be treated with similar success using stereotactic body radiation therapy (SBRT), where image-guidance allows for the delivery of precise high dose radiation in a few fractions. We report our experience with SRS/SBRT in the management of primary and metastatic RCC. Methods: The image-guided Novalis radiation therapy system was used. Thirty patients with brain metastases were treated with SRS (16–22 Gy in a single fraction). Five of these patients underwent resection of their metastatic lesions after SRS and their pathology were reviewed. Twenty patients with extra-cranial metastatic lesions (orbits, head and neck, lung, mediatinum, sternum, clavicle, scapula, humerus, rib, spine, abdomen) and 2 patients with biopsy proven primary RCC (not surgical candidates), were treated with SBRT (24–32 Gy in 3–4 fractions over 1–2 weeks). All patients were immobilized in body cast and image-guidance was used for all fractions. 4D-CT was utilized in the treatment planning to assess tumor motion. Results: Of the 30 patients who received SRS to brain metastases, 25 showed decreasing or stable lesion size. Five patients showed an increase in size and underwent resection. Their pathology revealed necrosis in >99% of the specimen, with no viable RCC. Nineteen patients who received SBRT to extra-cranial metastases achieved symptom relief. One patient had local progression, yielding a local control rate of 95%. In the 2 patients with primary RCC, tumor size remained unchanged but their pain improved, and their renal function was unchanged post SBRT. There was no significant treatment related side-effect. Conclusions: Precise high dose radiation can cause significant tumor cell death in “radio-resistant” metastases from RCC. It also offers excellent local control and symptom palliation, without significant toxicity. Therefore, SBRT may represent a novel non-invasive, nephron-sparing option for the treatment of primary RCC as well as extra-cranial metastatic RCC. A prospective clinical trial using SBRT for primary and metastatic RCC is on-going.

No significant financial relationships to disclose.

Long-term outcome and neuroradiological findings of 31 patients with 6-pyruvoyltetrahydropterin synthase deficiency

Tetrahydrobiopterin (BH(4)) deficiency is an autosomal recessive disorder caused by enzyme defects in the biosynthesis or recycling of BH(4). Patients with BH(4) deficiency present with severe neurological signs and symptoms and require a different treatment from classical phenylketonuria. During the last 12 years, 31 cases of BH(4) deficiency were identified in our department. They were all classified as 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency. They were diagnosed at the ages of 2.5-48 months and treated with BH(4), L-dopa and 5-hydroxytryptophan immediately after diagnosis. The average development quotients (DQ) at diagnosis and after treatment for more than 3 years were 53+/- 16, and 78+/- 15, respectively. A significant negative correlation was observed between the level of the DQ and the age at which treatment was commenced (r = -0.751, p = 0.002). Developmental profiles were uneven. Language, adaptability and at later age mathematics were particularly weak areas. Only two patients achieved a good performance in mathematics. Eleven patients who were treated with drugs from ages of 2.9-48 months had neuroradiological scanning. Computed tomography disclosed calcification in lentiform nuclei in one patient and magnetic resonance imaging disclosed delayed myelination and abnormal high intensity signal in cerebral white matter in all of them. Even though most of abnormalities were reversible, small patchy or spotted areas were still present on these regions after treatment for 10-46 months. In summary, our study supports the substantial efficacy of the current therapeutic approach in PTPS deficiency of normalizing amine neurotransmitters with three drugs as early as possible. For the first time, calcifications could be detected in patients with PTPS deficiency. Abnormalities in white matter on magnetic resonance imaging were not related to clinical manifestations and most were reversible.

Design and realisation of star-geometry dual-mode bandpass filter

A design of a planar dual-mode filter is proposed and developed for satellite and wireless communication systems. The novelty of the proposed structure consists of replacing simple diagonal design with a starlike one. This offers the ability of controlling the central frequency and the bandwidth. The filter was implemented on Rogers substrate with 10.8 dielectric constant. The proposed filter structure is 37% smaller in size in comparison with traditional dual mode filters.

Candida albicans: the estrogen target for vaginal colonization

BACKGROUND

Estradiol (E(2)) stimulates colonization of the vagina by Candida albicans. Although this yeast expresses an estrogen-binding protein (EBP), the cellular target for estrogenic modulation of this infection is unresolved. Findings support direct E(2)-induced C. albicans growth as well as indirect effects via E(2)-induced changes in the vaginal epithelium. Our primary goal was to pursue the issue of direct versus indirect estrogen action on vaginal candidiasis using diethylstilbestrol (DES), an efficacious mammalian estrogen receptor agonist, which exhibits no detectable affinity for the EBP of C. albicans.

METHODS

We used both in vitro and in vivo experimentation with an EBP-positive strain of C. albicans isolated from the human vagina. Ligand-binding studies were performed with steroidal and nonsteroidal estrogens and anti-estrogens using the soluble EBP from both the yeast and the rat uterus. Mature ovariectomized rats were treated with either E(2) or DES for 7 days before and after C. albicans inoculation into the vaginas. Subsequent estrogen-sensitive colonization was quantified based on cultures of vaginal homogenates on Sabouraud dextrose (SD) agar pour plates.

RESULTS

We confirmed that our isolate of C. albicans contained a high-affinity EBP, with no detectable affinity for DES. Vaginal colonization by C. albicans was 8.6-fold greater in response to in vivo treatment with E(2) than with the comparable dose regimen of DES.

CONCLUSIONS

The mechanism for estrogen-sensitive vaginal colonization by C. albicans includes a functional ligand-EBP interaction within the yeast.

Rapid determination of tramadol in human plasma by headspace solid-phase microextraction and capillary gas chromatography-mass spectrometry

A simple, rapid and sensitive method for determination of tramadol in plasma samples was developed using headspace solid-phase microextraction (HS-SPME) and gas chromatography with mass spectrometry (GC-MS). The optimum conditions for the SPME procedure were: headspace extraction on a 65-microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber; 0.5 mL of plasma modified with 0.5 mL of sodium hydroxide (0.1 M); extraction temperature of 100 degrees C, with stirring at 2000 rpm for 30 min. The calibration curve showed linearity in the range of 1-400 ng mL(-1) with regression coefficient corresponding to 0.9986 and coefficient of the variation of the points of the calibration curve lower than 10%. The detection limit for tramadol in plasma was 0.2 ng mL(-1). The proposed method was successfully applied to determination of tramadol in human plasma samples from 10 healthy volunteers after a single oral administration.