Comparison of scanning Kelvin probe with SEM/EPMA techniques for fingermark recovery from metallic surfaces.

Most traditional techniques to recover latent fingermarks from metallic surfaces do not consider the metal surface properties and instead focus on the fingermark chemistry. The scanning Kelvin probe (SKP) technique is a non-contact, non-destructive method, used under ambient conditions, which can be utilised to recover latent prints from metallic surfaces and does not require any enhancement techniques or prevent subsequent forensic analysis. Where a fingermark ridge contacted the metal, the contact potential difference (CPD) contrast between the background surface and the fingermark contact area was 10-50mV. Measurements were performed on the untreated brass, nickel-coated brass and copper metal surfaces and compared to traditional forensic enhancement techniques such as Vacuum Metal Deposition (VMD) using Au-Zn and Au-Ag. Using VMD, the CPD change ranged from 0 to 150mV between the dissimilar metal surfaces affected by the fingermark. In general, SKP worked best without additional enhancement techniques. Scanning Electron Microscope (SEM) scans were used to identify the fingermark contact areas through a sodium, chlorine and oxygen electron probe micro-analyzer (EPMA). The fingermark was observed in the backscattered electron image as the carbon deposits scattered the electrons less than the surrounding metal surface. The fingermark is shown clearly in a Cathodoluminescence scan on the copper sample as it blocks the photon emission at band gap (2.17eV) from the underlying copper oxide (Cu2O) surface. For the first time, SEM, EPMA and Cathodoluminescence techniques were compared to SKP data. Visible and latent fingermarks were tested with latent, eccrinous fingermarks more easily imaged by SKP. Results obtained were very encouraging and suggest that the scanning Kelvin probe technique, which does not need vacuum, could have a place as a first stage analysis tool in serious crime investigation.

Escalated median dose for pituitary macroadenomas using intensity-modulated radiation therapy.

Three-dimensional conformal radiotherapy (3D CRT) has become an established treatment for pituitary macroadenomas. This study is an investigation into the possible dosimetric advantages of intensity-modulated radiotherapy for such critically located tumors. Three consecutive patients with pituitary macroadenoma previously treated with 3D CRT were replanned with inverse-planned IMRT using Helax-TMS (V.6.0, Helax AB, Uppsala, Sweden. Fusion of computed tomography (CT) with postoperative magnetic resonance imaging (MRI) was performed within the planning system to define the gross tumor volume (GTV), planning target volume (PTV), and normal structures including the optic chiasm. Dose-volume histograms (DVHs) for the 3D CRT plans were then compared with those of the corresponding prospective IMRT plans. Both techniques maintained critical structure doses below tolerance levels while maintaining a minimum dose of 45 Gy to 100% of the PTV. While IMRT plans deliver consistently more heterogeneous dose distributions to the PTV, the median PTV dose is elevated in the IMRT plans compared with the 3D CRT plans. For critically located tumors like these pituitary macroadenomas, IMRT allows escalation of the median dose to the tumor without an accompanying loss in critical structure sparing or creating unacceptable cold spots within the PTV.

CT-targeted irradiation of the breast and internal mammary lymph nodes using a 5-field technique.

PURPOSE: To develop an effective and resource-efficient radiotherapy technique to treat the breast and regional nodes, including the ipsilateral internal mammary nodes. METHODS AND MATERIALS: Eighty female patients who underwent MRI scans for a variety of indications had coronal, T1-weighted images of the chest performed to determine the position of the internal mammary chain (IMC). Based on these results, a 5-field treatment technique was developed that would include the breast, supraclavicular fossa, and ipsilateral IMC, while maintaining a low dose to the heart, lungs, and contralateral breast. This technique was implemented in a cohort of 13 patients. RESULTS: The lateral position of the right and left IMC were measured in three cephalo-caudad positions: at the clavicular heads, upper manubrium, and midsternum (at the 2nd/3rd rib interspace). The mean lateral separation between the right and left IMC chains at each level (and 95% confidence interval) at each level were 5.8 cm (4.67-7.00), 5.6 cm (4.49-6.73), and 5.9 cm (4.66-7.19), respectively. Treatment was delivered to 13 patients using a 5-field technique, with tangential photon fields for the breast, anterior and posterior supraclavicular/axillary field, and a matching anterior electron field. Three-dimensional treatment planning of a representative case confirmed adequate coverage of the planning target volume (PTV). The median dose to the whole heart was 10 Gy, and 20% of the ipsilateral lung received more than 20 Gy. Seven of the 13 patients treated experienced moist desquamation at the junction of the electron field and breast tangents, and 1 patient had persistent ulceration at 3 months' follow-up. CONCLUSION: The 5-field technique described in this paper provides good coverage to the breast and regional nodes with acceptable toxicity, and without requiring three-dimensional treatment planning or intensity-modulated radiotherapy techniques.

Optic nerve sheath fenestration for a reversible optic neuropathy in radiation oncology.

To the authors' knowledge, there is a paucity of published accounts of management of radiation-induced optic neuropathy (RION) by optic nerve sheath fenestration (ONSF) in the conventional medical literature. With higher doses of radiation being given by using conformal techniques, more radiation-induced optic neuritis and neuropathy will be identified. We report here the successful use of ONSF to restore vision to three consecutive patients with pending anterior RION, and the importance of early identification and intervention in these potentially reversible cases.

Characterization of a novel transplantable orthotopic rat bladder transitional cell tumour model.

An animal tumour model that mimics the human counterpart is essential for preclinical evaluation of new treatment modalities. The objective of this study was to develop and characterize such a model. To accomplish this, the established AY-27 rat bladder transitional cell carcinoma (TCC) cell line was transplanted orthotopically into Fischer CDF344 female rats. AY-27 TCC cells were grown in monolayer cell culture and instilled intravesically as single cell suspensions into bladders that had been conditioned with mild acid washing. Tumour growth was assessed weekly by subjecting the rats to magnetic resonance imaging (MRI). At intervals following implantation and MRI tumour detection, the animals were sacrificed for necropsy, histological examination and immunocytochemical studies. Flow cytometry was also performed for detection of Fas or Fas-ligand expression on AY-27 cells. The overall tumour establishment was 95% (97/102 rats) at 12-50 days, while in a subgroup of animals sacrificed at 16 days, 80 out of 82 animals (97%) developed TCC, the majority of which was superficial. Tumour stage was assessed by gross pathology and light microscopy. Histological examination of the tumour specimens confirmed the presence of grade II-III TCC. Immunocytochemistry confirmed that the tumour model maintained the features of TCC. The changes seen on MRI correlated well with the extent of tumour invasion identified histologically. Patchy carcinoma in situ could be detected histologically 12-13 days post-inoculation, and progressed to papillary tumour or invasive disease thereafter. Neither Fas nor Fas-ligand was expressed on AY-27 cells. The orthotopic AY-27 TCC model is highly reproducible and is ideal for preclinical studies on experimental intravesical therapies.

Implantation metastasis of primary central nervous system lymphoma complicating radiotherapy outcome.

Computed tomography-guided stereotactic biopsy is commonly used in the diagnosis of brain lesions. An uncommonly reported risk of the procedure is the potential of implantation metastasis. This phenomenon has been reported in central nervous system malignancies. Although the role of prophylactic local radiotherapy at biopsy sites is well recognized in solid tumors, it has not been reported to occur after stereotactic biopsy of a brain tumor. The authors report a case of locally progressive primary central nervous system lymphoma at an unsuspiciously underdosed biopsy site complicating radiotherapy outcome.

Reactions of isocytochrome c2 in the photosynthetic electron transfer chain of Rhodobacter sphaeroides.

Rhodobacter sphaeroides strains lacking cytochrome c2 (cyt c2), the normal electron donor to P870+ in light-oxidized reaction center (RC) complexes, are unable to grow photosynthetically. However, spd mutations that suppress the photosynthetic deficiency of cyt c2 mutants elevate levels of the cyt c2 isoform, isocyt c2. We monitored photosynthetic electron transfer in whole cells, in chromatophores, and with purified components to ascertain if and how isocyt c2 reduced light-oxidized RC complexes. These studies revealed that several fundamental aspects of photosynthetic electron transfer were similar in strains that use isocyt c2 and wild-type cells. For example, P870+ reduction accompanied cytochrome c oxidation. In addition, photosynthetic electron transfer was blocked by the well-known cyt bc1 complex inhibitors antimycin and myxothiazol. However, even at the increased isocyt c2 levels present in these strains (approximately 40% that of cyt c2 in wild-type cells), there was little, if any, of the rapid (< 5 microns) electron transfer to P870+ that is characteristic of cytochromes bound to RC complexes at the time of the light flash. Thus, it appears that isocyt c2 function limits the in vivo rate of P870+ reduction. Indeed, at low ionic strength in vitro, the apparent affinity of isocyt c2 for RC complexes (KD approximately 40 microM) is significantly lower than that of cyt c2 (KD approximately 1.0 microM). This reduced affinity does not appear to result from an altered mode of RC binding by isocyt c2 since electrostatic interactions make similar overall contributions to the binding of both cyt c2 and isocyt c2 to this membrane-bound redox partner. Thus, sequence, structural, or local conformational differences between cyt c2 and isocyt c2 significantly alter their apparent affinities for this physiologically relevant redox partner.

Seasonal variation in volatile secondary compounds ofChrysothamnus nauseosus (Pallas) britt.; asteraceae ssp.hololeucus (Gray) hall. & clem. Influences herbivory.

Chrysothamnus nauseosus (rubber rabbitbrush) is used by browsing animals, especially mule deer (Odocoileus hemionus), as a forage in the winter months. It is used only slightly, if at all in the summer. This dietary difference may result from changes in the secondary chemical composition of the leaves. Solvent extracts from summer and winter rabbitbrush leaves were analyzed by gas chromatography and mass spectrometry, and the volatile compounds were quantified and identified. Hexane and chloroform extracts from winter leaves exhibit a marked concentration decrease in most chemicals when compared to summer extracts. The methanol extracts revealed the presence of several chemicals in the summer leaves that were absent in winter leaves. Rubber rabbitbrush has fewer secondary volatile chemicals in the winter than in the summer. These chemical differences may influence the seasonal dietary difference observed in mule deer and other browsing animals.

Portable scanning slit device for obese patients.

A portable apparatus with rotating scanning slits has been designed to reduce scatter in the radiographs of obese patients. Rotating scanning slit radiography reduces scatter efficiently, but previous instruments with linear or curved slits have been too heavy to be portable. The author's "dart-board" pattern of multiple sector-shaped holes is theoretically efficient at reducing scatter, compensates for potential ring artifacts by overlapping the holes and expands the holes in the lower plate to account for penumbra. Computer simulation with Monte Carlo techniques shows that the new design is free of concentric ring artifacts. This design should improve the quality of radiographs of very obese patients.

Coronal computed tomography.

The authors describe a method of direct coronal computed tomography (CT) of the body for infants and children who are introduced onto the gantry in a lateral decubitus position transversely across the examination table. Scans are planned from a lateral scout view, with the number of coronal scans ranging from four to six. Images are more informative and detail is sharper than routine axial cuts with coronal reformations. This method is valuable in resolving complex problems related to disease adjacent to the diaphragm and can accurately demonstrate the extension and relation of lesions to neighboring structures.