Sentinel lymph node biopsy for conjunctival melanoma

OBJECTIVE

To investigate the feasibility and safety of preoperative lymphoscintigraphy and sentinel lymph node (SLN) biopsy for conjunctival melanoma.

METHODS

A 49-year-old man with a biopsy-proven malignant melanoma of the conjunctiva (caruncle) underwent preoperative lymphoscintigraphy and SLN biopsy using a technique in which both isosulfan blue dye and technetium Tc 99 m sulfur colloid were injected in the subconjunctival space around the primary lesion. The conjunctival melanoma was excised just before identification and removal of the SLNs. The SLNs were excised along with concomitant dissection of their associated lymph node basins. The SLNs were evaluated histologically using serial sectioning and immunohistochemical staining with antisera against the S-100 protein and the melanoma antigen HMB-45.

RESULTS

Three SLNs were identified in the left submandibular and the left upper and middle jugular lymph node basins during the preoperative lymphoscintigraphy. The same three SLNs were successfully identified in the operating room. The SLNs were histologically negative, and the immunohistochemical staining against S-100 and HMB-45 was also negative. We did not observe any immediate adverse effects on the globe or the periocular structures from lymphatic mapping and SLN biopsy. By 24 hours after injection of blue dye, only a faint trace of blue was visible on the ocular surface.

CONCLUSIONS

Preoperative lymphoscintigraphy and SLN biopsy can be performed safely in patients with conjunctival melanoma. A larger study is planned to determine the sensitivity of this technique for the detection of occult regional nodal disease in patients with conjunctival melanoma.

Detection of pesticide model compounds in ethanolic and aqueous microdroplets by nonlinear Raman spectroscopy

Pesticide model compounds are detected in microdroplets by means of in situ nonlinear Raman spectroscopy. The chloro- and nitro-substituted aromatics are dissolved in ethanol as well as in water. Their vibrational spectroscopic fingerprint, that is, Raman bands characteristic of the functional groups attached to the aromatic system, is determined in bulk medium by linear Raman spectroscopy. As a result of the concept of group vibrations, the chosen compounds can be regarded as representatives for a whole class of pesticides containing these residues. External seeding of stimulated Raman scattering (SRS) is applied for the detection of these group vibrations of the pesticide model compounds. This technique can be utilized for in situ diagnostics and a noninvasive vibrational spectroscopic analysis of the chemical composition of microdroplets with natural or anthropogenic origin.

Canola screenings as a fiber source in barley-based feedlot diets: effects on rumen fermentation and performance of steers

Two experiments were conducted to determine the feeding value of canola screenings in combination with barley grain for beef steers. Four dietary treatments were used. These included canola screenings:barley grain ratios of 100:0; 75:25, 50:50, and 25:75 (as-fed basis). In a metabolic trial, the effects of dietary treatment on ruminal fermentation parameters were determined in a 4 × 4 Latin square design experiment using four ruminally fistulated steers. In a production trial, 66 individually fed steers were used in an 83-d finishing trial to determine the performance and carcass characteristics of feedlot cattle fed different levels of canola screenings. A barley grain/barley silage-based control diet was also fed for comparison purposes. Ruminal pH decreased (P < 0.05) while total volatile fatty acid concentrations increased (P < 0.05) as the level of barley grain in the diet increased. Ruminal NH3–N followed a pattern (P < 0.05) similar to that of pH. Inclusion level of canola screenings had no effect on DM intake. However, ADG and feed efficiency increased (P < 0.05) as the level of barley grain in the diet increased. Increasing the level of barley grain in the finishing diet decreased (P < 0.05) lean meat yield and increased (P < 0.05) carcass fat. It was concluded that canola screenings can be included as a source of fiber in barley-based diets. However, levels in excess of 500 g kg−1 reduced the performance of feedlot steers. Performance and cost of gain with 250 and 500 g kg−1 canola screenings in barley-based finishing diets were comparable with those fed an 800 g kg−1 barley grain and 200 g kg−1 barley silage diet. Key words: Canola screenings, ruminal fermentation, feedlot steer performance

Elastic light scattering from single microparticles on a femtosecond time scale

Experimentally measured and theoretically calculated elastic light-scattering spectra from single microparticles illuminated by 100-fs pulses are presented. Although in the theoretical calculation only a single incoming femtosecond laser pulse was used, the spectral behavior of scattered light shows all the features seen in the experimental spectrum from many femtosecond pulses, including morphology-dependent resonances (MDR's). The good agreement between experimental and theoretical elastic light-scattering data has stimulated a theoretical investigation of the time-dependent behavior of the elastically scattered light from a single microparticle on a femtosecond time scale. Since the spatial pulse length of the incoming laser pulse is smaller than the particle circumference, the temporal behavior of reflection, diffraction, refraction, and coupling into MDR's can be distinguished. Since the time-dependent scattering is strongly dependent on particle size, refractive index, and pulse chirp, it may be possible to encode several bits of information into a single laser pulse and therefore to increase optical data communication rates.

Minority species detection in aerosols by stimulated anti-Stokes-Raman scattering and external seeding

A novel technique applicable to remote sensing has been developed for determination of the chemical composition of microdroplets. Enhancement of stimulated anti-Stokes-Raman scattering (SARS) by external seeding of stimulated Raman scattering (SRS) at the Stokes shift lowers the detection limit of the minority species in multicomponent microdroplets. The technique is most useful in the investigation of microdroplets that contain fluorophores that can obscure the SRS signal. The SARS signal is to the blue of the pump laser and out of the fluorescence region of the fluorophore. Information about majority and minority species in multicomponent microdroplets can be determined from the enhanced SARS signals.

Angiogenesis and brain oedema in intracranial meningiomas: influence of vascular endothelial growth factor

The correlation between angiographic neovascularization, peritumoural brain oedema (PTBOe) and the expression of vascular endothelial growth factor (VEGF), was analysed in 30 patients with intracranial meningiomas. Pre-operative angiograms were examined for the existence of either an exclusively dural tumour blush or an additionally pial tumour supply from cerebral arteries. Furthermore the presence of macroscopic tumour-neovascularization and dysplastic changes of tumour-draining cerebral veins was evaluated. VEGF expression was investigated on histological tissue samples, using immunohistochemical techniques. VEGF immunohistochemistry and neuroradiological evaluations were performed in double blind fashion. Tumour volume and the amount of oedema were calculated by computerized tomography (CT) or magnetic resonance imaging (MRI). The oedema-tumour volume ratio was defined as oedema index (OeI). Compared to VEGF-negative meningiomas, tumours with striking VEGF staining revealed a significant higher mean oedema index (OeI = 4.2 vs. OeI = 1.5; p < 0.018), and a higher oedema incidence (91.7% vs. 44.4%; p < 0.046). Equally, meningiomas with additionally tumour supply from cerebral arteries were associated with a significant higher mean OeI (OeI = 4.1 vs. OeI = 1.2; p < 0.01) and oedema incidence (94.7% vs. 20.0%; p < 0.0023) than meningiomas with exclusively tumour supply from dural arteries. All meningiomas with striking VEGF-expression were associated with vascular tumour supply from cerebral arteries, but VEGF-negative tumours only in 50% (p < 0.029). These data suggest a link between VEGF-expression, arterial tumour supply and peritumoural brain oedema. The development of tumour supply from cerebral arteries may be important for formation of meningioma-related oedema. Therefore, VEGF may represent a potent mediator in the evolution of this type of vascularization in meningiomas.

FT-Raman investigation of alkaloids in the liana Ancistrocladus heyneanus

The applicability of the micro-FT-Raman technique for studying alkaloids in vitro and for observing alkaloids in plant cells is demonstrated. This technique is examined using fresh plant material of Ancistrocladus heyneanus, a tropical liana known to produce pharmacologically interesting naphthylisoquinoline alkaloids as secondary metabolites. It will be shown that it is possible to localize and identify some of these alkaloids in different parts of the plant by means of Raman microspectroscopic studies. Data on the in situ structure and the spatial distribution can be obtained, which could provide information about the biosynthesis of the alkaloids in the plant.

Q switching by saturable absorption in microdroplets: elastic scattering and laser emission

Laser-induced modification of cavity Q's has been achieved in a microdroplet containing a saturable absorber. The elastic-scattering spectra from such droplets for higher incident intensities show that cavity Q's are increased when the absorption is bleached. The lasing spectra from a droplet containing a saturable absorber and laser dye are modified when an intense bleaching field is injected into the droplet cavity after the pump field has initiated the lasing.

Investigation of a phase transition in a single optically levitated microdroplet by Raman-Mie scattering

Light-scattering measurements of optically levitated microdroplets containing three components, glycerin, water, and ammonium sulfate, are presented. Evaporation of the microdroplet is studied by means of morphology-dependent resonances observed in both Raman spectra as well as elastically scattered light and by the simultaneous measurement of the laser power. The phase transition from the liquid to the solid state of ammonium sulfate inside the microdroplet is observed by means of morphology-dependent resonances and Raman scattering.

Determination of size changes of optically trapped gas bubbles by elastic light backscattering

A technique for the determination of size changes of gas bubbles by means of Fabry-Perot resonances in elastic light backscattering and optical trapping is presented. A theoretical description of the interaction of a strongly focused laser beam with gas bubbles is also given. The differences in elastic light scattering for particles with a relative refractive index larger than one and for gas bubbles with a relative refractive index smaller than one are discussed in detail. The results of elastic light scattering experiments verify the theoretical considerations.

External seeding of stimulated Raman scattering in microdroplets

External seeding of stimulated Raman scattering (SRS) in microdroplets is achieved by light injection into the droplet at the Raman-shifted frequency. Two implementations permit observation of the seeding effect. First, a broadband seed laser (~2 nm FWHM) is used to spectrally discriminate the elastically scattered seed light from the narrow-linewidth SRS. Second, a crossed analyzer is used to reduce by several orders of magnitude the intensity of the detected elastically scattered seed laser, preventing saturation of the detector. Seeding of SRS in microdroplets is effective in enhancing the signal from weak-gain Raman modes but does not significantly increase the SRS intensity from strong-gain Raman modes.

Applications of the optical trapping technique to analyze chemical reactions in single emulsion particles

The applicability of the single beam gradient force optical trap and the optical levitation technique to investigate dynamic processes in microparticles is examined. The device allows to follow chemical reactions, like the emulsion polymerization and the ester hydrolysis reaction, in single emulsion droplets. Furthermore the usability of optical traps to investigate living cells is demonstrated.