Autofluorescence characterization for the early diagnosis of neoplastic changes in DMBA/TPA-induced mouse skin carcinogenesis

BACKGROUND AND OBJECTIVE: Squamous cell carcinoma (SCC), the second most common skin cancer, usually remains confined to the epidermis for some time but eventually penetrates the underlying tissues, if left untreated. The non-invasive early detection of the SCC is important for appropriate therapeutic strategies. In this study, we aim to characterize the tissue transformation in DMBA/TPA induced mouse skin tumor model using autofluorescence excitation emission matrix (EEM) in conjunction with a multivariate statistical method for early detection of the neoplastic changes. STUDY DESIGN/MATERIALS AND METHODS: The fluorescence EEM from experimental group (n = 40; DMBA/TPA application), control group (n = 6; acetone application), and the blank group (n = 6; no application of DMBA/TPA or acetone) were measured every week using a spectrofluorometer coupled with a fiber optic bundle. The EEM was recorded at excitation wavelengths from 280 to 460 nm at 10 nm intervals and the fluorescence emission was scanned from 300 to 750 nm. The fluorescence emission characteristics corresponding to different fluorophores were extracted from the EEM and the spectral data were used in a multiple/linear discriminant statistical algorithm. RESULTS: The changes in the fluorescence emission intensity were observed as early as the 1st week of tumor initiation by DMBA. Morphological changes as well as differences in the gross appearance of the skin surface were observed during the entire tumor initiation and promotion period of 15 weeks. The statistical analysis was performed for each excitation wavelength in the EEM and better classification accuracy was obtained for 280 and 410 nm excitations, corresponding to tryptophan and endogenous porphyrins, respectively. The statistical analysis of the combination wavelengths resulted in 11.6% increase in the overall classification accuracy when compared to the highest classification accuracy obtained with single wavelength analysis. CONCLUSION: The intensity ratio mapping using the combination of emission intensities of key fluorophores such as tryptophan, collagen, NADH, and endogenous porphyrins from the measured EEM in conjunction with a simple multivariate statistical analysis can be used as a potential tool for the discrimination of early neoplastic changes with improved classification accuracy. Tryptophan and endogenous porphyrins may be used as biomarkers for the discrimination of early neoplastic changes when single wavelength excitations are used.     

Evaluation of the clinical applicability of proton beams in definitive fractionated radiation therapy

We report on the treatment of 317 patients treated either wholly or in part with proton beams at the Harvard Cyclotron Laboratory. These include: 130 patients treated for definitive radiation therapy of choroidal melanoma; 17 patients treated for tumors of the base of skull, cervical spine and cranium, which abut structures of the central nervous system (CNS); 23 patients treated for sarcomas of soft tissue and bone; 65 patients treated for carcinoma of the prostate; 14 patients treated for carcinoma of the rectum and anus; and 23 patients treated for squamous carcinoma of the oral cavity and oro-pharynx. Data on causes of failure and morbidity of treatment are presented. Overall the results are judged to be extremely encouraging. In particular, the treatment of the choroidal melanomas and sarcomas abutting CNS structures have clear clinical value, and the treatment of prostatic tumors and tumors of the head and neck are thought to be promising.     

Early effects of inhaled Ca-DTPA on the rat lung

Inhalation of calcium trisodium diethylenetriaminepentaacetate (Ca-DTPA) increases the removal of plutonium and other transuranics from the body. Data are required to determine possible biological effects from inhaled DTPA. p]Female rats were given a single or 12 daily, 2–4-h, inhalation exposures to aerosols of 10, 20 and 40% Ca-DTPA and the lungs were examined at 21 and 42 days following the last exposure. No pulmonary pathology was found from the single inhalation treatment with Ca-DTPA while only a slight, peripheral, histiocytosis was observed in the lungs of multiple-treated rats. There was no significant effect of DTPA treatments on body weight, lung weight, hematology or serum chemistry values.     

Utilization of 1-hydroxybenzotriazole in mixed anhydride coupling reactions

The coupling of Boc-Val-OH to either H-Pro-OBzl or H-Pro-Gly-Val-Gly-OBzl by the mixed anhydride method leads to the formation of a urethane by-product in yields of 40–60%. This side reaction can be suppressed by the addition of HOBt to the reaction mixture before the amino component is added. This results in a substantially increased yield of the desired peptide.     

Regional energetic dysfunction in hippocampal epilepsy

OBJECTIVES: There is increasing evidence for a dysfunctional metabolic network in human mesial temporal lobe epilepsy (MTLE). To further describe this, we evaluated the bioenergetic status in unilateral MTLE inter-regionally and in relation to neuropathology. MATERIALS AND METHODS: We used whole brain high field (4 T) 31P MR spectroscopic imaging to determine in vivo PCr and ATP, studying n=22 patients (all candidates for hippocampal resection) and n=14 control volunteers. The degree of bioenergetic impairment was assessed by calculating the ratio of PCr to ATP. RESULTS: Compared to controls, patients demonstrated significant decreases in PCr/ATP from the ipsilateral amygdala and pes (0.84 +/- 0.14, 0.87 +/- 0.10, respectively, patients vs 0.97 +/- 0.15, 0.98 +/- 0.16, controls). In patients, the ipsilateral thalamic energetics positively correlated with contralateral hippocampal energetics. In addition, the ipsilateral thalamic and striatal energetics negatively correlated with hippocampal total glial counts. CONCLUSIONS: These data are consistent with a view that in MTLE, the bilateral hippocampi, ipsilateral thalamus and striatum are linked in their energetic depression, possibly reflecting the propagation of seizures throughout the brain.     

Heterogeneity in 1H-MRS profiles of presymptomatic and early manifest Huntington's disease

OBJECTIVE: To evaluate (1)H-MRS profiles of the putamen in presymptomatic and manifest Huntington's disease (HD) patients for spectroscopic markers that are reliable, consistent signs of early pathology and to look for hemispheric differences as signs of use activation in an accelerated degradative process of the dominant hemisphere. METHODS: A short echo time Point RESolved Spectroscopy (PRESS) spectroscopic imaging study was performed at low field (0.5 Tesla, T) on 27 right-handed patients (17 presymptomatic gene carriers and 10 manifest patients of less than 3 years from clinical onset) and 10 right-handed normal volunteers. Spectra from individual voxels (0.56 cm(3)) in the putamen were selected for analysis. Resonance areas of peaks were normalized to water as a concentration standard. Interhemispheric comparisons were made in individuals in all three groups to look for hemispheric differences. RESULTS: Two presymptomatic patients showed normal spectra but all other HD patients displayed some combination of reduced N-acetylaspartate (NAA), enhanced glutamate/glutamine (Glx) activity, and lactate (Lac) elevations or reduced creatine (Cr). Rather than showing any one metabolite as pathognomonic of early change, spectroscopic profiles showed heterogeneity between HD patients. Low creatine was common in the presymptomatic but not in the manifest group. Hemispheric ratios of abnormal metabolites showed lower values of NAA and Glx in the dominant hemisphere in all three groups but values of creatine were selectively lower in the dominant hemisphere of only the presymptomatic patients. Lac was elevated in both hemispheres but less so in the dominant hemisphere in all HD patients. CONCLUSIONS: (1)H-MRS profiles from the putamen of presymptomatic and manifest patients reflect heterogeneity in pathophysiology. With the possible exception of low creatine in presymptomatic patients (1)H-MRS spectra are not suggestive of hemispheric differences supportive of an overall accelerated degradative process in the dominant hemisphere.     

Three-dimensional isotropic contrast-enhanced MR angiography of the carotid artery using sensitivity-encoding and random elliptic centric k-space filling: technique optimization

We present a study that helped optimize a three-dimensional isotropic contrast-enhanced MR angiographic (CE-MRA) technique, using sensitivity encoding (SENSE) and random elliptic centric k-space filling. Two-dimensional gradient-echo sequence (TR/TE/flip angle 3.4/0.97/40°) was used to generate time–intensity curves in porcine carotid arteries for a fixed dose of Gd-DTPA (0.02 mmol/kg) at the following intravenous injection rates: 0.1, 0.3, 0.5, 1.0, 1.5, 2.0, and 3.0 ml/s. The time of contrast arrival and time to peak were recorded. Based on the time–intensity curves, three-dimensional high-resolution isotropic (1 mm³) CE-MRA sequence (TR/TE/flip angle: 4.9/2.4/30°), using SENSE (reduction factor of 2) and random elliptic centric k-space filling, was initiated twice for each of the above injection rates: first at the time of contrast arrival and second at the time of peak contrast. The three-dimensional CE-MRA images were analyzed for artifacts, signal-to-noise ratio, and venous contamination. For the three-dimensional CE-MRA acquisitions that were initiated at the time of contrast arrival, there was a gradual improvement in signal-to-noise ratio (SNR) in the carotid arteries with increasing injection rate. The same trend was not observed for the acquisitions that were initiated at the time of peak contrast. SENSE combined with random elliptic k-space acquisition in CE-MRA allows for higher SNR with fewer ringing artifacts at faster contrast injection rates.     

Proton MRS imaging in the follow-up of patients with suspected low-grade gliomas

We compared the value of changes in proton magnetic resonance spectroscopic imaging (¹H-MRSI) with changes in clinical status and/or contrast-enhanced magnetic resonance imaging (MRI) in the monitoring of patients with suspected low-grade glioma (LGG). From June 1, 1999 till May 31, 2002, we included consecutive, neurologically intact adult patients suspected of having an LGG, demonstrating non-enhancing supratentorial lesions without edema or mass effect on MRI, and in whom all treatment (including a diagnostic biopsy) was deferred. Till January 1, 2003, patients were surveyed clinically and radiologically (contrast-enhanced MRI and ¹H-MRSI). Patients who showed progression on clinical examination and/or MRI were denoted as progressive disease. Other patients were denoted as stable disease. A decrease in NAA/CHO ratio of 20% compared to the baseline value was considered as indicative for progression on ¹H-MRSI. We included 14 patients with suspected LGG. Seven patients demonstrated progressive disease during the follow-up period, preceded or accompanied by concomitant ¹H-MRSI changes in five patients. Four of these five patients were operated on within the follow-up interval. The histological diagnosis demonstrated high-grade glioma in three and LGG in one patient. In the other two patients with progressive disease, no progression was found on ¹H-MRSI. The other seven patients demonstrated stable disease, but four of them showed progression on ¹H-MRSI. Our data do not show convincing evidence that ¹H-MRSI contributes to adequate monitoring and follow-up of patients with suspected LGG. Future research should preferably include pathological data at the time of ¹H-MRSI changes.     

Orbital imaging: Part 1. Normal anatomy

Advanced imaging techniques enable the radiologist to detect an increasing number of structures within the orbit not previously identifiable. We describe the imaging techniques and orbital anatomy with an emphasis on radiologically identifiable structures. In a second review of orbital pathology we present pathological processes that may involve these structures.