Factors Influencing Carbon Stocks and Accumulation Rates in Eelgrass Meadows Across New England, USA.

Increasing the protection of coastal vegetated ecosystems has been suggested as one strategy to compensate for increasing carbon dioxide (CO2) in the atmosphere as the capacity of these habitats to sequester and store carbon exceeds that of terrestrial habitats. Seagrasses are a group of foundation species that grow in shallow coastal and estuarine systems and have an exceptional ability to sequester and store large quantities of carbon in biomass and, particularly, in sediments. However, carbon stocks (Corg stocks) and carbon accumulation rates (Corg accumulation) in seagrass meadows are highly variable both spatially and temporally, making it difficult to extrapolate this strategy to areas where information is lacking. In this study, Corg stocks and Corg accumulation were determined at 11 eelgrass meadows across New England, representing a range of eutrophication and exposure conditions. In addition, the environmental factors and structural characteristics of meadows related to variation in Corg stocks were identified. The objectives were accomplished by assessing stable isotopes of δ13C and δ15N as well as %C and %N in plant tissues and sediments, measuring grain size and 210Pb of sediment cores, and through assessing site exposure. Variability in Corg stocks in seagrass meadows is well predicted using commonly measured environmental variables such as grain size distribution. This study allows incorporation of data and insights for the northwest Atlantic, where few studies on carbon sequestration by seagrasses have been conducted.

Hot Bands of Water up to 6nu2-5nu2 in the 933-2500 cm-1 Region.

Emission spectra have been recorded for hot water at temperatures up to 1550 degreesC. Separate spectra have been recorded in the 800-1900 and 1800-2500 cm-1 range. Assignments are made using a linelist generated from high accuracy, variational nuclear motion calculations, and energy differences. The spectra contain many hot bending transitions of the form (0n0)-(0n-10), where states up to n = 6 have been assigned. Detailed analysis shows that the spectra contain lines from 34 separate vibrational bands including other hot bending transitions and the difference bands (030)-(100), (110)-(020), (011)-(020), (100)-(010), (040)-(110), (040)-(011), (120)-(030), (012)-(030), (011)-(100), (110)-(001), and (101)-(110), all of which have not been observed previously. From a total of 8959 lines recorded, 6810 have been assigned; 4556 of these lines are new. These spectra represent the first detection of the (060) vibrational band, for which a band origin of 8870.54 +/- 0.05 cm-1 is determined. The (050) band origin is confirmed as 7542.40 +/- 0.03 cm-1. The assignments extend the range of J and Ka values observed for the bending states, particularly for (050) and (060), where 63 and 27 different rotational levels, respectively, have now been observed; 53 frequencies given in HITRAN are corrected. Copyright 1999 Academic Press.

Infrared Spectroscopic Imaging of the Biochemical Modifications Induced in the Cerebellum of the Niemann-Pick type C Mouse.

We have applied Fourier transform infrared (IR) spectroscopic imaging to the investigation of the neuropathologic effects of a genetic lipid storage disease, Niemann-Pick type C (NPC). Tissue sections both from the cerebella of a strain of BALB/c mice that demonstrated morphology and pathology of the human disease and from control animals were used. These samples were analyzed by standard histopathological procedures as well as this new IR imaging approach. The IR absorbance images exhibit contrast based on biochemical variations and allow for the identification of the cellular layers within the tissue samples. Furthermore, these images provide a qualitative description of the localized biochemical differences existing between the diseased and control tissue in the absence of histological staining. Statistical analyses of the IR spectra extracted from individual cell layers of the imaging data sets provide concise quantitative descriptions of these biochemical changes. The results indicate that lipid is depleted specifically in the white matter of the NPC mouse in comparison to the control samples. Minor differences were noted for the granular layers, but no significant differences were observed in the molecular layers of the cerebellar tissue. These changes are consistent with significant demyelination within the cerebellum of the NPC mouse. © 1999 Society of Photo-Optical Instrumentation Engineers.

Infrared and Microwave Spectra and Force Field of DBO: The Coriolis Interaction between the nu1 and nu2 + nu3 States.

The nu1 and nu3 bands of D11BO and the nu1 band of D10BO were observed by using an infrared diode laser spectrometer. The DBO molecule was generated by an ac discharge in a mixture of BCl3, D2, O2, and He. As inferred previously, a strong Coriolis interaction was in fact found to take place between the nu1 and nu2 + nu3 states, and an analysis of the observed nu1 spectra, which explicitly took into account this Coriolis interaction, predicted the pure rotational transition frequencies of DBO in the nu1 state. Pure rotational lines were then detected by microwave spectroscopy, confirming the validity of the infrared assignment. In the microwave experiment DBO molecules were generated by a discharge in a mixture of B2D6 and O2. The three fundamental bands and a hot band of D11BO, as well as the nu1 and nu3 bands of D10BO, were subsequently recorded in emission with a Fourier transform infrared spectrometer. DBO molecules were generated by the reaction of D2 with HBO at temperatures above 800 degreesC in a ceramic tube furnace. All of the observed spectra were simultaneously subjected to a least-squares analysis to obtain molecular parameters in the ground, nu1, nu2, nu3, and nu2 + nu3 states. The results thus obtained improved the force field and molecular structure of the HBO/DBO molecules reported in a previous study (Y. Kawashima, Y. Endo, and E. Hirota, 1989, J. Mol. Spectrosc. 133, 116-127). Copyright 1998 Academic Press.

Altered beta-tubulin isotype expression in paclitaxel-resistant human prostate carcinoma cells.

To investigate the role of beta-tubulin isotype composition in resistance to paclitaxel, an anti-microtubule agent, human prostate carcinoma (DU-145) cells were intermittently exposed to increasing concentrations of paclitaxel. Cells that were selected and maintained at 10 nM paclitaxel (Pac-10) were fivefold resistant to the drug. Pac-10 cells accumulated radiolabelled paclitaxel to the same extent as DU-145 cells and were negative for MDR-1. Analysis of Pac-10 and DU-145 cells by flow cytometry showed similar cell cycle patterns. Immunofluorescent staining revealed an overall increase of alpha- and beta-tubulin levels in Pac-10 cells compared with DU-145 cells. Examination of beta-tubulin isotype composition revealed a significant increase in betaIII isotype in the resistant cells, both by immunofluorescence and by western blot analysis. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of the isotypes confirmed the increase observed for the betaIII by exhibiting ninefold higher betaIII mRNA levels and also showed fivefold increase of the betaIVa transcript. In addition, analysis of paclitaxel-resistant cells that were selected at increasing levels of the drug (Pac 2, 4, 6, 8 and 10) exhibited a positive correlation between increasing betaIII levels and increasing resistance to paclitaxel. Increased expression of specific beta-tubulin isotypes and subsequent incorporation into microtubules may alter cellular microtubule dynamics, providing a defence against the anti-microtubule effects of paclitaxel and other tubulin-binding drugs.

Combined-modality therapy for esophageal cancer: phase I trial of escalating doses of paclitaxel in combination with cisplatin, 5-fluorouracil, and high-dose radiation before esophagectomy.

Several recent reports support administering preoperative chemotherapy and radiotherapy to improve the outcome of patients with resectable esophageal malignancies. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), 5-fluorouracil (5-FU), and cisplatin are known radiosensitizers, and paclitaxel has demonstrated single-agent activity in patients with metastatic esophageal cancer. This study sought to define the maximum tolerated dose of paclitaxel given with 5-FU, cisplatin, and 60 Gy radiotherapy before esophagectomy to patients with potentially resectable lesions. Seventeen patients so treated underwent esophagectomy. Three patients with metastatic disease, treated to obtain more information about the toxicity of the combined-modality regimen, did not undergo surgery. Over 6 weeks, 60 Gy radiation was administered in 2-Gy fractions. During radiation treatment, continuous intravenous infusions of 5-FU 225 mg/m2/d were administered, with paclitaxel given weekly as a 1-hour intravenous infusion immediately preceding a 1-hour cisplatin infusion. Surgery was performed 4 to 6 weeks after the completion of radiotherapy. The 27 patients, one of whom was a woman, had a median age of 58 years and an Eastern Cooperative Oncology Group performance status of 0 (10 patients) or 1. Three patients had a squamous cell histology, while 22 had adenocarcinoma; two had other histologies. The paclitaxel dose levels were 25 mg/m2 in four patients, 40 mg/m2 in five patients, 60 mg/m2 in nine patients, and paclitaxel 50 mg/m2 with 5-FU reduced to 200 mg/m2 in nine patients. The latter proved to be the maximum tolerated dose combination, with cisplatin held constant at 25 mg/m2. This level represents weekly dose intensities of 9.6 Gy radiation, 48 mg/m2 paclitaxel, 24 mg/m2 cisplatin, and 192 mg/m2 5-FU. Diarrhea in four patients, mucositis and dehydration in seven, electrolyte wasting in two, gram-positive catheter-related infection in three, and neuropathy in one proved dose limiting. Hematologic toxicity was relatively mild, with three episodes of nonneutropenic bacteremia, one of which was fatal. Postoperative chemotherapy consisting of four cycles of paclitaxel 175 mg/m2 over 3 hours and cisplatin 75 mg/m2 over 1 hour every 3 weeks was planned but rarely feasible due to postoperative morbidity and poor tolerability of postoperative chemotherapy. Therefore, the use of two induction cycles of this regimen given before the combined-modality study regimen is currently being investigated. Of 17 patients whose surgical specimens were assessed pathologically, three had complete remissions and 14 had partial remissions, five of which were characterized as very good, showing only microscopic foci and marked radiation effects. The median follow-up of the 17 patients who underwent surgery is 50 weeks (range, 5 to 111 weeks). Three relapses occurred at 26, 33, and 43 weeks. We conclude that this is an intense combined-modality preoperative regimen for patients with esophageal cancer. Determining the efficacy of this regimen will require further follow-up and the performance of phase II trials.

Far-infrared emission spectra of selected gas-phase PAHs: spectroscopic fingerprints.

The emission spectra of the gaseous polycyclic aromatic hydrocarbons (PAHs) naphthalene, chrysene, and pyrene were recorded in the far-infrared (far-IR) region. The vibrational bands that lie in the far IR are unique for each PAH molecule and allow discrimination among the three PAH molecules. The far-IR PAH spectra, therefore, may prove useful in the assignment of unidentified spectral features from astronomical objects.

Successful parenteral desensitization to paclitaxel.

BACKGROUND: Paclitaxel, a member of a new class of antineoplastic agents called the taxanes, has been associated with anaphylactoid reactions. OBJECTIVE: We report a case of successful parental desensitization to paclitaxel. METHODS: Desensitization was performed with serial 10-fold dilutions (up to 1:100,000) of paclitaxel in sufficient volume to administer successive doses of 1, 2, 4, and 8 ml. Basophil histamine release tests were performed with paclitaxel alone, vehicle alone, and paclitaxel and vehicle combined to determine which agent was responsible for the anaphylactoid reactions. RESULTS: After parental desensitization was performed, the patient was able to tolerate infusion of paclitaxel without complications or need for antihistamines or steroids. Basophil histamine release occurred only with paclitaxel and not with the vehicle. CONCLUSIONS: Successful parenteral desensitization to paclitaxel can be achieved; it is paclitaxel, and not its vehicle, that is most likely responsible for anaphylactoid reactions in patients undergoing treatment.