Extinction risk of the endemic vascular flora of Kauai, Hawaii, based on IUCN assessments

The International Union for Conservation of Nature's Red List of Threatened Species (IUCN Red List) is the world's most comprehensive information source on the global conservation status of species. Governmental agencies and conservation organizations increasingly rely on IUCN Red List assessments to develop conservation policies and priorities. Funding agencies use the assessments as evaluation criteria, and researchers use meta-analysis of red-list data to address fundamental and applied conservation science questions. However, the circa 143,000 IUCN assessments represent a fraction of the world's biodiversity and are biased in regional and organismal coverage. These biases may affect conservation priorities, funding, and uses of these data to understand global patterns. Isolated oceanic islands are characterized by high endemicity, but the unique biodiversity of many islands is experiencing high extinction rates. The archipelago of Hawaii has one of the highest levels of endemism of any floristic region; 90% of its 1367 native vascular plant taxa are classified as endemic. We used the IUCN's assessment of the complete single-island endemic (SIE) vascular plant flora of Kauai, Hawaii, to assess the proportion and drivers of decline of threatened plants in an oceanic island setting. We compared the IUCN assessments with federal, state, and other local assessments of Kauai species or taxa of conservation concern. Finally, we conducted a preliminary assessment for all 1044 native vascular plants of Hawaii based on IUCN criterion B by estimating area of occupancy, extent of occurrence, and number of locations to determine whether the pattern found for the SIE vascular flora of Kauai is comparable to the native vascular flora of the Hawaiian Islands. We compared our results with patterns observed for assessments of other floras. According to IUCN, 256 SIE vascular plant taxa are threatened with extinction and 5% are already extinct. This is the highest extinction risk reported for any flora to date. The preliminary assessment of the native vascular flora of Hawaii showed that 72% (753 taxa) is threatened. The flora of Hawaii may be one of the world's most threatened; thus, increased and novel conservation measures in the state and on other remote oceanic islands are urgently needed.

Seed freeze sensitivity and ex situ longevity of 295 species in the native Hawaiian flora

PREMISE

Ex situ seed banking is critical for plant conservation globally, especially for threatened floras in tropical ecosystems like Hawai'i. Seed bank managers must maximize longevity, and species managers must plan restoration before seeds lose viability. Previous observations suggested some native Hawaiian seeds lost viability in frozen storage (-18°C). We investigated seed storage behavior in the Hawaiian flora to optimize storage conditions and recommend re-collection intervals (RCI) to maximize viability of stored seeds.

METHODS

Using 20+ years of real-time seed storage viability data, we tested freeze sensitivity for 197 species and calculated RCIs for 295 species. Using paired tests of accessions stored >2 yr at 5°C and -18°C, we developed an index of relative performance to determine freeze sensitivity. We calculated RCIs at 70% of highest germination (P70).

RESULTS

We identified four families (Campanulaceae, Cyperaceae, Rubiaceae, and Urticaceae) and four genera with seed freeze sensitivity and six additional genera with likely freeze sensitivity. Storage longevity was variable, but 195 species had viability >70% at the most recent tests (1 to 20+ yr), 123 species had RCIs >10 yr, and 45 species had RCIs <5 yr.

CONCLUSIONS

Freeze sensitive storage behavior is more widely observed in Hawai'i than any other regional flora, perhaps due to insufficient testing elsewhere. We present a new protocol to test seed freeze sensitivity, which is often not evident until 2-5 years of storage. Re-collection intervals will guide restoration practices in Hawai'i, and results inform seed conservation efforts globally, especially tropical and subtropical regions.

Flexural Bazex syndrome associated with tonsillar adenocarcinoma

Bazex Syndrome (acrokeratosis paraneoplastica) is characterized by a psoriasiform skin eruption that favors acral sites and has been associated with underlying malignancy in all reported cases. Squamous cell carcinoma of the upper third of the respiratory system and upper third of the gastrointestinal tract and squamous cell carcinoma of unknown primary with cervical lymph node metastasis are the most commonly associated neoplasms. Here we report a case of flexural Bazex syndrome with tonsillar adenocarcinoma.

Sensitivity of c-erbB positive cells to a ligand toxin and its utility in purging breast cancer cells from peripheral blood stem cell (PBSC) collections

Autografting following high-dose conditioning is being increasingly offered to breast cancer sufferers, without due regard to the reinfusion of malignant cells. We sought to determine if a breast cancer cell line could be successfully purged from peripheral blood stem cell (PBSC) harvests using a ligand-toxin molecule directed to heregulin-activated erbB receptors. Initial experiments demonstrated no reduction in hemopoietic colony-forming ability in the presence of ligand toxin (2 nM). Breast cancer cell lines which demonstrated differing sensitivities to the ligand toxin were subsequently seeded into stem cell collections and incubated with 2 nM ligand-toxin. One cell line, ZR-75-1, was completely sensitive to the ligand toxin in this mixture; a second, MDB-MA-361, was more profoundly sensitive to the ligand toxin in the presence of the PBSC, whereas a third was unaffected by the toxin. These results suggest purging may indeed be possible in the PBSC of breast cancer patients, but the parameters that define sensitivity are as yet unknown.

A membrane-bound Fas decoy receptor expressed by human thymocytes

Human thymocytes at several stages of maturation express Fas, yet resist apoptosis induction through its ligation. A proximal step in apoptotic signaling through Fas is implicated in this resistance, as these cells undergo normal levels of apoptosis induction after exposure to tumor necrosis factor-alpha. We studied the Fas receptors expressed in human thymocytes to search for mechanisms of receptor-mediated inhibition of Fas signaling in these cells. We describe here a unique, membrane-bound form of Fas receptor that contained a complete extracellular domain of Fas but that lacked a death domain due to alternative splicing of exon 7. This Fas decoy receptor (FDR) was shown to have nearly wild-type ability to bind native human Fas ligand and was expressed predominantly at the plasma membrane. Unlike soluble forms of Fas receptor, FDR dominantly inhibited apoptosis induction by Fas ligand in transfected human embryonic kidney cells. Titration of FDR in Fas-expressing cells suggests that FDR may operate through the formation of mixed receptor complexes. FDR also dominantly inhibited Fas-induced apoptosis in Jurkat T cells. In mixing experiments with wild-type Fas, FDR was capable of inhibiting death signaling at molar ratios less than 0.5, and this relative level of FDR:wild type message was observed in at least some thymocytes tested. The data suggest that Fas signal pathways in primary human cells may be regulated by expression of a membrane-bound decoy receptor, analogous to the regulation of tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-induced apoptosis by decoy receptors.

Fas is expressed early in human thymocyte development but does not transmit an apoptotic signal

We investigated the expression and function of Fas on human thymocytes prepared from fetal and pediatric tissue specimens and from SCID-hu Thy/Liv grafts. Unlike mouse thymocytes, human thymocytes exhibited a pattern of Fas expression skewed to immature cells, in that the highest expression was seen on double negative thymocytes and on intrathymic T progenitor cells. Fas expression was intermediate on double positive human thymocytes, and low or negative on mature single positive CD4 and CD8 medullary thymocytes. In spite of this relatively abundant surface expression, cross-linking of Fas with agonist mAb was incapable of triggering an apoptotic signal in human thymocytes. Apoptotic signaling was not enhanced by treatment with cycloheximide, nor by restoring a cosignaling milieu by addition of thymic stromal cells. Mouse thymocytes were induced to apoptosis by cross-linked recombinant soluble human Fas ligand both in vitro and in vivo, though human thymocytes were also resistant to this mode of receptor ligation. Membrane-bound Fas ligand also induced apoptotic death in murine thymocytes but not in human thymocytes. Human thymocytes were as sensitive as Jurkat cells, however, to apoptosis induced by TNF-alpha, suggesting that these cells have a signaling defect before activation of the earliest caspases. These data demonstrate a durable and specific resistance of human thymocytes to apoptosis induced through Fas receptor engagement, and reveal significant species-specific differences in the biology of thymocyte-programmed cell death.

The N-terminal domain of gamma-aminobutyric Acid(B) receptors is sufficient to specify agonist and antagonist binding

The recently identified gamma-aminobutyric acid type B receptors (GABA(B)Rs) share low sequence similarity with the metabotropic glutamate (mGlu) receptors. Like the mGlu receptors, the N-terminal extracellular domain (NTED) of GABA(B)Rs is proposed to be related to bacterial periplasmic binding proteins (PBPs). However, in contrast to the mGlu receptors, the GABA(B)Rs lack a cysteine-rich region that links the PBP-like domain to the first transmembrane domain. This cysteine-rich region is necessary for the PBP-like domain of mGlu receptors to bind glutamate. To delimit the ligand-binding domain of GABA(B)Rs, we constructed a series of chimeric GABA(B)R1/mGluR1 and truncated GABA(B)R1 receptor mutants. We provide evidence that despite the lack of a cysteine-rich region, the NTED of GABA(B)Rs contains all of the structural information that is necessary and sufficient for ligand binding. Moreover, a soluble protein corresponding to the NTED of GABA(B)Rs reproduces the binding pharmacology of wild-type receptors. This demonstrates that the ligand-binding domain of the GABA(B)Rs can correctly fold when dissociated from the transmembrane domains.

Composition and function of peripheral blood stem and progenitor cell harvests from patients with severe active rheumatoid arthritis

High-dose chemotherapy with autologous stem cell rescue has been proposed as an intensive therapy for severe rheumatoid arthritis (RA). In view of previous observations of abnormal haemopoiesis in RA patients, the composition and function of peripheral blood stem cell harvests (PBSCH) was investigated. Compared with PBSCH from healthy allogeneic donors mobilized with the same dose of G-CSF (filgrastim; 10 microg/kg/d, n = 14), RA PBSCH (n = 9) contained significantly fewer mononuclear cells (375 v 569 x 10(6)/kg, P = 0.03) and CD34+ cells (2.7 v 5.8 x 10(6)/kg, P = 0.003). However, there were increased proportions of CD14+ cells (P = 0.006) and CD14+ CD15+ cells (the phenotype of previously described 'abnormal' myeloid cells, P = 0.002) in the RA PBSCH which translated into 3.5- and 7-fold increases respectively on a per CD34+ cell basis. There were no differences in T-cell activation status as judged by proportions of CD4+ and CD8+ expressing CD45RA, CD45RO, HLA-DR and CD28 (RA PBSCH, n = 7, donor PBSCH, n = 5, P = 0.2-0.7). Phytohaemagglutinin responses determined fluorocytometrically with induction of CD69 expression were reduced in CD4+ and CD8+ cells following filgrastim administration in 3/3 RA patients tested. Compared with bone marrow as a potential source of CD34+ cells, PBSCH contained 11-fold more T cells (P < 0.0005), 8-fold more B cells (P < 0.0005) and 4-fold more monocytes (P = 0.02). In short-term methylcellulose culture there were no differences in colony counts (CFU-GM, CFU-GEMM, BFU-E) per CD34+ cell from PBSCH from RA patients (n = 11) and healthy donors (n = 10). Long-term culture initiator cells were cultured successfully from cryopreserved PBSCH from RA patients (n = 9). In conclusion, PBSCH from RA patients differed significantly in composition from normal individuals, but in vitro studies support normal stem and progenitor cell function. Changes in T-cell function occur during mobilization in RA patients. This work provides reassurance for the use of PBSCH as haematological rescue and baseline data for clinical trials of graft manipulation strategies in patients with RA.

The use of metoclopramide for the small bowel meal examination: pre-procedural versus peri-procedural oral administration

Administration of oral metoclopramide reduces the transit time for barium to reach the caecum during a small bowel meal (SBM). Current practice is to administer the metoclopramide 5-10 min prior to the barium. We devised a prospective randomized, controlled trial to assess whether administration of metoclopramide 90 min prior to the barium would further reduce the transit time without adversely affecting the quality of the study. Although administration of oral metoclopramide significantly reduced the transit time when compared with a control population, there was no significant difference in transit time between the groups which received metoclopramide.

Carboplatin pharmacokinetics in children: the development of a pediatric dosing formula. The United Kingdom Children's Cancer Study Group

PURPOSE

The aim of this study was to define the pharmacokinetics of carboplatin in children and use the data to develop a pediatric dose formula. It was anticipated that renal function would be a major determinant of carboplatin disposition and the relationship between carboplatin clearance and glomerular filtration rate (GFR) was examined in detail.

PATIENTS AND METHODS

Plasma carboplatin pharmacokinetics were measured as ultrafiltrable platinum in 22 patients (5 to 63 kg) following 200 to 1,000 mg/m2 of carboplatin. GFR was measured by the plasma clearance of chromium 51-edathamil (51Cr-EDTA).

RESULTS

Carboplatin pharmacokinetics in children were best described in most patients (16 of 22) by a two-compartment model. The dose-normalized area under the plasma carboplatin concentration versus time curve (AUC) ranged from 3.1 to 9.6 mg/mL.min/400 mg/m2 and there was only a weak linear relationship between carboplatin dose and AUC (R2 = .31). There was a significant relationship between absolute carboplatin and 51Cr-EDTA clearances (R2 = .56), but the relationship was weaker (R2 = .28) when both clearances were normalized for body surface area. Carboplatin plasma clearance was predicted by the equation: clearance = GFR (mL/min) + 0.36 x body weight (BW; kg), and a modified form of the adult carboplatin dose formula is proposed: dose (mg) = target AUC x (GFR [mL/min] + [0.36 x BW(kg)]). Two further equations were developed that use the 51Cr-EDTA half-life (t1/2) to calculate the GFR and these may reduce errors resulting from inaccurate measurement of the volume of distribution for 51Cr-EDTA. In patients treated with single-agent carboplatin or carboplatin plus vincristine, there was a significant sigmoidal relationship between AUC and thrombocytopenia (R2 = .56).

CONCLUSION

GFR-based carboplatin dosing in children should be feasible and will be evaluated prospectively.

Effect of guar on second-meal glucose tolerance in normal man

Whole body glucose turnover and absorption of a 50 g glucose drink was studied in six healthy volunteers on two occasions, 4 h after a 'breakfast' of 50 g of glucose, mixed on one occasion with 20 g of guar gum. Plasma glucose concentrations were significantly reduced with guar gum compared with those obtained without guar gum (P less than 0.0001). Whole body glucose turnover studied by an intravenous primed dose constant infusion technique using D-[3-3H]glucose showed no significant difference between the two groups: 353 +/- 15 mmol with guar and 350 +/- 9 mmol without guar. Total oral glucose absorption, followed with a D-[1-14C]glucose tracer, was significantly decreased by guar treatment, being 219 +/- 3 mmol with guar and 239 +/- 5 mmol without guar (P less than 0.05). Serum insulin levels were lowered by guar treatment (P less than 0.05) while those of C-peptide, gastric inhibitory polypeptide, glucagon, cortisol and pancreatic polypeptide did not differ significantly. Blood lactate concentrations were raised in the guar treated group (P less than 0.05) whereas pyruvate, alanine, glycerol and 3-hydroxybutyrate concentrations did not differ significantly. These results support the suggestion that guar improves second-meal tolerance to glucose by decreasing absorption.

Mycosis fungoides of the tonsil: a T-cell lymphoma involving the skin and tonsil

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Malignant histiocytosis

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