Degradation of macroalgal detritus in shallow coastal Antarctic sediments.

Glaciers along the western Antarctic Peninsula are retreating at unprecedented rates, opening up sublittoral rocky substrate for colonization by marine organisms such as macroalgae. When macroalgae are physically detached due to storms or erosion, their fragments can accumulate in seabed hollows, where they can be grazed upon by herbivores or be degraded microbially or be sequestered. To understand the fate of the increasing amount of macroalgal detritus in Antarctic shallow subtidal sediments, a mesocosm experiment was conducted to track 13C- and 15N-labeled macroalgal detritus into the benthic bacterial, meiofaunal, and macrofaunal biomass and respiration of sediments from Potter Cove (King George Island). We compared the degradation pathways of two macroalgae species: one considered palatable for herbivores (the red algae Palmaria decipiens) and other considered nonpalatable for herbivores (the brown algae Desmarestia anceps). The carbon from Palmaria was recycled at a higher rate than that of Desmarestia, with herbivores such as amphipods playing a stronger role in the early degradation process of the Palmaria fragments and the microbial community taking over at a later stage. In contrast, Desmarestia was more buried in the subsurface sediments, stimulating subsurface bacterial degradation. Macrofauna probably relied indirectly on Desmarestia carbon, recycled by bacteria and microphytobenthos. The efficient cycling of the nutrients and carbon from the macroalgae supports a positive feedback loop among bacteria, microphytobenthos, and meiofaunal and macrofaunal grazers, resulting in longer term retention of macroalgal nutrients in the sediment, hence creating a food bank for the benthos.

Complementary and alternative medicine use in patients before and after a cancer diagnosis.

Background: Cancer patients are increasingly seeking out complementary and alternative medicine (cam) and might be reluctant to disclose its use to their oncology treatment team. Often, cam agents are not well studied, and little is known about their potential interactions with chemotherapy, radiation therapy, or biologic therapies, and their correlations with outcomes. In the present study, we set out to determine the rate of cam use in patients receiving treatment at a Northern Ontario cancer centre. Methods: Patients reporting for treatment at the Northeast Cancer Centre (necc) in Sudbury, Ontario, were asked to complete an anonymous questionnaire to assess cam use. Changes in cam use before, compared with after, diagnosis were also assessed. Results: Patients in Northern Ontario reported significant cam use both before and after diagnosis. However, as a function of the cam type, cam use was greatly enhanced after cancer diagnosis. For example, the number of patients who reported use of biologic products increased to 51.8% after a cancer diagnosis from 15.6% before a cancer diagnosis. Patients reported much smaller changes in the use of alternative medical systems or spiritual therapy after diagnosis. Vitamin use was reported by 66% of respondents, and the number of different cams used correlated significantly with the reported number of vitamins used. Conclusions: Use of cam, particularly biologic products, increased significantly after a cancer diagnosis. Further studies are required to examine the effect of cam use on the efficacy and safety of cancer therapies.

Mutations in PIK3CD can cause hyper IgM syndrome (HIGM) associated with increased cancer susceptibility.

Autosomal dominant gain of function mutations in the gene encoding PI3K p110δ were recently associated with a novel combined immune deficiency characterized by recurrent sinopulmonary infections, CD4 lymphopenia, reduced class-switched memory B cells, lymphadenopathy, CMV and/or EBV viremia and EBV-related lymphoma. A subset of affected patients also had elevated serum IgM. Here we describe three patients in two families who were diagnosed with HIGM at a young age and were recently found to carry heterozygous mutations in PIK3CD. These patients had an abnormal circulating B cell distribution featuring a preponderance of early transitional (T1) B cells and plasmablasts. When stimulated in vitro, PIK3CD mutated B cells were able to secrete class-switched immunoglobulins. This finding implies that the patients' elevated serum IgM levels were unlikely a product of an intrinsic B cell functional inability to class switch. All three patients developed malignant lymphoproliferative syndromes that were not associated with EBV. Thus, we identified a novel subset of patients with PIK3CD mutations associated with HIGM, despite indications of preserved in vitro B cell class switch recombination, as well as susceptibility to non-EBV-associated malignancies.

Impact of source of sulfur on ruminal hydrogen sulfide and logic for the ruminal available sulfur for reduction concept.

Effects of organic and inorganic sources of S on intake, intake pattern, ruminal pH, VFA profile, and ruminal H2S gas concentration ([H2S]) were evaluated, which lead to development of a procedure to measure ruminal S availability for reduction [ruminal available S (RAS)] as well as compare with an estimated number [adjusted ruminal protein S (ARPS)]. Ruminally cannulated crossbred beef steers (n = 5; BW = 548 ± 46 kg) were assigned to 1 of 5 diets in a 5×5 Latin square design and fed ad libitum in five 21-d periods. Steers were fed a dry-rolled corn diet (CON), inorganic S source (ammonium sulfate; INORG), organic S source (corn gluten meal) fed at 9.8 (ORG-L) or 23% of diet DM (ORG-H), or wet distillers grains with solubles (WDGS) fed at 50% of diet DM. For the laboratory procedure, individual ingredients were incubated with ruminal fluid from heifers fed 60% corn-based diets (n = 2) and McDougall's buffer. Bottles were cooled in ice, centrifuged, and decanted, and the precipitate was analyzed for S. Steers fed INORG tended (P = 0.12) to consume 12% less DM. Total S intake was greater (P < 0.01) for steers fed WDGS (60 g/d) followed by ORG-H, and the lowest S intake was observed for CON (22 g/d). Intakes of ARPS and RAS were greater (P < 0.01) for steers fed WDGS followed by INORG, ORG-H, ORG-L, and CON diets. Steers fed WDGS and INORG diets spent 13% more time eating (P < 0.01) compared with other treatments. There was an interaction (P = 0.05) between treatment and time for ruminal [H2S]. Similar [H2S] were observed for steers fed INORG and WDGS diets (P = 0.28), which were greater (P ≤ 0.05) than other treatments. Greater ruminal [H2S] at 8 h compared with 13 h postfeeding was observed for steers fed ORG-H, ORG-L, and CON diets (P ≤ 0.04). Nearly 65% of ruminal [H2S] variation was explained (linear; P < 0.01) by RAS intake, ARPS explained 58% (linear; P < 0.01), S intake explained 29% (quadratic; P < 0.01), average ruminal pH explained 12% (linear; P < 0.01), and area below ruminal pH 5.6 explained 16% (linear, P < 0.01) of the variation. A 6% decrease in acetate (P = 0.01), 20% increase in propionate molar proportions (P = 0.02), and a lower acetate:proprionate ratio (P = 0.02) were observed for steers fed INORG compared with CON diet. The RAS concept is important for predicting ruminal [H2S] rather than just total S in the diet. Coefficients of RAS for individual ingredients can be predicted using in vitro procedures. Ruminal [H2S] may also modulate intake pattern.

Effect of corn bran and steep inclusion in finishing diets on diet digestibility, cattle performance, and nutrient mass balance.

One metabolism trial and 2 finishing trials were conducted to evaluate the effects of adding corn bran and steep liquor (steep) in replacement of dry-rolled corn (DRC) on diet digestibility, cattle performance, and nutrient mass balance in open feedlot pens. The metabolism trial (Exp. 1) used 8 ruminally cannulated heifers in a 4 × 4 Latin square design and the 2 finishing trials used 128 steer calves fed for 167 d (Exp. 2) and 256 yearling steers fed for 126 d (Exp. 3). Dietary treatments for all trials included a DRC-based control (CON), 30% corn bran (30/0), 30% corn bran plus 15% steep (30/15), and 45% corn bran plus 15% steep (45/15), in which by-products replaced DRC and molasses in the diet (DM basis). Diets were not isonitrogenous or isoenergetic. In the metabolism trial, feeding the by-product diets produced greater rumen pH (5.95) than CON (5.76; P < 0.01). Total tract DM and OM digestibility were greater for heifers fed CON than the by-product diets (P < 0.01). Dry matter and NDF ruminal disappearance (%/h) of corn bran were numerically less for cattle fed the CON diet than the by-product diets (2.36 vs. 2.84 and 0.72 vs. 1.66, respectively). In the performance trials, steers fed the by-product diets consumed more DM (P = 0.06) and G:F was either similar for all diets in Exp. 2 (P = 0.56) or less for cattle fed 30/0 than the other diets in Exp. 3 (P = 0.05). Percent N loss was reduced in Exp. 2 by including corn bran in diets compared with CON (P < 0.01). However, in Exp. 3, no differences in percent N loss were detected among treatments (P = 0.16), but more N was removed in the manure from pens where steers were fed by-products (P = 0.01). Although steep did not improve diet digestibility, it was beneficial in maintaining cattle performance in the feedlot studies. Feeding corn bran in combination with steep increased manure N removed and N in compost, but decreased percent N lost during the winter months only.

Ruminally undegradable protein content and digestibility for forages using the mobile bag in situ technique.

Four experiments were conducted to evaluate RUP content and digestibility for smooth bromegrass, subirrigated meadow, upland native range, and warm-season grasses. Samples were collected from esophageally cannulated cows or ruminally cannulated steers. Forages were ruminally incubated in in situ bags for durations of time based on 75% of total mean retention time, which was based on IVDMD and rate of passage calculations. One-half of the bags were duodenally incubated and excreted in the feces, and NDIN was analyzed on all bags for RUP calculations. Crude protein was numerically greater early in the growing cycle for grasses compared with later as grasses matured (P ≤ 0.32). The RUP was 13.3%, 13.3%, and 19.7% of CP for smooth bromegrass, subirrigated meadow, and upland native range, respectively. These values tended to be lower early in the growth cycle and increased (linear P ≤ 0.13) as forages matured for warm-season grasses and subirrigated meadows. Because both CP and RUP content change throughout the growing season, expressing RUP as a percentage of DM gives more consistent averages compared with RUP as a percentage of CP. Coefficient of variation values for RUP as a percentage of DM averaged 0.21 over all 4 experiments compared with 0.26 for RUP as a percentage of CP. Average RUP as a percentage of DM was 2.03%, 1.53%, and 1.94% for smooth bromegrass, subirrigated meadow, and upland native range, respectively. Total tract indigestible protein (TTIDP) linearly increased with maturity for subirrigated meadow samples (P < 0.01). A quadratic response (P ≤ 0.06) for TTIDP was observed in smooth bromegrass and warm-season grass samples. Digestibility of RUP varied considerably, ranging from 25% to 60%. Subirrigated meadow, native range, and smooth bromegrass samples tended to have linear decreases (P ≤ 0.11) in RUP digestibility throughout the growing season. The amount of digested RUP was fairly consistent across experiments and averages for smooth bromegrass, subirrigated meadow, and upland native range were 0.92%, 0.64%, and 0.49% of DM, respectively. Warm-season grasses in Exp. 2 had greater RUP (4.31% of DM) and amount of RUP digested (2.26% of DM), possibly because of cattle selecting for leadplant that contains more CP than the grasses. Forages can vary in CP, RUP, TTIDP, and RUP digestibility depending on the forage type, year, and time within year, but RUP digestibility is likely less than what previous sources have reported.

Effect of feeding combinations of wet distillers grains and wet corn gluten feed to feedlot cattle.

Three experiments were conducted to evaluate the use of combinations of wet corn gluten feed (WCGF) and wet distillers grain plus solubles (WDGS) in dry-rolled and high-moisture corn-based finishing diets for beef cattle. In Exp. 1, 250 steers (BW = 343 +/- 13.5 kg) were fed 5 treatments consisting of a corn-based, control diet with 0% coproducts, and diets including 30% WCGF, 30% WDGS, 15% WCGF plus 15% WDGS, or 30% WCGF plus 30% WDGS. No associative effects resulted from feeding 15% WCGF plus 15% WDGS; DMI, ADG, and G:F were intermediate between steers fed WCGF or WDGS at 30% of diet DM. Feeding coproducts in combinations at 30 and 60% of diet DM increased ADG, G:F, and final BW (P < 0.05) compared with the corn-based diet. In Exp. 2, 280 yearling steers (BW = 370 +/- 0.45 kg) were used to evaluate feeding 0, 25, 50, or 75% coproducts as a combination of 50% WCGF:50% WDGS (DM basis). Additional diets were fed containing decreased alfalfa hay at 5, 2.5, and 0% (DM basis) as coproduct blend inclusions increased at 25, 50, and 75% (DM basis), respectively. No interactions were observed between alfalfa hay and coproduct blend levels, and no effects on ADG or G:F (P > 0.21) were observed due to alfalfa hay. Intake, ADG, and G:F responded quadratically (P < 0.05) across coproduct levels, with the greatest ADG and G:F at 25 and 50% blend, and similar ADG and G:F for the 0 and 75% blend levels. In Exp. 3, 504 steers (BW = 376 +/- 16 kg) were fed to evaluate 0, 10, 15, 20, 25, and 30% (DM basis) WDGS in diets containing 30% WCGF (DM basis) as well as a control diet with no coproducts. The inclusion of 30% WCGF in the diets increased DMI, ADG, and G:F (P < 0.05) when compared with control. Response to inclusion level of WDGS tended to be quadratic for DMI (P = 0.12), quadratic for ADG (P = 0.05), and no effect for G:F (P = 0.96). Greatest ADG was achieved with 15 to 20% WDGS inclusion in diets containing 30% WCGF. The use of combinations of WCGF and WDGS in finishing diets resulted in similar or improved steer performance compared with corn, suggesting replacement of corn with coproduct combinations up to 75% diet DM is possible if a roughage source is fed.

Effect of corn processing method and corn wet distillers grains plus solubles inclusion level in finishing steers.

Two experiments were conducted to determine the effect of corn processing method and corn wet distillers grains plus solubles (WDGS) level on steer performance and metabolism. In Exp. 1, 480 crossbred steer calves (314 +/- 18 kg of BW) were used in a finishing experiment with a randomized complete block design and a 3 x 4 treatment structure. Diets were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked corn (SFC) with increasing levels of WDGS (0, 15, 27.5, or 40%; DM basis). A corn processing x WDGS level interaction (P < 0.01) was observed for ADG and G:F. Average daily gain and G:F increased linearly (P < 0.01) in steers fed DRC; ADG increased quadratically (P = 0.04) and G:F increased linearly (P = 0.02) in steers fed HMC; and ADG decreased quadratically (P = 0.02) with no change in G:F (P = 0.52) in steers fed SFC as WDGS increased. In Exp. 2, 7 ruminally fistulated steers (440 +/- 41 kg of BW) were used in a 6-period crossover design with 3 x 2 factorial treatment structure. Diets were the same as those fed in Exp. 1, except they contained only 2 levels of WDGS (0 or 40% of diet DM). Total tract starch digestibility was greater (P < 0.01) for steers fed SFC than for steers fed DRC or HMC. Minimum ruminal pH was less (P < 0.01) for steers fed SFC than for steers fed HMC or DRC. Variance of ruminal pH was different among all 3 processing methods with DRC < HMC < SFC (P < 0.10). In situ 22-h DM digestibility of DRC and HMC and starch digestibility of DRC were greater (P < 0.10) in steers fed DRC compared with steers fed HMC or SFC. Steers fed 0% WDGS had less (P < or = 0.02) intake of DM, OM, NDF, and ether extract compared with steers fed 40% WDGS. Total tract digestibility of DM and OM was greater (P < or = 0.08) and digestibility of ether extract tended (P = 0.11) to be less for steers fed 0% WDGS compared with steers fed 40% WDGS. Maximum ruminal pH and pH variance were greater (P < or = 0.08) in steers fed 0% WDGS. A corn processing x WDGS level interaction (P = 0.09) was observed for ruminal acetate to propionate ratio (A:P). Within diets containing 0% WDGS, A:P in steers fed SFC was less (P < or = 0.08). In diets containing 40% WDGS, A:P was similar between processing methods and not different from the SFC with 0% WDGS. The corn processing x WDGS level interaction observed in the finishing experiment may be due to the decreased ruminal A:P in DRC and HMC diets with 40% WDGS.

HIV tat and neurotoxicity.

HIV tat is the transactivator of HIV-1, supporting efficient viral replication by stabilizing the transcription of viral genes. Tat can be released from HIV-infected cells and alter several functions in uninfected cells. In the brain, tat induces neuronal dysfunction/toxicity, even though neurons cannot be directly infected with HIV, resulting in CNS pathology, such as the dementia and encephalitis associated with NeuroAIDS. This review discusses the most recent data addressing tat-induced neurotoxicity and integrates these new findings in the context of NeuroAIDS.

Shedding of PECAM-1 during HIV infection: a potential role for soluble PECAM-1 in the pathogenesis of NeuroAIDS.

Human immunodeficiency virus (HIV) infection is characterized by viral entry into the central nervous system (CNS), which is mediated, in part, by the transmigration of HIV-infected monocytes into the brain. The elaboration of chemokines and other factors by these infected cells contributes to CNS inflammation and cognitive impairment in a significant number of HIV-infected individuals. Recently, we demonstrated that HIV-infected monocyte transmigration into the CNS is enhanced greatly by the chemokine CC chemokine ligand 2 (CCL2)/monocyte chemoattractant protein-1. Platelet endothelial cell adhesion molecule-1 (PECAM-1) plays an important role in leukocyte transmigration across the endothelium of the systemic vasculature by mediating homophilic interactions between endothelial cells (EC)-EC and EC-leukocytes, thus preserving vessel integrity. The role of PECAM-1 in HIV-infected leukocyte transmigration across the blood brain barrier (BBB) and NeuroAIDS has not been characterized. We demonstrate that in brain tissue from individuals with HIV encephalitis, there is an accumulation of cleaved, soluble forms of the extracellular region of PECAM-1 (sPECAM-1). In addition, HIV-infected individuals have elevated levels of sPECAM-1 in their sera. Our in vitro data demonstrate that HIV-infected leukocytes, when treated with CCL2, shed sPECAM-1, suggesting a mechanism of extracellular PECAM-1 cleavage and release dependent on HIV infection and CCL2. We hypothesize that sPECAM-1 production by HIV-infected leukocytes, resulting in the accumulation of sPECAM-1 within the CNS vasculature and the generation of truncated, intracellular forms of PECAM-1 within leukocytes, alters PECAM-1 interactions between EC-EC and EC-leukocytes, thus contributing to enhanced transmigration of HIV-infected leukocytes into the CNS and changes in BBB permeability during the pathogenesis of NeuroAIDS.

Dose escalation of busulfan with pentoxifylline and ciprofloxacin in patients with breast cancer undergoing autologous transplants.

OBJECTIVE: There is evidence that pentoxifylline (PTX) and ciprofloxacin (Cipro) may protect patients from the effects of chemotherapy and radiation, which could allow further drug dose escalation. This study was conducted to determine whether oral and intravenous (IV) PTX and Cipro permits increased dose levels of oral busulfan (BU) with a fixed dose of IV cyclophosphamide (CY) in patients with breast cancer receiving autologous or syngeneic hematopoetic cell transplantation. METHODS: Sixty-seven patients received PTX and Cipro with CY of 150 mg/kg and escalating doses of BU. The BU dosing began at 15 mg/kg, escalating in 1 mg/kg increments in groups of 4 patients. If no grade 3 or 4 regimen- related toxicities (RRT) were observed, the next 4 patients were treated at a higher dose. RESULTS: Excessive RRT was not observed until BU 21 mg/kg was reached. Two patients at this dose level had RRTs and their BU steady-state concentration (Css) were 1,414 and 1,545 ng/ml. At a BU dose of 20 mg/kg , average BU Css 1,280 ng/ml, 0/4 had RRT. Among 10 patients who had BU Css targeted to 1,350 ng/ml, RRTs occurred in 2 (20%). CONCLUSIONS: In this preliminary study with PTX and Cipro, the maximum tolerated dose of BU that can be given with CY (150 mg/kg) was 20 mg/kg, a BU Css of approximately 1,300 ng/ml. A randomized trial is necessary to determine whether PTX and Cipro reduce the toxicities of this regimen.

Antigenic variations in the CD4 induced sites of the CCR5-tropic, pathogenic SHIVsf162p3 gp120 variants.

In vivo passage of non-pathogenic, CCR5-tropic simian/human immunodeficiency virus (SHIV) - SHIVsf162 resulted in a pathogenic isolate, SHIVsf162p3. In an attempt to characterize envelope (Env)-mediated properties that may contribute to its pathogenicity, major (P3 major) and minor (P3 minor) Env gp120 variants were cloned from the plasma of a SHIVsf162p3-infected animal, and expressed in the context of luciferase reporter viruses. Entry mediated by these envelopes and susceptibility to neutralization by CD4 induced-site (CD4i) antibodies (MAbs) was analyzed in comparison to parental SF162. Sequence analysis revealed that the P3 major and minor variant Envs contained 14 and 17 amino acid changes, respectively, compared with SF162. The rank order of entry mediated by the three envelopes was P3 major > SF162 > P3 minor, whereas the reverse order was observed for susceptibility to neutralization by CD4i MAbs. Since CD4i epitopes overlap the coreceptor (CoR) binding site, these findings suggest that the amino acid changes accumulated upon in vivo passage of SHIVsf162 result in Env gp120 structural rearrangements that modulate the exposure and/or conformation of the CoR binding site. This, in turn, led to increased entry and infectivity of the P3 major variant and may be responsible, in part, for the enhanced pathogenicity of SHIVsf162p3.

Infection of macaques with a molecular clone, SHIVSF33A2, provides evidence for tissue specific variants.

Infection of rhesus macaques with chimeric simian-human immunodeficiency viruses (SHIV) is an established model to study acquired immunodeficiency syndrome (AIDS) pathogenesis. Such a controlled system allows for detailed analysis of the molecular determinants of viral pathogenesis in addition to studying host-specific immune responses that modulate disease progression. Furthermore, the use of a pathogenic molecular clone affords the opportunity to study both viral evolution within a host and to examine the generation of tissue specific variants. In this report we describe viral diversification within tissues of two rhesus macaques infected intravenously with the CXCR4-specific molecular clone SHIVSF33A2. Heteroduplex tracking analysis (HTA) was used to determine the complexity of viral DNA within distinct lymphoid tissues. Not surprising, heterogeneity of the proviral quasispecies in tissues obtained during the acute infection was limited. However, tissues obtained at necropsy harbored a more diverse and often different population of env variants. As the inoculating virus is a molecular clone, the variants generated are likely due to the presence of tissue specific selective forces rather than a founder's effect.

Economic evaluation of filgrastim, sargramostim, and sequential sargramostim and filgrastim after myelosuppressive chemotherapy.

Filgrastim alone and sequential sargramostim and filgrastim have been shown to be more effective than sargramostim alone in the mobilization of CD34(+) cells after myelosuppressive chemotherapy (MC). We sought to compare costs and resource use associated with these regimens. Data were collected prospectively alongside a multicenter, randomized trial of filgrastim, sargramostim, and sequential sargramostim and filgrastim. Direct medical costs were calculated for inpatient and outpatient visits and procedures, including administration of growth factors and MC. We followed 156 patients for 30 days or until initiation of high-dose chemotherapy. The main outcome measures were resource use and costs of inpatient and outpatient visits, platelet and red blood cell transfusions, antibiotic use, and apheresis procedures. Hospital admissions, red blood cell transfusions, and use of i.v. antibiotics were significantly more common in the sargramostim group than in the other treatment arms. In univariate and multivariable analyses, total costs were higher for patients receiving sargramostim alone than for patients in the other groups. Mean costs in multivariable analysis for the filgrastim and sequential sargramostim and filgrastim arms were not significantly different. Filgrastim alone and sequential sargramostim and filgrastim are less costly than sargramostim alone after MC, as well as therapeutically more beneficial.

Autologous stem cell transplantation for non-Hodgkin's lymphoma: comparison of radiation-based and chemotherapy-only preparative regimens.

The aim of this study was to compare toxicity and efficacy of total body irradiation (TBI), cyclophosphamide (CY) and etoposide (E) (TBI/CY/E) vs busulfan, melphalan and thiotepa (Bu/Mel/T) in patients receiving autologous stem cell infusion (ASCI) for malignant lymphoma (NHL). Between September 1990 and July 1998, 351 patients with NHL were treated with TBI/CY/E (n = 221) or Bu/Mel/T (n = 130) followed by ASCI. Patients in first, or second remission, first responding or untreated relapse were defined as having less advanced disease before transplantation. The median follow-up was 5 years (range 1-9) and 3.5 years (1-6) for patients receiving TBI/CY/E and Bu/Mel/T, respectively. The cumulative probabilities of survival, event-free survival (EFS) and relapse at 5 years were 44%, 32%, 49% following TBI/CY/E and 42%, 34% and 42% following Bu/Mel/T. The probability of EFS at 5 years for patients who had prior dose-limiting radiation (n = 59) was 32% after Bu/Mel/T therapy. Transplant-related mortality was 16% for TBI/CY/E and 21% for Bu/Mel/T. In univariate and multivariate analyses, more advanced disease status was associated with poor outcome (TBI/CY/E: RR 0.70, CI 0.50 to 0.97 P = 0.04; Bu/Mel/T: RR 0.61, CI 0.39 to 0.97 P = 0.03). No significant differences in toxicities and outcomes were observed between these two regimens despite the inclusion of patients who had received dose-limiting irradiation in the Bu/Mel/T regimen.

Mobilization of peripheral blood stem cells following myelosuppressive chemotherapy: a randomized comparison of filgrastim, sargramostim, or sequential sargramostim and filgrastim.

Myelosuppressive chemotherapy is frequently used for mobilization of autologous CD34(+) progenitor cells into the peripheral blood for subsequent collection and support of high-dose chemotherapy. The administration of myelosuppressive chemotherapy is typically followed by a myeloid growth factor and is associated with variable CD34 cell yields and morbidity. The two most commonly used myeloid growth factors for facilitation of CD34 cell harvests are granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We performed a randomized phase III clinical trial comparing G-CSF, GM-CSF, and sequential administration of GM-CSF and G-CSF following administration of myelosuppressive chemotherapy. We evaluated CD34 yields, morbidity, and cost-effectiveness of the three cytokine schedules. One hundred and fifty-six patients with multiple myeloma, breast cancer, or lymphoma received cyclophosphamide with either paclitaxel or etoposide and were randomized to receive G-CSF 6 microg/kg/day s.c., GM-CSF 250 microg/m(2)/day s.c., or GM-CSF for 6 days followed by G-CSF until completion of the stem cell harvest. Compared with patients who received GM-CSF, patients who received G-CSF had faster recovery of absolute neutrophil count to 0.5 x 10(9) per liter (median of 11 vs14 days, P = 0.0001) with fewer patients requiring red blood cell transfusions (P= 0.008); fewer patients with fever (18% vs 52%, P = 0.001); fewer hospital admissions (20% vs 42%, P = 0.13); and less intravenous antibiotic therapy (24% vs 59%, P = 0.001). Patients who received G-CSF also yielded more CD34 cells (median 7.1 vs 2.0 x 10(6) kg per apheresis, P = 0.0001) and a higher percentage achieved 2.5 x 10(6) CD34 cells per kilogram (94% vs 78%, P = 0.21) and 5 x 10(6) CD34 cells per kilogram (88% vs 53%, P = 0.01) or more CD34 cells per kilogram with fewer aphereses (median 2 vs 3, P = 0.002) and fewer days of growth factor treatment (median 12 vs 14, P = 0.0001). There were no significant differences in outcomes between groups receiving G-CSF alone and the sequential regimen. After high-dose chemotherapy, patients who had peripheral blood stem cells mobilized with G-CSF or the sequential regimen received higher numbers of CD34 cells and had faster platelet recovery with fewer patients requiring platelet transfusions than patients receiving peripheral blood stem cells mobilized by GM-CSF. In summary, G-CSF alone is superior to GM-CSF alone for the mobilization of CD34(+) cells and reduction of toxicities following myelosuppressive chemotherapy. An economic analysis evaluating the cost-effectiveness of these three effective schedules is ongoing at the time of this writing.

The ability of an oligomeric human immunodeficiency virus type 1 (HIV-1) envelope antigen to elicit neutralizing antibodies against primary HIV-1 isolates is improved following partial deletion of the second hypervariable region.

Partial deletion of the second hypervariable region from the envelope of the primary-like SF162 virus increases the exposure of certain neutralization epitopes and renders the virus, SF162DeltaV2, highly susceptible to neutralization by clade B and non-clade B human immunodeficiency virus (HIV-positive) sera (L. Stamatatos and C. Cheng-Mayer, J. Virol. 78:7840-7845, 1998). This observation led us to propose that the modified, SF162DeltaV2-derived envelope may elicit higher titers of cross-reactive neutralizing antibodies than the unmodified SF162-derived envelope. To test this hypothesis, we immunized rabbits and rhesus macaques with the gp140 form of these two envelopes. In rabbits, both immunogens elicited similar titers of binding antibodies but the modified immunogen was more effective in eliciting neutralizing antibodies, not only against the SF162DeltaV2 and SF162 viruses but also against several heterologous primary HIV type 1 (HIV-1) isolates. In rhesus macaques both immunogens elicited potent binding antibodies, but again the modified immunogen was more effective in eliciting the generation of neutralizing antibodies against the SF162DeltaV2 and SF162 viruses. Antibodies capable of neutralizing several, but not all, heterologous primary HIV-1 isolates tested were elicited only in macaques immunized with the modified immunogen. The efficiency of neutralization of these heterologous isolates was lower than that recorded against the SF162 isolate. Our results strongly suggest that although soluble oligomeric envelope subunit vaccines may elicit neutralizing antibody responses against heterologous primary HIV-1 isolates, these responses will not be broad and potent unless specific modifications are introduced to increase the exposure of conserved neutralization epitopes.

Randomized trial of filgrastim, sargramostim, or sequential sargramostim and filgrastim after myelosuppressive chemotherapy for the harvesting of peripheral-blood stem cells.

PURPOSE: The purpose of this study was to compare the effects of filgrastim, sargramostim, or sequential sargramostim and filgrastim on CD34(+) cell yields and morbidity after myelosuppressive mobilization chemotherapy (MC). PATIENTS AND METHODS: One hundred fifty-six patients were randomized to receive filgrastim (n = 51), sargramostim (n = 52), or sargramostim for 5 days followed by filgrastim (n = 53) after MC with either cyclophosphamide and etoposide (n = 75) or paclitaxel and cyclophosphamide (n = 81). RESULTS: Compared with those who received sargramostim, patients who received filgrastim had faster recovery of an absolute neutrophil count of 0.5 x 10(9)/L or greater (a median of 11 v 14 days; P =. 0001), with fewer patients requiring RBC transfusions (P =.008), fewer patients with fever (18% v 52%; P = 0.001), fewer hospital admissions (20% v 42%; P =.013), and less intravenous antibiotic therapy (24% v 69%; P =.001). Patients who received filgrastim yielded more CD34(+) cells (median, 7.1 v 2.0 x 10(6)/kg/apheresis; P =.0001), and a higher fraction achieved 2.5 x 10(6) (94% v 78%; P =.021) and 5 x 10(6) (88% v 53%; P =.001) or more CD34(+) cells/kg with fewer aphereses (median, 2 v 3; P =.002) and fewer days of growth-factor treatment (median, 12 v 14; P =.0001). There were no major differences in outcomes between the filgrastim alone and the sequential regimens. After high-dose chemotherapy, patients who had peripheral-blood stem cells (PBSCs) mobilized with filgrastim or the sequential regimen received higher numbers of CD34(+) cells and had faster platelet recovery (P =.015), with fewer patients (P =.014) receiving fewer platelet transfusions (P =.001) than patients receiving sargramostim-mobilized PBSCs. CONCLUSION: It was concluded that filgrastim alone or sequential sargramostim and filgrastim were superior to sargramostim alone for the mobilization of CD34(+) cells and reduction of toxicities after MC.

Pharmacological examination of the neurokinin-1 receptor mediating relaxation of human intralobar pulmonary artery.

The effect of selective tachykinin receptor agonists and antagonists on human isolated intralobar pulmonary arterial rings was investigated. Neither Substance P (SP) nor neurokinin A (NKA) contracted the arteries. Both of these agonists, however, were potent and efficacious at relaxing the arteries that were precontracted with phenylephrine. The negative log (M) EC(50) values for SP and NKA were 9.0 and 8.3, respectively. The neurokinin (NK)-3 selective agonist, senktide-analog, and the NK-2 receptor selective agonist, [beta-Ala(8)]NKA(4-10), caused neither contractions nor relaxations of the arteries, whereas the NK-1 receptor agonist Ac-[Arg6, Sar9, Met(O2)11]SP(6-11) (ASM-SP) relaxed the tissue with a potency similar to SP. The relaxations to SP, NKA, and ASM-SP were competitively antagonized by the selective NK-1 receptor antagonist CP 99994, with a pK(b) in the nanomolar range. Antagonism of the ASM-SP-induced relaxations was also noted with FK 888, RP 67580, and L 732,138, although these antagonists were much less potent than CP 99994 in this regard. Another NK-1 receptor selective antagonist, SR 140333, caused an insurmountable antagonism of the SP-induced relaxations. The NK-1 receptor-mediated relaxations could be blocked by removing the endothelium, or by a combination of N-nitro-L-arginine and indomethacin. Measurement of prostanoid generation revealed that in endothelial-intact but not endothelial-denuded tissue, ASM-SP caused a selective increase in the production of 6-keto-PGF1alpha, the stable metabolite of prostacyclin. The results indicate that stimulation of NK-1 receptors leads to relaxation of human intralobar pulmonary arteries, which is mediated largely by nitric oxide and prostacyclin released from the endothelium of these vessels.