Notes from the field: outbreak of 2009 pandemic influenza A (H1N1) virus at a large public university in Delaware, April-May 2009

BACKGROUND

In late April 2009, the first documented 2009 pandemic influenza A (pH1N1) virus infection outbreak in a university setting occurred in Delaware, with large numbers of students presenting with respiratory illness. At the time of this investigation, little was known about the severity of illness, effectiveness of the vaccine, or transmission factors of pH1N1 virus infection. We characterized illness, determined the impact of this outbreak, and examined factors associated with transmission.

METHODS

Health clinic records were reviewed. An online survey was administered to all students, staff, and faculty to assess influenza-like illness (ILI), defined as documented or subjective fever with cough or sore throat.

RESULTS

From 26 April-2 May 2009, the health clinic experienced a sharp increase in visits for respiratory illness, with 1080 such visits among a total of 1430 student visits, and then a return to baseline visit levels within 2 weeks. More than 500 courses of oseltamivir were distributed, and 24 cases of influenza A (pH1N1) virus infection were confirmed. Of 29,000 university students and faculty/staff, 7450 (30%) responded to the survey. ILI was reported by 604 (10%) of the students and 73 (5%) of the faculty/staff. Travel to Mexico (relative risk [RR], 2.9; 95% confidence interval [CI], 1.8-4.7) and participation in "Greek Week" activities (RR, 2.2; 95% CI, 1.8-2.8) were associated with ILI. Recipients of the 2008-2009 seasonal influenza vaccine had the same risk of ILI as nonrecipients (RR, 1.0). Four (3%) of the students with ILI were hospitalized; there were no deaths.

CONCLUSIONS

pH1N1 spread rapidly through the University of Delaware community with a surge in illness over a 2-week period. Although initial cases appear to be associated with travel to Mexico, a rapid increase in cases was likely facilitated by increased student interactions during Greek Week. No protective effect from receiving seasonal influenza vaccine was identified. Although severe illness was rare, the outbreak caused a substantial burden and challenge to the university health care system. Preparedness efforts in universities and similar settings should include enhancing health care surge capacity.

CD4(+)CD25(+) T-cells control autoimmunity in the absence of B-cells

OBJECTIVE

Tumor necrosis factor ligand family members B-cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) can exert powerful effects on B-cell activation and development, type 1 T-helper cell (Th1) immune responses, and autoimmunity. We examined the effect of blocking BAFF and APRIL on the development of autoimmune diabetes.

RESEARCH DESIGN AND METHODS

Female NOD mice were administered B-cell maturation antigen (BCMA)-Fc from 9 to 15 weeks of age. Diabetes incidence, islet pathology, and T- and B-cell populations were examined.

RESULTS

BCMA-Fc treatment reduced the severity of insulitis and prevented diabetes development in NOD mice. BCMA-Fc-treated mice showed reduced follicular, marginal-zone, and T2MZ B-cells. B-cell reduction was accompanied by decreased frequencies of pathogenic CD4(+)CD40(+) T-cells and reduced Th1 cytokines IL-7, IL-15, and IL-17. Thus, T-cell activation was blunted with reduced B-cells. However, BCMA-Fc-treated mice still harbored detectable diabetogenic T-cells, suggesting that regulatory mechanisms contributed to diabetes prevention. Indeed, BCMA-Fc-treated mice accumulated increased CD4(+)CD25(+) regulatory T-cells (Tregs) with age. CD4(+)CD25(+) cells were essential for maintaining euglycemia because their depletion abrogated BCMA-Fc-mediated protection. BCMA-Fc did not directly affect Treg homeostasis given that CD4(+)CD25(+)Foxp3(+) T-cells did not express TACI or BR3 receptors and that CD4(+)CD25(+)Foxp3(+) T-cell frequencies were equivalent in wild-type, BAFF(-/-), TACI(-/-), BCMA(-/-), and BR3(-/-) mice. Rather, B-cell depletion resulted in CD4(+)CD25(+) T-cell-mediated protection from diabetes because anti-CD25 monoclonal antibody treatment precipitated diabetes in both diabetes-resistant NOD.microMT(-/-) and BCMA-Fc-treated mice.

CONCLUSIONS

BAFF/APRIL blockade prevents diabetes. BCMA-Fc reduces B-cells, subsequently blunting autoimmune activity and allowing endogenous regulatory mechanisms to preserve a prehyperglycemic state.

Vesicle movements are governed by the size and dynamics of F-actin cytoskeletal structures in bovine chromaffin cells

Dense vesicles can be observed in live bovine chromaffin cells using fluorescent reflection confocal microscopy. These vesicles display a similar distribution, cytoplasmic density and average size as the chromaffin granules visualized by electron microscopy. In addition, the acidic vesicles labeled with Lysotracker Red comprised a subpopulation of the vesicles that are visualized by reflection fluorescence. A combination of fluorescence reflection and transmitted light images permitted the movements of vesicles in relation to the cortical cytoskeleton to be studied. The movement of vesicles located on the outside of this structure was restricted, with an apparent diffusion coefficient of 1.0+/-0.4 x 10(-4) microm(2)/s. In contrast, vesicles located in the interior moved much more freely and escaped from the visual confocal plane. Lysotracker labeling was more appropriate to study the movement of the faster moving vesicles, whose diffusion coefficient was five times higher. Using this type of labeling we confirmed the restriction on cortical movement and showed a clear relationship between vesicle mobility and the kinetics of cytoskeletal movement on both sides of the cortical cytoskeleton. This relationship was further emphasized by studying cytoskeletal organization and kinetics. Indeed, an estimate of the size of the cytoskeletal polygonal cages present in the cortical region and in the cell interior agreed well with the calculation of the theoretical radius of the cages imprisoning vesicle movement. Therefore, these data suggest that the structure and kinetics of the cytoskeleton governs vesicle movements in different regions of chromaffin cells.

Perforin polymorphism A91V and susceptibility to B-precursor childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group

Perforin plays a key role in the cytotoxicity of natural killer and cytotoxic T cells. Genetic mutations in the perforin gene (PRF1) give rise to approximately 30% cases of familial hemophagocytic lymphohistiocytosis. A frequent polymorphism, A91V (C to T transition at position 272), may impair processing of perforin protein to the active form, and has been suggested to increase susceptibility to childhood acute lymphoblastic leukemia (ALL). To investigate the role of A91V in ALL, we genotyped 2272 children with de novo ALL registered on the Pediatric Oncology Group ALL Classification study P9900 and 655 normal controls. Allele frequencies in the controls showed a very low frequency of the variant allele in blacks, 0.7% compared to 4% in white controls. In light of this, analysis was restricted to a comparison of white cases and controls only. Overall genotype frequencies were similar in white ALL cases and normal white controls (P=0.58), indicating that in contrast to the previous report, A91V polymorphism is not associated with increased risk of childhood ALL. PRF1 A91V frequency was significantly increased in children with BCR-ABL positive ALL (24 vs 8.5%; P=0.0048); however, this observation includes a relatively small number of cases and needs further exploration.

Preliminary results of a randomized phase II study comparing two schedules of temozolomide in combination with sorafenib in patients with advanced melanoma

8009

Background: Sorafenib (SO) is an oral Raf kinase/VEGFR-2 inhibitor that has anti-melanoma activity when given with carboplatin/paclitaxel. The primary objective of this study is to estimate the duration of progression-free survival (PFS) for patients with metastatic melanoma (MM) taking SO + temozolomide (TEM). Secondary objectives are to determine the optimal dosing of TEM when given with SO, response, and toxicity rates. Correlative studies include BRAF genotyping and assessment of intratumoral Raf inhibition. Methods: Patients with MM and ECOG PS<2 are eligible. Prior therapy is allowed. Accrual is designed for 167 patients in one stage. All patients receive SO 400 mg po bid continuously. After one week of SO alone, patients without brain metastasis and no prior TEM are randomized to receive either extended daily dosing (EDD): TEM 75 mg/m2 po qd for 6 /8 weeks (Arm A), or standard dosing (STD): TEM 150 mg/m2 po qd for days1–5/28 (Arm B). Patients with prior TEM use are treated with EDD (Arm C) and patients with brain metastasis without prior TEM are treated with STD (Arm D). Responses are assessed using RECIST criteria. Results: 65 patients were evaluated for toxicity. Of these, 58 received SO + TEM and were evaluable for response (Table). SO + TEM resulted in a 24% overall response rate (ORR) [95% CI 11–41%] in patients without brain metastasis or prior TEM and 20% ORR [95% CI 3–56%] in patients with brain metastasis and no prior TEM. Observed grade 3 toxicities attributable to study medication were: hand-foot syndrome (12%), rash (8%), nausea (5%), anorexia (8%), and hypertension (3%). Nausea and anorexia were more prevalent with STD. Tumor blocks and 8 paired biopsy samples have been collected for correlative studies. Conclusions: Initial phase II results demonstrate encouraging antitumor activity and safety profile for SO + TEM in MM. Updated PFS data, response and toxicity rates, and correlative results will be presented.

[Table: see text]

[Table: see text]

Non-linear effects in the determination of paleotemperature Uk′37 alkenone ratios by chemical ionization mass spectrometry

The performance of gas chromatography coupled to mass spectrometry in the positive chemical ionization mode using ammonia as reagent gas (GC-PCI-MS) in the analysis of C37 alkenones for paleotemperature estimation has been re-evaluated. In some conditions, the discrepancies observed in the measurement of the U37(k') index with this technique as compared with GC equipped with flame ionization detection (GC-FID) cannot be explained by differences in sensitivity between the tri- and diunsaturated alkenones. Thus, at low (currently <0.3) or high (currently >0.4) U37(k') values the GC-PCI-MS determinations may be observed to be lower or higher, respectively, than those measured with GC-FID. As shown by analysis of a series of synthetic C37 alkenone standards these discrepant results can be explained by non linear effects in the GC-PCI-MS response factors. Second-order polynomial functions provide equations that describe better the signal to amount of analyte ratios. Users of GC-PCI-MS should calibrate their instruments with standards of known C37 alkenone composition in order to minimize non-linear effects.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) up-regulates death receptor 5 (DR5) mediated by NFkappaB activation in epithelial derived cell lines

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL/APO-2L) activates nuclear factor kappaB (NFkappaB). This activation is regulated by the recruitment of an adaptor protein Fas associating death domain (FADD) to TRAIL death receptors, death receptor 4 (DR4, TRAIL-R1) and death receptor 5 (DR5 TRAIL-R2). This leads to recruitment of caspase 8 and receptor interacting protein (RIP) to the receptor complex. Upon recruitment of caspase 8 and RIP, NFkappaB inducing kinase (NIK) becomes activated causing NFkappaB activation. The role of TRAIL induced NFkappaB activation in epithelial cells is unknown. Herein we demonstrate that TRAIL increases expression of DR5 in human embryonic kidney (HEK) 293, MCF-7 and MDA MB 231 epithelial cell lines while DR4 expression remains unchanged. Blockage of NFkappaB activation either by expression of dominant negative IkappaB or treatment with proteasome inhibitor lactacystin eliminates TRAIL induced DR5 expression. Expression of FADD dominant negative in HEK 293 cells that prevents the recruitment of caspase 8 and RIP to TRAIL death receptors also eliminates this increase. By over expression of the p65 subunit of NFkappaB that increases NFkappaB transcriptional activity, DR5 expression was increased compared to vector alone expressing cells. By blocking TRAIL induced NFkappaB activation, the sensitivity of cells to undergo TRAIL induced apoptosis was significantly decreased. Conversely, the amount of TRAIL induced apoptosis was increased in HEK 293 cells over expressing p65 subunit of NFkappaB. Finally blockage of NFkappaB activation eliminates the synergistic apoptotic response of TRAIL and etoposide. Thus, TRAIL mediated NFkappaB activation increases DR5 expression thereby amplifying the apoptotic response of TRAIL in epithelial derived cells.

Timing of cyclin D1 expression within G1 phase is controlled by Rho

The expression of cyclin D1 in mid-G1 phase is associated with sustained ERK activity, and we show here that Rho is required for the sustained ERK signal. However, we also report that Rho inhibits an alternative Rac/Cdc42-dependent pathway, which results in a strikingly early G1-phase expression of cyclin D1. Thus, cyclin D1 is induced in mid-G1 phase because a Rho switch couples its expression to sustained ERK activity rather than Rac and Cdc42. Our results show that Rho is crucial for maintaining the correct timing of cyclin D1 expression in G1 phase and describe a new role for cytoskeletal integrity in the regulation of cell cycle progression.

Monitoring the expression and purification of recombinant proteins by MALDI-TOF mass spectrometry

1Samples coming from biologic sources usually contain several contaminants that interfere seriously with Mass Spectrometry (MS) measurements. In this paper we report the application of MALDI-TOF MS to monitor recombinant protein expression and purification. The technique is based on the use of a C18 resin to clean and concentrate proteins in batch. The utility of this method is demonstrated for samples coming from different bacterial cultures expressing secreted and intracellular proteins ranging from 4 to 53 kDa. MALDI-TOF MS of peptide and proteins can be accomplished directly from complex bacterial cultures or from any purification step in a few minutes using the conventional stainless steel sample targets, allowing for a nearly instantaneous monitoring of the nature and integrity of recombinant expression products.

Low rate of acute lung allograft rejection after the use of daclizumab, an interleukin 2 receptor antibody

BACKGROUND

The incidence and the severity of acute lung allograft rejection has been linked to the development of bronchiolitis obliterans syndrome. Therefore, we investigated the effects of daclizumab, a humanized monoclonal antibody directed against the alpha subunit of the interleukin 2 receptor, in reducing acute rejection after transplantation.

METHODS

We retrospectively evaluated 27 patients who received daclizumab as induction immunosuppression and compared them with a historical control group of 34 patients. Both groups received similar immunosuppressive regimens involving tacrolimus, prednisone, and either azathioprine or mycophenolate mofetil. All patients received cytomegalovirus and aspergillus prophylaxis.

RESULTS

Twenty-one patients in the control group and 22 patients in the daclizumab group were available for analysis at 6 months after lung transplantation. Ten (48%) patients in the control group had at least grade 2 acute rejection compared with four (18%) in the daclizumab group (P<0.04). The incidence of infection was similar in both groups. One patient in each group developed posttransplant lymphoproliferative disease.

CONCLUSION

Therapy with daclizumab resulted in a significant decrease in the incidence of grade 2 or greater acute rejection after lung transplantation compared with historical controls. There seems to be no increase in the incidence of adverse effects in the patients treated with daclizumab.

Extracorporeal photopheresis for the treatment of lung allograft rejection

OBJECTIVES

Acute and chronic rejection continue to limit the survival of lung transplant recipients. Extracorporeal photopheresis has evolved as a possible therapy for patients with acute nd chronic lung allograft rejection.

METHODS

We retrospectively reviewed 14 patients diagnosed with BOS who underwent therapy with extracorporeal photopheresis.

RESULTS

Three patients were classified as BOS 0'b', five as BOS 1, three as BOS 2, and, three as BOS 3 at the time of diagnosis. Of the patients with BOS 0'b' or BOS 1 seven remain alive and one died of lung cancer. Two have progressed to BOS 2. Of the patients with BOS 2 or 3, four have died of BOS, one died of lung cancer, and one was re-transplanted. In three patients with BOS and concurrent acute rejection, therapy with extracorporeal photopheresis led to the resolution of the acute rejection episode. Two of the 14 patients developed line related sepsis.

CONCLUSION

Extracorporeal photopheresis appears to be a promising therapy for patients with early BOS. It may also have a role in the treatment of acute lung allograft rejection.

[The influence of reference electrode position on auditory evoked potentials in the brainstem]

INTRODUCTION

In view of the discrepancy in the placement of electrodes and their effects on the auditory evoked potentials of the brainstem (PEAT), we made a statistical study of these potentials using four different sites for the reference electrode to determine the best position for it.

SUBJECTS AND METHODS

The study was done in 30 healthy volunteers aged between 17 and 22 years, 15 men and 15 women. In each person successive measurements were made of the PEAT, with the reference electrode on the vertex (Cz), high frontal (Fz), ear lobe of the opposite side to that of the ear being stimulated and the spinal apophysis of the 7th cervical vertebra (CV). In all cases the active electrode was placed on the ipsilateral ear lobe of the ear being stimulated. After obtaining tables of the normal values for the latency and wave amplitude of waves I to VII in each electrode montage used, we made a study of sex differences and results from the other ear using Student's t test for paired data.

RESULTS

No statistically significant differences were found between the latencies and amplitudes of the waves I to VII for the PEAT obtained with the montage used.

CONCLUSIONS

From our results, we may conclude that the position of the reference electrode does not seem to be a major factor when obtaining PEAT. However, in view of the recordings made, we prefer the reference electrode to be at Cz or Fz when obtaining PEAT, since a clearer recording is obtained when these positions are used. Influence of the reference electrode on PEAT.

Horseradish peroxidase binding to intestinal brush-border membranes of Cyprinus carpio. Identification of a putative receptor

Morphologic studies have shown that the classic endocytosis tracer horseradish peroxidase (HRP) is actively internalized by vesicular transport in the carp intestine, suggesting the existence of specific binding sites in the apical membrane of enterocytes. The aim of the present study was to develop an in vitro binding assay using isolated carp intestinal brush-border membranes (BBM) to demonstrate and characterize these specific HRP binding sites. The results obtained show that HRP binding to BBM exhibits a saturable mode and high affinity (K(d) = 22 nM). In addition, HRP binding sites are highly enriched in BBM compared to basolateral membranes. On the other hand, HRP interaction with these sites is apparently of an ionic character because binding increased concomitantly with decreasing NaCl concentrations in the assay, reaching a maximum in the absence of NaCl. Other proteins that are also internalized in carp intestine did not significantly inhibit HRP binding to BBM. A lectin-type of interaction was discarded because neither manan nor ovoalbumin inhibited HRP binding. Proteinase K treatment of BBM reduced HRP binding by 70%, suggesting a proteic nature for this binding site. Finally, ligand blotting assays showed that HRP binds specifically to a 15.3-kDa protein. Taken together, these results are consistent with the existence of a functional receptor for HRP in carp intestinal mucosa that could mediate its internalization.

Predictors of blood lead levels in agricultural villages practicing wastewater irrigation in Central Mexico

To investigate whether the agricultural use of untreated wastewater (i.e. crop irrigation) was associated with elevated blood lead levels in a farming population in the Mezquital Valley and which risk factors, other than exposure to untreated wastewater, were associated with elevated blood lead levels, lead levels were measured in venous blood obtained from 735 individuals. Blood samples were analyzed by atomic absorption spectrophotometry. Food habits and dietary intake were gathered by interview, using a semi-quantitative food-frequency questionnaire. The average blood lead level was 7.8 microg/dL (SD 4.66 microg/dL; range 1.2-36.7 microg/dL). 23% of the study population had blood lead levels exceeding 10 microg/dL. The use of lead-glazed ceramics (LGC) was significantly associated with elevated lead levels (p = < 0.001). Other significant variables included age, gender (males), and non-farming-related occupations (e.g., technicians, factory workers). p = 0.005, 0.08, and 0.001, respectively. When the analysis was stratified by the use of LGC for food preparation, an inverse relationship between higher daily calcium intake and blood lead level was detected (beta = - 0.040, p = < 0.05). Thus, blood lead levels were positively associated with the use of LGC. Calcium intake showed a protective effect, maybe by decreasing absorption of lead in the gastrointestinal tract. No association between occupational exposure to untreated wastewater or crop consumption and blood lead levels was detected. Further environmental and health surveillance is recommended.