flu
Genic amplification of the entire coding region of the HEF RNA segment of influenza C virus.

Manuguerra JC, Hannoun C, Nicolson C, Robertson JS.

Institut Pasteur, Unite d'Ecologie Virale, Paris, France.

In order to provide an easy and powerful analysis of influenza C viral HEF RNA segment of a recent strain, a combination of reverse transcription and the polymerase chain reaction was used. We amplified the entire coding region of the HEF gene of a laboratory strain of virus called C/Johannesburg/1/66, widely used for binding and esterase activity studies as well as that of a strain isolated in 1991 (C/Paris/145/91) from a patient suffering from severe flu syndrome. The sequences we amplified were about 2 kilobases long. In this work, we show that the forward 'universal primer' Uni1, which has been used for influenza A and B viruses cDNA syntheses can also be used for influenza C virus. The PCR primers were designed to contain restriction sites to make the PCR products ready to be used for further purposes. A restriction analysis of the PCR products combined with analyses of all the human influenza C virus HEF gene sequences published so far permitted the design of sets of oligonucleotides which can prime PCR on cDNA of unknown influenza C virus for cloning.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8381795&dopt=Abstract flu, flu medicine, tamiflu



flu
Depletion of human NK and CD8 cells prior to in vitro H1N1 flu vaccine stimulation increases the number of gamma interferon-secreting cells compared to the initial undepleted population in an ELISPOT assay.

Dercamp C, Sanchez V, Barrier J, Trannoy E, Guy B.

Research Department, Aventis Pasteur, 69280 Marcy l'Etoile, France.

In order to study the respective roles of CD4, CD8, and CD56 (NK) cells in gamma interferon (IFN-gamma) production after in vitro stimulation with flu vaccine in a healthy adult human population, we depleted these cellular subtypes before stimulation with antigen (inactivated split vaccine, A/Texas H1N1, or A/Sydney H3N2). We observed that while CD4 cells were required for IFN-gamma secretion in both conditions in vitro, CD56 (NK) cells and, to a lesser extent, CD8 cells had a negative effect on such synthesis upon H1N1 stimulation, as judged by an increased number of spots compared to the initial undepleted population. This regulation of IFN-gamma secretion was associated with an increase in ICAM-1 expression, in particular on T and B cells. This study points out the importance of evaluating in vitro immune responses on a whole-cell population in addition to isolated subtypes if one needs to address potential cellular interactions occurring in vivo in some situations (H1N1 stimulation in the present case). Such cross-regulations occur even in vitro during the antigenic stimulation step.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11874857&dopt=Abstract flu, flu medicine, tamiflu



flu
Characterisation of different strains of poliovirus and influenza virus by differential scanning calorimetry.

Krell T, Manin C, Nicolai MC, Pierre-Justin C, Berard Y, Brass O, Gerentes L, Leung-Tack P, Chevalier M.

Vaccines against poliomyelitis and flu contain inactivated forms of the polio and influenza virus. These antigens are generated on industrial scale from the purified active viruses which have been analysed in this study by Differential Scanning Calorimetry (DSC). Multiple unfolding transitions are seen for the influenza virus A /New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2) and B/Shangdong/7/97. These data combined with previously reported data on other influenza viruses indicates that each influenza virus strain has a characteristic unfolding behaviour. Only minor changes were seen in the thermogram of beta-propiolactone (betaPL) inactivated influenza virus which is consistent with the proposition that betaPL reacts mainly with the nucleotide fraction of the virus. We demonstrate that a peak annotation of the thermogram of the native virus is possible using bromelain treated virus and virosomes. At pH 1.5 - 2.5 poliovirus of type I unfolds in a single unfolding event with respective T m values between 34 and 45 oC. At pH 2 polioviruses of type II unfolds equally in a single event, but compared to the type I virus with a T m value increased by 3.7 oC. At neutral pH, the DSC thermogram of type I poliovirus was very noisy. Data obtained offer the possibility to precisely characterise and to identify different viral strains.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15377284&dopt=Abstract flu, flu medicine, tamiflu



flu
Flu vaccines and patient decision making: what we need to know.

Mayo AM, Cobler S.

Southern California Kaiser Permanente, USA. Ann.M.Mayo kp.org

PURPOSE: To describe and compare patient-perceived barriers and motivators and decision-making conflict between two groups of hospitalized patients, those who received flu vaccines and those who did not. DATA SOURCES: Data collection included extracting data from databases and mailing two surveys to 436 discharged patients. One hundred eight patients participated in the study. CONCLUSIONS: Top motivators for obtaining a flu vaccine included previous vaccination (93%) and provider recommendation (62%). Top barriers included fear of side effects from the vaccine (35%) and fear of contracting the flu (30%). Motivators, barriers, and patient decisional conflict differed depending upon the patient's vaccination status. IMPLICATIONS FOR PRACTICE: Given the potential negative consequences of contracting the flu, prevention is the best strategy. Prevention is contingent upon motivating patients to obtain an annual flu vaccine. Recommending flu vaccinations, offering vaccinations in convenient locations free of charge, and discussing perceived barriers with patients may increase vaccinations among high-risk patients. Helping to clarify the advantages and disadvantages from the patient's perspective may decrease decisional conflict and increase vaccination rates.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15495694&dopt=Abstract flu, flu medicine, tamiflu



flu
[Appropriate use of rapid diagnostic testing for influenza]

[Article in Japanese]

Hata A, Asada J, Mizumoto H, Uematsu A, Takahara T, Iida M, Yoshimura T, Nagafuji H, Hata D.

Department of Pediatrics, Kitano Hospital, The Tazuke Kofukai Medical Research Institute.

To determine a more timely acquisition of accurate results for influenza patients, a rapid diagnostic testing for influenza were studied on 877 pediatric patients performed during the 2002-2003 flu season in our hospital. Of these, 337 patients were finally diagnosed as influenza based on the test results and treated with antiviral agents, amantadine or oseltamivir. Ten (29%) of the 34 patients whose tests were negative within 12 hours after onset became positive over 12 hours after onset. On the other hand, diagnoses based on antigen tests over 12 hours after onset were reliable because all 13 patients first confirmed negative were unchanged when tested afterward. These 10 patients missed the opportunity to take antivirals early, which possibly caused them to have significantly longer (p = 0.0003) febrile duration and higher frequency of admission (p < 0.0001) than the 106 patients first confirmed positive within 12 hours after onset. Days from onset until starting antivirals (mean 1.4 days), the febrile duration (mean 2.7 days) and frequency of hospitalization (20.5%) of the 219 patients who tested positive over 12 hours after onset were significantly worse (p < 0.0001, p < 0.0001 and p = 0.0406, respectively) than those of patients testing positive within 12 hours after onset (mean 0.2 days, mean 1.7 days and 11.3%, respectively). The febrile duration (mean 2.3 days) of the patients confirmed positive even over 12 hours, but within 48 hours, of onset was tolerable but significantly longer (p < 0.0001) than that of patients confirmed positive within 12 hours after onset. The frequency (19.6%) of hospitalization of the patients confirmed positive even over 12 hours, but within 48 hours, of onset was not significantly different from that of patients confirmed positive within 12 hours after onset. These results suggested that over 12 hours but within 48 hours after onset of illness is the best period for the rapid diagnosis to correctly determine whether a patient should be treated with antiviral agents based on the result.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15508719&dopt=Abstract flu, flu medicine, tamiflu



flu
[Evaluation of flow-through immunoassay for rapid detection of influenza A and B viruses]

[Article in Japanese]

Yamazaki M, Mitamura K, Ichikawa M, Kimura K, Komiyama O, Shimizu H, Kawakami C, Watanabe S, Imai M, Cho H, Takeuchi Y.

Zama Children's Clinic.

We evaluated a flow-through immunoassay for rapid detection of influenza A and B viral antigens, RapidTesta FLU AB (Daiichi Pure Chemicals Co., Ltd., Tokyo, Japan), by using 507 specimens collected from patients with influenza-like symptoms during the 2002/2003 influenza season in Japan. The specimens consisted of 239 nasal swabs and 268 nasal aspirates; 374 specimens were collected from pediatric patients (under 16 years of age) and 133 from adult patients. RapidTesta FLU AB was compared with cell culture and nested reverse transcription-polymerase chain reaction (RT-PCR). Cell culture detected influenza virus from 66.7% of the 507 specimens (influenza AH3: 44.0%, B: 22.7%). For nasal swabs, it had a sensitivity of 81.9% (77/94), a specificity of 97.9% (142/145) and an efficiency of 91.6% (219/239) for influenza A virus as well as a sensitivity of 80.0% (52/65), a specificity of 98.3% (171/174) and an efficiency of 93.3% (223/239) for influenza B. For nasal aspirates, RapidTesta FLU AB had a sensitivity of 83.2% (109/131), a specificity of 98.5% (135/137) and an efficiency of 91.0% (244/268) for influenza A as well as a sensitivity of 82.7% (43/52), a specificity of 97.7% (211/216) and an efficiency of 94.8% (254/268) for influenza B. RapidTesta FLU AB is characterized by high specificity, low false positive rate, and 10-minute detection of influenza virus. These advantages suggest that RapidTesta FLU AB is a useful kit to assist physicians in making a diagnosis of influenza on candidates for antiviral therapy.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15508721&dopt=Abstract flu, flu medicine, tamiflu