1) A combination of both drugs is recently launched in market L

1). A combination of both drugs is recently launched in market. Literature survey

revealed spectrophotometric6 and chromatographic7, 8, 9 and 10 methods for estimation of TDF in pharmaceutical formulation and biological fluids. Few chromatographic11, 12 and 13 methods has been reported for estimations of ETB from biological fluids. TDF and ETB are not official in IP, BP and USP. However, to our knowledge, no information related to the stability-indicating Hydroxychloroquine high-performance thin-layer chromatography (HPTLC) determination of TDF and ETB in pharmaceutical dosage forms has ever been mentioned in literature. The parent drug stability test guidelines (Q1A) issued by International Conference on Harmonisation (ICH) requires that analytical test procedures for stability samples should be fully validated and the assays should be stability-indicating.13, 14, 15 and 16 Selleckchem 5FU The present paper describes a reliable, rapid and accurate stability – indicating HPTLC method for determination of TDF and ETB using HPTLC densitometry. TDF

and ETB were kindly supplied as a gift sample by Emcure Pharmaceuticals Ltd., Pune India. All the reagents used were of analytical reagent grade (S.D. Fine Chemicals, Mumbai, India) and used without further purification. The samples were spotted in the form of bands of width 6 mm with 100 μL sample syringe on precoated silica gel aluminium plate 60 F254 (20 cm × 10 cm) with 250 μm thickness; (E MERCK, Darmstadt, Germany) using a Camag Linomat V (Switzerland). The plates were prewashed with methanol and activated at 110 °C for 5 min, prior to chromatography. A constant application rate of 150 nl/sec was employed and space between two bands was 15.4 mm. The slit dimension was kept at 6 mm × 0.45 mm. The mobile phase consists of toluene: ethyl acetate: methanol: acetic acid (6: 4: 3:0.4, v/v/v). Linear ascending development was carried out in 20 cm × 10 cm twin trough glass chamber (Camag, Muttenz, Switzerland). The optimised

chamber saturation time for mobile phase was 20 min, at temperature (25 °C ± 2); 17-DMAG (Alvespimycin) HCl the relative humidity (60% ± 5%); the length of chromatogram run was 8 cm and TLC plates were air dried. Densitometric scanning was performed on Camag TLC Scanner 3 equipped with winCATS software version 1.3.0 at 276 nm. The source of radiation utilised was deuterium lamp. Evaluation was performed using peak area with linear regression. Combined standard stock solution containing 1500 μg/ml of TDF and 1000 μg/ml of ETB was prepared in methanol. Calibration was done by Hamilton syringe with the help of automatic sample applicator Linomat V on TLC plate that gave concentration 150–1500 ng/spot of TDF and 100–1000 ng/spot of ETB, respectively. Each concentration was spotted six times on the TLC plates. The plates were developed using previously described mobile phase. The calibration graph was plotted as peak areas versus corresponding concentrations.

The first step in the replication cycle of influenza A virus is v

The first step in the replication cycle of influenza A virus is virus attachment to host cellular receptors [53]. This is mediated by the HA protein, which binds to glycans expressed on the surface of host cells. Avian influenza viruses preferentially bind to glycans harbouring sialic acids with α2,3 linkage to galactose [54] and [55]. These glycans are

abundantly expressed on the surface of avian intestinal and respiratory epithelial cells, contributing to the tissue tropism and route of transmission of these viruses in wild and domestic birds [56] and [57]. It is interesting to note however that they also are expressed in other tissues in birds, such as the heart, kidney, brain and endothelium [56], [57] and [58]. The presence and accessibility of glycans recognized

by avian ABT-888 order influenza viruses at the site of virus entry in humans are essential for successful selleck kinase inhibitor cross-species transmission. The presence of glycans harbouring sialic acids with α2,3 linkage to galactose has been demonstrated on the surface of cells from diverse tissues of mammals, including humans. Sialic acids with α2,3 linkage to galactose were shown to be expressed in the respiratory tract of humans on rare epithelial cells of the nasal mucosa and pharynx, focally on tracheal, bronchial and bronchiolar epithelial cells, and more abundantly on alveolar epithelial cells (type II pneumocytes), as determined by use of lectin histochemistry [59]. In other mammals, the same method revealed the presence of Parvulin these glycans on the surface of respiratory epithelial cells in the trachea of swine [60] and horses [61], in the bronchi of domestic dogs [62], and in the lungs of a seal and a whale (species unspecified) [63]. Binding studies of avian influenza viruses on tissues of the respiratory tract of mammals further demonstrated the presence of target cells for virus attachment in the lower respiratory tract (mainly bronchiolar cuboidal epithelial cells, type II pneumocytes and alveolar macrophages) of humans, swine, ferrets, and domestic cats

[64], [65] and [66]. In the trachea and bronchi of humans and ferrets, avian influenza viruses were also shown to bind acinar cells of the submucosal glands and mucus [64], in accordance with the detection of sialic acids with α2,3 linkage to galactose on these cell types [67] and in secreted mucins [68]. In extra-respiratory organs, sialic acids with α2,3 linkage to galactose were detected in humans on Kuppfer cells in the liver, on neurons in the brain and in the wall of the intestine, and on endothelial cells of the heart and kidney [59]. In the eye, sialic acids with α2,3 linkage to galactose were present on ocular and lachrymal duct epithelial cells, in accordance with binding of avian influenza viruses to corneal and conjunctival epithelial cells [69] and [70].

sinensis are too rare to obtain and very expensive In addition,

sinensis are too rare to obtain and very expensive. In addition, the content of each component of natural products is variable and it might be difficult to check their quality. Therefore, we chose the cultured fruiting body of C. sinensis produced by Xinhui Xinhan Artificial Cordyceps Factory (Guangdong, China) and supplied by Gunsei Co., Ltd. (Tokyo, Japan)

as our experimental material, and investigated the pharmacological effects of hot water extracts (70 °C for 5 min) of C. sinensis (WECS). We investigated the action of WECS on cancer, particularly on metastasis. As active ingredients of WECS, we focused on cordycepin (3′-deoxyadenosine) and examined its anticancer and antimetastatic effects and the mechanisms of these effects. It has been reported that cordycepin interacts in biochemical processes, including BIBW2992 purchase nucleic acid synthesis, platelet aggregation, metastasis, inflammatory reactions, apoptosis, and cell cycle signaling (3). In this review, we mainly present our research findings on cordycepin, as an active ingredient of WECS. In in vitro studies, Nakamura et al. investigated the anticancer effect of WECS against B16 mouse melanoma (B16) and Lewis lung carcinoma (LLC) cells, and WECS showed direct cytotoxicity against both B16

and LLC cells at 10 and 30 μg/mL (4). Nakamura R428 et al. indicated that WECS (100 μg/mL) induced the apoptosis of B16-F10 mouse melanoma cells after 48-h exposure in vitro, as determined by both the TdT-mediated dUTP-biotin nick end labeling

(TUNEL) method and the detection of a DNA ladder (5). Lee et al. also demonstrated that cordycepin induced apoptosis in human prostate PC-3 cells through a mitochondria-mediated, caspase-dependent pathway (6). Yoshikawa et al. reported that WECS (10 μg/mL) markedly inhibited the growth of B16-BL6 mouse melanoma (B16-BL6) cells, LLC cells, HT1080 human fibrosarcoma (HT1080) cells, and CW-2 human colon carcinoma (CW-2) cells, and the inhibitory effect of WECS was significantly antagonized by 1 μM 3-ethyl 5-benzyl 2-methyl-6-phenyl-4-phenylethynyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate ADP ribosylation factor (MRS1191), a selective adenosine A3 receptor antagonist. Furthermore, WECS included 2.34% w/w cordycepin and 0.12% w/w adenosine as components according to the HPLC-electrochemical detection (ECD) system (7). That is, one of the active ingredients of WECS inhibited the proliferation of four cancer cell lines by the stimulation of adenosine A3 receptors, and this active ingredient may be cordycepin and not adenosine. In in vitro studies, Nakamura et al. demonstrated that cordycepin showed marked inhibitory effects on the growth curves of B16-BL6 cells (IC50 = 39 μM) and LLC cells (IC50 = 48 μM), while adenosine and 2′-deoxyadenosine (up to 100 μM) had no effect on the growth of the two cancer cell lines.

In summary, the total synthesis of (5R,8S,13R,16S)-isomer

In summary, the total synthesis of (5R,8S,13R,16S)-isomer selleck compound of pyrenophorol was achieved from (R)-propylene oxide. The key features of this total synthesis include: i) Jacobsen’s hydrolytic kinetic resolution and ii) intermolecular Mitsunobu cyclization. All column chromatographic separations were performed using silica gel (60–120 mesh). 1H NMR spectra were acquired at 300 MHz, 500 MHz and 600 MHz, while, 13C NMR at 75 MHz and 125 MHz with TMS as internal standard in CDCl3. IR-spectra were recorded on FT IR spectrophotometer

with NaCl optics. Optical rotations were measured on digital polarimeter at 25 °C. Mass spectra were recorded on direct inlet system or LC by MSD trap SL. A suspension of Mg (3.97 g, 165.5 mmol) and dry ether (30 mL) was treated with allyl chloride (6.8 mL, 82.55 mmol) at room temperature and stirred for 30 min. It was cooled to −78 °C and a solution of 10 (4 mL, 55.17 mmol) in dry ether (10 mL) was added dropwise and the mixture was stirred at the same temperature for 2 h. The reaction mixture was quenched with aq. NH4Cl solution (10 mL) and

extracted ERK high throughput screening with ether (2 × 50 mL). Combined extracts were washed with brine (30 mL), dried (Na2SO4) and concentrated to afford the crude alcohol 11a (5.0 g, 90%) as a colorless liquid. It is used as such for next reaction. A mixture of the above alcohol 11a (5 g, 50 mmol) and imidazole (10.2 g, 150 mmol) in dry CH2Cl2 (50 mL) was treated with TBSCl (8.29 g, 55 mmol) at 0 °C under nitrogen atmosphere and stirred at room temperature for 4 h. The reaction mixture

was quenched with aq. NH4Cl solution Carnitine dehydrogenase (10 mL) and extracted with CH2Cl2 (2 × 50 mL). The combined extracts were washed with water (30 mL), brine (30 mL), dried (Na2SO4) and concentrated. 11b (7.5 g, 70%) as a colorless liquid, [α]D −57.4 (c 0.76, CHCl3); 1H NMR (200 MHz, CDCl3): δ 5.72 (m, 1H, olefinic), 4.89 (q, 2H, J = 17.3, 3.7 Hz, olefinic), 3.76 (q, 1H, J = 6.0 Hz, –CH), 2.02 (m, 2H, allylic –CH2), 1.44 (m, 2H, –CH2), 1.07 (d, 3H, J = 6.0 Hz, –CH3), 0.84 (s, 9H, 3× –CH3), 0.00 (s, 6H, 2× –CH3); 13C NMR (75 MHz, CDCl3): δ 139.5, 114.2, 77.1, 32.0, 29.5, 26.2, 22.9, 14.2, −3.2; IR (neat): 2956, 2858, 1467, 1370, 1254, 1135, 1053, 997 cm−1; ESIMS: 237 (M + Na)+. Ozone was bubbled through a cooled (−78 °C) solution of 11b (7.4 g, 34.57 mmol) in CH2Cl2 (70 mL) until the pale blue color persisted. The reaction mixture was concentrated under reduced pressure to give aldehyde, which was used for further reaction. To a solution of 11b in dry CH2Cl2 (50 mL) (ethoxycarbo-nylmethylene)triphenyl phosphorane (7.82 g, 0.79 mmol) dissolved in dry CH2Cl2 (20 mL) was added at 0 °C. After the addition, the reaction mixture was stirred at rt for 4 h. The reaction mixture was quenched with water (10 mL), organic layer separated, dried (Na2SO4) and evaporated.

We continued to investigate whether the advantages of three-compo

We continued to investigate whether the advantages of three-component regimes could be achieved in a simplified two-stage regime, by mixing protein and adjuvant with one or both viral vector components (Fig. 4A and MLN8237 B). We found that there was no significant difference by Kruskal–Wallis test between the three-immunization regimes and a two-immunization regime mixing protein and Montanide ISA720 with both adenovirus prime and MVA boost. Interestingly, there was a small but statistically significant increase in CD8+ T cell responses and decrease in antibody responses with the (A+P)–M regime relative to A–P–M (P < 0.05, ANOVA with Bonferroni post-test).

Antibody responses tended to be highest with the three component regimes, or when protein-adjuvant was co-administered with both viral vectors. Interestingly, in

C57BL/6 mice, (A+P) priming induced modestly but significantly higher CD8+ T cell responses than adenovirus alone ( Fig. 1D, P = 0.04, Mann–Whitney test). Thus a simplified two-shot immunization regime appears highly immunogenic and mixing of the viral vectors with protein and adjuvant did not appear to affect vector potency, a result which may encourage development of further strategies combining vectors with protein and adjuvant, including homologous vector–protein prime–boost immunization regimes. Serum antibody and splenic T cell responses were assayed by ELISA and IFNγ ELISPOT 138 days after final vaccination for selected groups of mice (Fig. 2 D291 time point and Fig. 5). Antibody responses to A–M–P AG-014699 price and A–P–M remained significantly higher than those for A–M (P < 0.05 for both comparisons by Kruskal–Wallis test with Dunn's multiple comparison post-test), while CD8+ T cell responses following A–M–P and A–M remained greater than those Dipeptidyl peptidase for A–P (P < 0.01 and P < 0.05 respectively by the same method). There was

a mean drop of 0.4 log units in ELISA titer between 14 and 138 days after final vaccination, with no significant difference in this rate of decline between groups ( Fig. 5C, P = 0.37 by Kruskal–Wallis test). Thus, as was the case with early post-vaccination responses, maximal long-lived IgG responses were detected with any regime including AdCh63 and protein, while any regime including AdCh63 and MVA induced maximal long-lived CD8+ T cell responses in the spleen. We also compared the antibody and CD8+ T cell responses of six mice receiving the A–M–P regime entirely intramuscularly versus six mice receiving the viral-vector components intradermally (i.d.) (Fig. 6). There was no significant difference by t-test between the two groups’ log ELISA titer (P = 0.26) or % IFNγ+ CD8+ T cells (P = 0.20) 14 days after final vaccination, nor was a difference found between groups for either ELISA or CD8+ T cell responses by repeat measures ANOVA taking into account all time points up to 14 days after final vaccination.

The current treatment approaches for beta-thalassemia have certai

The current treatment approaches for beta-thalassemia have certain limitations. Induction of HbF using natural agents is an effective approach for patients suffering with beta-thalassemia. Various

natural agents like angelicin, rapamycin, FT, bergamot, romidepsin, wheatgrass, Curcuma comosa, Astragalus, apicidin, curcuminoid, piceatannol and resveratrol have been reported to induce HbF level in beta-thalassemic patients. Developing new approaches to lower iron overload is one of the most important goals in the treatment Anti-cancer Compound Library cost of beta-thalassemia. Various natural compounds like wheatgrass, deferoxamine and Tetracarpidium conophorum have also been known for their iron chelation property for the treatment of beta-thalassemia. As there are no side Roxadustat chemical structure effects caused by these natural agents, more research is needed on their biological activity. There is a need to find out the most promising natural therapeutic agent which could effectively induce HbF production and reduce iron overload, thereby improving the life span of diseased patients. More data are needed on

the bioavailability of these natural compounds and their effects on human. AK initiated the paper, undertook the literature searches, extracted the data and wrote the draft manuscript. NW and AT contributed to the revisions of the paper. All authors approved the final version. Rajiv Gandhi Proudyogiki Vishwavidyalaya, Bhopal. All authors have none to declare. “
“Over the past 15 years, there has been increasing momentum in the delivery of surgical procedures towards a day case setting [1]. Controversy has persisted since thyroidectomy was first proposed as a suitable procedure and the issue remains hotly debated [2], [3], [4], [5] and [6] despite evidence that both generic aspects of day case safety and those specific to thyroid surgery have improved considerably [7] and [8]. Whilst benefits

in health outcomes and patient experience are cited it is the financial savings that remain the predominant driver behind ambulatory surgery. It is appropriate that costs are considered in all second healthcare settings irrespective of source of funding so long as ambulatory thyroidectomy does not expose the patient to additional risk. Medical literature often blends ambulatory surgery, which means same day discharge with a 23-hour stay model [9]. The former is now standard practice [2], [9], [10] and [11] for most routine cases whereas the latter, in Europe at least, is infrequent. As a consequence, the controversy only really applies to same day discharge as this is when the postoperative complications carry the most severe risk. For the purpose of this article, ambulatory thyroid surgery refers to day case thyroidectomy and is defined as that not involving an overnight stay in a hospital ward. Distinction between discharge settings is as relevant as timing.

Thus, US funding of US$ 10 million helped to initiate the WHO gra

Thus, US funding of US$ 10 million helped to initiate the WHO grant programme described in this Journal issue. Three subsequent cooperative agreements with WHO (2008, 2009 and 2010 to the present) have assisted in continued and expanded support of vaccine manufacturers in ten countries: Brazil, Egypt, India, Indonesia, Mexico, Romania, Russia, Serbia, Thailand and Vietnam. In 2009,

BARDA used its international capacity-building funds to establish a US$ 7.9 million cooperative agreement with PATH,1 which allowed the support of final developmental processes for an egg-grown influenza vaccine at one of the original WHO awardees, the Institute of Vaccines and Medical Biologicals (IVAC) in Vietnam. The PATH supported phase 1 clinical trials from vaccine produced at IVAC are expected to be initiated Regorafenib cost by 2012. The close working relationship between BARDA, PATH and WHO, as well as the Vietnam Trichostatin A Ministry of Health, has helped to assure that this project will be successful, and the egg-based production facility, partially funded through these collaborations, will be able to produce millions of doses per year of pandemic vaccine. While experts world-wide recognized the potential for an outbreak of pandemic influenza to occur at any time and many countries had begun preparing for such events, much more was needed to be fully prepared

when H1N1 emerged. Nevertheless, H1N1 had some positive effects on the progress of WHO grantee programmes. In several countries, it served to heighten awareness and interest at the government level to move from focusing solely on building influenza vaccine capacity to encouraging larger scale production and stimulating new markets. This is important to ensure sustainable production

and use of the vaccine. The best evidence for this is in India where the Serum Institute of India, supported by the HHS/WHO funding, has developed, licensed and distributed over 5 million doses of its H1N1 Fossariinae LAIV. Technology and intellectual property transfer activities mediated by WHO have resulted in expanded LAIV production in both India and Thailand using vaccines based upon the LAIV backbone developed by the Institute of Experimental Medicine in Russia. Coupled with the ground-work established by WHO, high-performing partners, and local government support, this vaccine was ready in unprecedented time. BARDA is now considering the next phases of this important international capacity-building effort. In addition to seeing through the milestones in the WHO cooperative agreements grantees, BARDA is committed to supporting new initiatives for 2010–2011 laid out in the WHO programme and cooperative agreement as well as US-based training for personnel from the WHO/HHS funded sites.

5% of eugenol oil on fresh carp, Cyprinus carpio L fillets durin

5% of eugenol oil on fresh carp, Cyprinus carpio L. fillets during storage in fish industry. 29 This breakthrough research suggests very high demand for isolation and quantification of eugenol from herbal formulations. With increasing human population food requirements and growing interest in need of animal protein sources from fishes, there is high demand for development of analytical method which can easily separate and quantify eugenol from other

plant interfering constituents, to be safely used in food preservation industry worldwide. Thus, validated RP-HPLC method demonstrated in this paper quantifies micrograms of eugenol in short span of time and is thus highly sensitive. This method will definitely aid in quantifying, separating potential anti-microbial commercial phytochemical like eugenol and provide highly reproducible data for quality control analysis in food technology related industries. In conclusion, solvent extraction methods by RP-HPLC PDA Lumacaftor detection method was developed and validated for quantitative estimation of eugenol from Ayurvedic formulations of Caturjata Churna, Lavangadi Vati, Sitopaladi Churna, Jatiphaladi Churna and Clove oil successfully. The developed analytical chromatographic method offered adequate calibration curve/linearity, LOD, LOQ, system suitability, precision,

accuracy, solution stability, robustness method application and has been fully validated as per ICH guidelines. This method can be successfully applied for quality control of herbal medicines containing eugenol to screen toxic botanicals, microbial toxins, pesticides, fumigation, foreign organic matter, fingerprinting/marker AZD6738 compound for identification and standardization of botanical drugs containing eugenol. This will aid in identification of chemical constituents marker compounds such as chemical and active marker compounds that possess therapeutic activity of the herbal drug which are major constituents of plant materials, identifying herbal materials and standardize botanic preparations during all aspects of manufacturing process. Non-specific serine/threonine protein kinase All authors have none to declare. The authors gratefully acknowledge the technical

assistance rendered by Mandar Mhatre, Sreenath Nandakumar Nair, Varun Satose, Ashish Singh, Naresh Shejawal,Kavita Mhatre, Dipti Singh, Santosh Daval and Karan Sarvaiya in completing this project. “
“The conventional tableting method used involves first making granules and then compressing into tablets by way of direct (granule) tableting, but the need in recent years for process validation, GMP and automation of production processes has focused renewal of attention on the direct tableting, which involves few steps. Direct tableting of pharmaceutical materials is desirable to reduce the cost of production and is a modern technique in the tablet manufacturing, many processing steps are limited in direct compression and also wet granulation cannot be used with sensitive drugs.

We observed small clusters of GFP+ cells in draining popliteal LN

We observed small clusters of GFP+ cells in draining popliteal LNs at 24 h post-injection, however amplification of the GFP signal using anti-GFP Ig was required to visualise these rare cells (Fig. 7C). These results suggest pDNA-encoded Ag is in the tissue draining lymph node as early

as 24 h post-injection. As previously described for the EαGFP system, we could detect Y-Ae+ EαRFP+ cells in the subcapsular sinus (Fig. 7D) and paracortical areas of draining LNs, 24 h after EαRFP injection. However many Y-Ae+ cells in the T cell areas were EαRFP negative, suggesting that Ag had already been processed and hence no longer fluorescent, or that these cells contained levels of EαRFP below the limits of detection by immunofluorescence microscopy. We observed cells of a similar phenotype, Y-Ae+EαRFP−, in mice immunised with pCI-EαRFP. Three days after plasmid injection, we detected rare, sparsely distributed Y-Ae+EαRFP− PLX 4720 cells in the subcapsular sinus JAK assay of draining inguinal lymph nodes (Fig. 7E and F). No staining was observed in pCIneo-immunised mice or using the isotype control, mIgG2b (data not shown). We were unable to conclusively demonstrate pMHC+ cells in the T cell areas of peripheral lymph nodes or spleen, presumably because the level of pMHC complex on these very rare cells was below the sensitivity of detection of the immunofluorescence staining protocol. Others

have shown previously that Ag dose has consequences for both the number of pMHC complexes generated and T cell activation in vivo and hence we were interested to know if the apparently low level pMHC we observed on CD11c+ cells was Histamine H2 receptor sufficient for T cell activation and whether the pMHC complex staining we observed 3 days after DNA injection correlated temporally with the activation of Eα-specific CD4+ T cells. We also wanted to establish the precise anatomical localisation and kinetics of CD4+ T cell activation and proliferation following

intramuscular DNA injection and hence determine the relationship between pDNA distribution, pMHC+ cells and T cell activation. Therefore we used adoptive transfer of Eα-specific TEa T cells and kinetic analysis of activation and cell division following injection with Eα-expressing plasmids, to readout antigen presentation in vivo. The TEa TcR recognises the same pMHC complex as the Y-Ae mAb [12] and thus the initial activation/blastogenesis of these cells should be a good indication of the first time these cells see Ag, i.e. the precise timing of Ag presentation. At early timepoints (e.g. 12 h), we observed a transient upregulation of surface CD69 in both non-Tg and Tg CD4 T cells in pCI-EαRFP- and pCIneo-immunised mice, indicative of DNA-induced non-specific activation (data not shown). However by 24 h surface CD69 had returned to control levels (data not shown).

Rare binding of avian influenza viruses was detected in the trach

Rare binding of avian influenza viruses was detected in the trachea of pigs [64], which contrasts with the reported presence of sialic acids with α2,3 linkage to galactose as determined by lectin histochemistry [60]. Conversely, avian influenza viruses were shown to abundantly bind to alveolar macrophages [64], whereas expression of sialic acids learn more with α2,3 linkage to galactose was not detected [59]. Furthermore, evidence of HPAIV H5N1

infection of respiratory epithelial cells in the upper respiratory tract and trachea of humans, as determined by immunohistochemistry on cultures of human tissues infected ex vivo [71] and on tissues from fatal human cases [72] contrasts with no or rare binding of lectin and avian influenza virus in these tissues. There may be several reasons for this lack of consensus on the target cells for avian influenza viruses in the human respiratory tract. First, the attachment

patterns of lectins used in find protocol lectin histochemistry studies are variable, and depend on the lectin isoform and pre-treatment regimens applied to the cells or tissues [73]. Second, the specificity of influenza virus for the glycan receptor on the host cell is determined not only by the type of glycan-sialic acid linkage, but also by glycan modifications such as fucosylation, sulphation, and additional sialylation [74] and [75] and thus cannot be determined by techniques

that only measure glycan-sialic acid linkages. Third, the respiratory cells or tissues tested in these studies differed in their history and origin, which may have a non-negligible effect on receptor expression on the cell surfaces. Therefore, further research is required to determine the affinity of avian and other influenza viruses for different parts of the human respiratory tract and other organs, calling for standardization of the methodology used to determine the distribution of target cells. The accessibility of receptors for virus attachment at the portal second of entry in humans is essential for successful cross-species transmission of influenza viruses from animal reservoirs to humans. Target cells for avian influenza viruses are most abundant in deeper regions of the respiratory tract [64]. Inhaled droplets of small size deposit abundantly in these regions [76] and may harbour and deposit influenza virus particles in the vicinity of target cells for attachment. However, mucins secreted by mucous cells along the respiratory tract can bind to and trap avian influenza virus particles, and the ciliated respiratory epithelium continuously propels particles away from the lower respiratory tract.