Effect of Plant Population Density on Growth and Weed Smothering Ability of Cowpea (Vigna unguiculata (L.) Walp.)

Akidi (cowpea), a landrace of Vigna unguiculata, was grown at densities of 30,121 (D1), 40,323 (D2), 50,000 (D3), 60,976 (D4), 80,645 (D5), and 0 (D6) plants/hectare in a randomized complete block design to assess the effect of intraspecific (between cowpeas) on its performance and weed smothering ability in the instance of utilizing it in intensive fallow management. At 10 weeks after sowing (WAS), the low-density plants (D1) were shorter (127.55 ± 1.84cm), produced highest stem diameter of 11.59 ± 0.86mm, and shoot dry weight/plant (12.46 ± 0.70g). The high-density cowpea treatment (D5) had the longest vines (197.93 ± 1.54cm) and relatively low shoot dry weight/plant (9.22 ± 0.64g). The D5 treatment was significantly better than other treatments in weed control and dry matter yield per unit area. Tithonia diversifolia and Sida acuta which are heliophytes were encountered in low-density treatments of D1 and D3, where the highest light intensities reached the soil

The practice of hepatocellular cancer surveillance in Nigeria

Background: Hepatocellular cancer is a disease of global and public health importance due to the widespread distribution of risk factors and associated high case fatality. Hepatocellular Cancer (HCC) in Sub-Saharan Africa is commonly seen among the younger age groups (<45 years) who present mostly in the terminal stage, when the disease is not amenable to any curative therapy. Hepatocellular Carcinoma surveillance employs the use of simple, cheap and readily available investigations, to detect early curable cancer in individuals with risk factors for HCC.Objectives:The aim of this study is to assess the practice of hepatocellular cancer screening among physicians.Methodolgy:This is a nationwide online survey carried out among physicians who care for patients with HCC. A questionnaire was sent out via a web link to all consenting doctors in Nigeria. The responses were collated in a cloud-based application and data was analysed using Epi-info version 20.Results:Atotal of 218 respondents, 142 were males (65.1 %) with a mean age of 37.6 ± 5.7 years. The modal age group was 31-40 years 153 (69.5%). The main factors considered as a hindrance to surveillance were; the cost of the tests (57.7%), failure of return of patients (50.5%) and not being aware of a surveillance program (45.2 %). The majority of the respondents were Gastroenterologists and Family Physicians. 54% of the gastroenterologists and 64% of the family physicians have never offered HCC surveillance to their patients.Conclusion:This survey highlights a knowledge gap in HCC surveillance among physicians. There is a need to make HCCsurveillance a daily routine among patients at risk by all physicians. Keywords: Surveillance, Hepatocellular Carcinoma, HBV, HCV, Cancer screening

Site-specific PEGylation of protein bisulfide bonds using a three-carbon bridge

MEDLINE® is the source for the MeSH terms of this document.The covalent conjugation of a functionalized poly(ethylene glycol) (PEG) to multiple nucleophilic amine residues results in a heterogeneous mixture of PEG positional isomers. Their physicochemical, biological, and pharmaceutical properties vary with the site of conjugation of PEG. Yields are low because of inefficient conjugation chemistry and production costs high because of complex purification procedures. Our solution to these fundamental problems in PEGylating proteins has been to exploit the latent conjugation selectivity of the two sulfur atoms that are derived from the ubiquitous disulfide bonds of proteins. This approach to PEGylation involves two steps: (1) reduction to release the two cysteine thiols and (2) re-forming the disulfide by bis-alkylation via a three-disulfide carbon bridge to which PEG was covalently attached. During this process, irreversible denaturation of the protein did not occur. Mechanistically, the conjugation is conducted by a sequential, interactive bis-alkylation using α,β-unsaturated β′- monosulfone functionalized PEG reagents. The combination of (a) maintaining the protein's tertiary structure after disulfide reduction, (b) the mechanism for bis-thiol selectivity of the PEG reagent, and (c) the steric shielding of PEG ensure that only one PEG molecule is conjugated at each disulfide bond. PEG was site-specifically conjugated via a three-carbon bridge to 2 equiv of the tripeptide glutathione, the cyclic peptide hormone somatostatin, the tetrameric protein L-asparaginase, and to the disulfides in interferon α-2b (IFN). SDS-PAGE, mass spectral, and NMR analyses were used to confirm conjugation, thiol selectivity, and connectivity. The biological activity of the L-asparaginase did not change after the attachment of four PEG molecules. In the case of IFN, a small reduction in biological activity was seen with the single-bridged IFN (without PEG attached). A significantly larger reduction in biological activity was seen with the three-carbon disulfide single-bridged PEG-IFNs and with the double-bridged IFN (without PEG attached). The reduction of the PEG-IFN's in vitro biological activity was a consequence of the steric shielding caused by PEG, and it was comparable to that seen with all other forms of PEG-IFNs reported. However, when a three-carbon bridge was used to attach PEG, our PEG-IFN's biological activity was found to be independent of the length of the PEG. This property has not previously been described for PEG-IFNs. Our studies therefore suggest that peptides, proteins, enzymes, and antibody fragments can be site-specifically PEGylated across a native disulfide bond using three-carbon bridges without destroying their tertiary structure or abolishing their biological activity. The stoichiometric efficiency of this approach also enables recycling of any unreacted protein. It therefore offers the potential to make PEGylated biopharmaceuticals as cost-effective medicines for global use.Peer reviewe