Intermolecular interactions between glycomodules of plant cell wall arabinogalactan-proteins and extensins

Hydroxyproline-rich glycoproteins (HRGPs) are a unique component of plant cell walls, undergoing extensive posttranslational modification such as proline hydroxylation and hydroxyproline-O-glycosylation. Arabinogalactan proteins (AGPs) and extensins are major members of the HRGP superfamily. AGPs have repetitive AlaHyp, SerHyp, and ThrHyp peptides, the Hyp residues being glycosylated with large type II arabinogalactan polysaccharides, while extensins contain characteristic SerHyp4 and SerHyp2 motifs with arabinosylated (1-4 residues) Hyp. Although they are less than ten percent in all wall materials, AGPs and extensins play important roles in all aspects of plant growth and development. The detailed mechanisms of their functions are still under investigation. However, many of the functions may be attributed to their adhesive properties. Here, we used a forced unbinding technique to measure relative adhesive potential of the well characterized (AlaHyp)51 and (SerHyp4)18 glycomodules representing AGPs and extensins, respectively. In the presence of different wall ions such as protons, Ca2+, and boron, the glycomodules exhibited different adhesive patterns, suggesting that the wall ion-regulated intermolecular interactions/adhesions between AGPs and/or extensins may be involved in maintaining wall-plasma membrane integrity during wall loosening processes such as wall elongation or expansion. This research applies a biophysical approach to understand the biological function of plant cell wall glycoproteins.

Does calculation of ankle brachial pressure index need revision?

Peripheral arterial disease (PAD) is a commonly encountered but a commonly under-diagnosed condition in clinical practice. Ankle brachial pressure index (ABI) is a widely used procedure in its detection. It is also a very good prognostic marker not only of PAD but also of mortality. According to the current guidelines ABI of a side i.e. either the left or the right, is the quotient of the higher of the systolic blood pressures (SBP) of the two ankle arteries of that limb (either the anterior tibial artery or the posterior tibial artery) and the higher of the two brachial SBP of upper limbs. With the currently existing method of ABI calculation, considering only the higher of the SBP of the two ankle arteries, a distal stenosis of the ankle arterial system with the lower SBP, may be missed. We suggest a modification to the currently existing of calculating ABI. The method has been termed by us as the low ankle pressure method. In this method the lowest ankle pressure between the two ankle arteries of a particular side is to be the numerator and the denominator could be the same as before. A study or a series of studies comparing our proposed method with the current one are needed to test its clinical utility.

Epidemiology of peripheral arterial disease

Peripheral arterial disease (PAD) is not an uncommon but a commonly neglected condition by many medical practitioners. It is a disease that threatens not only the limb but also life itself! Atherosclerosis is the commonest cause of PAD in the western nations. The cardinal symptom is intermittent claudication (IC) but majority of the patients are asymptomatic. Ankle-brachial pressure index (ABI) is an effective screening tool for PAD. A diminished ABI (< 0.9) is a definite sign of PAD. Its prevalence steadily increases with age. In Germany almost a fifth of the patients aged over 65 years suffer from it. With increasing life expectancy the prevalence of PAD is on the increase. PAD is a manifestation of diffuse and severe atherosclerosis. It is a strong marker of cardiovascular disease; a very strong association exists between PAD and other atherosclerotic disorders such as coronary artery disease (CAD) and cerebrovascular disease (CVD). PAD is an independent predictor of high mortality in patients with CAD. Smoking, diabetes mellitus and advancing age are the cardinal risk factors. A relatively small number of PAD patients lose limbs by amputation. Most paitients with PAD die of either heart attacks or strokes and they die of the former conditions far earlier than controls. PAD still remains an esoteric disease and there is a significant lack of awareness of this condition by many physicians, and therefore under-diagnosed and underestimated. Measures to promote awareness of PAD among physicians and the society in general are needed. Since most patients are asymptomatic and carry potentially significant morbidity and mortality risks, screening for PAD should be made a routine practice at primary care level.

Furazolidone in multi-resistant childhood typhoid fever

Multi-drug-resistant Salmonella typhi infection is an emerging public health problem in most developing countries. Fifty children up to the age of 12 years whose blood cultures were positive for S. typhi, mostly drug-resistant ones, were treated with oral furazolidone in a prospective year-long study. Defervescence occurred in 96% of the treated group with a mean duration for response of 5.9 days. No clinically significant side-effects were noted. Furazolidone was found to be efficacious, safe and cost-effective in the treatment of most cases of childhood typhoid fever caused by multi-resistant S. typhi.