Sequencing of 3-O sulfate containing heparin decasaccharides with a partial antithrombin III binding site

Heparin- and heparan sulfate-like glycosaminoglycans (HLGAGs) represent an important class of molecules that interact with and modulate the activity of growth factors, enzymes, and morphogens. Of the many biological functions for this class of molecules, one of its most important functions is its interaction with antithrombin III (AT-III). AT-III binding to a specific heparin pentasaccharide sequence, containing an unusual 3-O sulfate on a N-sulfated, 6-O sulfated glucosamine, increases 1,000-fold AT-III's ability to inhibit specific proteases in the coagulation cascade. In this manner, HLGAGs play an important biological and pharmacological role in the modulation of blood clotting. Recently, a sequencing methodology was developed to further structure-function relationships of this important class of molecules. This methodology combines a property-encoded nomenclature scheme to handle the large information content (properties) of HLGAGs, with matrix-assisted laser desorption ionization MS and enzymatic and chemical degradation as experimental constraints to rapidly sequence picomole quantities of HLGAG oligosaccharides. Using the above property-encoded nomenclature-matrix-assisted laser desorption ionization approach, we found that the sequence of the decasaccharide used in this study is DeltaU(2S)H(NS,6S)I(2S)H(NS, 6S)I(2S)H(NS,6S)IH(NAc,6S)GH(NS,3S,6S) (+/-DDD4-7). We confirmed our results by using integral glycan sequencing and one-dimensional proton NMR. Furthermore, we show that this approach is flexible and is able to derive sequence information on an oligosaccharide mixture. Thus, this methodology will make possible both the analysis of other unusual sequences in HLGAGs with important biological activity as well as provide the basis for the structural analysis of these pharamacologically important group of heparin/heparan sulfates.     

Dicarbonyl Electrophiles Mediate Inflammation-Induced Gastrointestinal Carcinogenesis

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Long-term medical management of gastro-esophageal reflux disease: how long and when to consider surgery?

Gastro-esophageal reflux disease is a chronic, long standing disease. Spontaneous remission of GERD is rare and conservative management including life style modification measures is unlikely to relieve symptoms. Majority of patients with reflux disease require long-term acid suppressants. Proton pump inhibitors are the choice of drugs in management of these patients. The end point of treatment is not clear. Duration of treatment is individual based. The symptoms may be intermittent or on most days of the week. The treatment is therefore either a short course which may be for 8 to 12 weeks or 6 months, or continuous, intermittent or 'on-demand' basis. The maintenance therapy is with the lowest proton pump inhibitor (PPI) dose necessary for adequate symptom relief. Whether long-term PPI actually alters the natural history of reflux disease other than to reduce the incidence of peptic stricture is not known. Reported adverse effects due to PPI include Clostridium difficile colitis and bacterial gastroenteritis, osteoporosis, and vitamin B12 deficiency. Anti-reflux surgery is indicated for youngsters, those not willing for long-term PPI i.e. for years, large volume refluxers, especially the supine refluxers and bile refluxers.     

Delivery of therapeutic levels of heparin and low-molecular-weight heparin through a pulmonary route

Although heparin and low-molecular-weight heparins (LMWH) have been widely used clinically as anticoagulants, their broader use has been limited by the lack of noninvasive delivery methods for this class of molecules. In this study, we demonstrate an efficient, rapid, and reproducible delivery system for heparin through the lungs that is not confined to particles of a certain geometric or aerodynamic diameter. Importantly, blood levels after intrapulmonary administration of either heparin or LMWH were comparable to that of s.c. administration but are characterized by a more rapid onset of action (t(1/2) = 40 min vs. 2.5 h, respectively). Furthermore, we show in animal models, that inhaled heparin species efficiently inhibit diseases such as thrombosis and emphysema, and that the repetitive inhalation of formulated LMWH results in no observable toxicity from the delivery of reproducible systemic levels of heparin or LMWH.     

Early postoperative deaths of recipients after deceased donor liver transplantation

Aim-Background

Liver transplant often results in haemodynamic and biochemical changes in the immediate postoperative period, often causing concern to the treating physician.

The aim

of the present study is to determine the preoperative clinical profile, along with the haematological and biochemical changes following deceased donor liver transplantation (DDLT) in the immediate 7-day postoperative period.

Method

A detailed assessment of the patients preoperative clinical diagnosis, presence of co-morbid illness and postoperative haematological, biochemical, and clinical events was made between survivors and those who died. Various parameters were compared between two groups to help us understand the variants that determined the early postoperative outcome in DDLT patients.

Results

A total of 26 patients were categorized into two groups: 18 patients were allocated to Group 1 (survivors) and 8 patients to Group 2 (mortality). There was no difference in the fluctuation of haemoglobin levels between the two groups. Early leukocytosis and persistent azotemia predicted early morbidity and mortality. A significant fall of platelet count predicted mortality. Transaminases showed a significant increase between the 2^nd and 3rd postoperative day, after which they stabilised and showed a downwards trend by the 7th to 9th postoperative day in both groups. Intraoperative events like cardiac arrhythmias, ischaemic cardiac events, pulmonary thromboembolism, hepatic artery thrombosis, sepsis and multiorgan failure rank among the causes of death.

Conclusion

Preoperative co-morbid illness, postoperative worsening azotemia, persistent leukocytosis, and sepsis and cardiac events in the immediate postoperative period are factors that appear to predict the outcome post DDLT.