Diabetic foot ulcers, their characteristics, and trends in survival: Real world outcomes at a tertiary care facility in India.

AIMS: Characteristics of diabetes-related foot ulcers (DFU), association with recurrence and amputation are poorly described in the Asian Indian population. METHODS: A prospectively maintained database was reviewed to characterize DFU and its association with amputation and recurrence. RESULTS: Of 200 patients, 63.5 % were male, the median age was 62 years (Min-Max:40-86), and median BMI was 27.90 kg/m2 (Min-Max:18.5-42.7). Median duration of Diabetes mellitus was 15 years (Min-Max:2-43). Complete healing occurred at a median of three months (Min-Max:0.23-37.62). Amputation for the current ulcer was required in 43.4 % of individuals. Ulcer recurrence was documented in 42.4 % instances, 66.1 % evolving on the ipsilateral side. Previous amputation was associated with the risk of subsequent amputation (Adjusted OR-3.08,p-0.047). Median time to ulcer recurrence was 4.23 years among those with amputation, in contrast to 9.61 years in those with healing. Cardiovascular death was the commonest cause of mortality, followed by sepsis. At a median follow up of 6.08 years, mortality at 1,3,5 and 10 years was 2.5 %,2.5 %,8.2 % and 30.9 % respectively among those who underwent amputation versus 0 %,0 %,10.1 % and 24.5 % respectively for those who achieved healing. CONCLUSIONS: Patients with DFU in India incur amputations at rates higher than conventionally described. With previous amputation, subsequent amputation risk triples. Ten-year mortality is 25%-30 %. Underestimates of the burden of recurrence and mortality are consequential of limited follow-up.

Polyamine-based small molecule epigenetic modulators.

Chromatin remodelling enzymes such as the histone deacetylases (HDACs) and histone demethylases such as lysine-specific demethylase 1 (LSD1) have been validated as targets for cancer drug discovery. Although a number of HDAC inhibitors have been marketed or are in human clinical trials, the search for isoform-specific HDAC inhibitors is an ongoing effort. In addition, the discovery and development of compounds targeting histone demethylases are in their early stages. Epigenetic modulators used in combination with traditional antitumor agents such as 5-azacytidine represent an exciting new approach to cancer chemotherapy. We have developed multiple series of HDAC inhibitors and LSD1 inhibitors that promote the re-expression of aberrantly silenced genes that are important in human cancer. The design, synthesis and biological activity of these analogues is described herein.

Enabling the intestinal absorption of highly polar antiviral agents: ion-pair facilitated membrane permeation of zanamivir heptyl ester and guanidino oseltamivir.

Antiviral drugs often suffer from poor intestinal permeability, preventing their delivery via the oral route. The goal of this work was to enhance the intestinal absorption of the low-permeability antiviral agents zanamivir heptyl ester (ZHE) and guanidino oseltamivir (GO) utilizing an ion-pairing approach, as a critical step toward making them oral drugs. The counterion 1-hydroxy-2-naphthoic acid (HNAP) was utilized to enhance the lipophilicity and permeability of the highly polar drugs. HNAP substantially increased the log P of the drugs by up to 3.7 log units. Binding constants (K(11(aq))) of 388 M(-1) for ZHE-HNAP and 2.91 M(-1) for GO-HNAP were obtained by applying a quasi-equilibrium transport model to double-reciprocal plots of apparent octanol-buffer distribution coefficients versus HNAP concentration. HNAP enhanced the apparent permeability (P(app)) of both compounds across Caco-2 cell monolayers in a concentration-dependent manner, as substantial P(app) (0.8-3.0 x 10(-6) cm/s) was observed in the presence of 6-24 mM HNAP, whereas no detectable transport was observed without counterion. Consistent with a quasi-equilibrium transport model, a linear relationship with slope near 1 was obtained from a log-log plot of Caco-2 P(app) versus HNAP concentration, supporting the ion-pair mechanism behind the permeability enhancement. In the rat jejunal perfusion assay, the addition of HNAP failed to increase the effective permeability (P(eff)) of GO. However, the rat jejunal permeability of ZHE was significantly enhanced by the addition of HNAP in a concentration-dependent manner, from essentially zero without HNAP to 4.0 x 10(-5) cm/s with 10 mM HNAP, matching the P(eff) of the high-permeability standard metoprolol. The success of ZHE-HNAP was explained by its >100-fold stronger K(11(aq)) versus GO-HNAP, making ZHE-HNAP less prone to dissociation and ion-exchange with competing endogenous anions and able to remain intact during membrane permeation. Overall, this work presents a novel approach to enable the oral delivery of highly polar antiviral drugs, and provides new insights into the underlying mechanisms governing the success or failure of the ion-pairing strategy to increase oral absorption.

Mechanism-based inhibitors of the aspartyl protease plasmepsin II as potential antimalarial agents.

Four aspartyl proteases known as plasmepsins are involved in the degradation of hemoglobin by Plasmodium falciparum, which causes a large percentage of malaria deaths. The enzyme plasmepsin II (Plm II) is the most extensively studied of these aspartyl proteases and catalyzes the initial step in the breakdown of hemoglobin by the parasite. Several groups have reported the design, synthesis, and evaluation of reversible peptidomimetic inhibitors of Plm II as potential antimalarial agents. We now report four peptidomimetic analogues, compounds 6-9, which are rationally designed to act as mechanism-based inhibitors of Plm II. Three of these analogues produce potent irreversible inactivation of the enzyme with IC(50) values in the low nanomolar range. Of these three compounds, two retain the low micromolar IC(50) values of the parent compound in Plasmodium falciparum (clone 3D7) infected erythrocytes. These analogues are the first examples of fully characterized mechanism-based inactivators for an aspartyl protease and show promise as novel antimalarial agents.

Biochemical effects of feeding soft drink and ethanol.

This work was undertaken to study whether consumption of alcoholic beverage mixed with soft drinks could reduce the metabolic effect caused by ethanol. When 24 hr fasted rats were intragastrically fed rum (with 40% ethanol) diluted (1:1) with water, 3.0 ml (0.5 g ethanol) per 100 g body weight and sacrificed 12 hr later in fasting condition, exhibited higher levels of triacyl glycerol, glucose, total cholesterol, high density lipoprotein (HDL), aspartate amino transferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP) in serum, higher levels of total cholesterol, triacyl glycerol and thiobarbituric acid reactive substances (TBARS) in both liver and kidneys, and lower levels of serum albumin. When fasted rats were fed 3.0 ml soft drink (0.31 mg caffeine), they showed increased levels of triacyl glycerol, glucose, ALT and ALP in the serum, TBARS in liver and kidneys, triacyl glycerol and total cholesterol in kidneys and lower levels of serum albumin. Soft drink feeding did not reduce serum total cholesterol but reduced HDL levels. Also soft drink did not alter liver lipids. When a mixture of 1.5 ml diluted rum (0.25 g ethanol) and 1.5 ml soft drink (0.154 mg caffeine) were fed to the fasted rats, the serum parameters increased similar to rats fed rum only except that total cholesterol and HDL cholesterol were unaltered. TBARS in kidneys and liver were also increased but triacyl glycerol levels were not altered. Thus feeding ethanol with soft drink does not reduce the metabolic effects of ethanol but it will prevent ethanol induced serum HDL cholesterol rise.

Quasi-equilibrium analysis of the ion-pair mediated membrane transport of low-permeability drugs.

The aim of this research was to gain a mechanistic understanding of ion-pair mediated membrane transport of low-permeability drugs. Quasi-equilibrium mass transport analyses were developed to describe the ion-pair mediated octanol-buffer partitioning and hydrophobic membrane permeation of the model basic drug phenformin. Three lipophilic counterions were employed: p-toluenesulfonic acid, 2-naphthalenesulfonic acid, and 1-hydroxy-2-naphthoic acid (HNAP). Association constants and intrinsic octanol-buffer partition coefficients (Log P(AB)) of the ion-pairs were obtained by fitting a transport model to double reciprocal plots of apparent octanol-buffer distribution coefficients versus counterion concentration. All three counterions enhanced the lipophilicity of phenformin, with HNAP providing the greatest increase in Log P(AB), 3.7 units over phenformin alone. HNAP also enhanced the apparent membrane permeability of phenformin, 27-fold in the PAMPA model, and 4.9-fold across Caco-2 cell monolayers. As predicted from a quasi-equilibrium analysis of ion-pair mediated membrane transport, an order of magnitude increase in phenformin flux was observed per log increase in counterion concentration, such that log-log plots of phenformin flux versus HNAP concentration gave linear relationships. These results provide increased understanding of the underlying mechanisms of ion-pair mediated membrane transport, emphasizing the potential of this approach to enable oral delivery of low-permeability drugs.

Polyaminohydroxamic acids and polyaminobenzamides as isoform selective histone deacetylase inhibitors.

A series of polyaminohydroxamic acids (PAHAs) and polyaminobenzamides (PABAs) were synthesized and evaluated as isoform-selective histone deacetylase (HDAC) inhibitors. These analogues contain a polyamine chain to increase affinity for chromatin and facilitate cellular import. Seven PAHAs inhibited HDAC >50% (1 microM), and two PABAs inhibited HDAC >50% (5 microM). Compound 17 increased acetylated alpha-tubulin in HCT116 colon tumor cells 253-fold but only modestly increased p21 (waf1) and acetylated histones 3 and 4, suggesting that 17 selectively inhibits HDAC 6. PABA 22 alone minimally increased p21 (waf1) and acetylated histones 3 and 4 but caused dose-dependent increases in p21 (waf1) in combination with 0.1 microM 5-azadeoxycytidine. Finally, 22 appeared to be a substrate for the polyamine transport system. None of these compounds were cytotoxic at 100 microM. PAHAs and PABAs exhibit strikingly different cellular effects from SAHA and have the potential for use in combination antitumor therapies with reduced toxicity.

Alkyl-substituted polyaminohydroxamic acids: a novel class of targeted histone deacetylase inhibitors.

The reversible acetylation of histones is critical for regulation of eukaryotic gene expression. The histone deacetylase inhibitors trichostatin (TSA, 1), MS-275 (2) and suberoylanilide hydroxamic acid (SAHA, 3) arrest growth in transformed cells and in human tumor xenografts. However, 1-3 suffer from lack of specificity among the various HDAC isoforms, prompting us to design and synthesize polyaminohydroxamic acid (PAHA) derivatives 6-21. We felt that PAHAs would be selectively directed to chromatin and associated histones by the positively charged polyamine side chain. At 1 microM, compounds 12, 15 and 20 inhibited HDAC by 74.86, 59.99 and 73.85%, respectively. Although 20 was a less potent HDAC inhibitor than 1, it was more potent than 2, more effective as an initiator of histone hyperacetylation, and significantly more effective than 2 at re-expressing p21Waf1 in ML-1 leukemia cells. On the basis of these results, PAHAs 6-21 represent an important new chemical class of HDAC inhibitors.