Development of 3D-QSAR and pharmacophoric models to design new anti-Trypanosoma cruzi agents based on 2-aryloxynaphthoquinone scaffold

In this work we have collected a set of 30 trypanosomicidal naphthoquinones and developed pharmacophoric and 3D-QSAR models as tools for the design of new potential anti-Chagasic compounds. Firstly, qualitative information was obtained from SAR and pharmacophoric models identifying some fragments around the 2-aryloxynaphthoquinone scaffold important for the antiparasitic activity. Then, 3D-QSAR CoMFA and CoMSIA models were developed. The models showed adequate statistical parameters where the steric, electrostatic, and hydrophobic features explain the trypanosomicidal effect. Therefore, to validate our models, we carried out the design, synthesis, and biological evaluation on T. cruzi epimastigotes of five new compounds (33a-e). According to CoMFA model, three out of five compounds showed pIC₅₀ values within one logarithmic unit of deviation. The two compounds that did not fit the predictions were those with high lipophilicity, which agreed with the SAR and pharmacophore models. Docking and molecular dynamic studies were performed on T. cruzi trypanothione reductase, in a proposed binding site for this type of naphthoquinone. Interestingly, 33a-e showed the same interaction pattern as a naphthoquinone inhibitor (2). Finally, predicted drug-likeness properties indicated that 33a-e have optimal oral bioavailability. Thus, this study provides new in silico models for obtaining novel trypanosomicidal compounds.

Salubrinal enhances eIF2α phosphorylation and improves fertility in a mouse model of Classic Galactosemia

Loss of galactose-1 phosphate uridylyltransferase (GALT) activity in humans results in Classic Galactosemia, and the GalT-deficient (GalT^-/-) mouse mimics the patient condition. GalT^-/- ovaries display elevated endoplasmic reticulum (ER) stress marker, BiP, and downregulated canonical phosphatidylinositol 3-kinase (Pi3k)/protein kinase B (Akt) growth/pro-survival signaling. Numbers of primordial follicles are reduced in the mutants, recapitulating the accelerated ovarian aging seen in human patients. We previously found that oral administration of the compound Salubrinal (an eIF2α phosphatase inhibitor), resulted in reduction of ovarian BiP expression, rescued Pi3k/Akt signaling, and a doubling of primordial follicles in GalT^-/- adults. Here, we further characterized galactosemic stress in GalT^-/- mice versus wild-type (WT) controls, and examined whether Salubrinal treatment improved broader reproductive parameters. We assessed the expression levels of factors of the unfolded protein response (UPR), and found that BiP, phospho-Perk, and phospho-eIF2α were all elevated in GalT^-/- ovaries. However, neither IKK activation (NFκB pathway) nor alternative Xbp1 splicing downstream of ER membrane protein Ire1α activation was induced, suggesting an Xbp1-independent UPR in galactosemic stress. Moreover, Salubrinal treatment significantly increased the number of ovulated eggs in mutant animals after gonadotrophic superovulation. Salubrinal treatment also normalized estrus cycle stage lengths and resulted in significantly larger litter sizes than vehicle-treated mutants. Overall, we show that Salubrinal protects against galactosemia-induced primordial follicle loss in a fashion that includes suppressing the de-phosphorylation of eIF2α, and that intervention in this way significantly improves and extends ovarian function, fertility, and fecundity.

Topological properties of a bipartite lattice of domain wall states

We propose a generalization of the Su-Schrieffer-Heeger (SSH) model of the bipartite lattice, consisting of a periodic array of domain walls. The low-energy description is governed by the superposition of localized states at each domain wall, forming an effective mono-atomic chain at a larger scale. When the domain walls are dimerized, topologically protected edge states can appear, just like in the original SSH model. These new edge states are formed exclusively by soliton-like states and therefore, the new topological states are qualitatively different from the regular SSH edge states. They posses a much longer localization length and are more resistant to on-site disorder, in marked contrast to the standard SSH case.

A combined CoMFA and CoMSIA 3D-QSAR study of benzamide type antibacterial inhibitors of the FtsZ protein in drug-resistant Staphylococcus aureus

A major problem today is bacterial resistance to antibiotics and the small number of new therapeutic agents approved in recent years. The development of new antibiotics capable of acting on new targets is urgently required. The filamenting temperature-sensitive Z (FtsZ) bacterial protein is a key biomolecule for bacterial division and survival. This makes FtsZ an attractive new pharmacological target for the development of antibacterial agents. There have been several attempts to develop ligands able to inhibit FtsZ. Despite the large number of synthesized compounds that inhibit the FtsZ protein, there are no quantitative structure-activity relationships (QSAR) that allow for the rational design and synthesis of promising new molecules. We present the first 3D-QSAR study of a large and diverse set of molecules that are able to inhibit the FtsZ bacterial protein. We summarize a set of chemical changes that can be made in the steric, electrostatic, hydrophobic and donor/acceptor hydrogen-bonding properties of the pharmacophore, to generate new bioactive molecules against FtsZ. These results provide a rational guide for the design and synthesis of promising new antibacterial agents, supported by the strong statistical parameters obtained from CoMFA (r(2)(pred) = 0.974) and CoMSIA (r(2)(pred) = 0.980) analyses.

Interaction of 5-aminosalicylic acid with nitrous acid: formation of the diazonium derivative and nitric oxide release

The reaction of 5-aminosalicylic acid (5-ASA) with nitrous acid has been studied at low pH under conditions that simulate a gastric environment. The course of the reaction was followed by UV–visible and fluorescence spectroscopy and the products were analyzed by high performance liquid chromatography (HPLC) with UV–visible and mass spectroscopic detectors. In addition, the formation of nitric oxide (NO) was estimated electrochemically. 5-ASA was readily consumed in a process catalyzed by chloride and thiocyanate, whose rate is first order in 5-ASA and second order in nitrous acid. 2-Hydroxy-5-diazonium benzoic acid (diazonium derivative) and NO were detected as products of the reaction. From the NO formation profiles, it is concluded that NO is produced as a minor product in a process parallel to the path that leads to generation of the diazonium derivative. While the formation of NO could be beneficial for the protection of the stomach, the generation of the diazonium derivative could be considered a potentially toxic process.

Population-based audit of colorectal cancer management in two UK health regions. Colorectal Cancer Working Group, Royal College of Surgeons of England Clinical Epidemiology and Audit Unit

BACKGROUND

To obtain information on the contemporary management of colorectal cancer in the UK to assist in the development of management guidelines, an independent, 1-year population audit was carried out in Trent Region and Wales.

METHODS

Data were collected on all patients admitted to hospital with a new diagnosis of colorectal cancer in a 1-year period.

RESULTS

Of 3520 patients, 3221 (91.5 per cent) had surgery. Emergency/urgent operations were carried out as the first procedure in 552 (17.1 per cent). Resection of the primary disease was achieved in 2859 (81.2 per cent) and this was deemed curative in 2070 (58.8 per cent). Twenty-one per cent of all patients had metastatic disease at presentation. Overall, 30-day operative mortality was 7.6 per cent (21.7 per cent for emergency/urgent and 5.5 per cent for scheduled/elective procedures). Anastomotic dehiscence occurred in 105 patients (4.9 per cent); this was 3.9 per cent after colonic resections and 7.9 per cent after anterior rectal resections. Elective rectal excision resulted in a permanent stoma in 486 of 1054 patients (46 per cent).

CONCLUSION

This initial report from a comprehensive, independent audit of colorectal cancer management shows improvement in some aspects of treatment as evidenced by improved anastomotic dehiscence and stoma rates when compared with previous studies. However, there has been little improvement in the proportion of patients presenting with advanced disease, and curative resection rates remain low.

Population-based audit of colorectal cancer management in two UK health regions. Colorectal Cancer Working Group, Royal College of Surgeons of England Clinical Epidemiology and Audit Unit

BACKGROUND

To obtain information on the contemporary management of colorectal cancer in the UK to assist in the development of management guidelines, an independent, 1-year population audit was carried out in Trent Region and Wales.

METHODS

Data were collected on all patients admitted to hospital with a new diagnosis of colorectal cancer in a 1-year period.

RESULTS

Of 3520 patients, 3221 (91.5 per cent) had surgery. Emergency/urgent operations were carried out as the first procedure in 552 (17.1 per cent). Resection of the primary disease was achieved in 2859 (81.2 per cent) and this was deemed curative in 2070 (58.8 per cent). Twenty-one per cent of all patients had metastatic disease at presentation. Overall, 30-day operative mortality was 7.6 per cent (21.7 per cent for emergency/urgent and 5.5 per cent for scheduled/elective procedures). Anastomotic dehiscence occurred in 105 patients (4.9 per cent); this was 3.9 per cent after colonic resections and 7.9 per cent after anterior rectal resections. Elective rectal excision resulted in a permanent stoma in 486 of 1054 patients (46 per cent).

CONCLUSION

This initial report from a comprehensive, independent audit of colorectal cancer management shows improvement in some aspects of treatment as evidenced by improved anastomotic dehiscence and stoma rates when compared with previous studies. However, there has been little improvement in the proportion of patients presenting with advanced disease, and curative resection rates remain low.

Surgeons' follow-up practice after resection of colorectal cancer

Consultant surgeons in two United Kingdom Health Regions were invited to complete a questionnaire on details of their personal management of patients with colon and rectal cancer, with particular emphasis on follow-up. Replies from 140 (94%) were analysed by the surgeon's subspecialty of colorectal and gastrointestinal surgery (group 1) and all others (group 2). There was a wide variation in the duration of followup, but no difference between the two groups. More group 1 surgeons carried out investigations as a routine after colonic (P < 0.01) and rectal (P < 0.01) resection. Colonoscopy was used more frequently by group 1 (P < 0.0001) and barium enema by group 2 surgeons (P < 0.05). Investigations to detect asymptomatic metastases were used as a routine by 33.3% of surgeons, in whom there was no concordance over the choice or combination of tests and no difference between the two groups of surgeons. There is no consensus among surgeons as to the ideal duration, intensity and method of follow-up after resection for colorectal cancer and little difference between the practice of colorectal and gastrointestinal surgeons and that of other specialists, except in the use of colonoscopy and barium enema. These results reflect the continuing lack of evidence on which to base the follow-up of patients after surgery for colorectal cancer.

Colorectal cancer pathology reporting: a regional audit

AIMS

To audit the information content of pathology reports of colorectal cancer specimens in one National Health Service region.

METHODS

All reports of colorectal cancer resection specimens from the 17 NHS histopathology laboratories in Wales during 1993 were evaluated against: (a) standards previously agreed as desirable by pathologists in Wales; and (b) standards considered to be the minimum required for informed patient management.

RESULTS

1242 reports were audited. There was notable variation in the performance of different laboratories and in the completeness of reporting of individual items of information. While many items were generally well reported, only 51.5% (640/ 1242) of rectal cancer reports contained a statement on the completeness of excision at the circumferential resection margin and only 30% (373/1242) of all reports stated the number of involved lymph nodes. All of the previously agreed items were contained in only 11.3% (140/1242) of reports on colonic tumours and 4.0% (40/1242) of reports on rectal tumours. Seventy eight per cent (969/1242) of colonic carcinoma reports and 46.6% (579/ 1242) of rectal carcinoma reports met the minimum standards.

CONCLUSIONS

The informational content of many routine pathology reports on colorectal cancer resection specimens is inadequate for quality patient management, for ensuring a clinically effective cancer service through audit, and for cancer registration. Template proforma reporting using nationally agreed standards is recommended as a remedy for this, along with improved education, review of laboratory practices in the light of current knowledge, and further motivation of pathologists through their involvement in multidisciplinary cancer management teams.