Treatment challenges in the management of difficult-to-treat gram-positive infections: A consensus view apropos therapeutic role of novel anti-MRSA antibiotics, levonadifloxacin (IV) and alalevonadifloxacin (oral).

PURPOSE: Treatment of antibiotic-resistant Gram-positive infections (GPIs), including methicillin-resistant Staphylococcus aureus (MRSA) is becoming increasingly difficult, particularly in patients with multiple co-morbidities who require antibiotics with greater safety and a consistent pharmacokinetic/pharmacodynamic (PK/PD) profile. Such difficult-to-treat GPIs are often associated with poor outcomes, extended hospital stay and increased expenditure. This can be partly attributed to the limited safety and aberrant PK/PD profile of existing anti-MRSA antibiotics. In this context, intravenous levonadifloxacin and its oral prodrug alalevonadifloxacin are novel anti-MRSA antibiotics that have significant advantages over conventional anti-Gram-positive antibiotics. The purpose of this paper was to generate a consensus on the optimal use of levonadifloxacin and alalevonadifloxacin for tackling resistant Gram-positive infections in patients with multiple co-morbidities. METHOD: Using a modified Delphi approach that combines critical appraisal of evidence and expert opinion, therapeutic use of levonadifloxacin and alalevonadifloxacin in various clinical scenarios and specific unmet conditions was deliberated. Fifteen expert members from medicine, critical-care, emergency, microbiology, and intensive-care disciplines participated and voted on 11 pre-conceived statements. When there was at least 70 % agreement, a consensus was reached. RESULTS: Following the voting, agreements were reached on 10 out of the 11 statements. Broadly, a consensus was reached in defining the therapeutic role of levonadifloxacin and alalevonadifloxacin in the treatment of various clinical indications involving resistant Gram-positive pathogens, including MRSA, in patients with co-morbidities, such as co-existing or increased risk for kidney dysfunction or hepatic disease and/or immunosuppression; also, in therapeutically challenging conditions caused by Gram-positive bacteria such as bacteraemia, bone and joint infection, diabetic foot infection, febrile neutropenia, and hospital-acquired pneumonia. CONCLUSIONS: This consensus supports the therapeutic use of levonadifloxacin and alalevonadifloxacin in the treatment of antibiotic-resistant GPIs, including those caused by MRSA and certain polymicrobial infections, in patients with multiple co-morbidities requiring drug with adequate safety and consistent efficacy.

Topical Esmolol Hydrochloride as a Novel Treatment Modality for Diabetic Foot Ulcers: A Phase 3 Randomized Clinical Trial.

Importance: Preclinical and phase 1/2 studies with esmolol hydrochloride suggest its potential role in treatment of diabetic foot ulcers (DFUs). Objective: To study the efficacy of topical esmolol for healing of uninfected DFUs. Design, Setting, and Participants: A randomized, double-blind, multicenter, phase 3 clinical trial was conducted from December 26, 2018, to August 19, 2020, at 27 referral centers across India. Participants included adults with DFUs. Interventions: Participants were randomized after a run-in phase (1 week) to receive esmolol, 14%, gel with standard of care (SoC), SoC only, or vehicle with SoC (3:3:1 proportion) for 12 weeks (treatment phase) and followed up subsequently until week 24. Main Outcomes and Measures: The primary outcome was the proportion of wound closure within the 12-week treatment phase in the esmolol with SoC and SoC only groups. Analysis was conducted using an intention-to-treat safety evaluable population, full analysis set or efficacy-evaluable population, and per-protocol population comparing the esmolol plus SoC and SoC only treatment groups. Results: In the study, 176 participants (122 men [69.3%]; mean [SD] age, 56.4 [9.0] years; mean [SD] hemoglobin A1c level, 8.6% [1.6%]) with DFUs classified as University of Texas Diabetic Wound Classification system grade IA and IC (mean [SD] ulcer area, 4.7 [2.9] cm2) were randomized to the 3 groups. A total of 140 participants were analyzed for efficacy. The proportion of participants in the esmolol with SoC group who achieved target ulcer closure within 12 weeks was 41 of 68 (60.3%) compared with 30 of 72 (41.7%) participants in the SoC only group (odds ratio [OR], 2.13; 95% CI, 1.08-4.17; P = .03). A total of 120 participants completed the end of study visit which were analyzed. Target ulcer closure by the end of the study (week 24) was achieved in 44 of 57 (77.2%) participants in the esmolol with SoC group and 35 of 63 (55.6%) participants in the SoC only group (OR, 2.71; 95% CI, 1.22-5.99; P = .01). The median time for ulcer closure was 85 days for the esmolol with SoC group and was not estimable for SoC only group. Significant benefits of Esmolol with SoC were seen in patients with factors that impede the healing of DFU. Treatment-emergent adverse events were noted in 18.8% of the participants, but most (87.3%) of these events were not attributable to the study drug. Conclusions and Relevance: In this multicenter, randomized, double-blind clinical trial, the addition of esmolol to SoC was shown to significantly improve the healing of DFUs. With these results, topical esmolol may be an appropriate addition to SoC for treating DFUs. Trial Registration: ClinicalTrials.gov Identifier: NCT03998436; Clinical Trial Registry, India CRI Number: CTRI/2018/11/016295.

Novel Topical Esmolol Hydrochloride (Galnobax) for Diabetic Foot Wound: Phase 1/2, Multicenter, Randomized, Double-Blind, Vehicle-Controlled Parallel-Group Study.

We aimed to assess safety and dose-finding efficacy of esmolol hydrochloride (Galnobax) for healing of diabetic foot ulcer (DFU). This is phase 1/2 multicenter, randomized, double-blind vehicle-controlled study. Participants having diabetes and noninfected, full-thickness, neuropathic, grade I or II (Wagner classification) DFU, area 1.5-10 cm2, and unresponsive to standard wound care (at least 4 weeks) were randomized to receive topical Galnobax 14% twice daily (BID), Galnobax 20% BID, Galnobax 20% once daily (OD)+vehicle, or vehicle BID with standard of care. The primary efficacy end point was the reduction in area and volume of target ulcer from baseline to week 12 or wound closure, whichever was earlier. The wound duration was 12.5 weeks (5-49.1 weeks) and wound area 4.10 ± 2.41 cm2 at baseline. The ulcer area reduction was 86.56%, 95.80%, 80.67%, and 82.58% (p = 0.47) in the Galnobax 14%, Galnobax 20%, Galnobax20%+vehicle, and vehicle only groups, respectively. Ulcer volume reduction was 99.40% in the Galnobax14%, 83.36% in Galnobax20%, 55.41% in the Galnobax20%+vehicle, and 84.57% in vehicle group (p = 0.86). The systemic concentration of esmolol was below the quantification limit (10 ng/mL) irrespective of doses of Galnobax (Cmax esmolol acid 340 ng/mL for 14% Galnobax, AUC 2.99 ± 4.31 h*µg/mL after single dose). This is the first clinical study of the short acting beta blocker esmolol hydrochloride used as novel formulation for healing of DFU. We found that esmolol when applied topically over wounds had minimal systemic concentration establishing its safety for wound healing in patients with diabetes. Esmolol hydrochloride is a safe novel treatment for DFU.

Novel topical esmolol hydrochloride improves wound healing in diabetes by inhibiting aldose reductase, generation of advanced glycation end products, and facilitating the migration of fibroblasts.

Aims/Objectives: Wound healing in people with diabetes is delayed secondary to impaired nitric oxide generation, advanced glycation end products (AGE), and poor migration of epithelial cells. We developed a novel topical esmolol hydrochloride (Galnobax) and assessed its efficacy for wound healing in streptozocin-induced diabetic hairless rat. Methods: All experiments were performed at an animal laboratory and tertiary-care research facility. Ex vivo aldose reductase inhibition was assessed from enzymes obtained from a bacterial culture (spectrophotometer), sorbitol content in homogenized red blood cells, and AGE in glucose and bovine serum by fluorometry following the addition of esmolol in varying concentrations. A scratch assay of human fibroblasts, endothelial cells, and keratinocytes was assessed under a high-glucose environment and after esmolol by phase-contrast microscopy. The efficacy evaluation of the topical application of Galnobax (14 and 20%) or vehicle was conducted in streptozotocin-induced diabetic hairless rats, and endogenous nitrite and hydroxyproline from homogenized wound tissue were measured along with pharmacokinetic and dermal toxicity in Hanford miniature swine. Results: Esmolol inhibited the formation of sorbitol by 59% in erythrocytes in comparison to glucose-induced sorbitol levels. AGE generation in bovine serum albumin was reduced at 1 mM esmolol concentrations (2.6 ± 1.7) compared with control (p < 0.05) and similar to that of diclofenac (2.5 ± 1.3). Esmolol at 1 and 10 µM enhanced the migration of fibroblasts, epithelial cells, and keratinocytes compared with control. The nitric oxide levels (day 7) were 44 and 112% higher with Galnobax (14%) than those of the diabetic group (p < 0.05) and the vehicle control group (p < 0.05), respectively. The days 7 and 14 hydroxyproline in the wound was higher by 22 and 44% following Galnobax (14%) compared with the diabetic and vehicle control groups. The wound area exhibited better reduction with Galnobax at 14% up to day 10 follow-up compared with the controls. The pharmacokinetic and dermal toxicity in miniature swine suggested no significant adverse event with Galnobax. Conclusions: Topical esmolol hydrochloride is a novel, safe, and effective treatment modality that acts through pleotropic mechanisms to hasten wound healing in diabetes.

Calcific Myonecrosis: Solving the Diagnostic Dilemma.

We report the clinico radiological presentation of an unusual case of an ossified soft tissue mass in the leg in a 74-year-old man. Calcific myonecrosis is a rare soft tissue condition characterized by calcified mass within a compartment. Differential diagnosis of myonecrosis include myositis ossificans and sarcomas with propensity for extra-osseous calcification like extra-skeletal osteosarcoma, Ewing's sarcoma and epithelioid sarcoma. This entity is a late complication to trauma and prolonged high pressure state within the leg compartments. With imaging alone, the differential of soft tissue sarcoma could be ruled out but typical natural history of disease and radiopathological features aided in the diagnosis.

[Homeopathic Medicine Reduces Pain and Hemarthrosis in Moderate and Severe Hemophilia: A Multicentric Study].

BACKGROUND: Hemarthrosis is a common clinical presentation of patients with severe and moderately severe hemophilia. Severe pain, swelling, and loss of function involving knee, ankle, elbow, and shoulder joints are commonly seen. In India, except for paracetamol and some non-steroidal anti-inflammatory drugs (NSAIDs), opiate analgesics are not easily available even in the mainstay of treatment; i.e., factor concentrates are also not available regularly. Hence, there is an unmet need for exploring alternative management strategies in this condition in India. OBJECTIVE: To assess the effect of homeopathic medicines on pain and acute hemarthrosis in hemophilia when factor concentrates are not available and paracetamol in adequate doses proves inadequate. PATIENTS: 343 patients with hemophilia (PWH) from Nashik, Mumbai, and Surat presenting with hemarthrosis were prescribed homeopathic medicines in addition to paracetamol and RICE (rest, immobilization, cold application, and elevation). They were assessed using standard techniques. RESULTS: 1,679 episodes of hemarthrosis in major joints were encountered between December 2007 and March 2014, in 343 patients. In 1,580 of the 1,679 hemarthrosis episodes (94.1%), bleeding/inflammation was arrested and pain relieved with homeopathic medication. Additional factor concentrate was required in 99 patients (4.48%). The mean pain score improved from 6.88 ± 2.118 to 1.5 ± 0.34 over 6-24 h following the homeopathic medicines (p < 0.0001). The swellings were also substantially reduced (p < 0.001). The number of joint bleeds per month was reduced significantly under the influence of therapy (p < 0.0001), showing the long-term disease-modifying effect of the treatment. CONCLUSION: Homeopathic medicines without factor concentrates appeared to reduce bleeding and pain in PWH presenting with hemarthrosis and could have influenced the long-term frequency of bleeding.

Story of a Giant Endometrial Polyp in Asymptomatic Postmenopausal Female.

Endometrial polyps are localized overgrowth of endometrial glands and stoma through the uterine cavity. They are associated with postmenopausal bleeding, infertility and menorrhagia and are affected by unbalanced oestrogen therapy or increased frequency of tamoxifen exposure. We report a case of giant endometrial polyp in postmenopausal female without vaginal bleeding and hormone or drug use. A 65-year-old, postmenopausal female P3L2 with hypertension and Diabetes Mellitus (DM) came for routine health check-up. Her physical examination was normal. Pelvic examination uterus was multiparous sized, mid positioned and bilateral fornices were free. Patient was planned for hysteroscopic guided biopsy as her Ultrasonography (USG) showed endometrial thickness to be 12.3 mm. On hysteroscopy, there was hyperplastic endometrium with large endometrial polyp of size 8.5 cm. Polypectomy was done and the same was sent for histopathological evaluation. Report showed cystic hyperplasia without atypia. To summarize, postmenopausal female will not always present with symptoms and USG can also quite frequently miss the diagnosis, so proper evaluation is needed using hysteroscopy which is gold standard for diagnosis and treatment of endometrial polyp.

Synthesis of isofagomine-pyrrolidine hybrid sugars and analogues of (-)-steviamine and (+)-hyacinthacine C5 using 1,3-dipolar cycloaddition reactions.

Highly regioselective 1,3-dipolar cycloadditions between d-arabinose-derived nitrones and d-mannitol-derived trans-olefins have been utilized to synthesize isofagomine-pyrrolidine hybrid sugars, hydroxymethylated analogues of (-)-steviamine and analogues of (+)-hyacinthacine C5. All of the new compounds were subsequently tested against several commercially available glycosidases, and some of them showed good and selective glycosidase inhibition.

Homeopathic medicines substantially reduce the need for clotting factor concentrates in haemophilia patients: results of a blinded placebo controlled cross over trial.

BACKGROUND: Modern management of haemophilia patients is expensive: 90% of expenditure is on clotting factor concentrates. Any intervention which reduces the need for clotting factor concentrates in these patients without compromising the quality of life is of interest. AIMS AND OBJECTIVES: To investigate the effectiveness of individualised homeopathic medicines in reducing the requirement of factor concentrates in haemophilia patients. MATERIALS AND METHODS: In a single blind placebo controlled cross over trial 28 consecutive persons with haemophilia (PWH) with severe (24) or moderately severe (4) disease received standard management with placebo homeopathy for 1 year and active homeopathic treatment in the subsequent year with the same conventional management. There was no wash out period. They received standard managements for any acute emergency during the study period. Development of inhibitor during the study period was a withdrawal criterion. Sample size for the trial was calculated as 24 PWH. Transfusion requirements, bleeding scores, pain scores were evaluated blind by independent experts. Homeopathic medicines were selected by experienced homeopathic physicians depending on clinical condition of the patient. Chi-squared and paired t tests were used in statistical analysis. RESULTS: 28 patients were recruited. Homeopathic medicines improved frequency of bleeding, extent of bleeding, blood products consumed and pain scores (P<0.0001). There was also significant improvement in well being. Plasma levels of clotting factors did not change. No patients developed inhibitors during the study there were no dropouts. CONCLUSION: Individualised homeopathic medicines may have an important supportive role in the management of PWH, where blood products and factor concentrates are not easily available. Larger, perhaps multicentric trials are warranted.

Application of GQSAR for Scaffold Hopping and Lead Optimization in Multitarget Inhibitors.

Many literature reports suggest that drugs against multiple targets may overcome many limitations of single targets and achieve a more effective and safer control of the disease. However, design of multitarget drugs presents a great challenge. The present study demonstrates application of a novel Group based QSAR (GQSAR) method to assist in lead optimization of multikinase (PDGFR-beta, FGFR-1 and SRC) and scaffold hopping of multiserotonin target (serotonin receptor 1A and serotonin transporter) inhibitors. For GQSAR analysis, a wide variety of structurally diverse multikinase inhibitors (225 molecules) and multiserotonin target inhibitors (162 molecules) were collected from various literature reports. Each molecule in the data set was divided into four fragments (kinase inhibitors) and three fragments (serotonin target inhibitors) and their corresponding two-dimensional fragment descriptors were calculated. The multiresponse regression GQSAR models were developed for both the datasets. The developed GQSAR models were found to be useful for scaffold hopping and lead optimization of multitarget inhibitors. In addition, the developed GQSAR models provide important fragment based features that can form the building blocks to guide combinatorial library design in the search for optimally potent multitarget inhibitors.

A comprehensive structure-activity analysis of protein kinase B-alpha (Akt1) inhibitors.

Protein kinase B (PKB, also known as Akt) belongs to the AGC subfamily of the protein kinase superfamily. Akt1 has been reported as a central player in regulation of metabolism, cell survival, motility, transcription and cell-cycle progression, among the signalling proteins that respond to a large variety of signals. In this study an attempt was made to understand structural requirements for Akt1 inhibition using conventional QSAR, k-nearest neighbour QSAR and novel GQSAR methods. With this intention, a wide variety of structurally diverse Akt1 inhibitors were collected from various literature reports. The conventional QSAR analyses revealed the key role of Baumann's alignment independent topological descriptors along with other descriptors such as the number of hydrogen bond acceptors, hydrogen bond donors, rotatable bonds and aromatic oxygen (SaaOcount) along with molecular branching (chi3Cluster), alkene carbon atom type (SdsCHE-index) in governing activity variation. Further, the GQSAR analyses show that chemical variations like presence of hetero-aromatic ring, flexibility, polar surface area and fragment length present in the hinge binding fragment (in the present case fragment D) are highly influential for achieving highly potent Akt1 inhibitors. In addition, this study resulted in a k-nearest neighbour classification model with three descriptors suggesting the key role of oxygen (SssOE-index) and aromatic carbon (SaaCHE-index and SaasCE-index) atoms electro-topological environment that differentiate molecules binding to Akt1 kinase or PH domain. The developed models are interpretable, with good statistical and predictive significance, and can be used for guiding ligand modification for the development of potential new Akt1 inhibitors.

Rationalizing protein-ligand interactions for PTP1B inhibitors using computational methods.

Protein tyrosine phosphatase 1B inhibitors were reported to have anti-diabetic properties and hence this enzyme has become interesting drug target in the recent time. Huge amount of data is available in public domain about the PTP1B inhibitors in the form of X-ray structures. This study is an attempt to transform this data into useful knowledge which can be directly used to design more effective protein tyrosine phosphatase inhibitors. In this study, we have built quantitative models for activity of co-crystallized protein tyrosine phosphatase inhibitors using two new approaches developed in our group, i.e. receptor-ligand interaction and Structure-based compound optimization, prioritization and evolution based on receptor-ligand interaction descriptors and residue-wise interaction energies as descriptors, respectively. These models have given insights into the receptor-ligand interactions essential for modulating the activity of PTP1B inhibitors. An external validation set of 22 molecules was used to test predictive power of these models on external set molecules.

Structure-based design of novel Chlamydomonas reinhardtii D1-D2 photosynthetic proteins for herbicide monitoring.

The D1-D2 heterodimer in the reaction center core of phototrophs binds the redox plastoquinone cofactors, Q(A) and Q(B), the terminal acceptors of the photosynthetic electron transfer chain in the photosystem II (PSII). This complex is the target of the herbicide atrazine, an environmental pollutant competitive inhibitor of Q(B) binding, and consequently it represents an excellent biomediator to develop biosensors for pollutant monitoring in ecosystems. In this context, we have undertaken a study of the Chlamydomonas reinhardtii D1-D2 proteins aimed at designing site directed mutants with increased affinity for atrazine. The three-dimensional structure of the D1 and D2 proteins from C. reinhardtii has been homology modeled using the crystal structure of the highly homologous Thermosynechococcus elongatus proteins as templates. Mutants of D1 and D2 were then generated in silico and the atrazine binding affinity of the mutant proteins has been calculated to predict mutations able to increase PSII affinity for atrazine. The computational approach has been validated through comparison with available experimental data and production and characterization of one of the predicted mutants. The latter analyses indicated an increase of one order of magnitude of the mutant sensitivity and affinity for atrazine as compared to the control strain. Finally, D1-D2 heterodimer mutants were designed and selected which, according to our model, increase atrazine binding affinity by up to 20 kcal/mol, representing useful starting points for the development of high affinity biosensors for atrazine.

A novel copper complex of 3-benzoyl-alpha methyl benzene acetic acid with antitumor activity mediated via cyclooxygenase pathway.

Pancreatic cancer (PC) is characterized as one of the deadliest malignancies and its treatment is a great challenge to clinical oncologists. Expression of COX-2 is detectable in 75% of PCs among which 50% showed overexpression, suggesting the importance of COX-2 enzyme and its metabolic product prostaglandin E2 (PGE(2)) in PC. Here the authors report the synthesis and biological activity of a novel COX-2 inhibitor, FPA-306, and its effects on PC cells with different levels of COX-2 expression. Using MTT assay, the authors found a significant growth inhibition of BxPC-3 cells treated by FPA-306 with an IC(50) of 10 micromol/L, which was lower than that of ketoprofen (IC(50) = 35.4 micromol/L) and celecoxib (IC(50) > 100 micromol/L). There was no such effect found in MIAPaCa cell line, which does not express COX-2. The authors also found dose dependent reduction in cell survival and induction of apoptosis by FPA-306 treatment in BxPC-3 cells but not in MIAPaCa cells. These results were correlated with apoptosis data and secreted PGE(2) levels. The molecular modeling of FPA-306 in the COX-2 active site showed that FPA-306 is potentially able to inhibit the activity of enzyme by blocking the active site, thereby resulting in decreased PGE(2) production. The authors also found a significant reduction of COX-2 at the mRNA and protein levels together with downregulation of NF-kappaB DNA binding activity and its downstream genes, Bcl-2 and survivin. These results suggest that FPA-306 is an effective and potent agent in inhibiting the growth of PC cells.

Synthesis, molecular characterization, and biological activity of novel synthetic derivatives of chromen-4-one in human cancer cells.

The synthesis and characterization of Schiff base derivatives of 3-formylchromone 3-6 (FPA-120 to FPA-123), the minimal biologically active structural motif of soy isoflavone, genistein, and their copper(II) complexes 7-10 (FPA-124 to FPA-127) are reported here. These copper complexes possess distorted square-planar geometries capable of stabilizing Cu2+/Cu+ redox forms. The molecular modeling study revealed that the key interaction of the metal complexes was with amino acids in the pleckstrin homology (PH) and the kinase domain of the PKB (Akt) protein. Copper complex 7 significantly forms stronger charge interactions in the kinase domain than genistein, leading to better stabilization in the active pocket. In vitro evaluation of copper complexes against hormone-independent and metastatic breast (BT20), prostate (PC-3), and K-ras mutant (COLO 357) and K-ras wild-type (BxPC-3) pancreatic cancer cells revealed that 7 was the most potent compound which exhibited PKB (Akt protein) inhibitory activities and caused NF-kappaB inactivation in a well-established orthotopic pancreatic tumor model using COLO 357 cells. An inverse relationship was observed between IC50 values of the anti-proliferative activities and the Cu2+/Cu+ redox couple for these compounds, which may provide a rapid screen for evaluating the efficacy of active metallodrugs affecting redox-sensitive transcription factors such as NF-kappaB and its upstream target, the PKB (Akt) pathway, in multiple cancers.

The role of genistein and synthetic derivatives of isoflavone in cancer prevention and therapy.

Genistein, one of the predominant soy isoflavones, has been shown to compete with 17beta-estradiol for estrogen receptor binding because of its structural similarity, resulting in agonistic or antagonistic activity. It causes inhibition of cell growth in breast and prostate cancers in vivo and in vitro. From gene expression profiles, genistein has been found to regulate the genes that are critical for the control of cell proliferation, cell cycle, apoptosis, oncogenesis, transcription regulation, and cell signal transduction pathways. It has been reported that genistein induces apoptosis and inhibits activation of NF-kappaB and Akt signaling pathways, both of which are known to maintain a balance between cell survival and apoptosis. Recently, we found that genistein sensitized cancer cells to apoptosis induced by chemotherapeutic agents including docetaxel, gemcitabine and cisplatin through inactivation of NF-kappaB in multiple cancer cell lines. To enhance the anti-cancer activity of genistein, we have synthesized structurally-modified derivatives of isoflavone based on the structural requirements for optimal anti-cancer effect. We found that these synthetic derivatives of isoflavone exerted higher anti-cancer activity with lower IC50. These derivatives of isoflavone also induced more apoptosis compared to genistein. These results suggest that genistein and synthetic structurally-modified derivatives of isoflavone may be promising agents for cancer chemoprevention and therapy either alone or in combination with existing chemotherapeutic agents.

Three-dimensional QSAR using the k-nearest neighbor method and its interpretation.

In this paper we report a novel three-dimensional QSAR approach, kNN-MFA, developed based on principles of the k-nearest neighbor method combined with various variable selection procedures. The kNN-MFA approach was used to generate models for three different data sets and predict the activity of test molecules through each of these models. The three data sets used were the standard steroid benchmark, an antiinflammatory and an anticancerous data set. The study resulted in kNN-MFA models having better statistical parameters than the reported CoMFA models for all the three data sets. It was also found that stochastic methods generate better models resulting in more accurate predictions as compared to stepwise forward selection procedures. Thus, kNN-MFA method represents a good alternative to CoMFA-like methods.

Modeling and interactions of Aspergillus fumigatus lanosterol 14-alpha demethylase 'A' with azole antifungals.

Recent identification of the sterol 14-alpha demethylase genes (CYP51 A and B) from Aspergillus fumigatus and other species by Mellado et al. (J. Clin. Microbiol. 2001, 39(7), 2431-2438), has opened up possibilities of investigating the interactions of azole antifungals with the enzyme(s) from fungi. This study describes for the first time, a model of the three-dimensional structure of A. fumigatus 14-alpha demethylase (AF-CYP51A), using the crystal structure of Mycobacterium tuberculosis 14-alpha demethylase (PDB code:1EA1) as a template. The paper also describes the various interactions between azole antifungals and the target from A. fumigatus (AF-CYP51A). Quantitative evaluation of these interactions is done using COMBINE analysis to understand contributions of active site residues to ligand activity. It also provides explanation for the activity/inactivity of different ligands for AF-CYP51A.