Mechanisms of Action of Dorsal Root Ganglion Stimulation.

The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.

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.

COVID-19 infection and vaccination against COVID-19: Impact on managing demyelinating CNS disorders in Southern India- experience from a demyelinating disease registry.

BACKGROUND AND OBJECTIVE: The impact of COVID-19 infection and the effect of COVID-19 vaccinations on patients with demyelinating central nervous system disease in low middle income countries (LMIC's) have not been reported in detail earlier. We sought to identify risk factors associated with COVID-19 infection and the role of vaccination in order to develop management guidelines relevant to our patients. METHODS: A total of 621 patients from our registry that included 297 MS and 324 non MS disorders (Aquaporin- 4 antibody positive [50], Myelin oligodendrocyte glycoprotein antibody positive [81], seronegative [162] and clinically isolated syndrome [31]) were contacted. COVID-19 infection and vaccination status were queried. Patients who self reported COVID-19 infection based on a positive RT PCR report were compared with non infected patients to identify factors associated with susceptibility for COVID-19 infection. Univariate and multivariate analysis of potential risk factors included demographic and clinical features, body mass index (BMI), presence of comorbidities, absolute lymphocyte count, treatment types and vaccination status. RESULTS: Sixty seven patients with MS and 27 with non MS disorders developed COVID-19 infection. Among them 81 patients had mild infection and remained quarantined at home. All 13 patients who needed hospitalization recovered. Vaccination status was known in 582 patients among whom 69.8% had completed or taken one dose of vaccine at the time of inquiry. Majority of treated patients (61.3%) were on nonspecific immunosuppressants. In univariate analysis, presence of ≥1 comorbidity was significantly associated with COVID-19 infection in both MS (p value 0.01, OR-2.28, 95%CI- 1.18-4.4) and non MS patients (p- 0.001, OR-4.4, 95% CI-1.88-10.24). In the latter, BMI ≥ 30 (p-0.04, OR-3.27, 95% CI- 0.98-10.87) and EDSS score ≥ 3 (p-0.02, OR- 2.59,95% CI- 1.08-6.23) were other significant associations. History of prior COVID-19 vaccination was associated with reduced frequency of COVID-19 infection among MS (p- 0.001,OR- 0.24,95% CI- 0.13-0.43) and non MS patients (p- 0.0001,OR-0.14, 95% CI- 0.058-0.35). In multivariate analysis presence of comorbidities significantly increased and prior vaccination significantly reduced frequency of COVID-19 infection for both MS and related disorders. Concurrent disease modifying treatments showed a trend for association with infection. In the unvaccinated group, patients on disease modifying treatment were significantly at risk of infection, 81.5% unvaccinated and treated versus 18.5% who were unvaccinated and untreated (p- 0.0001, OR-10.1, 95% CI-0.56-2.11). CONCLUSION: Frequency and severity of COVID-19 infection was low among our patient cohort. Higher rate of infection in the treated group was significantly seen among unvaccinated patients. Our preliminary results suggests that in LMIC's, where "off label therapies" with inexpensive immunosuppressives are the main disease modifying drugs, mRNA vaccinations appear safe and effective against severe COVID-19 infection.

Clinical efficacy and pharmacokinetics of colistimethate sodium and colistin in critically ill patients in an Indian hospital with high endemic rates of multidrug-resistant Gram-negative bacterial infections: A prospective observational study.

BACKGROUND: Safe and effective use of colistin requires robust pharmacokinetic (PK) and pharmacodynamic (PD) data to guide dosing. AIM: To evaluate the pharmacokinetics of colistimethate sodium and colistin in critically ill patients and correlate with clinical efficacy and renal function. MATERIALS AND METHODS: Twenty critically ill adult patients with colistin-susceptible multidrug-resistant (MDR) infections and normal renal function treated with intravenous colistimethate sodium - at a 9 million units (270 mg CBA) loading dose followed by maintenance (MD) of 3 million units t.i.d, 24 hours later - were evaluated for clinical cure (CC) at the end of therapy. Patient characteristics and plasma colistin levels at 0, 0.5, 1, 2, 4, 8 and 12 hours after the loading dose and at 1, 2 and 8 hours after the eighth and ninth infusion of MD were evaluated. Colistimethate sodium and colistin levels were measured by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). RESULTS: Among the 20 patients who were evaluated, 60% had pneumonia. Predominant pathogens were Klebsiella pneumoniae and Acinetobacter spp. Clinical cure was 50% (10/20). Mean peak loading dose concentrations were 3 ± 1.1 mg/L (1.75-5.14) and 2.37 ± 1.2 mg/L (1.52-5.54) for 'cure' and 'failure' groups, respectively (p = 0.13), while mean steady-state (Cssavg) concentrations were 2.25 ± 1.3 mg/L and 1.78 ± 1.1 mg/L in 'cure' and 'failure' groups, respectively (p = 0.19). Nephrotoxicity was 5% on day 7 of therapy. However, bacteriological cure could not be correlated with PK/PD. CONCLUSIONS: Subtherapeutic Cssavg with clinical failure and lower efficacy without significant nephrotoxicity highlights the need for therapeutic drug monitoring to guide colistin dosing.

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.

Incidence of spontaneous non-neoplastic lesions in transgenic CBYB6F1-Tg(HRAS)2Jic mice.

Since 2003, the Tg.rasH2 model has been accepted by regulatory agencies worldwide for 26-week short-term carcinogenicity assays as an alternative to the standard 2-year assays in conventional mice. However, over the decade, the number of actual studies conducted with alternative mouse models has remained low. The primary cause for low acceptance of this model has been lack of a historical database for the incidence of spontaneous lesions. Recently, we published the historical control database on spontaneous tumors in the Tg.rasH2 mice. The purpose of this publication is to present a large database pertaining to the non-neoplastic spontaneous lesions noted in Tg.rasH2 mice from studies conducted at our facility. Lesions that are considered unique in Tg.rasH2 mice are skeletal muscle myopathy, vascular anomalies involving various organs, and mesenteric arterial thrombosis. Other notable lesions are extramedullary hematopoiesis of spleen, subacute inflammatory foci in the liver, and infiltration of histiocytes in the lungs.

Historical control data of spontaneous tumors in transgenic CByB6F1-Tg(HRAS)2Jic (Tg.rasH2) mice.

The Tg.rasH2 mouse is a hemizygous transgenic mouse, approved by regulatory agencies for carcinogenicity assessment. However, the absence of a historical database for the incidence of spontaneous neoplasms has subsequently led to reluctance by some pharmaceutical companies to adopt the use of this short-term carcinogenicity assay. Our laboratory has generated a database summarizing the mortality, body weights, and the incidence of spontaneous tumors in 1420 male and female mice assigned to 26 studies conducted at our facility. In addition, we present the incidence of tumors in positive control mice treated with urethane from these studies. Mortality in the vehicle-treated Tg.rasH2 mouse was low (average of 1% in each study). The most common spontaneous tumors in the Tg.rasH2 mice were alveolar bronchiolar adenoma of the lungs (10.14% in males and 5.77% in females) and hemangiosarcoma of the spleen (3.66% in both males and females). The incidence of all other tumors was generally very low. In the positive control, urethane-treated animals, the incidence of alveolar bronchiolar adenomas and alveolar bronchiolar carcinomas in the lungs was 93.69% and 42.88% in males and 92.43% and 72.79% in females, respectively. In addition, the incidence of splenic hemangiosarcomas in urethane-treated males was 89.18% and 92.25% in females. The 6-month Tg.rasH2 assay is more precise, faster, and more economical than the conventional 2-year mouse assays because of the low incidence of background tumors, very high survival, shorter duration, and the lower number of animals used.

Reduction in the number of animals and the evaluation period for the positive control group in Tg.rasH2 short-term carcinogenicity studies.

The lack of a clear guidance on the adequate number of animals used for positive controls in the short-term (26-weeks) transgenic mouse carcinogenicity studies has resulted in the use of high number of animals. In our earlier Tg.rasH2 studies, 25 mice/sex were used in the urethane-positive control dose groups that were sacrificed by 18 weeks. Based on a robust response, several of our protocols for Tg.rasH2 studies with 15 mice/sex and terminal sacrifice at 17 ± 1 weeks were submitted and accepted by the Carcinogenicity Assessment Committee of the US Food and Drug Administration since we demonstrated close to 100% response for the development of lung and splenic tumors (target organs) in 500 mice/sex. These 500 mice/sex included 17 groups of 25 mice/sex and 5 groups of 15 mice/sex.  The objective of this investigation was to determine whether the number of animals can be further reduced along with the shortened duration of exposure to urethane. Accordingly, 10 Tg.rasH2 mice/sex/group were administered a total of 3 intraperitoneal (IP) injections of urethane (1000 mg/kg per day) on study days 1, 3, and 5, and the presence of tumors in the lungs and spleen was evaluated after 8, 10, 12, 14, or 16 weeks. Our results demonstrate that 100% of the mice at 8 weeks had developed lung tumors, whereas close to 100% of the mice at 14 weeks had developed splenic tumors. Based on the development of lung tumors alone in 100% of the mice, we recommend that 10 mice/sex are sufficient and that these mice can also be sacrificed as early as 10 ± 1 weeks following the administration of urethane.

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.

Genotoxic assessment and toxicity evaluation of peginesatide in CByB6F1 hybrid mice.

Peginesatide is a PEGylated, investigational, peptide-based erythropoiesis-stimulating agent (ESA) that was designed and engineered to stimulate specifically the erythropoietin receptor dimer that governs erythropoiesis. Clinical use of peginesatide is anticipated to result in chronic dosing in chronic kidney disease (CKD) patients, and the nonclinical data to support development should include an evaluation of carcinogenic potential evaluation. Peginesatide was not mutagenic or clastogenic in a standard genotoxicity battery of tests. Doses for a rasH2 transgenic mouse carcinogenicity assay were defined in a 28-day study in the wild-type littermates of the rasH2 transgenic mouse strain, using intravenous doses of 1-25 mg/kg on days 1 and 22. The findings were consistent with exaggerated pharmacology, including polycythemia, with associated increases in hemoglobin level and extramedullary hematopoiesis and bone marrow hypercellularity.

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.

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.