Impact of DNA ligase inhibition on the nick sealing of polβ nucleotide insertion products at the downstream steps of base excision repair pathway

DNA ligase (LIG) I and IIIα finalize base excision repair (BER) by sealing a nick product after nucleotide insertion by DNA polymerase (pol) β at the downstream steps. We previously demonstrated that a functional interplay between polβ and BER ligases is critical for efficient repair, and polβ mismatch or oxidized nucleotide insertions confound final ligation step. Yet, how targeting downstream enzymes with small molecule inhibitors could affect this coordination remains unknown. Here, we report that DNA ligase inhibitors, L67 and L82-G17, slightly enhance hypersensitivity to oxidative stress-inducing agent, KBrO3, in polβ+/+ cells more than polβ-/- null cells. We showed less efficient ligation after polβ nucleotide insertions in the presence of the DNA ligase inhibitors. Furthermore, the mutations at the ligase inhibitor binding sites (G448, R451, A455) of LIG1 significantly affect nick DNA binding affinity and nick sealing efficiency. Finally, our results demonstrated that the BER ligases seal a gap repair intermediate by the effect of polβ inhibitor that diminishes gap filling activity. Overall, our results contribute to understand how the BER inhibitors against downstream enzymes, polβ, LIG1, and LIGIIIα, could impact the efficiency of gap filling and subsequent nick sealing at the final steps leading to the formation of deleterious repair intermediates.

DeepADRA2A: predicting adrenergic α2a inhibitors using deep learning

Adrenergic α2a (ADRA2A) receptors play a crucial role in modulating various physiological actions, thereby influencing the proper functioning of different systems in the body. ADRA2A regulation is associated with a wide range of effects, including alterations in blood pressure, hypertension, heightened heart rate, etc. Inhibition of these receptors results in the release of noradrenaline, leading to heightened physiological activity, improved alertness, reduced blood pressure, and alleviation of hypertension. Conventional approaches for identifying ADRA2A inhibitors are burdened with high costs, labor-intensive procedures, and time-consuming processes. In light of these challenges, leveraging the power of artificial intelligence offers a promising solution for drug discovery and development. This study endeavors to harness the potential of artificial intelligence to develop robust models capable of accurately predicting ADRA2A inhibitors and non-inhibitors. By doing so, we aim to streamline and expedite the identification of potential drug candidates in this domain. In this study, we employed four different machine learning (ML) and deep learning (DL) algorithms to develop prediction models based on various molecular descriptors (1D, 2D, and molecular fingerprints). Among these models, the DL-based prediction model demonstrated superior performance, achieving accuracies of 98.25% and 97.23% on the training and test datasets, respectively. These results underscore the efficacy of DL-based model, as a highly effective tool for predicting ADRA2A inhibitors. The model is made available at https://github.com/PGlab-NIPER/DeepADRA2A.git.Communicated by Ramaswamy H. Sarma.

Regression of lipoedematous scalp following cryolipolysis using an icepack, with a novel dermoscopic feature of yellow background

The novel use of cryolipolysis via icepacks, a readily available and inexpensive device, is described for lipoedematous scalp with subjective and objective relief. This is a simple solution to a troublesome, intractable condition and may readily be utilized for patient benefit. Juxtaposing pre and post clinical images.

DNA ligase I variants fail in the ligation of mutagenic repair intermediates with mismatches and oxidative DNA damage

DNA ligase I (LIG1) joins DNA strand breaks during DNA replication and repair transactions and contributes to genome integrity. The mutations (P529L, E566K, R641L and R771W) in LIG1 gene are described in patients with LIG1-deficiency syndrome that exhibit immunodeficiency. LIG1 senses 3'-DNA ends with a mismatch or oxidative DNA base inserted by a repair DNA polymerase. However, the ligation efficiency of the LIG1 variants for DNA polymerase-promoted mutagenesis products with 3'-DNA mismatches or 8-oxo-2'-deoxyguanosine (8-oxodG) remains undefined. Here, we report that R641L and R771W fail in the ligation of nicked DNA with 3'-8-oxodG, leading to an accumulation of 5'-AMP-DNA intermediates in vitro. Moreover, we found that the presence of all possible 12 non-canonical base pairs variously impacts the ligation efficiency by P529L and R771W depending on the architecture at the DNA end, whereas E566K exhibits no activity against all substrates tested. Our results contribute to the understanding of the substrate specificity and mismatch discrimination of LIG1 for mutagenic repair intermediates and the effect of non-synonymous mutations on ligase fidelity.

Association of Serum Ferritin Levels with Hematological Manifestations in Systemic Lupus Erythematosus Patients from Western India

OBJECTIVE

To identify the hematological manifestations and its association with serum ferritin levels in SLE patients from Western India.

METHODS

Ninety clinically diagnosed SLE patients fulfilling ACR criteria were included. Disease activity was assessed at the time of evaluation using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Sera were tested for serum ferritin levels by ELISA (Calbiotech, USA). Autoantibodies such as ANA, anti-dsDNA by indirect immunofluorescence test (IFA- Bio-Rad, USA) and anti-cardiolipin antibodies (ACA) to IgG and IgM isotypes and Anti-β2 GP antibodies to IgG and IgM isotypes were detected by ELISA using commercially available kits (Euroimmun, Lubeck, Germany).

RESULTS

Out of 90 SLE patients studied, 41 patients (45.6%) showed hematological abnormalities, where anemia (82.9%), leucopenia (26.8%), autoimmune hemolytic anemia (AIHA) (14.6%) and idiopathic thrombocytopenic purpura (ITP) were noted in (34.1%) patients. Mean±SD serum ferritin levels among SLE patients were 270.2±266.0 ng/ml as compared to 29.0±15.8 ng/ml healthy normal controls (p<0.0001). A positive correlation between serum ferritin levels and SLEDAI scores (r= 0.2640, p=0.0124) and anti-dsDNA positivity was noted (r=0.32, p<0.0001). Serum ferritin levels were negatively correlated with hemoglobin levels (r=-0.5964, p=0.0001), WBC count (r=-0.1705, p=0.2316), platelet count ((r=-0.1701, P=0.2375), C3 levels (r=-0.4417, p=0.0034) and C4 levels (r=-0.0363, p=0.8215).

CONCLUSIONS

Serum ferritin is an excellent marker of SLE which can be used for an evaluation of disease activity particularly in active stage of the disease mainly in patients having hematological and renal manifestations.

Pharmacokinetics of mycophenolate mofetil in Omani patients on cyclosporine or tacrolimus

BACKGROUND

Mycophenolate mofetil (MMF) reduces rejection in organ transplantation and is effective in controlling autoimmune diseases. Determining the area under the receiver operating characteristic curve (AUC) of MMF is not routine despite interindividual variability. The aim of this study was to look into MMF-AUC in Omani patients on cyclosporine (CsA) or tacrolimus (Tac).

METHODS

We measured MMF-AUC in 27 stable Omani patients. We used the 4-time-points-limited sampling strategy.

RESULTS

Sixteen, 8, and 3 recipients were receiving Tac, CsA, and calcineurin inhibitor (CNI)-free regimens, respectively. The mean MMF dose was 1,685 ± 442 mg/d. All except 3 patients were within or above the target AUC. The AUC was significantly higher in patients receiving Tac versus CsA. All patients on Tac were within or above the target AUC. Seven of the 8 patients with MMF-AUC above target were receiving Tac. Two of the 3 patients with MMF-AUC below target were on CsA.

DISCUSSION

These preliminary results confirm the significant interindividual variability of MMF-AUC. None of the recipients on Tac had an AUC below target. Most patients above the target AUC were receiving Tac. Two of the 3 patients with MMF-AUC below target were on CsA and receiving 1 g/d MMF. Patients on Tac are at risk of having higher than the target AUC, exposing them to overimmunosuppression. Recipients on CsA seem to require >1 g/d MMF.

CONCLUSIONS

These preliminary results encourage measuring the AUC of MMF. The fixed MMF dose regimen seems to be unreliable to predict the AUC. Preventing under- or overimmunosuppression offsets the burden.

Selenium intoxication with selenite broth resulting in acute renal failure and severe gastritis

Selenium (Se) is an essential trace element in human and animal nutrition. It is also widely utilized in industrial processes. Reports of acute selenium toxicity in humans are rare. We report a case of a 23-year-old female who consumed about 100 mL of liquid selenite broth and presented with severe nausea, vomiting, abdominal pain, hematemesis and acute renal failure (ARF). The serum selenium level was significantly increased. Gastro-duodenoscopy revealed severe corrosive gastritis. Renal biopsy showed features of acute tubular necrosis (ATN), affecting primarily the proximal tubules. The patient was managed with gastric lavage, blood transfusions, infusion of fresh frozen plasma (FFP) and platelet concentrates and hemo-dialysis. The patient was discharged five weeks after admission and her renal functions recovered completely by eight weeks after admission. She continues to be on regular follow-up for any possible sequelae of mucosal corrosive damage. This case highlights a case of selenium intoxication from selenite broth resulting in ARF and corrosive gastritis. The recovery was complete.

Retinal injury as an early manifestation of posttransplant thrombotic microangiopathy: recovery with plasma exchanges and conversion to sirolimus--case report and review of the literature

Thrombotic microangiopathy (TMA) remains a serious event. We report a case of occurrence of TMA in the immediate postoperative period after a living-related renal transplantation. A distinguished feature of the case was major, early involvement of the retina with marked by decreased visual acuity along with thrombocytopenia and renal functional impairment. The syndrome was reversible with plasma exchange and conversion from tacrolimus to sirolimus. The patient's renal function is excellent at 11 months after transplantation. Decreased visual acuity and cotton wool exudates may be the first manifestation of posttransplant TMA.

Donor Gender Balance in a Living-Related Kidney Transplantation Program in Oman

It has been observed in several Eastern and Western countries that there is a gender imbalance among kidney donors. In the international experience, approximately 65% of live kidney donors have been women. We retrospectively studied the distribution of female and male donors or recipients among living kidney transplantations performed from 1980 to 2005, namely 198 Omani recipients of living-related kidney transplantations. To examine cultural influences, transplantations performed or expatriates were excluded from the study. For the whole period, 98 out of 198 donors (49.5%) were women. The number of female recipients 75 of 198 (38%) versus males were 123 (62%) recipients. We then subdivided the period into three intervals: 1980 to 1990, 1991 to 2000, and 2001 to 2005. The numbers of female donors for these three periods were 29 of 64 (45%), 42 of 89 (47%), and 27 of 45 (60%), respectively. There was a persistent preponderance of male recipients ranging from 58% to 66% during these periods. We concluded that there was no gender imbalance for kidney donors. Nevertheless, there was a male preponderance in the recipient group.

Complete Regression of Cutaneous B-Cell Lymphoma in a Renal Transplant Patient After Conversion From Cyclosporin to Sirolimus

Posttransplant lymphoproliferative disease remains a serious morbidity. Herein we have reported a case of complete regression of a biopsy-proven B-cell lymphoma that occurred in the posttransplant period. A 48-year-old man received a living donor renal transplant for end-stage renal disease due to undetermined etiology. His initial immunosuppression consisted of corticosteroid, mycophenolate mofetil, and cyclosporin. The patient developed severe pneumonia within the first 2 months after transplantation due to Acineotobacter, fungus, and cytomegalovirus infections. He experienced a complete recovery and was discharged for regional follow-up. Four months after discharge, he was referred again because of presence of two nodules on his trunk. A biopsy of the nodules revealed B-cell lymphoma. Cyclosporin was stopped and he was converted to sirolimus. The lesions regressed progressively and completely within 7 weeks. The patient remains well without clinical relapses at 19 months after conversion. Renal functions remained stable. We postulated that the antincoplastic properties of sirolimus may have played an active part in the positive outcome.

Rhinocerebral mucormycosis associated with diabetic ketoacidosis

Rhinocerebral mucormycosis with hemiparesis occurred in a young woman who was not a known diabetic. Rhyzopus species grew from the initial nasal biopsy. The patient was treated with amphotericin B, in addition to control of diabetic ketoacidosis. Surgical intervention was not done. The patient died on the fourth day of hospitalisation.

Rhabdomyolysis and acute renal failure following a single dose of succinylcholine

A 30-year old with rhabdomyolysis and acute renal failure is presented. The attack followed a minor operation under general anaesthesia during which succinylcholine was administered as muscle relaxant. The fasciculations which occurred immediately after injection of succinylcholine may possibly have precipitated rhabdomyolysis.