PREX: the plastidic DNA replication/repair enzyme complex of the apicomplexan parasites

Plasmodium and Toxoplasma nuclear genomes possess an ORF for a putative protein which contains domains homologous to the T7 bacteriophage primase-helicase like Twinkle enzyme and the prokaryotic family A polymerase enzyme. It has been hypothesised that this nuclear encoded protein may be responsible for the replication and repair of the apicoplast genome. Thus it was named PREX (Plastidic DNA Replication/Repair Enzyme complex). In Plasmodium falciparum the ORF (Pfprex) is 6,051 bp with no introns. RT-PCR data revealed that prex is present as a single transcript but western blot analysis of Plasmodium falciparum asexual parasite extracts revealed smaller size proteins indicating post-translational cleavage of the protein. Gene knock out studies have shown that the Pfprex genome locus is recombinogenic although parasites with a disrupted Pfprex locus appear to be unable to survive in culture. The analysis of the recombinant polymerase domain confirmed the polymerase property of the protein. In Toxoplasma gondii, the gene (Tgprex) is 7,740 bp long and interrupted by 19 introns as identified by RT-PCR. The polymerase functionality of the PREX protein was also confirmed by a study on recombinant protein from Toxoplasma gondii. The recombinant protein can be inhibited by known family A polymerase inhibitors. Other related apicomplexan parasites including Theileria, Babesia and Eimeria also possess this prex homologous gene in their nuclear genome. This PREX protein, apparently an amalgamation of functions derived from viral and bacterial origins, is probably important for maintenance of genomic integrity of the apicoplast. The recombinant protein and the assay system may provide the platform for screening of compounds for future drug search against the apicomplexan parasites

Acute abdomen in pregnancy due to nonobstetric surgical diseases: a challenge for the surgeon

Background of study: Acute abdomen may occur during pregnancy due to several non obstetric surgical diseases. Diagnosis is often difficult because clinical features may be masked and diagnostic radiology is constrained. Management may be delayed due to hesitancy of the surgeon to operate on the pregnant mother. Objectives: To identify the cases presenting with an acute abdomen due to non obstetric surgical diseases in an antenatal population; to note the frequency, incidence, clinical features, and to evaluate the managementMaterials and methods: This was a prospective observational study in a tertiary teaching hospital. The study period extended over one year( January- December 2019). All antenatal patients attending the OPD/ER during the study period were assessed for the presence of acute abdomen due to non obstetric surgical diseases. All such patients were admitted and received initial medical management followed by emergency surgery if indicated. The patients were discharged after clinical resolution and followed up till delivery to note feto-maternal outcome. The institution ethics committee approved the study. The data was analysed by Statististical Package of Social Sciences , version 24. Results:54 patients were detected out of 9768 antenatal cases with an incidence of 0.55%. Acute cholecystitis was most frequent(46.29%) followed by acute appendicitis(29.62%). 33 cases(61.11%) were treated medically while 21 cases (38 88%) required emergency surgery.The maternal mortality rate was 1.851% (out of all cases of acute abdomen) and 4.76% among surgically treated patients. Foetal loss was 5.55%( among all cases of acute abdomen) and was 14.28% following surgery. Preterm labour occurred in 9.25% cases of acute abdomen and 14.28% of cases following surgery. Conclusion: A multidisciplinary approach, effective diagnostic modalities, and safe surgery are imperative for management of acute abdomen in pregnancy due to non obstetric surgical diseases

Hydroxychloroquine for chronic myeloid leukemia: complete cure on the horizon?

No abstract available

A randomised Phase II trial of Hydroxychloroquine and Imatinib versus Imatinib alone for patients with Chronic Myeloid Leukaemia in Major Cytogenetic Response with residual disease

In chronic-phase chronic myeloid leukaemia (CP-CML), residual BCR-ABL1+ leukaemia stem cells are responsible for disease persistence despite TKI. Based on in vitro data, CHOICES (CHlorOquine and Imatinib Combination to Eliminate Stem cells) was an international, randomised phase II trial designed to study the safety and efficacy of imatinib (IM) and hydroxychloroquine (HCQ) compared with IM alone in CP-CML patients in major cytogenetic remission with residual disease detectable by qPCR. Sixty-two patients were randomly assigned to either arm. Treatment ‘successes’ was the primary end point, defined as ≥0.5 log reduction in 12-month qPCR level from trial entry. Selected secondary study end points were 24-month treatment ‘successes’, molecular response and progression at 12 and 24 months, comparison of IM levels, and achievement of blood HCQ levels >2000 ng/ml. At 12 months, there was no difference in ‘success’ rate (p = 0.58); MMR was achieved in 80% (IM) vs 92% (IM/HCQ) (p = 0.21). At 24 months, the ‘success’ rate was 20.8% higher with IM/HCQ (p = 0.059). No patients progressed. Seventeen serious adverse events, including four serious adverse reactions, were reported; diarrhoea occurred more frequently with combination. IM/HCQ is tolerable in CP-CML, with modest improvement in qPCR levels at 12 and 24 months, suggesting autophagy inhibition maybe of clinical value in CP-CML

ATG7 regulates energy metabolism, differentiation and survival of Philadelphia chromosome-positive cells

A major drawback of tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) is that primitive CML cells are able to survive TKI-mediated BCR-ABL inhibition, leading to disease persistence in patients. Investigation of strategies aiming to inhibit alternative survival pathways in CML is therefore critical. We have previously shown that a nonspecific pharmacological inhibition of autophagy potentiates TKI-induced death in Philadelphia chromosome-positive cells. Here we provide further understanding of how specific and pharmacological autophagy inhibition affects nonmitochondrial and mitochondrial energy metabolism and reactive oxygen species (ROS)-mediated differentiation of CML cells and highlight ATG7 (a critical component of the LC3 conjugation system) as a potential specific therapeutic target. By combining extra- and intracellular steady state metabolite measurements by liquid chromatography-mass spectrometry with metabolic flux assays using labeled glucose and functional assays, we demonstrate that knockdown of ATG7 results in decreased glycolysis and increased flux of labeled carbons through the mitochondrial tricarboxylic acid cycle. This leads to increased oxidative phosphorylation and mitochondrial ROS accumulation. Furthermore, following ROS accumulation, CML cells, including primary CML CD34+ progenitor cells, differentiate toward the erythroid lineage. Finally, ATG7 knockdown sensitizes CML progenitor cells to TKI-induced death, without affecting survival of normal cells, suggesting that specific inhibitors of ATG7 in combination with TKI would provide a novel therapeutic approach for CML patients exhibiting persistent disease

A comparative study between oral pregabalin and gabapentin in prolongation of postoperative pain relief after spinal anesthesia

Background: Preemptive analgesia involves the introduction of an analgesic regimen before the onset of noxious stimuli, with the goal of preventing sensitization of the nervous system to subsequent stimuli that could amplify pain. Aims: To compare the efficacy of pregabalin and gabapentin as preemptive analgesics in surgery below the umbilicus under spinal anesthesia. Materials and Methods: This study was conducted in a time span of 1 year in a tertiary care hospital of eastern India after obtaining institutional ethical clearance and informed consent of the subjects. Sixty-two patients were randomly allocated to two groups using an online randomizer. Group G (n = 31) received single dose of gabapentin 1,200 mg and Group P (n = 31) received a single dose of pregabalin 300 mg. the parameters were studied for comparing the quality of intraoperative and postoperative analgesia and sedation and complications. Results: In the 24 h of postoperative period, the mean visual analogue scale (VAS) scores at rest of Group P was always significantly lower than those of Group G. In Group G (gabapentin group) rescue analgesic was given after 9.41 ± 1.84 h while in Group P (pregabalin group), rescue analgesic was required after 15.38 ± 3.52 h. In Group G subsequent rescue analgesic was required in only three cases while in Group P, subsequent rescue analgesic was required in only two cases. In the pregabalin group, the incidence of somnolence and dizziness was significantly less than the other group. Conclusion: Single oral dose of pregabalin (300 mg) given preoperatively provides better postoperative pain control and decreases postoperative rescue analgesic consumption compared to a single dose of gabapentin (1,200 mg)

Ileal perforation-etiopathology and outcome – An observational study

Background: Ileal perforations have a diverse etiology and often present with perforative peritonitis in the surgical emergency. This study is based on the scenario of management of ileal perforation encountered in a tertiary teaching hospital in West Bengal. Aims and Objectives: The aim and objective of this study is to document and evaluate the post-operative outcome based on the diverse etiopathology, clinical presentation, and surgical management performed in patients having ileal perforation. Materials and Methods: A prospective cross-sectional observational study was conducted in the Deben Mahata Government Medical College, Purulia, West Bengal, for a period of 2 years from February 2020 to January 2022 with 60 patients introperatively diagnosed with ileal perforation. Emergency exploratory laparotomy was done in all the cases presenting with perforative peritonitis. Ileal perforation was identified and an edge biopsy was taken. Appropriate surgical treatment in the forms of primary repair/resection-anastomosis/resection-ileostomy was done. The histopathological report was reviewed following surgery. The patients were evaluated in the post-operative period for post-operative morbidity and mortality. Results: Typhoid fever (68.33%) was the predominant cause in our study. The most common symptoms were abdominal pain (93%), fever (85%), and abdominal distension (75%). Widal test was performed preoperatively and was positive in 41 cases (68.33%). In our study, primary repair (58.33%), resection-anastomosis (15%), and resection-ileostomy (26.67%) were the main surgical treatment performed. Sepsis, surgical site infections (SSIs), fecal fistula, and wound dehiscence were the common post-operative complications found. Among them, SSI (51.67%) was the most common post-operative complication (P<0.0001) found and fecal fistula was the most dreaded post-operative complication with 50% mortality. Histopathological reports following surgery showed cases were mainly due to enteric fever (51.67%) and tuberculosis (25%). Conclusion: Early surgical intervention was the mainstay of treatment of ileal perforation. Delayed presentation of perforation is responsible for the development of surgical site infections (SSIs). Uncontrolled generalized sepsis, wound dehiscence, and fecal fistula were the main causes of post-operative mortality

Comparison of prophylactic and therapeutic immunisation with an ErbB-2 (HER2) fusion protein and immunoglobulin V-gene repertoire analysis in a transgenic mouse model of spontaneous breast cancer

ErbB-2 is associated with several solid tumours of which breast cancer is the commonest cancer in women worldwide. Though anti-ErbB-2 antibody appears to play a significant role in prevention and therapy, naturally occurring anti-ErbB-2 antibody associated with the cleaved ectodomain of overexpressed ErbB-2 self antigen is detectable in patients. It is therefore essential to understand the course of antibody mediated protection during disease progression. 100% of FVB/N&lt;sup&gt;neu&lt;/sup&gt; mice expressing mutated, constitutively active ErbB-2 develop mammary carcinoma. It has been shown that vaccination with ErbB-2 associated with a T helper cell epitope P30 can offer protection against transplantable tumour but it is unclear whether the same vaccine protects against naturally developing tumour. We have analysed the course of the disease following prophylactic, and therapeutic vaccination in this spontaneous, eutopic mammary carcinoma model that more closely resembles the human disease. 100% protection against tumour development was observed subsequent to prophylactic immunisation but disease progression was unaffected by therapeutic vaccination. The antibody response exhibited restricted expansion of the Immunoglobulin (Ig) variable (V)-gene repertoire by ErbB-2 specific B cells compared with the non-antigen specific B cell pool and control mice. The serum antibody profile was similar in therapeutically injected mice without any effect on tumour burden