Unwinding Helicase MCM Functionality for Diagnosis and Therapeutics of Replication Abnormalities Associated with Cancer: A Review.

The minichromosome maintenance (MCM) protein is a component of an active helicase that is essential for the initiation of DNA replication. Dysregulation of MCM functions contribute to abnormal cell proliferation and genomic instability. The interactions of MCM with cellular factors, including Cdc45 and GINS, determine the formation of active helicase and functioning of helicase. The functioning of MCM determines the fate of DNA replication and, thus, genomic integrity. This complex is upregulated in precancerous cells and can act as an important tool for diagnostic applications. The MCM protein complex can be an important broad-spectrum therapeutic target in various cancers. Investigations have supported the potential and applications of MCM in cancer diagnosis and its therapeutics. In this article, we discuss the physiological roles of MCM and its associated factors in DNA replication and cancer pathogenesis.

Deciphering the molecular functionality of Cdc45 in replisomal complex.

The members of DHH superfamily have been reported with diverse substrate spectrum and play pivotal roles in replication, repair, and RNA metabolism. This family comprises phosphatases, phosphoesterase and bifunctional enzymes having nanoRNase and phosphatase activities. Cell cycle factor Cdc45, a member of this superfamily, is crucial for movement of the replication fork during DNA replication and an important component of the replisome. The specific protein-protein interactions of Cdc45 with other factors along with helicase moderate the faithful DNA replication process. However, the exact biochemical functions of this factor are still unknown and need further investigation. Here, we studied the biochemical roles of Cdc45 and its molecular interactions within the replisomal complex. The alteration in the level of protein, observed when DNA damage is induced in-vivo, suggests its association with DNA replication stress. We analyzed protein Cdc45, providing new insights about the molecular and biochemical functionality of this replisomal factor.

People with dyssomnia showed increased vulnerability to CoVID-19 pandemic: a questionnaire-based study exploring the patterns and predictors of sleep quality using the latent class analysis technique in Indian population.

INTRODUCTION: CoVID-19 pandemic and the subsequent lockdown have impacted the sleep quality and the overall wellbeing of mankind. The present epidemiological study measured various aspects of sleep disturbance such as sleep quality, daytime impairments, negative emotionality, sleep hygiene, and well-being associated with CoVID-19 pandemic among the Indian population. METHODS: This cross-sectional voluntary online survey (using Google form) was communicated across the country from 4th June to 3rd July 2020 through mail and social media applications. The responses received (N = 450) were categorized and validated using the latent class analysis and logistic regression tests respectively, and the classes and subclasses derived were profiled. These techniques are used for the first time in a CoVID-19 sleep study. RESULTS: Out of the three classes derived from the LCA, people with severe dyssomnia belonging to class 1 (33.3%) showed high daytime impairments, negative emotionality and high vulnerability towards CoVID-19 pandemic measures. In addition, the two subclasses derived from the severe dyssomnia group; one with negative emotionality predominance and the other with excessive daytime sleepiness, were similarly affected by CoVID-19 measures. People with moderate dyssomnia (class 2, 28.5%) showed frequent arousals with daytime impairments and the majority (38.2%) which fell in to class 3, the 'no dyssomnia' category, were not impacted by CoVID-19 pandemic. CONCLUSION: People with existing sleep problems or those who were vulnerable to the same were the ones affected by CoVID-19 pandemic. Those with inadequate emotional coping styles have showed heightened vulnerability. Proper medical and cognitive interventions are highly recommended for this population. No or moderate dyssomnia categories (class 3 and 2 respectively) were less impacted by CoVID-19.

Effect site concentration of propofol at induction and recovery of anaesthesia - A correlative dose-response study.

BACKGROUND AND AIMS: Sound knowledge about effect site concentration (Ce) of propofol aids in smooth induction, maintenance and early recovery. We studied the correlation between Ce of propofol at loss of response to verbal command and recovery concentration using target-controlled infusion (TCI) in Indian patients who underwent spine surgeries. METHODS: Ninety patients undergoing spine surgeries were included. Total intravenous anaesthesia (TIVA) technique with TCI for propofol using modified Marsh model was used. Entropy and neuromuscular transmission were used. Ce at induction and recovery and the corresponding state entropy (SE) values were noted. RESULTS: The mean propofol Ce and SE at induction were 2.34 ± 0.24 µg/ml and 52 ± 8, respectively. The mean propofol Ce and SE at recovery were 1.02 ± 0.22 µg/ml and 86.80 ± 2.86, respectively. The Ce at recovery was approximately 50% of the induction value. The correlation coefficient 'r' between Ce at induction and recovery was 0.56. The mean infusion dose of propofol during the maintenance period was 81 ± 14.33 µg/kg/min. The average induction dose of propofol was 1.17 ± 0.2 mg/kg. CONCLUSION: There is a positive correlation between Ce at induction and recovery. Ce for recovery may have to be set at a lower level during TCI-TIVA and appropriately infusion should be stopped for early recovery. The induction and maintenance doses of propofol are lower than the recommended doses. Data emphasise the need for pharmacokinetic model based on our population characteristics.

Categories of Wistar Rats Based on Anxiety Traits: A Study Using Factor and Cluster Method.

BACKGROUND: Outcomes of neurobehavioral studies are invariably affected by the variations in the anxiety traits of animals in the same species. Identifying those traits and categorizing them accordingly would improve the reproducibility of results, and reduce the variation in the results from different laboratories. PURPOSE: The present study was done to identify the possible groups among the normal population of outbred adult male Wistar rats. METHODS: Anxiety traits were measured in elevated plus maze (EPM) test and open field test (OFT). The various anxiety responses from these tests were subjected to exploratory factor and hierarchical cluster analyses. Different clusters thus derived were compared with each other. RESULTS AND CONCLUSION: In exploratory factorial analysis, 2 components, that is, anxiety and activity were derived from the EPM and OFT parameters. Cluster analysis of EPM parameters classified the rats into 3 groups "high anxiety and low activity", "medium anxiety and high activity", and "low anxiety and medium activity". Whereas, cluster analysis on OFT parameters identified one more group namely "low anxiety and high activity". The rats which came under the clusters formed from the EPM and OFT parameters were not identical. Moreover, EPM and OFT may be measuring different aspects of anxiety.

Infusion dose requirement of rocuronium in patients on phenytoin therapy - A prospective comparative study.

BACKGROUND AND AIMS: Patients with intracranial tumour are usually on anticonvulsants. Patients on phenytoin therapy demonstrate rapid metabolism of nondepolarising muscle relaxants secondary to enzyme induction. Infusion dose requirement of rocuronium in such patients has been sparingly studied. We studied the continuous infusion dose requirement of rocuronium bromide in patients on phenytoin therapy and its correlation with serum levels of phenytoin. METHODS: Seventy-five patients scheduled for supratentorial tumour surgery were included in the study. Patients not on phenytoin were taken as control. The primary outcome variable studied was the infusion dose requirement of rocuronium in patients on phenytoin. Based on pre-operative serum phenytoin levels, study group patients were divided into two groups: sub-therapeutic level group (phenytoin level <10 µg/mL) and therapeutic level group (phenytoin level >10 µg/mL). Following anaesthesia induction, rocuronium bromide 0.6 mg/kg was administered to achieve tracheal intubation. Rocuronium infusion was titrated to maintain zero response on the train-of-four response. RESULTS: Demographic data were comparable. Patients receiving phenytoin required higher infusion dose compared to the control group (0.429 ± 0.2 mg/kg/h vs. 0.265 ± 0.15 mg/kg/h, P < 0.001). The serum phenytoin level had no correlation to infusion dose requirement of rocuronium (0.429 ± 0.205 mg/kg/h vs. 0.429 ± 0.265 mg/kg/h (P = 0.815). The recovery was faster in the phenytoin group compared to the control group. Haowever, it was not clinically significant. CONCLUSION: The infusion dose requirement of rocuronium bromide in patients on phenytoin is higher and the serum levels of phenytoin does not influence the dose required.

Sleep promoting potential of low dose α-Asarone in rat model.

Commonly used hypnotics have undesirable side-effects, especially during continuous usage. On the other hand, some herbal products, which are used for prolonged periods, are suggested to have a sleep inducing property, though the claims have not been validated scientifically. The hypnotic potential of α-Asarone, an active principle of Acorus species, was tested in the present study by first identifying the optimal dose of α-Asarone for improving sleep, followed by studies that evaluated the effect of repeated administration of this optimal dose for five days on sleep deprived rats. Of all the doses tested (2, 10, 40, 80 and 120 mg/kg), 10 mg/kg α-Asarone improved the quality of sleep, as indicated by an increased NREM bout duration, reduced arousal index, and decreased bout frequencies of NREM sleep and wakefulness. A marginal decrease in the hypothalamic and body temperatures was also observed. Higher doses, on the other hand, not only reduced the quantity and quality of sleep, but also produced hypothermia. In sleep deprived rats, administration of 10 mg/kg α-Asarone for five consecutive days improved the quality of sleep in contrast to the vehicle and a known hypnotic midazolam. Improvement in NREM sleep quality was observed when the difference between the hypothalamic and the body temperature was minimum. An enhanced association between NREM sleep bout duration and hypothalamic temperature was also observed after administration of 10 mg/kg α-Asarone. This comprehensive study is the first report on the hypnotic property of α-Asarone, which validates its potential to be considered for treatment of insomnia.

Dynamic changes in sleep pattern during post-partum in normal pregnancy in rat model.

To develop an animal model for studies on peri-partum sleep disorders, sleep patterns in female Wistar rats during pregnancy, post-partum and after weaning, were assessed and associated adaptive changes in their anxiety were examined. Adult nulliparous female rats, maintained in standard laboratory conditions with ad libitum food and water, were surgically implanted with electroencephalogram and electromyogram electrodes under anaesthesia for objective assessment of sleep-wakefulness (S-W). After post-surgical recovery, three control recordings of S-W were taken for 24h before the animals were kept for mating. After confirmation of pregnancy, S-W recordings were acquired during different days of pregnancy, post-partum lactation/nursing days, and also after weaning. Their anxiety levels were tested in the elevated plus maze. During pregnancy, sleep increased primarily due to increase in light non-REM sleep during dark period. There was an increase in non-REM sleep delta power after parturition, though the sleep was fragmented, especially during daytime. Simultaneous behavioural recording showed increased anxiety during third trimester of pregnancy and gradual reversal of it after parturition. This is the first report where diurnal and nocturnal variations in S-W and delta power, along with adaptive changes in anxiety, were studied before, during and after pregnancy. This study also provides an animal model for drug trials and studies on sleep disorders during peri-partum window.

Sleep deprivation during late pregnancy produces hyperactivity and increased risk-taking behavior in offspring.

Sleep deprivation in women resulting from their modern lifestyle, especially during pregnancy, is a serious concern as it can affect the health of the newborn. Anxiety disorders and cognitive deficits in the offspring are also on the rise. However, experimental studies on the effects of sleep loss during pregnancy, on emotional development and cognitive function of the newborn, are scanty in literature. In the current study, female rats were sleep-deprived for 5h by gentle handling, during the 6 days of the third trimester (days 14-19 of pregnancy). The effects of this sleep deprivation on anxiety-related behaviors of pups during their peri-adolescence age were studied using elevated plus maze (EPM). In addition to body weights of dams and offspring, the maternal behavior was also monitored. The weanlings of sleep-deprived dams showed heightened risk-taking behavior as they made increased explorations into the open arms of EPM. They also showed higher mobility in comparison to the control group. Though the body weights of sleep-deprived dams were comparable to those of the control group, their newborns had lower birth weight. Nevertheless, these pups gained weight and reached the control group values during the initial post-natal week. But after weaning, their rate of growth was lower than that of the control group. This is the first report providing evidences for the role of sleep during late pregnancy in shaping the neuropsychological development in offspring.

Reduction in ultrasonic vocalizations in pups born to rapid eye movement sleep restricted mothers in rat model.

The effects of rapid eye movement sleep restriction (REMSR) in rats during late pregnancy were studied on the ultrasonic vocalizations (USVs) made by the pups. USVs are distress calls inaudible to human ears. Rapid eye movement (REM) sleep was restricted in one group of pregnant rats for 22 hours, starting from gestational day 14 to 20, using standard single platform method. The USVs of male pups were recorded after a brief isolation from their mother for two minutes on alternate post-natal days, from day one till weaning. The USVs were recorded using microphones and were analysed qualitatively and quantitatively using SASPro software. Control pups produced maximum vocalization on post-natal days 9 to 11. In comparison, the pups born to REMSR mothers showed not only a reduction in vocalization but also a delay in peak call making days. The experimental group showed variations in the types and characteristics of call types, and alteration in temporal profile. The blunting of distress call making response in these pups indicates that maternal sleep plays a role in regulating the neural development involved in vocalizations and possibly in shaping the emotional behaviour in neonates. It is suggested that the reduced ultrasonic vocalizations can be utilized as a reliable early marker for affective state in rat pups. Such impaired vocalization responses could provide an important lead in understanding mother-child bonding for an optimal cognitive development during post-partum life. This is the first report showing a potential link between maternal REM sleep deprivation and the vocalization in neonates and infants.