Astrocyte and L-lactate in the anterior cingulate cortex modulate schema memory and neuronal mitochondrial biogenesis.

Astrocyte-derived L-lactate was shown to confer beneficial effects on synaptic plasticity and cognitive functions. However, how astrocytic Gi signaling in the anterior cingulate cortex (ACC) modulates L-lactate levels and schema memory is not clear. Here, using chemogenetic approach and well-established behavioral paradigm, we demonstrate that astrocytic Gi pathway activation in the ACC causes significant impairments in flavor-place paired associates (PAs) learning, schema formation, and PA memory retrieval in rats. It also impairs new PA learning even if a prior associative schema exists. These impairments are mediated by decreased L-lactate in the ACC due to astrocytic Gi activation. Concurrent exogenous L-lactate administration bilaterally into the ACC rescues these impairments. Furthermore, we show that the impaired schema memory formation is associated with a decreased neuronal mitochondrial biogenesis caused by decreased L-lactate level in the ACC upon astrocytic Gi activation. Our study also reveals that L-lactate-mediated mitochondrial biogenesis is dependent on monocarboxylate transporter 2 (MCT2) and NMDA receptor activity - discovering a previously unrecognized signaling role of L-lactate. These findings expand our understanding of the role of astrocytes and L-lactate in the brain functions.

Zebrafish Models of Rare Neurological Diseases like Spinocerebellar Ataxias (SCAs): Advantages and Limitations.

Spinocerebellar ataxia (SCA) is a heterogeneous group of rare familial neurodegenerative disorders that share the key feature of cerebellar ataxia. Clinical heterogeneity, diverse gene mutations and complex neuropathology pose significant challenges for developing effective disease-modifying therapies in SCAs. Without a deep understanding of the molecular mechanisms involved for each SCA, we cannot succeed in developing targeted therapies. Animal models are our best tool to address these issues and several have been generated to study the pathological conditions of SCAs. Among them, zebrafish (Danio rerio) models are emerging as a powerful tool for in vivo study of SCAs, as well as rapid drug screens. In this review, we will summarize recent progress in using zebrafish to study the pathology of SCAs. We will discuss recent advancements on how zebrafish models can further clarify underlying genetic, neuroanatomical, and behavioral pathogenic mechanisms of disease. We highlight their usefulness in rapid drug discovery and large screens. Finally, we will discuss the advantages and limitations of this in vivo model to develop tailored therapeutic strategies for SCA.

Patients' characteristics and 30-day mortality for those undergoing elective surgeries during the COVID-19 pandemic in Bangladesh.

BACKGROUND: The COVID-19 pandemic has significantly impacted the surgical practice throughout the world, including elective surgical care. This study investigated the characteristics of patients undergoing elective surgery, the prevalence of COVID-19 infection, the surgical procedures performed, and 30-day mortality in general and pediatric surgical settings in selected tertiary-level hospitals in Bangladesh from November 2020 to August 2021. METHODS: This serial cross-sectional study included 264 patients scheduled for elective surgeries during the study period. All patients underwent COVID-19 real-time polymerase chain reaction (RT-PCR) testing within 24 hours before surgery. Data on age, sex, common comorbidities, surgical procedures, and 30-day mortality were collected and analyzed. Furthermore, comparisons were made between COVID-19 positive and negative patients. RESULTS: The prevalence of COVID-19 infection among patients was 10.6%. Older age, a history of major surgery within the last three months, hypertension, and diabetes mellitus were significantly associated with COVID-19 infection. All COVID-19-negative patients underwent surgery, while only 46.4% of COVID-19-positive patients underwent surgery. The most common surgical procedures were related to the digestive system, breast, and urinary system. Only one patient (0.4%) died within 30 days after surgery among the COVID-19-negative patients, whereas two patients (7.1%) died among the COVID-19-positive patients: one before surgery and one after surgery. CONCLUSIONS: This study provides valuable insights into the characteristics, burden of COVID-19 infection, and 30-day mortality of patients undergoing elective surgery in tertiary care centers in Bangladesh during the pandemic.

Exogenous L-lactate administration in rat hippocampus increases expression of key regulators of mitochondrial biogenesis and antioxidant defense.

L-lactate plays a critical role in learning and memory. Studies in rats showed that administration of exogenous L-lactate into the anterior cingulate cortex and hippocampus (HPC) improved decision-making and enhanced long-term memory formation, respectively. Although the molecular mechanisms by which L-lactate confers its beneficial effect are an active area of investigations, one recent study found that L-lactate supplementation results in a mild reactive oxygen species burst and induction of pro-survival pathways. To further investigate the molecular changes induced by L-lactate, we injected rats with either L-lactate or artificial CSF bilaterally into the dorsal HPC and collected the HPC after 60 minutes for mass spectrometry. We identified increased levels of several proteins that include SIRT3, KIF5B, OXR1, PYGM, and ATG7 in the HPC of the L-lactate treated rats. SIRT3 (Sirtuin 3) is a key regulator of mitochondrial functions and homeostasis and protects cells against oxidative stress. Further experiments identified increased expression of the key regulator of mitochondrial biogenesis (PGC-1α) and mitochondrial proteins (ATPB, Cyt-c) as well as increased mitochondrial DNA (mtDNA) copy number in the HPC of L-lactate treated rats. OXR1 (Oxidation resistance protein 1) is known to maintain mitochondrial stability. It mitigates the deleterious effects of oxidative damage in neurons by inducing a resistance response against oxidative stress. Together, our study suggests that L-lactate can induce expression of key regulators of mitochondrial biogenesis and antioxidant defense. These findings create new research avenues to explore their contribution to the L-lactate's beneficial effect in cognitive functions as these cellular responses might enable neurons to generate more ATP to meet energy demand of neuronal activity and synaptic plasticity as well as attenuate the associated oxidative stress.

Genetics of Hirschsprung's disease.

Hirschsprung's disease (HSCR) is a classical model of enteric neuropathy, occurring in approximately 2-2.8 in 10,000 newborns. It is the commonest form of congenital bowel obstruction and is characterized by the absence of enteric ganglia in distal colon. Recent advances in genome-wide association analysis (GWAS) and next generation sequencing (NGS) studies have led to the discovery of a number of new HSCR candidate genes, thereby providing new insights into the genetic architecture and molecular mechanisms of the disease. Altogether, these findings indicated that genetic heterogeneity, variable penetrance and expressivity, and genetic interaction are the pervasive characteristics of HSCR genetics. In this review, we will provide an update on the genetic landscape of HSCR and discuss how the common and rare variants may act together to modulate the phenotypic manifestation. Translating the genetic findings to genetic risk prediction and to optimize clinical outcomes are undoubtedly the ultimate goals for genetic studies on HSCR. From this perspective, we will further discuss the major obstacles in the clinical translation of these latest genetic findings. Lastly, new measures to address these clinical challenges are suggested to advance precision medicine and to develop novel alternative therapies.

Ultra-Wide Band Gap Ga2O3-on-SiC MOSFETs.

Ultra-wide band gap semiconductor devices based on ß-phase gallium oxide (Ga2O3) offer the potential to achieve higher switching performance and efficiency and lower manufacturing cost than that of today's wide band gap power electronics. However, the most critical challenge to the commercialization of Ga2O3 electronics is overheating, which impacts the device performance and reliability. We fabricated a Ga2O3/4H-SiC composite wafer using a fusion-bonding method. A low-temperature (≤600 °C) epitaxy and device processing scheme was developed to fabricate MOSFETs on the composite wafer. The low-temperature-grown epitaxial Ga2O3 devices deliver high thermal performance (56% reduction in channel temperature) and a power figure of merit of (∼300 MW/cm2), which is the highest among heterogeneously integrated Ga2O3 devices reported to date. Simulations calibrated based on thermal characterization results of the Ga2O3-on-SiC MOSFET reveal that a Ga2O3/diamond composite wafer with a reduced Ga2O3 thickness (∼1 µm) and a thinner bonding interlayer (<10 nm) can reduce the device thermal impedance to a level lower than that of today's GaN-on-SiC power switches.

The Emerging Genetic Landscape of Hirschsprung Disease and Its Potential Clinical Applications.

Hirschsprung disease (HSCR) is the leading cause of neonatal functional intestinal obstruction. It is a rare congenital disease with an incidence of one in 3,500-5,000 live births. HSCR is characterized by the absence of enteric ganglia in the distal colon, plausibly due to genetic defects perturbing the normal migration, proliferation, differentiation, and/or survival of the enteric neural crest cells as well as impaired interaction with the enteric progenitor cell niche. Early linkage analyses in Mendelian and syndromic forms of HSCR uncovered variants with large effects in major HSCR genes including RET, EDNRB, and their interacting partners in the same biological pathways. With the advances in genome-wide genotyping and next-generation sequencing technologies, there has been a remarkable progress in understanding of the genetic basis of HSCR in the past few years, with common and rare variants with small to moderate effects being uncovered. The discovery of new HSCR genes such as neuregulin and BACE2 as well as the deeper understanding of the roles and mechanisms of known HSCR genes provided solid evidence that many HSCR cases are in the form of complex polygenic/oligogenic disorder where rare variants act in the sensitized background of HSCR-associated common variants. This review summarizes the roadmap of genetic discoveries of HSCR from the earlier family-based linkage analyses to the recent population-based genome-wide analyses coupled with functional genomics, and how these discoveries facilitated our understanding of the genetic architecture of this complex disease and provide the foundation of clinical translation for precision and stratified medicine.

Size matters: Large copy number losses in Hirschsprung disease patients reveal genes involved in enteric nervous system development.

Hirschsprung disease (HSCR) is a complex genetic disease characterized by absence of ganglia in the intestine. HSCR etiology can be explained by a unique combination of genetic alterations: rare coding variants, predisposing haplotypes and Copy Number Variation (CNV). Approximately 18% of patients have additional anatomical malformations or neurological symptoms (HSCR-AAM). Pinpointing the responsible culprits within a CNV is challenging as often many genes are affected. Therefore, we selected candidate genes based on gene enrichment strategies using mouse enteric nervous system transcriptomes and constraint metrics. Next, we used a zebrafish model to investigate whether loss of these genes affects enteric neuron development in vivo. This study included three groups of patients, two groups without coding variants in disease associated genes: HSCR-AAM and HSCR patients without associated anomalies (HSCR-isolated). The third group consisted of all HSCR patients in which a confirmed pathogenic rare coding variant was identified. We compared these patient groups to unaffected controls. Predisposing haplotypes were determined, confirming that every HSCR subgroup had increased contributions of predisposing haplotypes, but their contribution was highest in isolated HSCR patients without RET coding variants. CNV profiling proved that specifically HSCR-AAM patients had larger Copy Number (CN) losses. Gene enrichment strategies using mouse enteric nervous system transcriptomes and constraint metrics were used to determine plausible candidate genes located within CN losses. Validation in zebrafish using CRISPR/Cas9 targeting confirmed the contribution of UFD1L, TBX2, SLC8A1, and MAPK8 to ENS development. In addition, we revealed epistasis between reduced Ret and Gnl1 expression and between reduced Ret and Tubb5 expression in vivo. Rare large CN losses-often de novo-contribute to HSCR in HSCR-AAM patients. We proved the involvement of six genes in enteric nervous system development and Hirschsprung disease.

A random forest-based framework for genotyping and accuracy assessment of copy number variations.

Detection of copy number variations (CNVs) is essential for uncovering genetic factors underlying human diseases. However, CNV detection by current methods is prone to error, and precisely identifying CNVs from paired-end whole genome sequencing (WGS) data is still challenging. Here, we present a framework, CNV-JACG, for Judging the Accuracy of CNVs and Genotyping using paired-end WGS data. CNV-JACG is based on a random forest model trained on 21 distinctive features characterizing the CNV region and its breakpoints. Using the data from the 1000 Genomes Project, Genome in a Bottle Consortium, the Human Genome Structural Variation Consortium and in-house technical replicates, we show that CNV-JACG has superior sensitivity over the latest genotyping method, SV2, particularly for the small CNVs (≤1 kb). We also demonstrate that CNV-JACG outperforms SV2 in terms of Mendelian inconsistency in trios and concordance between technical replicates. Our study suggests that CNV-JACG would be a useful tool in assessing the accuracy of CNVs to meet the ever-growing needs for uncovering the missing heritability linked to CNVs.

Multicenter Study of 342 Anorectal Malformation Patients: Age, Gender, Krickenbeck Subtypes, and Associated Anomalies.

INTRODUCTION: Published studies based on Krickenbeck classification of anorectal malformations (ARMs) are still insufficient to assess the global as well as regional relative incidence of different ARM subtypes, gender distribution, and associated anomalies. The primary purpose of this study was to provide an estimate of those in Global Initiative for Children's Surgery (GICS) research group. MATERIALS AND METHODS: We collected ARM data prospectively for 1 year from four institutes of different geographic locations. A total of 342 patients were included in this study (195, 126, 11, and 10 from Bangladesh, Iran, Papua New Guinea, and Oxford, United Kingdom, respectively). RESULTS: Overall male to female ratio was 1:1. The most frequent ARM subtype was perineal fistula (23.7% = 81/342). About 48.5% (166/342) patients had at least one associated anomaly. Cardiac and genitourinary systems were the most commonly affected systems, 31.6% (108/342) and 18.4% (63/342), respectively. These organ-systems were followed by anomalies of vertebral/spinal (9.9% = 34/342), musculoskeletal (4.4% = 15/342), and gastrointestinal/abdominal (3.2% = 11/342) systems. Rectovesical fistula had the highest percentage (96.4% = 27/28) of associated anomalies. About 18.1% (62/342) patients had multiple anomalies. ARMs (both isolated and with associated anomalies) occurred equally in males and females. Comparison between patients from Bangladesh and Iran showed differences in relative incidence in ARM subtypes. In addition, Iranian patient group had higher percentage of associated anomalies compared with Bangladeshi (73 vs. 35.4%). CONCLUSION: Our study provides important insights about ARM subtypes, gender distribution and associated anomalies based on Krickenbeck classification especially from Bangladesh and Iran.

Cost Incurred by the Family for Surgery in Their Children: A Bangladesh Perspective.

BACKGROUND: Cost of getting health services is a major concern in Bangladesh as well as in many other countries. A family has to bear more than half of the health care cost despite many facilities provided by the public hospitals. This out-of-pocket (OOP) expenditure drives many families under the poverty line. The aim of this study was to find out the exact cost incurred by the family for a surgical operation of their child in the public and private sectors in Bangladesh. METHODS: A cross-sectional study was conducted to find out the cost of child surgery in different settings of public and private hospitals in Chittagong division, Bangladesh. Cost of herniotomy was then compared across different settings. RESULTS: In this study, cost of operation in urban private hospitals was highest mostly due to surgeon and anesthetist fee. The cost was lowest in outreach programs as surgeon fee, anesthetist fee and accommodation cost was nil; food and transport cost was minimum. However, cost of accommodation, food, transport and medicine contributed significantly to OOP expenditure especially in tertiary-level public hospitals, in both indoor and day care settings, and also in private urban hospitals. CONCLUSIONS: Our study provides some insight into the OOP expenditure in different health care settings in Bangladesh. This study might be useful in developing a strategy to minimize the OOP expenditure in this country.

Epidemiological characteristics of Hirschsprung's disease (HSCR): Results of a case series of fifty patients from Bangladesh.

BACKGROUND: The epidemiology of Hirschsprung's disease (HSCR) in Bangladesh has never been studied. The aim of this study was to determine the epidemiological characteristics of HSCR in Bangladesh. METHODS: Data from fifty patients were collected prospectively from two hospitals in Chittagong, Bangladesh. RESULTS: The rate of consanguinity (16%) among parents of HSCR patients was higher than that of the general population (10%). Maternal age at the time of birth of the affected child was ≤30years in all cases except one. No association was found between parents' occupation and HSCR. No patient was born preterm and only three patients (6%) had low birth weight. Nine patients (18%) had associated anomalies. We found coexistence of bilateral accessory tragi and ankyloglossia in one patient, and coexistence of rectal duplication cyst in another. Neither anomaly had been previously reported in HSCR patients. CONCLUSIONS: Our study suggests that consanguinity might increase the risk of HSCR whereas advanced maternal age does not. HSCR patients were found more likely to born at term and with normal birth weight. The coexistence of HSCR with previously unreported anomalies highlights the diversity of conditions that can co-occur with HSCR. LEVELS OF EVIDENCE: IV.

De novo mutations in Caudal Type Homeo Box transcription Factor 2 (CDX2) in patients with persistent cloaca.

The cloaca is an embryonic cavity that is divided into the urogenital sinus and rectum upon differentiation of the cloacal epithelium triggered by tissue-specific transcription factors including CDX2. Defective differentiation leads to persistent cloaca in humans (PC), a phenotype recapitulated in Cdx2 mutant mice. PC is linked to hypo/hyper-vitaminosis A. Although no gene has ever been identified, there is a strong evidence for a genetic contribution to PC. We applied whole-exome sequencing and copy-number-variants analyses to 21 PC patients and their unaffected parents. The damaging p.Cys132* and p.Arg237His de novo CDX2 variants were identified in two patients. These variants altered the expression of CYP26A1, a direct CDX2 target encoding the major retinoic acid (RA)-degrading enzyme. Other RA genes, including the RA-receptor alpha, were also mutated. Genes governing the development of cloaca-derived structures were recurrently mutated and over-represented in the basement-membrane components set (q-value < 1.65 × 10-6). Joint analysis of the patients' profile highlighted the extracellular matrix-receptor interaction pathway (MsigDBID: M7098, FDR: q-value < 7.16 × 10-9). This is the first evidence that PC is genetic, with genes involved in the RA metabolism at the lead. Given the CDX2 de novo variants and the role of RA, our observations could potentiate preventive measures. For the first time, a gene recapitulating PC in mouse models is found mutated in humans.

Prospective case-control study of the association between common enteric protozoal parasites and diarrhea in Bangladesh.

BACKGROUND: The parasitic causes of diarrhea have historically been identified by use of microscopy; however, the use of this technique does not allow one to distinguish between subspecies or genotypes of parasites. Our objective was to determine, by use of modern diagnostic methods, the proportion of diarrhea cases in Bangladesh attributable to Cryptosporidium hominis, Cryptosporidium parvum, Entamoeba histolytica, and Giardia lamblia assemblages A and B. METHODS: A prospective case-control study was performed involving 3646 case patients (both children and adults) who presented with diarrhea to the Dhaka hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, and 2575 control subjects with asymptomatic infection. Parasitic infection was detected by use of a stool parasite antigen test, and the parasite load and the species and/or genotypes were determined by use of polymerase chain reaction (PCR). RESULTS: Cryptosporidium species and E. histolytica were more prevalent in patients with acute diarrhea than in healthy control subjects, for all ages (2.1% vs. 1.4%; P = .039) and, specifically, for those 0-12 months of age (2.2% vs. 0.4%; P = .009). G. lamblia assemblage A was also more prevalent in case patients with diarrhea than in healthy control subjects (20% vs. 5%; P = .001). For case patients with diarrhea, the parasite load in feces, as measured by quantitative real-time PCR cycle threshold, was not higher that that for control subjects with asymptomatic infection. Case patients with diarrhea and cryptosporidiosis were less likely to have abdominal pain, compared with control subjects (15% vs. 37%; P = .001); case patients with amebiasis more likely to have visible blood in stool, compared with control subjects (8% vs. 1.6%; P = .001); and case patients with giardiasis more likely to be dehydrated, compared with control subjects (81% vs. 71%; P = .001). CONCLUSION: E. histolytica, C. hominis, C. parvum, and G. lamblia assemblage A infections are important causes of diarrheal illness in Bangladesh.

Psychotropic drug versus psychotropic drug-update.

Psychotropic drugs are not necessarily the drugs of psychiatry. Seventy percent of antidepressants, and 90% of anxiolytics are prescribed by nonpsychiatric physicians. Since psychotropic medications are so frequently employed by nonpsychiatric physicians, e.g., neurologists, primary care physicians, internists, and because large numbers of their patients are concurrently on medical drugs for somatic reasons, the interactions of psychotropic versus medical drugs and psychotropic versus psychotropic drugs as listed below must be understood before primary care physicians or psychiatrists prescribe psychotropic medications, especially to the medically ill. Seventy commonly prescribed psychotropic drugs were examined for their interactions with other psychotropic medications using six reference tools: 1) MEDLINE (PubMed) employing the first generic psychotropic drug name, the second generic psychotropic drug name, and the term "interaction;" 2) Hanston's Drug Interaction Analysis and Management Text (quarterly updated version); 3) Drug Interactions Facts (Facts and Comparisons) (July 2001 quarterly updated version); 4) Micromedex Drug-dex; 5) American Hospital Formulary Service Drug Information; and 6) Food and Drug Administration (MedWatch) (Dear Doctor Letters and new labeling) ( for (1999, 2000, and 2001). The authors recognized that all of the above sources do not necessarily cover the entire information database regarding drug-drug interactions. (Citations regarding children, reports in foreign languages or concerning food, animals, in vitro experiments, analgesics, and naturalistic-herbal or natural products-treatment interactions were excluded).

Comparison of three methods for identifying medical drug-psychotropic drug interactions.

Three methods for examining drug-drug interactions were compared to understand advantages and disadvantages of each: ePocrates; Interact; The Mount Sinai multiple source for the evaluation of drug-drug interactions (MS). ePocrates is a commonly employed software system utilized in a hand held computer, the PalmPilot. Interact is on a CD-ROM, and promoted by the American Psychiatric Association Press. The MS system was developed by the authors and utilizes six separate references sources to ascertain the presence and significance of drug-drug interactions. Commonly prescribed neurology and psychotropic medication interactions were compared using the three systems. ePocrates did not list the significance level of the interaction, e.g., (major, moderate, minor), often did not include a mechanism of action, and several commonly employed medications were not included. It did permit examining several drugs at the same time, and was easily carried on the person of the physician. Interact often contained old references, several drugs were not included, was not adapted to a hand held computer format, and had no update since 1999. The MS system listed level of significance, provided mechanism of action, and advice to the practitioner including recommendations. It is not portable, requiring a laptop or desk top computer or hard copy, and only searches one drug at a time. It is hoped that the advantages of each of these three systems may be incorporated into systems of the future.

Neurologic drug-psychotropic drug update.

It is essential that both the neurologist and the psychiatrist be aware of the neurology drug-psychotropic drug interactions because neurologists prescribe many psychotropic medications and psychiatric consultants often recommend the use of psychotropic drugs for neurology patients. Six methods of examining drug-drug interactions were employed: 1) PubMed (MEDLINE); 2) Hanston's Drug Interaction Analysis and Management Text (July 2001 quarterly updated version); 3)Drug Interactions Facts (quarterly updated version through July 2001); 4) Micromedex Drug-dex; 5) American Hospital Formulary Service Drug Information; 6) Food and Drug Administration (MedWatch) Dear Doctor Letters and new labeling. Over eighty important interactions of significance level 1 (major), or significance level 2 (minor) were found. Furthermore, over one-third of the neurologist's most commonly administered medications were those also employed by the psychiatrist, but not necessarily for the same reason, e.g., carbamazepine, for seizure control (neurologist) or mood stabilization (psychiatrist).

Cardiac drug-psychotropic drug update.

This is an update from the report-Cardiac Drug and Psychotropic Drug Interactions: Significance and Recommendations-published in this journal in November-December 1999. As mentioned in that article there has been an explosion of new drugs both in psychiatry and cardiology without a sufficient understanding of their potential interactions. Also there is a need for methods to update drug interactions on an ongoing basis. This report describes: 1) examples of actual adverse interactions from clinical cases that move beyond some of the hypothesized contraindications included in the 2000 millennium publication; 2) confirmation of previous adverse interactions reported if they strengthen the earlier findings; 3) listing of new drugs, e.g., sildenafil (viagra) now commonly prescribed by psychiatrists and cardiologists; 4) reports explaining and/or refining mechanisms of adverse interactions; and 5) cautions and important associated phenomenon of either a cardiac or a psychotropic drug, e.g., valproic acid and cases of life-threatening pancreatitis. Methods of publicizing the new knowledge of cardiac drug-psychotropic drug interactions, e.g., the Internet and web sites are described.