A comparison of the pharmacokinetics and NMDAR antagonism-associated neurotoxicity of ketamine, (2R,6R)-hydroxynorketamine and MK-801.

With the increasing use of ketamine as an off-label treatment for depression and the recent FDA approval of (S)-ketamine for treatment-resistant depression, there is an increased need to understand the long-term safety profile of chronic ketamine administration. Of particular concern is the neurotoxicity previously observed in rat models following acute exposure to high doses of ketamine, broadly referred to as 'Olney's lesions'. This type of toxicity presents as abnormal neuronal cellular vacuolization, followed by neuronal death and has been associated with ketamine's inhibition of the N-methyl-d-aspartate receptor (NMDAR). In this study, a pharmacological and neuropathological analysis of ketamine, the potent NMDAR antagonist MK-801, and the ketamine metabolite (2R,6R)-hydroxynorketamine [(2R,6R)-HNK)] in rats is described following both single dose and repeat dose drug exposures. Ketamine dosing was studied up to 20 mg/kg intravenously for the single-dose neuropathology study and up to 60 mg/kg intraperitoneally for the multiple-dose neuropathology study. MK-801 dosing was studied up to 0.8 mg/kg subcutaneously for both the single and multiple-dose neuropathology studies, while (2R,6R)-HNK dosing was studied up to 160 mg/kg intravenously in both studies. These studies confirm dose-dependent induction of 'Olney's lesions' following both single dose and repeat dosing of MK-801. Ketamine exposure, while showing common behavioral effects, did not induce wide-spread Olney's lesions. Treatment with (2R,6R)-HNK did not produce behavioral effects, toxicity or any evidence of Olney's lesion formation. Based on these results, future NMDAR-antagonist neurotoxicity studies should strongly consider taking pharmacokinetics more thoroughly into account.

Gastric Residual Volumes Versus Abdominal Girth Measurement in Assessment of Feed Tolerance in Preterm Neonates: A Randomized Controlled Trial.

BACKGROUND: Preterm neonates often have feed intolerance that needs to be differentiated from necrotizing enterocolitis. Gastric residual volumes (GRV) are used to assess feed tolerance but with little scientific basis. PURPOSE: To compare prefeed aspiration for GRV and prefeed measurement of abdominal girth (AG) in the time taken to reach full feeds in preterm infants. METHODS: This was a randomized controlled trial. Infants with a gestational age of 27 to 37 weeks and birth weight of 750 to 2000 g, who required gavage feeds for at least 48 hours, were included. Infants were randomized into 2 groups: infants in the AG group had only prefeed AG measured. Those in the GRV group had prefeed gastric aspiration obtained for the assessment of GRV. The primary outcome was time to reach full enteral feeds at 150 mL/kg/d, tolerated for at least 24 hours. Secondary outcomes were duration of hospital stay, need for parenteral nutrition, episodes of feed intolerance, number of feeds withheld, and sepsis. RESULTS: Infants in the AG group reached full feeds earlier than infants in the GRV group (6 vs 9.5 days; P = .04). No significant differences were found between the 2 groups with regard to secondary outcomes. IMPLICATIONS FOR PRACTICE: Our research suggests that measurement of AG without assessment of GRV enables preterm neonates to reach full feeds faster than checking for GRV. IMPLICATIONS FOR RESEARCH: Abdominal girth measurement as a marker for feed tolerance needs to be studied in infants less than 750 g and less than 26 weeks of gestation.

Pilot testing of the effectiveness of nurse-guided, patient-centered heart failure education for older adults.

Heart failure (HF) is the most common cause of hospitalization and rehospitalization among those 65 years and older. Effective HF self-management is recommended for reducing readmissions. This pilot study, through a one-group, pretest-posttest design, examines the effects of nurse-guided, patient-centered HF education on readmissions among older adults (n = 26) in a post-acute care unit. All selected participants received 3 sessions of tailored patient education. Their knowledge and self-care skills were measured pre- and post-intervention with the Atlanta Heart Failure Knowledge Test (A-HFKT) and the Self-Care of Heart Failure Index (SCHFI). Patients' HF-related knowledge and self-care skills showed statistically significant improvements, and only 1 patient was rehospitalized for any HF-related reason within 30 days post-discharge. These results suggest that HF rehabilitation teams could support better patient outcomes by assigning nursing staff to provide individualized patient education, as this can help ensure that patients understand discharge instructions for effective self-care.

Efficacy of expressed breast milk in reducing pain during ROP screening--a randomized controlled trial.

OBJECTIVE: To assess the effectiveness of expressed breast milk (EBM) on neonatal pain during screening for retinopathy of prematurity (ROP). METHODS: Neonates who were on oral feeds undergoing ROP screening were included. Babies were randomized into intervention group (EBM + Standard practice) and control group. The standard practice is proparacaine, nesting and swaddling. Pain was assessed by PIPP scale, during and at 1 and 5 min after the procedure by the principal investigator who was blinded. RESULTS: The groups were similar in baseline characteristics. The group receiving EBM had significantly lower PIPP scores during the procedure 12.7 ± 1.69 compared to the control group 15.5 ± 1.78 (p < 0.05). The beneficial effect persisted at 1 min and 5 min after the procedure 6.20 ± 1.9 vs. 12.4 ± 2.54 (p ≤ 0.05) at 1 min; 3.2 ± 1.5 and 6.85 ± 2.4 (p < 0.05) at 5 min. CONCLUSION: Oral EBM significantly reduces pain during and after ROP screening.

In silico studies of medicinal compounds against hepatitis C capsid protein from north India.

Hepatitis viral infection is a leading cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Over one million people are estimated to be persistently infected with hepatitis C virus (HCV) worldwide. As capsid core protein is the key element in spreading HCV; hence, it is considered to be the superlative target of antiviral compounds. Novel drug inhibitors of HCV are in need to complement or replace the current treatments such as pegylated interferon's and ribavirin as they are partially booming and beset with various side effects. Our study was conducted to predict 3D structure of capsid core protein of HCV from northern part of India. Core, the capsid protein of HCV, handles the assembly and packaging of HCV RNA genome and is the least variable of all the ten HCV proteins among the six HCV genotypes. Therefore, we screened four phytochemicals inhibitors that are known to disrupt the interactions of core and other HCV proteins such as (a) epigallocatechin gallate (EGCG), (b) ladanein, (c) naringenin, and (d) silybin extracted from medicinal plants; targeted against active site of residues of HCV-genotype 3 (G3) (Q68867) and its subtypes 3b (Q68861) and 3g (Q68865) from north India. To study the inhibitory activity of the recruited flavonoids, we conducted a quantitative structure-activity relationship (QSAR). Furthermore, docking interaction suggests that EGCG showed a maximum number of hydrogen bond (H-bond) interactions with all the three modeled capsid proteins with high interaction energy followed by naringenin and silybin. Thus, our results strongly correlate the inhibitory activity of the selected bioflavonoid. Finally, the dynamic predicted capsid protein molecule of HCV virion provides a general avenue to target structure-based antiviral compounds that support the hypothesis that the screened inhibitors for viral capsid might constitute new class of potent agents but further confirmation is necessary using in vitro and in vivo studies.

Expression of GABA signaling molecules KCC2, NKCC1, and GAD1 in cortical development and schizophrenia.

GABA signaling molecules are critical for both human brain development and the pathophysiology of schizophrenia. We examined the expression of transcripts derived from three genes related to GABA signaling [GAD1 (GAD67 and GAD25), SLC12A2 (NKCC1), and SLC12A5 (KCC2)] in the prefrontal cortex (PFC) and hippocampal formation of a large cohort of nonpsychiatric control human brains (n = 240) across the lifespan (from fetal week 14 to 80 years) and in patients with schizophrenia (n = 30-31), using quantitative RT-PCR. We also examined whether a schizophrenia risk-associated promoter SNP in GAD1 (rs3749034) is related to expression of these transcripts. Our studies revealed that development and maturation of both the PFC and hippocampal formation are characterized by progressive switches in expression from GAD25 to GAD67 and from NKCC1 to KCC2. Previous studies have demonstrated that the former leads to GABA synthesis, and the latter leads to switching from excitatory to inhibitory neurotransmission. In the hippocampal formation, GAD25/GAD67 and NKCC1/KCC2 ratios are increased in patients with schizophrenia, reflecting a potentially immature GABA physiology. Remarkably, GAD25/GAD67 and NKCC1/KCC2 expression ratios are associated with rs3749034 genotype, with risk alleles again predicting a relatively less mature pattern. These findings suggest that abnormalities in GABA signaling critical to brain development contribute to genetic risk for schizophrenia.

Alpha7 nicotinic acetylcholine receptor mRNA expression and binding in postmortem human brain are associated with genetic variation in neuregulin 1.

Studies in cell culture and in animals suggest that neuregulin 1 (NRG1), a probable schizophrenia susceptibility gene, regulates the expression of the alpha7 nicotinic acetylcholine receptors (nAChRs). We hypothesized that schizophrenia-associated allelic variations within the NRG1 gene, via their effects on NRG1 isoform expression, would be associated with alterations in nAChR alpha7 receptor levels. We examined the effects of four disease-associated single-nucleotide polymorphisms (SNPs) in the 5' region of the NRG1 gene on nAChR alpha7 mRNA transcript expression in both the dorsolateral prefrontal cortex (DLPFC) and hippocampus of normal controls and patients with schizophrenia using quantitative real-time PCR. NRG1 risk alleles at SNPs SNP8NRG221132 and rs6994992 predicted significantly lower nAChR alpha7 mRNA expression in the DLPFC. Haplotypes containing the risk alleles at the above SNPs were also associated with lower expression of nAChR alpha7 in the DLPFC. The genotype effect for rs6994992 and the haplotype effect were more pronounced within the schizophrenic patient group. To determine whether receptor levels follow that of mRNA expression, we performed receptor binding and autoradiography using [(125)I] alpha-bungarotoxin in the DLPFC. Consistent with the mRNA findings, we found a decrease in binding in risk allele carriers of SNP8NRG221132 as compared with heterozygous individuals. Together, these results suggest that the molecular mechanism of the association between NRG1 risk alleles and schizophrenia may include down-regulation of nAChR alpha7 expression.

Functional genomics in postmortem human brain: abnormalities in a DISC1 molecular pathway in schizophrenia.

The disrupted in schizophrenia 1 (DISC1) gene has been identified as a schizophrenia susceptibility gene based on linkage and single nucleotide polymorphism (SNP) association studies and clinical data, suggesting that risk SNPs impact on hippocampal structure and function. We hypothesized that altered expression of DISC1 and/or its molecular partners (nuclear distribution element-like [NUDEL], fasciculation and elongation protein zeta-i [FEZ1], and lissencephaly 1 [LIS1]) may underlie its pathogenic role in schizophrenia and explain its genetic association. We examined the expression of DISC1 and its binding partners in the hippocampus and dorsolateral prefrontal cortex of postmortem human brains of schizophrenic patients and controls. We found no difference in the expression of DISC1 mRNA in schizophrenia, and no association with previously identified risk SNPs. However, the expression of NUDEL, FEZ1, and LIS1 was significantly reduced in tissue from schizophrenic subjects, and the expression of each showed association with high-risk DISC1 polymorphisms. These data suggest involvement of genetically linked abnormalities in the DISC1 molecular pathway in the pathophysiology of schizophrenia.