Novel LC-MS/MS Method for Simultaneous Determination of Monoamine Neurotransmitters and Metabolites in Human Samples

For the simultaneous determination of monoamine neurotransmitters (NTs) like dopamine, serotonin, noradrenaline, and epinephrine, and their metabolites (metanephrine, normetanephrine, 3-methoxytyramine, vanillylmandelic acid, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid), a robust liquid chromatography method coupled with tandem mass spectrometry (LC-MS/MS) was introduced as the analytical method. This analytical method proved to be accurate for the simultaneous measurement of the amounts of 11 NTs and their metabolites in biological samples. The method proved to be more efficient and better than the previously reported method in terms of precision, recovery, sample requirement, and extraction procedure. The reported method requires only 100 μL of blood and 200 μL of urine, and the extraction procedure requires acetonitrile precipitation, filtration, drying, and reconstitution in water. The separation of all analytes was performed on an C18 column (4.6 mm × 150 mm and 1.8 μm). A 10 min gradient elution program with a mobile phase consisting of phase A (0.2% formic acid in water) and phase B (methanol) was used. The positive ionization mode was used for the detection of all analytes in multiple reaction monitoring (MRM). The proposed method was validated with an internal standard and yielded lower limits of detection and quantification ranges of 0.0182-0.0797 ng/mL and 0.0553-0.2415 ng/mL, respectively, with a good linearity (R2) between 0.9959 and 0.9994. The recoveries ranged from 73.37% to 116.63% in blood and from 80.9% to 115.33% in urine. For the NTs and metabolites, the intra- and interday % CV were 0.24-9.36 and 0.85-9.67, respectively. The developed LC-MS/MS method was successfully used for the determination of trace amounts of endogenous compounds in human blood and urine samples.

Sex Differences in Animal Models of Sodium-Valproate-Induced Autism in Postnatal BALB/c Mice: Whole-Brain Histoarchitecture and 5-HT2A Receptor Biomarker Evidence

Simple Summary

Valproic acid (VPA) is a well-known antiepileptic medication and mood stabiliser that is frequently prescribed for the treatment of epilepsy, particularly in children, and has proven human teratogenic activity. VPA inhibits histone deacetylase, which causes teratogenicity and cell toxicity. VPA-induced autism in rodents during the pre- and postnatal periods has shown the development of an autism-like phenotype. In mice, the 14th postnatal day is thought to correspond to the third trimester of human development; it is an important period in which neuronal migration, differentiation, myelination, synaptogenesis and gliogenesis occur in the cerebellum, striatum and hippocampus. Therefore, we exposed postnatal day 14 (PND 14) mice to VPA, which resulted in autistic-like behaviours manifested as reduced social interaction, increased repetitive stereotyped behaviour and anxiety, cognitive dysfunction, lowered sensitivity to pain and neurodevelopmental delay. BALB/c mice were used in this work because they are less reactive to social contact in VPA-induced autism than many other inbred mouse strains, such as C57/129 mice. In humans, two to three times more men are affected by autism spectrum disorder (ASD) than women, and, for this reason, the current study compares the histopathological changes and 5-hydroxy-tryptamine 2A (5-HT2A) receptor protein expression in the brain tissue of male and female animals with VPA-induced autism.

Abstract

Autism spectrum disorder (ASD) is characterised by problems with social interaction, verbal and nonverbal communication and repetitive behaviour. In mice, the 14th postnatal day is believed to correspond to the third trimester of human embryonic development and is considered a vital period for central nervous system development. It has been shown that ASD affects 2 to 3 times more male than female individuals. In the present study, ASD was induced in 14 postnatal day (PND) BALB/c mice using valproic acid (VPA). VPA administration brought about substantial differences in the histoarchitecture of the brain in both male and female mice, linked to behavioural deficits. We observed that both male and female mice showed similar morphological changes in the prefrontal cortex, hippocampus and Purkinje cells. We also observed hair loss from PND 17 to 25, which was again similar between male and female mice. However, there were higher rates of change in the cerebral cortex, frontal cortex and temporal lobe and hippocampus in VPA-treated male animals. With respect to the cerebellum, we did not observe any alterations by haematoxylin and eosin (H&E) staining, but detailed morphological observation using scanning electron microscopy (SEM) showed a higher rate of phenotype changes in VPA-treated male animals. Moreover, 5-HT2A receptor protein levels were upregulated in the cerebral cortex, hippocampus and Purkinje cells in VPA-treated male mice compared with control animals and VPA-treated female mice, as shown by immunohistochemical analysis. Based on all these findings, we conclude that male animals are more susceptible to VPA-induced ASD than females.

Minimally-invasive surgery for liver metastases

The practice of laparoscopic liver surgery has developed gradually, and most liver resections seem currently feasible and safe for selected patients in centers where surgeons are experienced both in liver surgery and in laparoscopic surgery. However, further studies would be required, especially for long-term oncological results and for major hepatectomy follow-up, before laparoscopic hepatectomy becomes a common alternative to open liver surgeries. Laparoscopic major hepatectomy is a recent technique, due to its significant complexity. In this review, we showed that patients undergoing laparoscopic hepatectomy for liver metastases experienced decreased rates of overall and major postoperative complications without any compromise on long-term outcomes compared to patients treated by open resection.

Thoracoscopic and endovascular management of retained haemothoarx associated with an intercostal artery pseudoaneurysm

Intercostal artery pseudoaneurysm (IAP) is a rare entity and may complicate a percutaneous intervention through an intercostal space or follow thoracic trauma. Its rupture into the pleural space can give rise to haemothorax, which if untreated may lead to a retained haemothorax (RH). Traditionally both the IAP and the RH are managed by a thoracotomy. We report a patient who developed an IAP with haemothorax following a trauma. The diagnosis was established by computed tomography. The patient was treated by endovascular embolisation of the IAP followed by thoracoscopic decortications of the RH.

Safety and efficiency of metered dose inhaler delivery of salbutamol in the intubated rabbit

OBJECTIVE

To determine the safety and efficiency of metered dose inhaler salbutamol delivered to the intubated rabbit.

DESIGN

Prospective, comparative, five-group laboratory investigation.

SETTING

Animal laboratory, Department of Nuclear Medicine.

SUBJECTS

A total of 30 adult, anesthetized New Zealand White rabbits.

INTERVENTIONS

Three groups of rabbits underwent tracheal intubation through a tracheostomy and received 5 puffs of 99mTcO4 salbutamol delivered at the elbow connector (group 1) or via a catheter with its distal tip positioned at the midpoint (group 2) or bevel of the endotracheal tube (group 3). No intervention was provided for the rabbits in the fourth group. A fifth group underwent tracheal intubation through the mouth and received salbutamol (5 puffs) delivered at the bevel of the endotracheal tube.

MEASUREMENTS

Delivery efficiency was expressed as the ratio of radioactivity emitted from lungs and trachea to the total radioactivity of the administered dose. Histopathologic injury scores were assigned to each trachea or lung specimen.

MAIN RESULTS

Delivery efficiency was 30 times greater in groups 3 and 5 (full catheter) than in group 1 (elbow). The injury scores were similar in all groups.

CONCLUSION

We conclude that the increased efficiency obtained by administration of metered dose inhaler salbutamol at the distal tip of endotracheal tube is not necessarily associated with increased epithelial injury.