Pharmacological Modulation of the Ca2+/cAMP/Adenosine Signaling in Cardiac Cells as a New Cardioprotective Strategy to Reduce Severe Arrhythmias in Myocardial Infarction.

Acute myocardial infarction (AMI) is the main cause of morbidity and mortality worldwide and is characterized by severe and fatal arrhythmias induced by cardiac ischemia/reperfusion (CIR). However, the molecular mechanisms involved in these arrhythmias are still little understood. To investigate the cardioprotective role of the cardiac Ca2+/cAMP/adenosine signaling pathway in AMI, L-type Ca2+ channels (LTCC) were blocked with either nifedipine (NIF) or verapamil (VER), with or without A1-adenosine (ADO), receptors (A1R), antagonist (DPCPX), or cAMP efflux blocker probenecid (PROB), and the incidence of ventricular arrhythmias (VA), atrioventricular block (AVB), and lethality (LET) induced by CIR in rats was evaluated. VA, AVB and LET incidences were evaluated by ECG analysis and compared between control (CIR group) and intravenously treated 5 min before CIR with NIF 1, 10, and 30 mg/kg and VER 1 mg/kg in the presence or absence of PROB 100 mg/kg or DPCPX 100 µg/kg. The serum levels of cardiac injury biomarkers total creatine kinase (CK) and CK-MB were quantified. Both NIF and VER treatment were able to attenuate cardiac arrhythmias caused by CIR; however, these antiarrhythmic effects were abolished by pretreatment with PROB and DPCPX. The total serum CK and CK-MB were similar in all groups. These results indicate that the pharmacological modulation of Ca2+/cAMP/ADO in cardiac cells by means of attenuation of Ca2+ influx via LTCC and the activation of A1R by endogenous ADO could be a promising therapeutic strategy to reduce the incidence of severe and fatal arrhythmias caused by AMI in humans.

Immunosuppression Protocols in Intestinal and Multivisceral Transplantation-A Literature Review.

BACKGROUND: Intestinal transplantation (IT) and multivisceral transplantation (MVT) are curative therapies for patients with intestinal failure and severe complications associated with total parenteral nutrition. High levels of immunosuppression are required to prevent acute cellular rejection (ACR) from the bowel. Studies regarding pre-treatment, induction, and post-transplant therapy have improved graft acceptance, reducing immunosuppression doses and infectious complications. However, the low rate of IT and MVT and the small number of specialized centers have resulted in a limited number of evidence-based immunosuppression protocols. We reviewed immunosuppression in IT and MVT to draw useful conclusions regarding the best protocol strategies for the induction, maintenance, and management of ACR. METHODS: A review was performed using the PubMed database. Articles on immunosuppression protocols in IT and MVT that addressed graft rejection, infection, or survival, published between 2006 and 2022, were selected. RESULTS: A total of 690 articles were selected. Two researchers applied the inclusion and exclusion criteria and selected 14 articles independently. For induction, thymoglobulin, alemtuzumab, and basiliximab are the most frequently used immunosuppressants for induction. Classic maintenance therapy consists of a combination of corticosteroids and tacrolimus. Methylprednisolone with an increased tacrolimus dose is used most frequently to manage ACR. Depending on the receptor response, such as thymoglobulin, infliximab, adalimumab, or bortezomib, other immunosuppressants should be considered. CONCLUSIONS: There have been great advances in IT and TMV immunosuppression. We conclude that the gold standard immunosuppressive protocol is triple therapy, comprising induction with thymoglobulin, maintenance with steroids for a few months, and tacrolimus and mycophenolate therapy. Innovative approaches for treating intestinal rejection episodes with more appropriate drugs, such as infliximab, adalimumab, or bortezomib, are necessary.

Application of the Balance of Risk Score to Liver Transplantation.

BACKGROUND: To evaluate the capacity of BARS to predict 90-day, 1-year, 3-year, and 5-year survival after liver transplantation (LTx). The Balance of Risk Score (BARS), proposed by the Swiss Hepato-pancreato-biliary and Transplant Center, University Hospital Zurich, Switzerland, was conceptualized to determine survival after LTx preemptively. SAMPLE AND METHODS: This was a retrospective observational study on 866 cases of LTx among adults (>18 years) performed within the transplantation program at Hospital Israelita Albert Einstein between January 1, 2010, and December 31, 2015. Cases of loss from follow-up, split-liver transplantation, transplantation from a live donor, and combinations of LTx with transplantation of other organs were excluded. BARS was calculated for each transplantation performed. The survival estimates were accompanied by 95% CIs, and the associations between the variables of interest and the patients' overall survival were evaluated using Cox proportional risk models. Receiver operating characteristic curves and the estimated area under the curve were used with 95% CIs and P values for the equality test on the area at .5. RESULTS: The area under the curve for the 90-day period was 0.725, with a 95% CI from 0.670 to 0.81 and a P value < .001 for the equality test at 0.5. In the stratified analysis, the score of 18 presented the highest sensitivity, taking a minimum specificity of 90%. The BARS >18 gave rise to a significant decline in survival, from 89.7% to 60.4% over the first 90 days, from 83.3% to 56.2% over a 1-year period, from 75.7% to 49.5% over 3 years, and from 72.2% to 43.4% over 5 years. CONCLUSION: The BARS was shown to be reproducible and can be used as a tool for estimating survival among LTx patients. LTx performed on patients with BARS >18 significantly predicts lower survival for such patients.

Questioning the Yelp Effect: Mixed Methods Analysis of Web-Based Reviews of Urgent Cares.

BACKGROUND: Providers of on-demand care, such as those in urgent care centers, may prescribe antibiotics unnecessarily because they fear receiving negative reviews on web-based platforms from unsatisfied patients-the so-called Yelp effect. This effect is hypothesized to be a significant driver of inappropriate antibiotic prescribing, which exacerbates antibiotic resistance. OBJECTIVE: In this study, we aimed to determine the frequency with which patients left negative reviews on web-based platforms after they expected to receive antibiotics in an urgent care setting but did not. METHODS: We obtained a list of 8662 urgent care facilities from the Yelp application programming interface. By using this list, we automatically collected 481,825 web-based reviews from Google Maps between January 21 and February 10, 2019. We used machine learning algorithms to summarize the contents of these reviews. Additionally, 200 randomly sampled reviews were analyzed by 4 annotators to verify the types of messages present and whether they were consistent with the Yelp effect. RESULTS: We collected 481,825 reviews, of which 1696 (95% CI 1240-2152) exhibited the Yelp effect. Negative reviews primarily identified operations issues regarding wait times, rude staff, billing, and communication. CONCLUSIONS: Urgent care patients rarely express expectations for antibiotics in negative web-based reviews. Thus, our findings do not support an association between a lack of antibiotic prescriptions and negative web-based reviews. Rather, patients' dissatisfaction with urgent care was most strongly linked to operations issues that were not related to the clinical management plan.

Brain orchestration of pregnancy and maternal behavior in mice: A longitudinal morphometric study.

Reproduction induces changes within the brain to prepare for gestation and motherhood. However, the dynamic of these central changes and their relationships with the development of maternal behavior remain poorly understood. Here, we describe a longitudinal morphometric neuroimaging study in female mice between pre-gestation and weaning, using new magnetic resonance imaging (MRI) resources comprising a high-resolution brain template, its associated tissue priors (60-µm isotropic resolution) and a corresponding mouse brain atlas (1320 regions of interest). Using these tools, we observed transient hypertrophies not only within key regions controlling gestation and maternal behavior (medial preoptic area, bed nucleus of the stria terminalis), but also in the amygdala, caudate nucleus and hippocampus. Additionally, unlike females exhibiting lower levels of maternal care, highly maternal females developed transient hypertrophies in somatosensory, entorhinal and retrosplenial cortices among other regions. Therefore, coordinated and transient brain modifications associated with maternal performance occurred during gestation and lactation.

Mucinous cystic neoplasm of the liver with biliary communication: case report and surgical therapeutic option.

BACKGROUND: Mucinous cyst neoplasm of the liver (MCN-L) comprise less than 5% of all cystic liver lesions and is characterized by the presence of ovarian stroma and absence of bile duct communication. CASE PRESENTATION: Here, we discuss a 45-year-old woman who presented with symptomatic liver mass. Diagnostic workup detected a 4.2 × 3.6 cm septate cyst located in segments I, V, and VIII of the liver in communication with the right hepatic duct. An open right liver resection with total bile duct excision and hilar lymphadenectomy was performed. Pathology revealed a multiloculated cyst with lined mucinous epithelium and ovarian-like stroma, consistent with low-grade MCN-L. CONCLUSIONS: This case shows that unusual location and bile duct communication can be present in MCN-L.

Chronic pancreatitis with ductal stones in the pancreatic head treated by surgery: a case report.

Pancreatic duct stones are direct sequelae of chronic pancreatitis (CP) and can occur in ∼50% of patients. Selection of the appropriate treatment method for pancreatic duct stones depends on location, size and number of stones. We present a patient with upper abdominal pain and weight loss for the previous 3 months. Diagnostic workup detected a chronic inflammation of the pancreas with stone in the main pancreatic duct and a nodular lesion in the head of the pancreas. Endoscopic retrograde cholangiopancreatography was performed without success. Given the rise in incidence and prevalence of CP, the potential complications and high mortality rate, it is imperative that physicians understand the risk factors, disease process and management of this disease. Pancreaticoduodenectomy in patients with CP is a feasible option for the treatment of focal cystic lesions to the head of the pancreas associated to pancreatic stone in selected cases.

Liver transplantation in undifferentiated embryonal sarcoma of the liver in adults: a case report / Transplante hepático em sarcoma embrionário indiferenciado de fígado em adultos: relato de caso

Undifferentiated embryonal sarcoma of the liver (UESL) consists of a rare malignant neoplasm with a still poorly known etiopathogenesis, affecting mostly children between the ages of 6 and 10 years. It corresponds to 7% of primary liver tumors, and is the fourth most common liver cancer in pediatrics. The diagnosis of UESL is based on a set of imaging findings, age and level of alpha-fetoprotein (AFP), which is usually normal, as well as liver function tests. Early diagnosis is hampered by non-specific symptoms, such as abdominal pain, a rapidly growing palpable abdominal mass, fever, weight loss, and gastrointestinal symptoms. The most characteristic image finding is that of a large, unique, and well-defined mass. Ultrasonography shows a predominantly solid and echogenic mass. Computed tomography, on the other hand, shows a mass that takes on a mainly cystic characteristic. Histologically, myxoid tissue with spindle-shaped neoplastic cells is evidenced. Some immunohistochemical studies indicate UESL mesenchymal origin. The macroscopic aspect of the tumor appears as a large hepatic mass, with a predominantly solid component, with some cystic areas, hemorrhage, and necrosis in up to 80% of its surface. The best approach for the treatment of primary liver sarcoma is not yet well defined. Therapeutic options include surgical resection, chemotherapy, radiotherapy, and liver transplantation (LT). However, in cases of unresectable tumors, LT is an option that must be considered, since in this histological type both chemotherapy and radiotherapy have questionable benefits. This article aims to report a case of giant UESL, with vascular invasion, submitted to LT with good postoperative evolution and without signs of recurrence after nine months of LT.

O sarcoma embrionário indiferenciado de fígado (SEIF) consiste em uma neoplasia maligna rara com etiopatogenia ainda pouco conhecida, acometendo em sua maioria crianças na faixa etária entre 6 e 10 anos. Corresponde a 7% dos tumores primários de fígado, e é a quarta neoplasia hepática mais frequente na pediatria. O diagnóstico do SEIF se dá em um conjunto de achados de imagem, idade e nível de alfa-fetoproteína (AF), que geralmente está normal, assim como as provas de função hepática. O diagnóstico precoce é prejudicado pelos sintomas inespecíficos, como dor abdominal, massa abdominal palpável de rápido crescimento, febre, perda de peso e sintomas gastrintestinais. O achado de imagem mais característico é o de massa grande, única e bem-delimitada. A ultrassonografia mostra massa predominantemente sólida e ecogênica. Já a tomografia computadorizada evidencia uma massa que assume característica principalmente cística. Histologicamente é evidenciado tecido mixoide com células neoplásicas fusiformes. Alguns estudos imuno-histoquímicos indicam origem mesenquimal do SEIF. O aspecto macroscópico do tumor se apresenta como grande massa hepática, de componente sólido predominantemente, com algumas áreas císticas, hemorragia e necrose em até 80% de sua superfície. Ainda não é bem-definida a melhor abordagem para o tratamento do sarcoma primário de fígado. As opções terapêuticas incluem ressecção cirúrgica, quimioterapia, radioterapia e transplante hepático (TH). Porém, nos casos de tumores irressecáveis, o TH é uma opção que deve ser considerada, uma vez que nesse tipo histológico tanto quimioterapia como radioterapia têm benefício questionável. Este artigo tem por objetivo relatar um caso de SEIF gigante, com invasão vascular, submetido a TH com boa evolução pós-operatória e sem sinais de recidiva após nove meses de TH.

Encapsulating Peritoneal Sclerosis in a kidney transplant recipient - Case Report.

Encapsulating Peritoneal Sclerosis (EPS) is a severe and rare condition frequently associated with peritoneal dialysis, characterized by bowel obstruction, with lethal consequences in 20% of the patients. The disease presents as a mass of fibrous tissue encapsulating visceral organs that may potentially compromise digestive tract function. This report describes the case of a patient under peritoneal dialysis (PD) due to chronic kidney disease secondary to focal segmental glomerulosclerosis diagnosed with EPS. The patient had undergone two living-donor kidney transplant procedures. Surgical techniques and clinical measures employed to unravel bowel obstruction are described, which have been shown to ameliorate EPS secondary complications. Parenteral nutrition has significantly contributed to afford adequate nutrition, improving tissue healing as well as serum protein levels, vitamins and electrolytes. Therapy with tamoxifen and sodium thiosulfate effectively delayed the development of EPS.

Publisher Correction: Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Paracetamol is a centrally acting analgesic using mechanisms located in the periaqueductal grey.

BACKGROUND AND PURPOSE: We previously demonstrated that paracetamol has to be metabolised in the brain by fatty acid amide hydrolase enzyme into AM404 (N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z-eicosatetraenamide) to activate CB1 receptors and TRPV1 channels, which mediate its analgesic effect. However, the brain mechanisms supporting paracetamol-induced analgesia remain unknown. EXPERIMENTAL APPROACH: The effects of paracetamol on brain function in Sprague-Dawley rats were determined by functional MRI. Levels of neurotransmitters in the periaqueductal grey (PAG) were measured using in vivo 1 H-NMR and microdialysis. Analgesic effects of paracetamol were assessed by behavioural tests and challenged with different inhibitors, administered systemically or microinjected in the PAG. KEY RESULTS: Paracetamol decreased the connectivity of major brain structures involved in pain processing (insula, somatosensory cortex, amygdala, hypothalamus, and the PAG). This effect was particularly prominent in the PAG, where paracetamol, after conversion to AM404, (a) modulated neuronal activity and functional connectivity, (b) promoted GABA and glutamate release, and (c) activated a TRPV1 channel-mGlu5 receptor-PLC-DAGL-CB1 receptor signalling cascade to exert its analgesic effects. CONCLUSIONS AND IMPLICATIONS: The elucidation of the mechanism of action of paracetamol as an analgesic paves the way for pharmacological innovations to improve the pharmacopoeia of analgesic agents.

Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management.

Improvements in the survival of breast cancer patients have led to the emergence of bone health and pain management as key aspects of patient's quality of life. Here, we used a female rat MRMT-1 model of breast cancer-induced bone pain to compare the effects of three drugs used clinically morphine, nabilone and zoledronate on tumor progression, bone remodeling and pain relief. We found that chronic morphine reduced the mechanical hypersensitivity induced by the proliferation of the luminal B aggressive breast cancer cells in the tumor-bearing femur and prevented spinal neuronal and astrocyte activation. Using MTT cell viability assay and MRI coupled to 18FDG PET imaging followed by ex vivo 3D µCT, we further demonstrated that morphine did not directly exert tumor growth promoting or inhibiting effects on MRMT-1 cancer cells but induced detrimental effects on bone healing by disturbing the balance between bone formation and breakdown. In sharp contrast, both the FDA-approved bisphosphonate zoledronate and the synthetic cannabinoid nabilone prescribed as antiemetics to patients receiving chemotherapy were effective in limiting the osteolytic bone destruction, thus preserving the bone architecture. The protective effect of nabilone on bone metabolism was further accompanied by a direct inhibition of tumor growth. As opposed to zoledronate, nabilone was however not able to manage bone tumor-induced pain and reactive gliosis. Altogether, our results revealed that morphine, nabilone and zoledronate exert disparate effects on tumor growth, bone metabolism and pain control. These findings also support the use of nabilone as an adjuvant therapy for bone metastases.

High-Throughput Total Internal Reflection Fluorescence and Direct Stochastic Optical Reconstruction Microscopy Using a Photonic Chip.

Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced contrast due to optical sectioning. The conventional approach is to use high numerical aperture microscope TIRF objectives for both excitation and collection, severely limiting the field of view and throughput. We present a novel approach to generating TIRF excitation for imaging with optical waveguides, called chip-based nanoscopy. The aim of this protocol is to demonstrate how chip-based imaging is performed in an already built setup. The main advantage of chip-based nanoscopy is that the excitation and collection pathways are decoupled. Imaging can then be done with a low magnification lens, resulting in large field of view TIRF images, at the price of a small reduction in resolution. Liver sinusoidal endothelial cells (LSECs) were imaged using direct stochastic optical reconstruction microscopy (dSTORM), showing a resolution comparable to traditional super-resolution microscopes. In addition, we demonstrate the high-throughput capabilities by imaging a 500 µm x 500 µm region with a low magnification lens, providing a resolution of 76 nm. Through its compact character, chip-based imaging can be retrofitted into most common microscopes and can be combined with other on-chip optical techniques, such as on-chip sensing, spectroscopy, optical trapping, etc. The technique is thus ideally suited for high throughput 2D super-resolution imaging, but also offers great opportunities for multi-modal analysis.

Mapping insoluble indole metabolites in the gastrointestinal environment of a murine colorectal cancer model using desorption/ionisation on porous silicon imaging.

Indole derivatives are a structurally diverse group of compounds found in food, toxins, medicines, and produced by commensal microbiota. On contact with acidic stomach conditions, indoles undergo condensation to generate metabolites that vary in solubility, activity and toxicity as they move through the gut. Here, using halogenated ions, we map promising chemo-preventative indoles, i) 6-bromoisatin (6Br), ii) the mixed indole natural extract (NE) 6Br is found in, and iii) the highly insoluble metabolites formed in vivo using desorption/ionisation on porous silicon-mass spectrometry imaging (DIOS-MSI). The functionalised porous silicon architecture allowed insoluble metabolites to be detected that would otherwise evade most analytical platforms, providing direct evidence for identifying the therapeutic component, 6Br, from the mixed indole NE. As a therapeutic lead, 0.025 mg/g 6Br acts as a chemo-preventative compound in a 12 week genotoxic mouse model; at this dose 6Br significantly reduces epithelial cell proliferation, tumour precursors (aberrant crypt foci; ACF); and tumour numbers while having minimal effects on liver, blood biochemistry and weight parameters compared to controls. The same could not be said for the NE where 6Br originates, which significantly increased liver damage markers. DIOS-MSI revealed a large range of previously unknown insoluble metabolites that could contribute to reduced efficacy and increased toxicity.

In vivo magnetic resonance imaging reveals the effect of gonadal hormones on morphological and functional brain sexual dimorphisms in adult sheep.

Sex differences in the brain and behavior are produced by the perinatal action of testosterone, which is converted into estradiol by the enzyme aromatase in the brain. Although magnetic resonance imaging (MRI) has been widely used in humans to study these differences, the use of animal models, where hormonal status can be properly manipulated, is necessary to explore the mechanisms involved. We used sheep, a recognized model in the field of neuroendocrinology, to assess brain morphological and functional sex differences and their regulation by adult gonadal hormones. To this end, we performed voxel-based morphometry and a resting-state functional MRI approach to assess sex differences in gonadally intact animals. We demonstrated significant sex differences in gray matter concentration (GMC) at the level of the gonadotropic axis, i.e., not only within the hypothalamus and pituitary but also within the hippocampus and the amygdala of intact animals. We then performed the same analysis one month after gonadectomy and found that some of these differences were reduced, especially in the hypothalamus and amygdala. By contrast, we found few differences in the organization of the functional connectome between males and females either before or after gonadectomy. As a whole, our study identifies brain regions that are sexually dimorphic in the sheep brain at the resolution of the MRI and highlights the role of gonadal hormones in the maintenance of these differences.

Structural and functional alterations in the retrosplenial cortex following neuropathic pain.

Human and animal imaging studies demonstrated that chronic pain profoundly alters the structure and the functionality of several brain regions. In this article, we conducted a longitudinal and multimodal study to assess how chronic pain affects the brain. Using the spared nerve injury model which promotes both long-lasting mechanical and thermal allodynia/hyperalgesia but also pain-associated comorbidities, we showed that neuropathic pain deeply modified the intrinsic organization of the brain functional network 1 and 2 months after injury. We found that both functional metrics and connectivity of the part A of the retrosplenial granular cortex (RSgA) were significantly correlated with the development of neuropathic pain behaviours. In addition, we found that the functional RSgA connectivity to the subiculum and the prelimbic system are significantly increased in spared nerve injury animals and correlated with peripheral pain thresholds. These brain regions were previously linked to the development of comorbidities associated with neuropathic pain. Using a voxel-based morphometry approach, we showed that neuropathic pain induced a significant increase of the gray matter concentration within the RSgA, associated with a significant activation of both astrocytes and microglial cells. Together, functional and morphological imaging metrics of the RSgA could be used as a predictive biomarker of neuropathic pain.

Combination of high-fat/high-fructose diet and low-dose streptozotocin to model long-term type-2 diabetes complications.

The epidemic of type 2 diabetes mellitus (T2DM) is fueled by added fructose consumption. Here, we thus combined high-fat/high-fructose diet, with multiple low-dose injections of streptozotocin (HF/HF/Stz) to emulate the long-term complications of T2DM. HF/HF/Stz rats, monitored over 56 weeks, exhibited metabolic dysfunctions associated with the different stages of the T2DM disease progression in humans: an early prediabetic phase characterized by an hyperinsulinemic period with modest dysglycemia, followed by a late stage of T2DM with frank hyperglycemia, normalization of insulinemia, marked dyslipidemia, hepatic fibrosis and pancreatic ß-cell failure. Histopathological analyses combined to [18F]-FDG PET imaging further demonstrated the presence of several end-organ long-term complications, including reduction in myocardial glucose utilization, renal dysfunction as well as microvascular neuropathy and retinopathy. We also provide for the first time a comprehensive µ-PET whole brain imaging of the changes in glucose metabolic activity within discrete cerebral regions in HF/HF/Stz diabetic rats. Altogether, we developed and characterized a unique non-genetic preclinical model of T2DM adapted to the current diet and lifestyle that recapitulates the major metabolic features of the disease progression, from insulin resistance to pancreatic ß-cell dysfunction, and closely mimicking the target-organ damage occurring in type 2 diabetic patients at advanced stages.

Investigation of lithium distribution in the rat brain ex vivo using lithium-7 magnetic resonance spectroscopy and imaging at 17.2 T.

Lithium is the first-line mood stabilizer for the treatment of patients with bipolar disorder. However, its mechanisms of action and transport across the blood-brain barrier remain poorly understood. The contribution of lithium-7 magnetic resonance imaging (7 Li MRI) to investigate brain lithium distribution remains limited because of the modest sensitivity of the lithium nucleus and the expected low brain concentrations in humans and animal models. Therefore, we decided to image lithium distribution in the rat brain ex vivo using a turbo-spin-echo imaging sequence at 17.2 T. The estimation of lithium concentrations was performed using a phantom replacement approach accounting for B1 inhomogeneities and differential T1 and T2 weighting. Our MRI-derived lithium concentrations were validated by comparison with inductively coupled plasma-mass spectrometry (ICP-MS) measurements ([Li]MRI  = 1.18[Li]MS , R = 0.95). Overall, a sensitivity of 0.03 mmol/L was achieved for a spatial resolution of 16 µL. Lithium distribution was uneven throughout the brain (normalized lithium content ranged from 0.4 to 1.4) and was mostly symmetrical, with consistently lower concentrations in the metencephalon (cerebellum and brainstem) and higher concentrations in the cortex. Interestingly, low lithium concentrations were also observed close to the lateral ventricles. The average brain-to-plasma lithium ratio was 0.34 ± 0.04, ranging from 0.29 to 0.39. Brain lithium concentrations were reasonably correlated with plasma lithium concentrations, with Pearson correlation factors ranging from 0.63 to 0.90.