Chronic SIV-induced neuroinflammation disrupts CCR7+CD4+ T cell immunosurveillance in the rhesus macaque brain

CD4 T cells survey and maintain immune homeostasis in the brain, yet their differentiation states and functional capabilities remain unclear. Our approach, combining single-cell transcriptomic analysis, ATAC-seq, spatial transcriptomics, and flow cytometry, revealed a distinct subset of CCR7+ CD4 T cells resembling lymph node central memory (TCM) cells. We observed chromatin accessibility at the CCR7, CD28, and BCL-6 loci, defining molecular features of TCM. Brain CCR7+ CD4 T cells exhibited recall proliferation and interleukin-2 production ex vivo, showcasing their functional competence. We identified the skull bone marrow as a local niche for these cells alongside CNS border tissues. Sequestering TCM cells in lymph nodes using FTY720 led to reduced CCR7+ CD4 T cell frequencies in the cerebrospinal fluid, accompanied by increased monocyte levels and soluble markers indicating immune activation. In macaques chronically infected with SIVCL757 and experiencing viral rebound due to cessation of antiretroviral therapy, a decrease in brain CCR7+ CD4 T cells was observed, along with increased microglial activation and initiation of neurodegenerative pathways. Our findings highlight a role for CCR7+ CD4 T cells in CNS immune surveillance and their decline during chronic SIV highlights their responsiveness to neuroinflammation.

CCR7+ CD4 T Cell Immunosurveillance Disrupted in Chronic SIV-Induced Neuroinflammation in Rhesus Brain

CD4 T cells survey and maintain immune homeostasis in the brain, yet their differentiation states and functional capabilities remain unclear. Our approach, combining single-cell transcriptomic analysis, ATAC-seq, spatial transcriptomics, and flow cytometry, revealed a distinct subset of CCR7+ CD4 T cells resembling lymph node central memory (T CM ) cells. We observed chromatin accessibility at the CCR7, CD28, and BCL-6 loci, defining molecular features of T CM . Brain CCR7+ CD4 T cells exhibited recall proliferation and interleukin-2 production ex vivo, showcasing their functional competence. We identified the skull bone marrow as a local niche for these cells alongside other CNS border tissues. Sequestering T CM cells in lymph nodes using FTY720 led to reduced CCR7+ CD4 T cell frequencies in the cerebrospinal fluid, accompanied by increased monocyte levels and soluble markers indicating immune activation. In macaques chronically infected with SIVCL57 and experiencing viral rebound due to cessation of antiretroviral therapy, a decrease in brain CCR7+ CD4 T cells was observed, along with increased microglial activation and initiation of neurodegenerative pathways. Our findings highlight a role for CCR7+ CD4 T cells in CNS immune surveillance and their decline during chronic SIV-induced neuroinflammation highlights their responsiveness to neuroinflammatory processes.

GRAPHICAL ABSTRACT

In Brief

Utilizing single-cell and spatial transcriptomics on adult rhesus brain, we uncover a unique CCR7+ CD4 T cell subset resembling central memory T cells (T CM ) within brain and border tissues, including skull bone marrow. Our findings show decreased frequencies of this subset during SIV- induced chronic neuroinflammation, emphasizing responsiveness of CCR7+ CD4 T cells to CNS disruptions.

Highlights

CCR7+ CD4 T cells survey border and parenchymal CNS compartments during homeostasis; reduced presence of CCR7+ CD4 T cells in cerebrospinal fluid leads to immune activation, implying a role in neuroimmune homeostasis. CNS CCR7+ CD4 T cells exhibit phenotypic and functional features of central memory T cells (T CM ) including production of interleukin 2 and the capacity for rapid recall proliferation. Furthermore, CCR7+ CD4 T cells reside in the skull bone marrow. CCR7+ CD4 T cells are markedly decreased within the brain parenchyma during chronic viral neuroinflammation.

SARS-CoV-2 infects neurons and induces neuroinflammation in a non-human primate model of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), can induce a plethora of neurological complications in some patients. However, it is still under debate if SARS-CoV-2 directly infects the brain or if CNS sequelae result from systemic inflammatory responses triggered in the periphery. Using high-resolution microscopy, we investigated whether SARS-CoV-2 reaches the brain and how viral neurotropism can be modulated by aging in a non-human primate model of COVID-19. Seven days after infection, SARS-CoV-2 was detected in the olfactory cortex and interconnected regions, accompanied by robust neuroinflammation and neuronal damage exacerbated in aged diabetic animals. Our study provides an initial framework for identifying the molecular and cellular mechanisms underlying SARS-CoV-2 neurological complications, which will be essential to reducing both the short- and long-term burden of COVID-19.

Neuroinflammatory transcriptional programs induced in rhesus pre-frontal cortex white matter during acute SHIV infection

Background

Immunosurveillance of the central nervous system (CNS) is vital to resolve infection and injury. However, immune activation within the CNS in the setting of chronic viral infections, such as HIV-1, is strongly linked to progressive neurodegeneration and cognitive decline. Establishment of HIV-1 in the CNS early following infection underscores the need to delineate features of acute CNS immune activation, as these early inflammatory events may mediate neurodegenerative processes. Here, we focused on elucidating molecular programs of neuroinflammation in brain regions based on vulnerability to neuroAIDS and/or neurocognitive decline. To this end, we assessed transcriptional profiles within the subcortical white matter of the pre-frontal cortex (PFCw), as well as synapse dense regions from hippocampus, superior temporal cortex, and caudate nucleus, in rhesus macaques following infection with Simian/Human Immunodeficiency Virus (SHIV.C.CH505).

Methods

We performed RNA extraction and sequenced RNA isolated from 3 mm brain punches. Viral RNA was quantified in the brain and cerebrospinal fluid by RT-qPCR assays targeting SIV Gag. Neuroinflammation was assessed by flow cytometry and multiplex ELISA assays.

Results

RNA sequencing and flow cytometry data demonstrated immune surveillance of the rhesus CNS by innate and adaptive immune cells during homeostasis. Following SHIV infection, viral entry and integration within multiple brain regions demonstrated vulnerabilities of key cognitive and motor function brain regions to HIV-1 during the acute phase of infection. SHIV-induced transcriptional alterations were concentrated to the PFCw and STS with upregulation of gene expression pathways controlling innate and T-cell inflammatory responses. Within the PFCw, gene modules regulating microglial activation and T cell differentiation were induced at 28 days post-SHIV infection, with evidence for stimulation of immune effector programs characteristic of neuroinflammation. Furthermore, enrichment of pathways regulating mitochondrial respiratory capacity, synapse assembly, and oxidative and endoplasmic reticulum stress were observed. These acute neuroinflammatory features were substantiated by increased influx of activated T cells into the CNS.

Conclusions

Our data show pervasive immune surveillance of the rhesus CNS at homeostasis and reveal perturbations of important immune, neuronal, and synaptic pathways within key anatomic regions controlling cognition and motor function during acute HIV infection. These findings provide a valuable framework to understand early molecular features of HIV associated neurodegeneration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02610-y.

Neuroanatomical abnormalities in a nonhuman primate model of congenital Zika virus infection

We evaluated neuropathological consequences of fetal ZIKV exposure in rhesus monkeys, a translatable animal model for human neural development, by carrying out quantitative neuroanatomical analyses of the nearly full-term brains of fetuses infected with ZIKV and procedure-matched controls. For each animal, a complete cerebral hemisphere was evaluated using immunohistochemical (IHC) and neuroanatomical techniques to detect virus, identify affected cell types, and evaluate gross neuroanatomical abnormalities. IHC staining revealed the presence of ZIKV in the frontal lobe, which contained activated microglia and showed increased apoptosis of immature neurons. ZIKV-infected animals exhibited macrostructural changes within the visual pathway. Regional differences tracked with the developmental timing of the brain, suggesting inflammatory processes related to viral infiltration swept through the cortex, followed by a wave of cell death resulting in morphological changes. These findings may help explain why some infants born with normal sized heads during the ZIKV epidemic manifest developmental challenges as they age.

Towards developing a rhesus monkey model of early Alzheimer's disease focusing on women's health

Alzheimer's disease (AD) is the most common cause of elderly dementia, affecting nearly 50 million people worldwide, with two-thirds of the cases in the USA in women. Despite considerable investment, this prevalence is expected to increase further in the coming decades, based on the projected demographics of the population. Currently, most of the preclinical AD studies rely on transgenic mice carrying mutations associated with the early onset familiar form of AD, although the vast majority of cases are sporadic. A prevailing current hypothesis is that the cascade of events leading to AD starts with the accumulation of small soluble oligomers of the Aβ peptide (AβOs) that target and disrupt synapses. Taking advantage of the high translational power of rhesus monkeys due to their physiological and genetic similarities to humans, we recently developed a female rhesus monkey model of early AD pathogenesis based on exogenous administration AβOs. Here we review and discuss how soluble oligomers of Aβ can target vulnerable spines in the neocortex and hippocampus of female middle-aged monkeys and induce neuroinflammatory responses, similar to what is known to occur in the human brain. Developing a rhesus monkey model of early AD focusing on women's health is critical for the understanding of how hormonal changes during menopause transition affect brain health and ultimately may contribute to AD neurodegeneration.

Cerebrospinal Fluid Neurotransmitters, Cytokines, and Chemokines in Alzheimer's and Lewy Body Diseases

BACKGROUND

Alzheimer's disease (AD) and Lewy body disease (LBD) are complex neurodegenerative disorders that have been associated with brain inflammation and impaired neurotransmission.

OBJECTIVE

We aimed to determine concentrations of multiple cytokines, chemokines, and neurotransmitters previously associated with brain inflammation and synapse function in cerebrospinal fluid (CSF) from AD and LBD patients.

METHODS

We examined a panel of 50 analytes comprising neurotransmitters, cytokines, chemokines, and hormones in CSF in a cohort of patients diagnosed with mild cognitive impairment (MCI), AD, LBD, or non-demented controls (NDC).

RESULTS

Among neurotransmitters, noradrenaline (NA) was increased in AD CSF, while homovanillic acid (HVA), a dopamine metabolite, was reduced in both AD and LBD CSF relative to NDC. Six cytokines/chemokines out of 30 investigated were reliably detected in CSF. CSF vascular endothelial growth factor (VEGF) was significantly reduced in LBD patients relative to NDC.

CONCLUSIONS

CSF alterations in NA, HVA, and VEGF in AD and LBD may reflect pathogenic features of these disorders and provide tools for improved diagnosis. Future studies are warranted to replicate current findings in larger, multicenter cohorts.

A novel tau-based rhesus monkey model of Alzheimer's pathogenesis

INTRODUCTION

Alzheimer's disease (AD) is a devastating condition with no effective treatments, with promising findings in rodents failing to translate into successful therapies for patients.

METHODS

Targeting the vulnerable entorhinal cortex (ERC), rhesus monkeys received two injections of an adeno-associated virus expressing a double tau mutation (AAV-P301L/S320F) in the left hemisphere, and control AAV-green fluorescent protein in the right ERC. Noninjected aged-matched monkeys served as additional controls.

RESULTS

Within 3 months we observed evidence of misfolded tau propagation, similar to what is hypothesized to occur in humans. Viral delivery of human 4R-tau also coaptates monkey 3R-tau via permissive templating. Tau spreading is accompanied by robust neuroinflammatory response driven by TREM2+ microglia, with biomarkers of inflammation and neuronal loss in the cerebrospinal fluid and plasma.

DISCUSSION

These results highlight the initial stages of tau seeding and propagation in a primate model, a more powerful translational approach for the development of new therapies for AD.

Construction and reconstruction of brain circuits: normal and pathological axon guidance

Perception of our environment entirely depends on the close interaction between the central and peripheral nervous system. In order to communicate each other, both systems must develop in parallel and in coordination. During development, axonal projections from the CNS as well as the PNS must extend over large distances to reach their appropriate target cells. To do so, they read and follow a series of axon guidance molecules. Interestingly, while these molecules play critical roles in guiding developing axons, they have also been shown to be critical in other major neurodevelopmental processes, such as the migration of cortical progenitors. Currently, a major hurdle for brain repair after injury or neurodegeneration is the absence of axonal regeneration in the mammalian CNS. By contrasts, PNS axons can regenerate. Many hypotheses have been put forward to explain this paradox but recent studies suggest that hacking neurodevelopmental mechanisms may be the key to promote CNS regeneration. Here we provide a seminar report written by trainees attending the second Flagship school held in Alpbach, Austria in September 2018 organized by the International Society for Neurochemistry (ISN) together with the Journal of Neurochemistry (JCN). This advanced school has brought together leaders in the fields of neurodevelopment and regeneration in order to discuss major keystones and future challenges in these respective fields.

Exercise-linked FNDC5/irisin rescues synaptic plasticity and memory defects in Alzheimer's models

Defective brain hormonal signaling has been associated with Alzheimer’s disease (AD), a disorder characterized by synapse and memory failure. Irisin is an exercise-induced myokine released upon cleavage of membrane-bound precursor protein FNDC5, also expressed in the hippocampus. Here we show that FNDC5/irisin levels are reduced in AD hippocampi and cerebrospinal fluid, and in experimental AD models. Knockdown of brain FNDC5/irisin impaired long-term potentiation and novel object recognition memory in mice. Conversely, boosting brain levels of FNDC5/irisin rescued synaptic plasticity and memory in AD mouse models. Peripheral overexpression of FNDC5/irisin rescued memory impairment, whereas blockade of either peripheral or brain FNDC5/irisin attenuated the neuroprotective actions of physical exercise on synaptic plasticity and memory in AD mice. By showing that FNDC5/irisin is an important mediator of the beneficial effects of exercise in AD models, our findings place FNDC5/irisin as a novel agent capable of opposing synapse failure and memory impairment in AD.

A roadmap for investigating the role of the prion protein in depression associated with neurodegenerative disease

The physiological properties of the native, endogenous prion protein (PrP(C)) is a matter of concern, due to its pleiotropic functions and links to neurodegenerative disorders and cancer. In line with our hypothesis that the basic function of PrP(C) is to serve as a cell surface scaffold for the assembly of signaling modules, multiple interactions have been identified of PrP(C) with signaling molecules, including neurotransmitter receptors. We recently reported evidence that PrP(C) may modulate monoaminergic neurotransmission, as well as depressive-like behavior in mice. Here, we discuss how those results, together with a number of other studies, including our previous demonstration that both inflammatory and behavioral stress modulate PrP(C) content in neutrophils, suggest a distributed role of PrP(C) in clinical depression and inflammation associated with neurodegenerative diseases. An overarching understanding of the multiple interventions of PrP(C) upon physiological events may both shed light on the pathogenesis of, as well as help the identification of novel therapeutic targets for clinical depression, Prion and Alzheimer's Diseases.

Brain infusion of α-synuclein oligomers induces motor and non-motor Parkinson's disease-like symptoms in mice

Parkinson's disease (PD) is characterized by motor dysfunction, which is preceded by a number of non-motor symptoms including olfactory deficits. Aggregation of α-synuclein (α-syn) gives rise to Lewy bodies in dopaminergic neurons and is thought to play a central role in PD pathology. However, whether amyloid fibrils or soluble oligomers of α-syn are the main neurotoxic species in PD remains controversial. Here, we performed a single intracerebroventricular (i.c.v.) infusion of α-syn oligomers (α-SYOs) in mice and evaluated motor and non-motor symptoms. Familiar bedding and vanillin essence discrimination tasks showed that α-SYOs impaired olfactory performance of mice, and decreased TH and dopamine levels in the olfactory bulb early after infusion. The olfactory deficit persisted until 45days post-infusion (dpi). α- SYO-infused mice behaved normally in the object recognition and forced swim tests, but showed increased anxiety-like behavior in the open field and elevated plus maze tests 20 dpi. Finally, administration of α-SYOs induced late motor impairment in the pole test and rotarod paradigms, along with reduced TH and dopamine content in the caudate putamen, 45 dpi. Reduced number of TH-positive cells was also seen in the substantia nigra of α-SYO-injected mice compared to control. In conclusion, i.c.v. infusion of α-SYOs recapitulated some of PD-associated non-motor symptoms, such as increased anxiety and olfactory dysfunction, but failed to recapitulate memory impairment and depressive-like behavior typical of the disease. Moreover, α-SYOs i.c.v. administration induced motor deficits and loss of TH and dopamine levels, key features of PD. Results point to α-syn oligomers as the proximal neurotoxins responsible for early non-motor and motor deficits in PD and suggest that the i.c.v. infusion model characterized here may comprise a useful tool for identification of PD novel therapeutic targets and drug screening.

Diazepam Inhibits Electrically Evoked and Tonic Dopamine Release in the Nucleus Accumbens and Reverses the Effect of Amphetamine

Diazepam is a benzodiazepine receptor agonist with anxiolytic and addictive properties. Although most drugs of abuse increase the level of release of dopamine in the nucleus accumbens, here we show that diazepam not only causes the opposite effect but also prevents amphetamine from enhancing dopamine release. We used 20 min sampling in vivo microdialysis and subsecond fast-scan cyclic voltammetry recordings at carbon-fiber microelectrodes to show that diazepam caused a dose-dependent decrease in the level of tonic and electrically evoked dopamine release in the nucleus accumbens of urethane-anesthetized adult male Swiss mice. In fast-scan cyclic voltammetry assays, dopamine release was evoked by electrical stimulation of the ventral tegmental area. We observed that 2 and 3 mg of diazepam/kg reduced the level of electrically evoked dopamine release, and this effect was reversed by administration of the benzodiazepine receptor antagonist flumazenil in doses of 2.5 and 5 mg/kg, respectively. No significant effects on measures of dopamine re-uptake were observed. Cyclic voltammetry experiments further showed that amphetamine (5 mg/kg, intraperitoneally) caused a significant increase in the level of dopamine release and in the half-life for dopamine re-uptake. Diazepam (2 mg/kg) significantly weakened the effect of amphetamine on dopamine release without affecting dopamine re-uptake. These results suggest that the pharmacological effects of benzodiazepines have a dopaminergic component. In addition, our findings challenge the classic view that all drugs of abuse cause dopamine release in the nucleus accumbens and suggest that benzodiazepines could be useful in the treatment of addiction to other drugs that increase the level of dopamine release, such as cocaine, amphetamines, and nicotine.

Microglial dysfunction connects depression and Alzheimer's disease

Alzheimer's disease (AD) and major depressive disorder (MDD) are highly prevalent neuropsychiatric conditions with intriguing epidemiological overlaps. Depressed patients are at increased risk of developing late-onset AD, and around one in four AD patients are co-diagnosed with MDD. Microglia are the main cellular effectors of innate immunity in the brain, and their activation is central to neuroinflammation - a ubiquitous process in brain pathology, thought to be a causal factor of both AD and MDD. Microglia serve several physiological functions, including roles in synaptic plasticity and neurogenesis, which may be disrupted in neuroinflammation. Following early work on the 'sickness behavior' of humans and other animals, microglia-derived inflammatory cytokines have been shown to produce depressive-like symptoms when administered exogenously or released in response to infection. MDD patients consistently show increased circulating levels of pro-inflammatory cytokines, and anti-inflammatory drugs show promise for treating depression. Activated microglia are abundant in the AD brain, and concentrate around senile plaques, hallmark lesions composed of aggregated amyloid-β peptide (Aβ). The Aβ burden in affected brains is regulated largely by microglial clearance, and the complex activation state of microglia may be crucial for AD progression. Intriguingly, recent reports have linked soluble Aβ oligomers, toxins that accumulate in AD brains and are thought to cause memory impairment, to increased brain cytokine production and depressive-like behavior in mice. Here, we review recent findings supporting the inflammatory hypotheses of AD and MDD, focusing on microglia as a common player and therapeutic target linking these devastating disorders.

Prion Protein Modulates Monoaminergic Systems and Depressive-like Behavior in Mice

We sought to examine interactions of the prion protein (PrP(C)) with monoaminergic systems due to: the role of PrP(C) in both Prion and Alzheimer diseases, which include clinical depression among their symptoms, the implication of monoamines in depression, and the hypothesis that PrP(C) serves as a scaffold for signaling systems. To that effect we compared both behavior and monoaminergic markers in wild type (WT) and PrP(C)-null (PrP(-/-)) mice. PrP(-/-) mice performed poorly when compared with WT in forced swimming, tail suspension, and novelty suppressed feeding tests, typical of depressive-like behavior, but not in the control open field nor rotarod motor tests; cyclic AMP responses to stimulation of D1 receptors by dopamine was selectively impaired in PrP(-/-) mice, and responses to serotonin, but not to norepinephrine, also differed between genotypes. Contents of dopamine, tyrosine hydroxylase, and the 5-HT5A serotonin receptor were increased in the cerebral cortex of PrP(-/-), as compared with WT mice. Microscopic colocalization, as well as binding in overlay assays were found of PrP(C) with both the 5HT5A and D1, but not D4 receptors. The data are consistent with the scaffolding of monoaminergic signaling modules by PrP(C), and may help understand the pathogenesis of clinical depression and neurodegenerative disorders.

Alzheimer-associated Aβ oligomers impact the central nervous system to induce peripheral metabolic deregulation

Alzheimer's disease (AD) is associated with peripheral metabolic disorders. Clinical/epidemiological data indicate increased risk of diabetes in AD patients. Here, we show that intracerebroventricular infusion of AD-associated Aβ oligomers (AβOs) in mice triggered peripheral glucose intolerance, a phenomenon further verified in two transgenic mouse models of AD. Systemically injected AβOs failed to induce glucose intolerance, suggesting AβOs target brain regions involved in peripheral metabolic control. Accordingly, we show that AβOs affected hypothalamic neurons in culture, inducing eukaryotic translation initiation factor 2α phosphorylation (eIF2α-P). AβOs further induced eIF2α-P and activated pro-inflammatory IKKβ/NF-κB signaling in the hypothalamus of mice and macaques. AβOs failed to trigger peripheral glucose intolerance in tumor necrosis factor-α (TNF-α) receptor 1 knockout mice. Pharmacological inhibition of brain inflammation and endoplasmic reticulum stress prevented glucose intolerance in mice, indicating that AβOs act via a central route to affect peripheral glucose homeostasis. While the hypothalamus has been largely ignored in the AD field, our findings indicate that AβOs affect this brain region and reveal novel shared molecular mechanisms between hypothalamic dysfunction in metabolic disorders and AD.

The effects of metergoline and 8-OH-DPAT injections into arcuate nucleus and lateral hypothalamic area on feeding in female rats during the estrous cycle

The present study examined the effects of local injections of metergoline (MET, an antagonist of 5-HT1/2 receptors, 2 and 20 nmol) and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, selective 5-HT1A receptor agonist, 0.6 and 6 nmol) into the arcuate nucleus (ARC) and the lateral hypothalamus (LH), on ingestive and non-ingestive behaviors of female rats. These effects were examined during the diurnal periods of diestrus and estrus in rats adapted to eat a wet mash diet (enriched with 10% sucrose) during 1h for 3 consecutive days at the recording chamber. The results showed that 8-OH-DPAT injected into the LH significantly reduced food intake at all doses and both cycle stages, while in the ARC these treatments evoked hypophagia only at the highest 8-OH-DPAT dose and only at the estrous phase. MET administered into the ARC (at all doses) failed to affect food intake during both estrous stages. On the other hand, food intake decreased after injection of both doses of MET into the LH of rats during estrous and diestrus phases. In estrus stage, injections of the higher dose of 8-OH-DPAT into the ARC and into the LH decreased the duration of feeding. Latency to start feeding, drinking, and non-ingestive behaviors were not affected by 8-OH-DPAT or MET treatments in the ARC or the LH in both cycle phases. These results indicated that 5-HT1A receptors participate in the serotonergic control of feeding-related mechanisms located at the ARC and the LH. These feeding-related serotonergic circuits in both areas are possibly affected by ovarian hormones that could increase sensitivity of ARC neurons to the hypophagic effects of 8-OH-DPAT or increase the efficacy of satiety signals that terminate feeding. In addition, the present data indicated that serotonergic inputs do not exert a tonic inhibitory activity on the ARC and the LH feeding-related circuits.

PAM-4 Signaling over VCSELs with 0.13microm CMOS Chip Technology

We present results for VCSEL based links operating PAM-4 signaling using a commercial 0.13microm CMOS technology. We perform a complete link analysis of the Bit Error Rate, Q factor, random and deterministic jitter by measuring waterfall curves versus margins in time and amplitude. We demonstrate that VCSEL based PAM-4 can match or even improve performance over binary signaling under conditions of a bandwidth limited, 100meter multi-mode optical link at 5Gbps. We present the first sensitivity measurements for optical PAM-4 and compare it with binary signaling. Measured benefits are reconciled with information theory predictions.

Divalproex sodium in sex offenders with bipolar disorders and comorbid paraphilias: an open retrospective study

BACKGROUND

This study evaluated divalproex response in sex offenders with a bipolar disorder.

METHODS

We reviewed the records of all sex offenders who participated in a residential rehabilitative program who received divalproex for treatment of a bipolar disorder. Patients' mood symptoms and, when present, comorbid paraphilic symptoms, were retrospectively assessed using the CGI severity scale.

RESULTS

Sex offenders displayed significant improvement in manic symptoms with divalproex treatment. However, there was no significant improvement in paraphilic symptoms in the subset of patients admitting to these symptoms.

CONCLUSION

Divalproex may be effective for manic symptoms in sex offenders with a bipolar disorder. However, for bipolar sex offenders with comorbid paraphilias, the drug may not be effective for paraphilic symptoms.

LIMITATIONS

This study was limited by its retrospective, open-label design, lack of systematic means of assessing manic and paraphilic symptoms, and small sample size.

CLINICAL RELEVANCE

Divalproex may be a helpful adjunct in the treatment of the subset of sex offenders who have a bipolar disorder.

Rat embryo cultures for in vitro teratology

Mammalian embryos provide a particular challenge to those who wish to study developmental processes because development takes place inside the mother's body, thus limiting the investigator's ability to directly affect and observe the embryonic stages of development. Fortunately, as this unit illustrates, methods have been developed for in vitro culture of rodent embryos during early postimplantation (gestation days 9 to 11) and early fetal (gestation days 12 to 14) stages, which are the periods during which the major systems of the embryo are established. Embryos at these stages are particularly suitable for screening studies to determine the effects of teratological agents.

Utilization of intravenous immunoglobulin to ameliorate alloantibodies in a highly sensitized patient with a cardiac assist device awaiting heart transplantation. Fluorescence-activated cell sorter analysis

Surgery surrounding the use of mechanical assistance in cardiac transplant candidates often leads to multiple blood/platelet transfusions and subsequent development of alloantibodies. This is a case report of a 50-year-old male patient who had received blood transfusions during coronary bypass grafting 9 years earlier. He presented in acute and chronic heart failure and, despite therapy, became moribund with multisystem organ failure. His ejection fraction was 10%. A Novacor ventricular assist device was implanted on May 19, 1995 (day 0). The patient received 44 U of blood and 20 U of platelets. Although his percent reactive antibodies (PRA) were negative before surgery by fluorescence-activated cell sorter analysis, the PRA 3 days after implantation of the ventricular assist device was 80%; it increased to 100% by day 7. In an attempt to decrease the PRA, intravenous immunoglobulin was given at 3-week intervals. The PRA became negative and the patient received a donor heart that was negative by fluorescence-activated cell sorter cross-match on day 64. On days 69-72, a dramatic increase in alloantibody activity was promptly reversed with additional intravenous immunoglobulin. Currently at posttransplant month 12, the patient shows no humoral, cellular, or vascular evidence of rejection.

The use of tranexamic acid to reduce postoperative bleeding following cardiac surgery: a double-blind randomized trial

Bleeding during the first 24 hours following cardiac surgery using cardio-pulmonary bypass (CPB) is a serious complication. Attempts to modify the degree of postoperative bleeding with pharmacologic therapy have met with limited success. Tranexamic acid, a potent inhibitor of plasminogen, may decrease the amount of mediastinal bleeding following surgery utilizing CPB. We assigned 30 patients who were about to undergo cardiac surgery to a double-blind randomized trial. The treatment group received tranexamic acid, given intravenously as 10 mg/kg over 30 minutes, at the time of skin incision, followed by a 1 mg/kg/hr infusion for 12 hours. The control group received a placebo (saline) of equal volume. Measurements of shed mediastinal blood and transfused homologous blood were made at 6, 12, and 24 hours postoperatively. Mediastinal blood loss in the treatment and control groups was 382 mL versus 594 mL at 6 hours (P = 0.08), 502 mL versus 848 mL at 12 hours (P = 0.04), and 711 mL versus 1160 mL at 24 hours (P = 0.02). The mean transfusion volumes after 24 hours were 356 mL in the treatment group and 528 mL in the placebo group (P = NS). Prophylactic tranexamic acid infusion decreases mediastinal blood loss following cardiopulmonary assisted cardiac surgery.

Improved visualization of the internal mammary artery with a new retractor system

A new sternal retractor system was developed to improve exposure of the internal mammary artery and protect the lung. This retractor can be used for either single or bilateral dissection of the internal mammary artery. It has been used in more than 2,000 cases with excellent results.

Intraoperative pulmonary angioscopy using the flexible fiberoptic choledochoscope

The use of fiberoptic angioscopy can be an important adjunct to the performance of pulmonary embolectomy. This technique can be performed rapidly and allows direct visualization of the pulmonary arteries.

Heart transplantation at a private institution: a two year experience

Since October 1982, 45 patients were referred and 15 underwent orthotopic heart transplantations. Eleven patients are presently alive. The donor heart ischemic time averaged 104 minutes for locally procured hearts and 183 minutes for hearts harvested in distant cities. Ninety-three percent of the patients survived the perioperative period. Survival rate at six months was 84%, at one and two years 72% and 52%, respectively. The one year survivors spent 80% of their time out of the hospital. The average cost for the transplant admission was $58,023. Four patients died 11 days, 57 days, 8 and 12 months after the operation. During the first three months there were 0.75 rejection episodes, 1.13 infections and 1.40 other complications per patient. We conclude that heart transplantation can be successfully carried out at a private institution, with excellent survival rates and at reasonable costs. In spite of progress, infection and rejection still account for most of the mortality and morbidity.

Hypokalemia and massive transfusion

To investigate the etiology of the hypokalemia that is more commonly associated with massive transfusions than hyperkalemia, we determined the plasma potassium concentrations of 26 stored packed cell preparations and reviewed a series of 15 patients who received massive transfusions with whole blood or packed cells. Our results confirm that stored packed cell preparations, like stored whole blood preparations, are hyperkalemic, and suggest that metabolic alkalosis, catecholamine release, and hemorrhagic shock are important factors in the development of hypokalemia associated with massive blood transfusions. In view of the association of hypokalemia and hyperkalemia with massive transfusion, plasma potassium levels should be carefully monitored in patients receiving massive transfusions.

[Studies on the metabolism of oestrone and oestradiol-17 beta in the kidneys of minipigs of different ages and sexes (author's transl)]

After incubation of [4-14C]oestrone (E1) with kidney cortex slices of minipigs, [4-14C]oestradiol-17 beta (E2) and small amounts of a polar metabolite were detected in the ether-soluble fraction. E1, E2 and polar metabolites were found in the protein-bound fraction. The water-soluble fraction contained E1-3-glucuronide (80% of total glucuronides), E2-3-glucuronide and trace amounts of the 3-monoglucuronide of oestriol (E3). When E2 was used as substrate, the main product formed was E1; it was detected in both the ether-soluble and protein-bound fractions. E1-3-Glucuronide was the main metabolite in the water-soluble fraction, which also contained some E2-3-Glucuronide. In male minipigs, the mast, the rate of conversion of E1 and E2 as well as the formation of glucuronides were significantly greater in fertile females than in infertile females. Whereas no sex difference was observed in the metabolism of oestrogens in kidneys of infertile minipigs, the rate of oxidoreduction and glucuronidation was more pronounced in fertile female animals than in the corresponding males. The present results suggest that, in the kidneys of minipigs, the ratio of E1 to E2 is shifted towards the former; furthermore, by a comparatively rapid metabolism of the oestrogenic hormone, the renal tissue contributes to the maintenance of hormonal equilibrium.

Temperature-sensitive nonsense mutations in essential genes of Escherichia coli

Cells containing nonsense mutations in essential genes have been isolated in a strain of Escherichia coli that carried the su4(ts) gene which specifies a temperature-sensitive tyrosine transfer ribonucleic acid. Such cells are unable to form colonies at temperatures which inactivate this suppressor transfer ribonucleic acid. A screening procedure for the identification of mutants that carry temperature-sensitive nonsense mutations in essential genes is described, and certain properties of two such mutants are reported.