The role of adipokines in the rapid antidepressant effects of ketamine.

We previously found that body mass index (BMI) strongly predicted response to ketamine. Adipokines have a key role in metabolism (including BMI). They directly regulate inflammation and neuroplasticity pathways and also influence insulin sensitivity, bone metabolism and sympathetic outflow; all of these have been implicated in mood disorders. Here, we sought to examine the role of three key adipokines-adiponectin, resistin and leptin-as potential predictors of response to ketamine or as possible transducers of its therapeutic effects. Eighty treatment-resistant subjects who met DSM-IV criteria for either major depressive disorder (MDD) or bipolar disorder I/II and who were currently experiencing a major depressive episode received a single ketamine infusion (0.5 mg kg-1 for 40 min). Plasma adipokine levels were measured at three time points (pre-infusion baseline, 230 min post infusion and day 1 post infusion). Overall improvement and response were assessed using percent change from baseline on the Montgomery-Asberg Depression Rating Scale and the Hamilton Depression Rating Scale. Lower baseline levels of adiponectin significantly predicted ketamine's antidepressant efficacy, suggesting an adverse metabolic state. Because adiponectin significantly improves insulin sensitivity and has potent anti-inflammatory effects, this finding suggests that specific systemic abnormalities might predict positive response to ketamine. A ketamine-induced decrease in resistin was also observed; because resistin is a potent pro-inflammatory compound, this decrease suggests that ketamine's anti-inflammatory effects may be transduced, in part, by its impact on resistin. Overall, the findings suggest that adipokines may either predict response to ketamine or have a role in its possible therapeutic effects.

cAMP signaling in brain is decreased in unmedicated depressed patients and increased by treatment with a selective serotonin reuptake inhibitor.

Basic studies exploring the importance of the cyclic adenosine monophosphate (cAMP) cascade in major depressive disorder (MDD) have noted that the cAMP cascade is downregulated in MDD and upregulated by antidepressant treatment. We investigated cAMP cascade activity by using 11C-(R)-rolipram to image phosphodiesterase-4 (PDE4) in unmedicated MDD patients and after ~8 weeks of treatment with a selective serotonin reuptake inhibitor (SSRI). 11C-(R)-rolipram positron emission tomographic (PET) scans were performed in 44 unmedicated patients during a major depressive episode and 35 healthy controls. Twenty-three of the 44 patients had a follow-up 11C-(R)-rolipram PET scan ~8 weeks after treatment with an SSRI. Patients were moderately depressed (Montgomery-Åsberg Depression Rating Scale=30±6) and about half were treatment naïve. 11C-(R)-rolipram binding was measured using arterial sampling to correct for individual differences in radioligand metabolism. We found in unmedicated MDD patients widespread, ~20% reductions in 11C-(R)-rolipram binding compared with controls (P=0.001). SSRI treatment significantly increased rolipram binding (12%, P<0.001), with significantly greater increases observed in older patients (P<0.001). Rolipram binding did not correlate with severity of baseline symptoms, and increased rolipram binding during treatment did not correlate with symptom improvement. In brief, consistent with the results of basic studies, PDE4 was decreased in unmedicated MDD patients and increased after SSRI treatment. The lack of correlation between PDE4 binding and depressive symptoms could reflect the heterogeneity of the disease and/or the heterogeneity of the target, given that PDE4 has four subtypes. These results suggest that PDE4 inhibitors, which increase cAMP cascade activity, may have antidepressant effects.

Baseline vitamin B12 and folate levels do not predict improvement in depression after a single infusion of ketamine.

INTRODUCTION: Deficiencies in both vitamin B12 and folate have been associated with depression. Recently, higher baseline vitamin B12 levels were observed in individuals with bipolar depression who responded to the antidepressant ketamine at 7 days post-infusion. This study sought to -replicate this result by correlating peripheral vitamin levels with ketamine's antidepressant efficacy in bipolar depression and major depressive disorder (MDD). METHODS: Baseline vitamin B12 and folate levels were obtained in 49 inpatients with treatment-resistant MDD and 34 inpatients with treatment-resistant bipolar depression currently experiencing a major depressive episode. All subjects received a single intravenous ketamine infusion. Post-hoc Pearson correlations were performed between baseline vitamin B12 and folate levels, as well as antidepressant response assessed by percent change in Hamilton Depression Rating Scale (HDRS) scores from baseline to 230 min, 1 day, and 7 days post-infusion. RESULTS: No significant correlation was observed between baseline vitamin B12 or folate and percent change in HDRS for any of the 3 time points in either MDD or bipolar depression. DISCUSSION: Ketamine's antidepressant efficacy may occur independently of baseline peripheral vitamin levels.

Excluding medical and haematological conditions as a cause of bruising in suspected non-accidental injury.

A mistaken diagnosis of child abuse can occur in a number of medical conditions, many of which can be readily diagnosed by experienced paediatricians. Bleeding disorders offer a greater challenge, especially when court proceedings may demand their exclusion. Some of these disorders are rare but more prevalent in areas which have a high incidence of consanguinity. We advocate two stages of laboratory investigations but the limitations of some of these tests and their inability to exclude a bleeding disorder with absolute certainty should be recognised. However, if personal and family histories are absent and both first-stage and second-stage investigations are normal, it is highly unlikely that a bleeding disorder will be missed.

Postischemic oxidative stress promotes mitochondrial metabolic failure in neurons and astrocytes.

Oxidative stress and mitochondrial dysfunction have been closely associated in many subcellular, cellular, animal, and human studies of both acute brain injury and neurodegenerative diseases. Our animal models of brain injury caused by cardiac arrest illustrate this relationship and demonstrate that both oxidative molecular modifications and mitochondrial metabolic impairment are exacerbated by reoxygenation of the brain using 100% ventilatory O(2) compared to lower levels that maintain normoxemia. Numerous molecular mechanisms may be responsible for mitochondrial dysfunction caused by oxidative stress, including oxidation and inactivation of mitochondrial proteins, promotion of the mitochondrial membrane permeability transition, and consumption of metabolic cofactors and intermediates, for example, NAD(H). Moreover, the relative contribution of these mechanisms to cell injury and death is likely different among different types of brain cells, for example, neurons and astrocytes. In order to better understand these oxidative stress mechanisms and their relevance to neurologic disorders, we have undertaken studies with primary cultures of astrocytes and neurons exposed to O(2) and glucose deprivation and reoxygenation and compared the results of these studies to those using a rat model of neonatal asphyxic brain injury. These results support the hypothesis that release and or consumption of mitochondrial NAD(H) is at least partially responsible for respiratory inhibition, particularly in neurons.

Platelet size has diagnostic predictive value in patients with thrombocytopenia.

We studied 473 unselected patients with thrombocytopenia. The mean platelet volume (MPV) was 8.1 fl in patients with marrow disease and 9.8 fl in patients without marrow disease (P < 0.001). A total of 5% of patients with an MPV >or=10.5 fl have marrow disease (odds ratio 0.05, 95% CI 0.02-0.13). Conversely over three quarters of patients with an MPV of <8.0 fl have marrow disease (odds ratio 8.1, 95% CI 5.0-13.0). Therefore the MPV can strongly guide the clinician as to the likely presence or absence of bone marrow disease in thrombocytopenic patients.

Angiotensin II type 1 receptor-modulated signaling pathways in neurons.

Mammalian brain contains high densities of angiotensin II (Ang II) type 1 (AT1) receptors, localized mainly to specific nuclei within the hypothalamus and brainstem regions. Neuronal AT1 receptors within these areas mediate the stimulatory actions of central Ang II on blood pressure, water and sodium intake, and vasopressin secretion, effects that involve the modulation of brain noradrenergic pathways. This review focuses on the intracellular events that mediate the functional effects of Ang II in neurons, via AT1 receptors. The signaling pathways involved in short-term changes in neuronal activity, membrane ionic currents, norepinephrine (NE) release, and longer-term neuromodulatory actions of Ang II are discussed. It will be apparent from this discussion that the signaling pathways involved in these events are often distinct.

Rapid anti-helminthic response of B lymphocytes in the intestinal mucosal tissues of rats.

B cell response to Trichinella spiralis (Ts) adult antigen (Ag) was studied in rats 1-20 days postinfection. B cell recoveries from the mesenteric lymph node (MLN), Peyer's patches (PP), thoracic duct lymph (TDL), and the spleen were determined by FACS analysis and Ag-specific antibody-producing cells (Ab-pc) in these tissues were enumerated using the immunoplaque assay. Total B cell numbers increased 2-70 times from day 3 postinfection in the MLN and TDL obtained from MLN-resected rats (MX) and such proliferation was not found in the PP or the spleen. Ab-pc of all isotypes increased from day 3 in the MLN and from day 2 in the MX-TDL. Among all isotypes, IgE- and IgG1-pc showed the strongest response. Immunofluorescence study revealed that these B cells were activated in the non-PP region of the small intestine. These results indicate an early isotype switch to IgG1 and IgE production in Ts-infected small intestine.

Angiotensin II type 2 receptor-mediated apoptosis of cultured neurons from newborn rat brain.

Angiotensin II (Ang II) type 2 (AT2) receptors are highly expressed in neonate brain and may have a role in developmental processes such as apoptosis. Concurrent activation of c-Jun N-terminal kinase (JNK) and inhibition of Erk mitogen-activated protein kinase activities is important for apoptosis in many cells, and we previously demonstrated that stimulation of AT2 receptors causes decreased mitogen-activated protein kinase activity in neurons cultured from newborn rat hypothalamus and brain stem. Using such cultures we have employed terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling and internucleosomal DNA fragmentation to assess the role of AT2 receptors in neuronal apoptosis. Ang II (100 nM; 4-72 h) alone produced no significant neuronal apoptosis, and AT2 receptor activation did not stimulate JNK activity. However, exposure of cultures to UV radiation (6 J/m2/sec for 4 sec) to stimulate JNK elicited neuronal apoptosis that was significantly enhanced by Ang II, an effect that was abolished by the AT2 receptor antagonist PD 123,319 (1 microM) or the serine/threonine phosphatase inhibitor okadaic acid (3 nM). Additionally, Ang II enhanced the UV radiation-induced decrease in the levels of the DNA repair enzyme poly-(ADP-ribose) polymerase. These data indicate that Ang II, via AT2 receptors and activation of a serine/threonine phosphatase, contributes to neuronal apoptosis.

Early induction and augmentation of parasitic antigen-specific antibody-producing B lymphocytes in the non-Peyer's patch region of the small intestine.

In this study, B lymphocytes from the small intestine of immunized rats were examined for their expression of specific antibodies against Trichinella spiralis (TS) antigen. The isotypes of the antigen-specific antibodies on B cells were examined via immunofluorescence microscopy. Monoclonal mouse anti-rat IgE, IgG1, IgG2a, IgG2b, IgG2c, IgA and IgM primary antibodies in conjunction with FITC-conjugated goat anti-mouse Ig secondary antibody and XRITC-conjugated 9D4 T. spiralis antigen were used to study the dynamics of the appearance of activated B lymphocytes in the small intestine, Peyer's patch, both the germinal center (PP-GC) and the non-germinal center (PP-NGC), the mesenteric lymph node (MLN), and the spleen. The results demonstrate that activated B cells are elicited by TS in the non-Peyer's patch region of the small intestine to express all isotypes of antibodies against TS antigen. IgG- and IgE-producing cells (Ab-PC) began proliferation only 1 and 2 days after infection, respectively. The strongest response was mounted by the IgE-PC in the lamina propria of the intestine. The response by IgA-PC generated was not only significantly delayed and also much weaker than that of the IgE- and IgG-PC. Peyer's patches failed to be a significant contributor in this immune response. Although this antigen-specific immune response was produced in the MLN and the spleen, it was weaker than that of the small intestine. The study indicates the potential ability of an immunized host to generate an early, yet effective, humoral immunity against T. spiralis in the non-Peyer's patch region of the small intestine."

Regulation of alpha2A-adrenergic receptor expression by epinephrine in cultured astroglia from rat brain.

Epinephrine (Epi) mediates various physiological effects via alpha2A-adrenergic receptors (alpha2A-ARs). Studies in mice with a point mutation in the gene for alpha2A-AR have shown that these receptors are responsible for the centrally mediated depressor effects of alpha2-AR agonists. These studies underscore the importance of understanding the basic cellular mechanisms involved in the expression of alpha2A-ARs, of which little is known. We use astroglia cultured from the hypothalamus and brainstem of adult Sprague-Dawley rats as a model system in which to study factors that regulate alpha2A-AR expression. These cells contain alpha2-ARs, which are predominately of the alpha2A-AR subtype. Our studies have shown that Epi causes a dose- and time-dependent decrease in steady-state levels of alpha2A-AR mRNA and number of alpha2A-ARs, effects that are mediated via alpha1- and beta-adrenergic receptors (alpha1-ARs and beta-ARs). These effects of Epi on alpha2A-AR mRNA and alpha2A-AR number are mimicked by activation of protein kinase C or increases in cellular cyclic AMP, which are intracellular messengers activated by alpha1-ARs and beta-ARs, respectively. Taken together, these results indicate that expression of alpha2A-ARs is regulated in a heterologous manner by Epi, via alpha1-AR- and beta-AR-mediated intracellular pathways.

The successful use of protein C concentrate during pregnancy in a patient with type 1 protein C deficiency, previous thrombosis and recurrent fetal loss.

The risks of venous thrombosis and fetal loss are increased in patients with protein C deficiency. We describe a patient with a history of thrombosis and recurrent fetal loss who was found to have type 1 protein C deficiency. In view of her history and intolerance of heparin preparations, she was treated with protein C concentrate during the first and third trimesters of her seventh pregnancy. The patient suffered no thromboembolic event during this pregnancy and gave birth to a healthy infant. The implications of the success of this therapeutic strategy are discussed.

Thrombocytopenia following liver transplantation is associated with platelet consumption and thrombin generation.

Thrombocytopenia frequently occurs immediately after orthotopic liver transplantation. We have investigated the cause of this phenomenon in a cohort of 45 consecutive liver transplant recipients. The median preoperative platelet count (range) of 129 x 10(9)/l (14-719) fell to 56 x 10(9)/l (23-334) by the fourth postoperative day. The median preoperative reticulated platelet percentage (range) of 6.7% (2.2-23.9) increased to 16.4% (4.6-40.8) on day 7. There was a significant rise in prothrombin fragment F1.2 by the first postoperative day which was followed by rises in fibrinogen and fibrin degradation products. There was no increase in platelet-associated immunoglobulin or markers of endothelial activation. We conclude that there is an increased rate of platelet consumption associated with thrombin generation that reflects the magnitude of liver transplant surgery.

Modulation of angiotensin II type 2 receptor mRNA in rat hypothalamus and brainstem neuronal cultures by growth factors.

This study investigates the regulatory effects of growth factors upon angiotensin II type 2 (AT2) mRNA levels in neurons co-cultured from newborn rat hypothalamus and brainstem. Incubation of cultured neurons with nerve growth factor (NGF; 5-50 ng/ml) caused time-dependent changes in the steady-state levels of AT2 receptor mRNA. Short-term (0.5-1.0 h) incubations with NGF resulted in significant increases in AT2 receptor mRNA, whereas longer-term incubations (4-24 h) caused significant decreases. Activation of NGF receptors is known to stimulate phospholipase C-gamma and subsequently activate protein kinase C (PKC). Incubation of cultures with the PKC activator, phorbol-12-myristate-13-acetate (PMA; 100 nM), caused temporal changes in AT2 receptor mRNA levels similar to those observed with NGF. By contrast, insulin (0.1-10 microg/ml) elicited only significant decreases in AT2 receptor mRNA levels. The observed abilities of NGF and insulin to regulate the expression of AT2 receptor mRNA are consistent with the fact that the AT2 receptor gene promoter region contains several cis DNA regulatory elements that respond to growth factor-stimulated transcription factors. These novel observations which show that NGF and insulin can regulate AT2 receptor mRNA in neurons derived from neonatal rat CNS lend support to the idea that AT2 receptors have a role in development and differentiation.

In vivo coagulation activation following infusion of highly purified factor XI concentrate.

The use of factor XI concentrates has been associated with thrombosis. Plasma markers of coagulation activation were measured before and 30, 60, 120 and 240 min after six infusions of the BPL factor XI concentrate. Five studies were completed before surgical intervention, one was undertaken in a patient with an intracerebral haemorrhage. Significant elevation of levels of fibrinopeptide A (FpA) (P < 0.05) and thrombin-antithrombin (TAT) were demonstrated following six infusions and prothrombin fragment F1.2 following four. Levels of all three markers had risen 60 min following concentrate administration and FpA levels remained elevated throughout the study period. Levels of D-dimer rose in four patients at 240 min. These results indicate significant thrombin generation by 60 min and subsequent plasmin generation consistent with coagulation activation by the factor XI concentrate. The greatest elevation of activation markers was seen in those subjects with pre-existing coagulation activation. We advise caution in the use of these products and awareness of the risks in patients who may already have activated coagulation states.

Regulation of alpha 2A-adrenergic receptor mRNA in rat astroglial cultures: role of cyclic AMP and protein kinase C.

In this study we investigated regulation of alpha 2A-adrenergic receptor (alpha 2A-AR) mRNA in rat astroglial cultures by increases in intracellular cyclic AMP levels and by protein kinase C (PKC) activation. Treatment of astroglial cultures with forskolin (FSK), an adenylyl cyclase activator, or with the membrane-permeable cyclic AMP analogues dibutyryl cyclic AMP or Sp-adenosine 3',5'-cyclic monophosphothioate triethylamine caused time- and concentration-dependent decreases in the levels of a approximately 4.0-kb alpha 2A-AR mRNA transcript. Levels of alpha 2A-AR mRNA were reduced to approximately 10% of control levels within 4 h of 1 microM FSK treatment. PKC agonists [phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-dibutyrate, and mezerein] also decreased alpha 2A-AR mRNA levels in a time- and concentration-dependent fashion. A 90% decrease in alpha 2A-AR mRNA levels was observed with 50 nM PMA in 4 h. The decrease in alpha 2A-AR mRNA levels caused by FSK and PMA treatment appears to be the result of decreases in transcription of the alpha 2A-AR gene and is not due to decreases in alpha 2A-AR mRNA degradation rate. These observations suggest that alpha 2A-AR mRNA levels are regulated by cyclic AMP and PKC.

t(9;13)(q34;q12) chromosomal translocation persisting 4 years post autologous bone marrow transplantation for secondary AML despite morphological remission.

A 42-year-old male patient with a history of occupational exposure to benzene presented with pancytopenia. His bone marrow showed evidence of trilineage dysplasia and cytogenetic analysis revealed a unique t(9;13)(q34;q12) translocation. Five months after diagnosis he developed secondary AML. He was treated with four courses of chemotherapy and an autologous bone marrow transplantation (BMT). Four years post-transplantation he remains in haematological and morphological remission though the cytogenetic abnormality is still present in all metaphases examined.

Measurement of reticulated platelets following peripheral blood progenitor cell and bone marrow transplantation: implications for marrow reconstitution and the use of thrombopoietin.

Neutrophil and platelet engraftment times are significantly shorter in patients undergoing PBPCT compared with ABMT. The explanation for this is unclear. The reticulated platelet percentage (RP%) has been established as a measure of bone marrow platelet production. Using this measurement we have followed thrombopoiesis over the transplant period in 10 patients undergoing PBPCT, eight ABMT and four alloBMT. Neutrophil and platelet engraftment times were significantly shorter in patients undergoing PBPCT than either ABMT or alloBMT. The RP% fell to a nadir in parallel with the platelet count in all patients following conditioning therapy consistent with an aplastic state and rose before platelet recovery as young platelets were released. The peak rise in the RP% was significantly greater and occurred earlier in PBPCT compared with BMT. The total number of reticulated platelets released during the time of engraftment was significantly greater in PBPCT than BMT. The potential role of the RP% in the timing of thrombopoietin therapy is explored. Finally the diagnostic use of the RP% in post-transplant thrombocytopenia is illustrated by a case in which a persistently high RP% accurately predicted a consumptive aetiology.