Since the inception of radiosurgery, the management of brain metastases has become a common problem for neurosurgeons. Although the use of stereotactic radiosurgery and/or whole brain radiation ...therapy serves to control the majority of disease burden, patients who survive longer than 6–8 months sometimes face the problem of symptomatic radiographically regrowing lesions with few treatment options. Here we investigate the feasibility of use of MRI-guided stereotactic laser induced thermotherapy (LITT) as a novel treatment option for these lesions. Six patients who had previously undergone gamma knife stereotactic radiosurgery for brain metastases were selected. All patients had an initial favorable response to radiosurgery but subsequently developed regrowth of at least one lesion associated with recurrent edema and progressive neurological symptoms requiring ongoing steroids for symptom control. All lesions were evaluated for craniotomy, but were deemed unresectable due to deep location or patient’s comorbidities. Stereotactic biopsies were performed prior to the thermotherapy procedure in all cases. LITT was performed using the Visualase system and follow-up MRI imaging was used to determine treatment response. In all six patients biopsy results were negative for tumor and consistent with adverse radiation effects also known as radiation necrosis. Patients tolerated the procedure well and were discharged from the hospital within 48 h of the procedure. In 4/6 cases there was durable improvement of neurological symptoms until death. In all cases steroids were weaned off within 2 months. One patient died from systemic causes related to his cancer a month after the procedure. One patient had regrowth of the lesion 3 months after the procedure and required re-initiation of steroids and standard craniotomy for surgical resection. There were no complications directly related to the thermocoagulation procedure. Stereotactic laser induced thermotherapy is a feasible alternative for the treatment of symptomatic regrowing metastatic lesions after radiosurgery. The procedure carries minimal morbidity and, in this small series, shows some effectiveness in the symptomatic relief of edema and neurological symptoms paralleled by radiographic lesional control. Further studies are necessary to elucidate the safety of this technology.
Background Marijuana use by teenagers often predates the use of harder drugs, but the neurobiological underpinnings of such vulnerability are unknown. Animal studies suggest enhanced heroin ...self-administration (SA) and dysregulation of the endogenous opioid system in the nucleus accumbens shell (NAcsh) of adults following adolescent Δ9 -tetrahydrocannabinol (THC) exposure. However, a causal link between proenkephalin ( Penk ) expression and vulnerability to heroin has yet to be established. Methods To investigate the functional significance of NAcsh Penk tone, selective viral-mediated knockdown and overexpression of Penk was performed, followed by analysis of subsequent heroin SA behavior. To determine whether adolescent THC exposure was associated with chromatin alteration, we analyzed levels of histone H3 methylation in the NAcsh via chromatin immunoprecipitation at five sites flanking the Penk gene transcription start site. Results Here we show that regulation of the Penk opioid neuropeptide gene in NAcsh directly regulates heroin SA behavior. Selective viral-mediated knockdown of Penk in striatopallidal neurons attenuates heroin SA in adolescent THC-exposed rats, whereas Penk overexpression potentiates heroin SA in THC-naïve rats. Furthermore, we report that adolescent THC exposure mediates Penk upregulation through reduction of histone H3 lysine 9 (H3K9) methylation in the NAcsh, thereby disrupting the normal developmental pattern of H3K9 methylation. Conclusions These data establish a direct association between THC-induced NAcsh Penk upregulation and heroin SA and indicate that epigenetic dysregulation of Penk underlies the long-term effects of THC.
Background
Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described.
Objective
To present clinical and radiographic outcomes for ...the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs.
Methods
We performed a retrospective single-center cohort study and a systematic literature review.
Results
Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm
3
preoperatively to 9.9 ± 11.4 cm
3
immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm
3
; max 7.5 cm
3
). Median length of stay was 3 days (range 2–8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM.
Conclusion
The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach. Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.
Background Attentional deficits accompany many psychiatric disorders, underscoring the need for rodent models of attention to screen novel therapeutic agents and characterize the biological basis of ...attention. The five-choice serial reaction time task (5CSRTT) is one such model. Here, we characterized the effects of four standard psychotropic agents on performance in the 5CSRTT. Methods Male Sprague-Dawley rats were trained in the 5CSRTT (5-sec inter-trial interval and .5-sec stimulus duration) until they reliably performed at > 60% accuracy and < 20% omissions. They were then treated systemically with the stimulant methylphenidate (MPH) (.063–2.0 mg/kg), the N -methyl-D-aspartate antagonist dizocilpine (MK-801) (.008–.25 mg/kg), the norepinephrine reuptake inhibitor desipramine (DMI) (.63–10 mg/kg), or the κ-receptor agonist U69,593 (.25–2.0 mg/kg) 30 min before testing. Results Methylphenidate (.5 mg/kg) increased accuracy. Dizocilpine impaired accuracy (.25 mg/kg), increased premature responses (.063–.25 mg/kg), and increased omissions (.25 mg/kg). Desipramine decreased premature responses (5.0 mg/kg) but increased omissions (10 mg/kg), correct response latencies (5.0–10.0 mg/kg), and reward latencies (5.0–10.0 mg/kg). The κ-opioid agonist U69,593 (1.0–2.0 mg/kg) increased omissions and correct response latencies. Conclusions In Sprague-Dawley rats, psychotropic drugs with distinct pharmacological profiles produced distinguishable effects in the 5CSRTT. The effects of these classes of drugs under our testing conditions are qualitatively similar to their effects in humans.
We showed previously that cAMP response element-binding protein (CREB) within the nucleus accumbens (NAc) of rats regulates immobility in the forced swim test (FST), an assay used to study ...depression. Because CREB regulates expression of dynorphin (which acts at kappa-opioid receptors) in NAc neurons, these findings raised the possibility that kappa-receptors mediate immobility behaviors in the FST. Here, we report that i.c.v. administration of the kappa-antagonist nor-binaltorphimine dose dependently decreased immobility in the FST, suggesting that it has antidepressant-like effects. Implicating a specific effect at kappa-receptors, similar antidepressant-like effects were seen after treatment with either of two novel, structurally dissimilar kappa-antagonists: 5'-guanidinonaltrindole, which was effective after i.c.v. but not systemic treatment, and 5'-acetamidinoethylnaltrindole (ANTI), which was potent and effective after systemic treatment. The behavioral effects of the kappa-antagonists resembled those of tricyclic antidepressants (desipramine) and selective serotonin reuptake inhibitors (fluoxetine and citalopram). Conversely, systemic administration of the kappa-agonist 5alpha,7alpha,8beta-N-methyl-N-7-1-pyrrolidinyl-1-oxaspiro4.5dec8-yl-benzenacetamide (U-69593) dose dependently increased immobility in the FST, consistent with prodepressant-like effects. The effects of the kappa-ligands in the FST were not correlated with nonspecific effects on locomotor activity. Furthermore, the most potent and effective kappa-antagonist (ANTI) did not affect the rewarding impact of lateral hypothalamic brain stimulation at a dose with strong antidepressant-like effects. These findings are consistent with the hypothesis that CREB-mediated induction of dynorphin in the NAc "triggers" immobility behavior in the FST. Furthermore, they raise the possibility that kappa-antagonists may have efficacy as antidepressants, but lack stimulant or reward-related effects.
Background Increasing evidence indicates that brain kappa-opioid receptors (KORs) are involved in regulation of mood states. In animal models often used to study psychiatric illness, KOR agonists ...produce depressive-like effects (e.g., anhedonia), whereas KOR antagonists produce antidepressant- and anxiolytic-like effects. The ability of KOR agonists to produce anhedonia-like signs in laboratory animals raises the possibility that this class of drugs might be useful to ameliorate states characterized by excess reward or motivation, such as mania or stimulant intoxication. Methods We examined how the selective KOR agonist U69,593 affects cocaine-induced facilitation of intracranial self-stimulation (ICSS), a model of the abnormally increased reward function that characterizes mania and stimulant intoxication. Rats with stimulating electrodes implanted in the medial forebrain bundle (MFB) were tested with intraperitoneal injections of U69,593 (.063–.5 mg/kg) alone, cocaine (1.25–10 mg/kg) alone, and combinations of the drugs. Results Cocaine dose-dependently decreased ICSS thresholds, indicating that it enhanced the rewarding impact of MFB stimulation. In contrast, U69,593 dose-dependently increased ICSS thresholds, indicating that it decreased the rewarding impact of the stimulation. Pretreatment with U69,593 blocked cocaine-induced decreases in ICSS thresholds at doses that had negligible effects on their own. Conclusions Activation of KORs reduces the reward-related effects of cocaine. Inasmuch as cocaine-induced behavioral stimulation in rodents may model key aspects of enhanced mood in humans, these findings raise the possibility that KOR agonists might ameliorate symptoms of conditions characterized by increased motivation and hyperfunction of brain reward systems, such as mania and stimulant intoxication.
Evidence suggests that a novel type of magnetic resonance imaging (MRI) scan called echo planar magnetic resonance spectroscopic imaging (EP-MRSI) has mood-elevating actions in humans during the ...depressive phases of bipolar disorder. We examined whether a low-energy component of EP-MRSI (low-field magnetic stimulation LFMS) has antidepressant-like, locomotor-stimulating, or amnestic effects in rats.
We examined the effects of LFMS on immobility in the forced swim test (FST) and activity within an open field in separate groups of rats. After exposure to forced swimming, rats received LFMS (three 20-min sessions at 1.5 G/cm and .75 V/m) before behavioral testing. We also examined the effects of LFMS on fear conditioning (FC), a learning paradigm that also involves exposure to stressful conditions.
Low-field magnetic stimulation reduced immobility in the FST, an antidepressant-like effect qualitatively similar to that of standard antidepressants. Low-field magnetic stimulation did not alter locomotor activity or FC.
Low-field magnetic stimulation has antidepressant-like effects in rats that seem unrelated to locomotor-activating or amnestic effects. These findings raise the possibility that electromagnetic fields can affect the brain biology and might have physiologic consequences that offer novel approaches to therapy for psychiatric disorders. These same consequences might render MRI-based scans more invasive than previously appreciated.
Attentional deficits accompany many psychiatric disorders, underscoring the need for rodent models of attention to screen novel therapeutic agents and characterize the biological basis of attention. ...The five-choice serial reaction time task (5CSRTT) is one such model. Here, we characterized the effects of four standard psychotropic agents on performance in the 5CSRTT. Methods Male Sprague-Dawley rats were trained in the 5CSRTT (5-sec inter-trial interval and .5-sec stimulus duration) until they reliably performed at > 60% accuracy and < 20% omissions. They were then treated systemically with the stimulant methylphenidate (MPH) (.063-2.0 mg/kg), the N-methyl-D-aspartate antagonist dizocilpine (MK-801) (.008-.25 mg/kg), the norepinephrine reuptake inhibitor desipramine (DMI) (.63-10 mg/kg), or the mu -receptor agonist U69,593 (.25-2.0 mg/kg) 30 min before testing. Results Methylphenidate (.5 mg/kg) increased accuracy. Dizocilpine impaired accuracy (.25 mg/kg), increased premature responses (.063-.25 mg/kg), and increased omissions (.25 mg/kg). Desipramine decreased premature responses (5.0 mg/kg) but increased omissions (10 mg/kg), correct response latencies (5.0-10.0 mg/kg), and reward latencies (5.0-10.0 mg/kg). The mu -opioid agonist U69,593 (1.0-2.0 mg/kg) increased omissions and correct response latencies. Conclusions In Sprague-Dawley rats, psychotropic drugs with distinct pharmacological profiles produced distinguishable effects in the 5CSRTT. The effects of these classes of drugs under our testing conditions are qualitatively similar to their effects in humans.
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