Universidad Simón Bolívar

Convergent evidence suggests that disrupted reward processing may be associated with observed alterations in frontostriatal activity in persons with major depressive disorder (MDD). Replicated evidence suggests that glutamatergic modulators may benefit persons experiencing disrupted reward function compared to healthy controls (HC). Herein, we systematically reviewed functional magnetic resonance imaging (fMRI) studies that examined the effects of glutamatergic modulators on frontostriatal activity and/or reward function in persons with MDD or healthy controls (HC).

A systematic literature search of online databases (PubMed, OVID, Scopus, Web of Science) and manual search of reference lists and Google Scholar was conducted from inception to July 22, 2025. Studies were included if they employed fMRI to assess changes in frontostriatal activation or connectivity following administration of glutamatergic agents with known or proposed antidepressant effects in persons with MDD or HC.

We identified 11 fMRI studies that investigated the effects of ketamine (n = 9), nitrous oxide (n = 1) or memantine (n = 1) on frontostriatal activity in persons with MDD or HCs. Preliminary evidence suggests that intravenous ketamine may affect functional connectivity in striatal regions that may be relevant to improved reward function in persons with TRD.

Future studies should evaluate the impact of glutamatergic modulators on brain structures subserving reward and the temporality of the effect, as select glutamatergic modulators have a rapid onset of action. Future studies should also compare the effects of glutamatergic modulators on frontostriatal connectivity between persons with TRD and HCs, and aim to identify baseline characteristics that may mediate/moderate antidepressant response.

We describe a radioisotope-excited energy dispersive X-ray fluorescence spectrometric facility for the elemental analysis of minerals containing the rare earth elements (REEs) by the use of the K-line X-rays. Two 241 Am sources are used in purpose-designed holders that fit a high-resolution solid-state germanium detector. The system is capable of exciting all the light actinides up to element 69, Tm. The analysis through the well-separated K-lines allows an easy identification of lanthanide elements with advantages over traditional L-line detection particularly in mineral samples with high Fe concentration, enabling the recognition of most lanthanide elements at values close to 10 ppm. We report the achieved elemental sensitivity obtained with a set of pure element standards and spectra of mineral concentrates derived from a REEcontaining Venezuelan Laterite.

Fever can be described as a coordinated rise in temperature in response to infectious and noninfectious causes, which varies with the anatomical site. This adaptive heat shock response has been conserved for millions of years in vertebrates. Elevated temperature stimulates and optimizes innate and adaptive immune responses. In addition, most microorganisms have shown thermal stress–related growth inhibition, and in vitro data indicate that β-lactam antibiotics in particular appear to have significantly improved susceptibility profiles in the presence of fever-range temperatures. Despite these favorable effects of fever, many physicians consider fever a harmful event that should be treated without discrimination of the underlying cause. Observational studies have indicated that attempts to lower the temperature in patients with sepsis are associated with increased mortality. This article aims to summarize the most relevant results of the existing clinical data and provide the clinician with guidance on how to manage fever in patients with sepsis.