SARS-CoV-2 Infection Impacts Carbon Metabolism and Depends on Glutamine for Replication in Syrian Hamster Astrocytes

COVID‐19 causes more than million deaths worldwide. Although much is understood about the immunopathogenesis of the lung disease, a lot remains to be known on the neurological impact of COVID‐19. Here we evaluated immunometabolic changes using astrocytes in vitro and dissected brain areas of SARS‐CoV‐2 infected Syrian hamsters. We show that SARS‐CoV‐2 alters proteins of carbon metabolism, glycolysis, and synaptic transmission, many of which are altered in neurological diseases. Real‐time respirometry evidenced hyperactivation of glycolysis, further confirmed by metabolomics, with intense consumption of glucose, pyruvate, glutamine, and alpha ketoglutarate. Consistent with glutamine reduction, the blockade of glutaminolysis impaired viral replication and inflammatory response in vitro. SARS‐CoV‐2 was detected in vivo in hippocampus, cortex, and olfactory bulb of intranasally infected animals. Our data evidence an imbalance in important metabolic molecules and neurotransmitters in infected astrocytes. We suggest this may correlate with the neurological impairment observed during COVID‐19, as memory loss, confusion, and cognitive impairment.

Short-Term Free-Floating Slice Cultures from the Adult Human Brain

Organotypic, or slice cultures, have been widely employed to model aspects of the central nervous system functioning in vitro. Despite the potential of slice cultures in neuroscience, studies using adult nervous tissue to prepare such cultures are still scarce, particularly those from human subjects. The use of adult human tissue to prepare slice cultures is particularly attractive to enhance the understanding of human neuropathologies, as they hold unique properties typical of the mature human brain lacking in slices produced from rodent (usually neonatal) nervous tissue. This protocol describes how to use brain tissue collected from living human donors submitted to resective brain surgery to prepare short-term, free-floating slice cultures. Procedures to maintain and perform biochemical and cell biology assays using these cultures are also presented. Representative results demonstrate that the typical human cortical lamination is preserved in slices after 4 days in vitro (DIV4), with expected presence of the main neural cell types. Moreover, slices at DIV4 undergo robust cell death when challenged with a toxic stimulus (H2O2), indicating the potential of this model to serve as a platform in cell death assays. This method, a simpler and cost-effective alternative to the widely used protocol using membrane inserts, is mainly recommended for running short-term assays aimed to unravel mechanisms of neurodegeneration behind age-associated brain diseases. Finally, although the protocol is devoted to using cortical tissue collected from patients submitted to surgical treatment of pharmacoresistant temporal lobe epilepsy, it is argued that tissue collected from other brain regions/conditions should also be considered as sources to produce similar free-floating slice cultures.

Pouteria torta: a native species of the Brazilian Cerrado as a bioindicator of glyphosate action

In Brazil, the expansion of agricultural activity and the associated indiscriminate use of herbicides such as glyphosate is directly related to the loss of biodiversity in the Cerrado. The identification of plant species as bioindicators of herbicide action, especially species native to the area, can help in monitoring the impacts of xenobiotics in the remaining Cerrado. Thus, this study was designed to evaluate the possible use of the native Cerrado species Pouteria torta as a bioindicator of glyphosate action via changes in physiological performance. At 16 months after sowing, the effect of glyphosate was evaluated by applying the following doses: 0 (control), 25, 50, 100, 200, 400, 800, and 1200 g a.e. ha-1. In response to glyphosate, P. torta exhibited reductions in photosynthesis and chloroplastid pigment content, as well as accumulation of shikimic acid and the occurrence of chlorosis and necrosis. These changes demonstrate the high sensitivity of P. torta to glyphosate and its potential for use as a bioindicator of this herbicide.

Targeting miR-21 induces autophagy and chemosensitivity of leukemia cells

Overexpression of oncomiR-21 has been observed in most cancer types, such as leukemia. This miR has been implicated in a number of cellular processes, including chemoresistance, possibly by directly modulating the expression of several apoptotic related proteins. It was recently shown to directly target Bcl-2 mRNA and upregulate Bcl-2 protein expression. Nevertheless, the possible effect of miR-21 in autophagy has never been addressed. This study investigates the effects of targeting miR-21 with antimiRs on chronic myeloid leukemia cellular autophagy and on associated drug sensitivity. We observed that miR-21 downregulation decreased cellular viability and proliferation, although no changes to the normal cell cycle profile were observed. miR-21 downregulation also caused increased programmed cell death and a decrease in the expression levels of Bcl-2 protein, although PARP cleavage was not affected, indicating that apoptosis was not the relevant mechanism underlying the observed results. Treatment with antimiR-21 caused an increase in the autophagy related proteins Beclin-1, Vps34 and LC3-II. Accordingly, autophagic vacuoles were visualized both by monodansylcadaverine (MDC) and acridine orange (AO) staining and also by transmission electron microscopy (TEM). Additionally, miR-21 downregulation increased K562 and KYO-1 cellular sensitivity to etoposide or doxorubicin. This chemosensitivity was reverted by pre-treating cells with 3-MA, an autophagy inhibitor. Finally, serum starvation (an autophagy inducer) also increased sensitivity to these drugs, confirming that autophagy sensitized these cells to the effect of these drugs. To the best of our knowledge, this is the first description of autophagy induction via miR-21 targeting and its involvement in drug sensitivity.

Radiation-induced transgenerational alterations in genome stability and DNA damage

Mutation induction in directly exposed cells is currently regarded as the main component of the genetic risk of ionizing radiation for humans. However, recent data on the transgenerational increases in mutation rates in the offspring of irradiated parents indicate that the genetic risk could be greater than predicted previously. Here, we have analysed transgenerational changes in mutation rates and DNA damage in the germline and somatic tissues of non-exposed first-generation offspring of irradiated inbred male CBA/Ca and BALB/c mice. Mutation rates at an expanded simple tandem repeat DNA locus and a protein-coding gene (hprt) were significantly elevated in both the germline (sperm) and somatic tissues of all the offspring of irradiated males. The transgenerational changes in mutation rates were attributed to the presence of a persistent subset of endogenous DNA lesions (double- and single-strand breaks), measured by the phosphorylated form of histone H2AX (gamma-H2AX) and alkaline Comet assays. Such remarkable transgenerational destabilization of the F(1) genome may have important implications for cancer aetiology and genetic risk estimates. Our data also provide important clues on the still unknown mechanisms of radiation-induced genomic instability.

Sex-based differences in serum cardiac troponin I, a specific marker for myocardial injury, after cardiac surgery

BACKGROUND

Prevalence and causes of sex-based differences in morbidity and mortality secondary to cardiovascular disease remain controversial. Cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Serial cTnI measurements have been used to identify perioperative myocardial cell injury.

OBJECTIVE

To determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients.

DESIGN

A total of 17 male and 17 female patients were prospectively studied in an age- and case-matched manner. Arterial cTnI were obtained preinduction, 30 mins after the application of the aortic cross-clamp, at arrival to the intensive care unit, and on postoperative day 1.

SETTING

Tertiary cardiac surgery center at a major teaching hospital.

RESULTS

There was no difference between men and women in body mass index (kg/m2), duration of cardiopulmonary bypass, and aortic cross-clamp times. Preoperative cTnI measurements were similar in men (0.24 +/- 0.15 ng/mL) and women (0.25 +/- 0.13 ng/mL, mean +/- sem). The maximum serum cTnI occurred on postoperative day 1 in all patients, and it was 3-fold higher in men (18.5 +/- 5.7 ng/mL) compared with women (6.4 +/- 1.0 ng/mL).

CONCLUSIONS

Men had markedly higher serum cTnI compared with women, although they were case matched with respect to age and cardiac risk factors. Our results may suggest there may be sex-related differences in the myocardial response to ischemia and reperfusion injury or intrinsic differences between the male and female myocardium.

The capsular polysaccharides of Cryptococcus neoformans activate normal CD4(+) T cells in a dominant Th2 pattern

Capsular components of Cryptococcus neoformans induce several deleterious effects on T cells. However, it is unknown how the capsular components act on these lymphocytes. The present study characterized cellular and molecular events involved in immunoregulation of splenic CD4(+) T cells by C. neoformans capsular polysaccharides (CPSs). The results showed that CPSs induce proliferation of normal splenic CD4(+) T cells, but not of normal CD8(+) T or B lymphocytes. Such proliferation depended on physical contact between CPSs and viable splenic adherent cells (SAC) and CD40 ligand-induced intracellular signal transduction. The absence of lymphoproliferation after fixation of SAC with paraformaldehyde has discarded the hypothesis of a superantigen-like activation. The evaluation of a cytokine pattern produced by the responding CD4(+) T lymphocytes revealed that CPSs induce a dominant Th2 pattern, with high levels of IL-4 and IL-10 production and undetectable inflammatory cytokines, such as TNF-alpha and IFN-gamma. Blockade of CD40 ligand by relevant mAb down-regulated the CPS-induced anti-inflammatory cytokine production and abolished the enhancement of fungus growth in cocultures of SAC and CD4(+) T lymphocytes. Our findings suggest that CPSs induce proliferation and differentiation of normal CD4(+) T cells into a Th2 phenotype, which could favor parasite growth and thus important deleterious effects to the host.

Dandy-Walker syndrome: posterior fossa craniectomy and cyst fenestration after several shunt revisions

Ventriculoperitoneal or cyst-peritoneal shunts are the usual treatment for children with Dandy-Walker syndrome. A combined ventricular and cyst shunt is often necessary and, in some cases, multiple revisions have to be done. Two patients with this syndrome were treated with posterior fossa exploration and cyst fenestration after several shunt revisions. The procedure was well tolerated with good results in both cases. The patients' data and preliminary results are presented here.

Hemispheric arteriovenous fistulae with giant venous dilation

A direct fistula between cerebral cortical arteries and venous channels may result in an impressive aneurysm-like, saccular dilation of the venous portion. We had the opportunity to treat two children with this rare arteriovenous malformation, with excellent results. The controversy on the classification and treatment of this pathology is discussed briefly.

[Teratoma of the 4th ventricle and precocious puberty. Case report]

A case of precocious puberty and diabetes insipidus in a 7 years old boy due to a malignant teratoma in the IVth ventricle is reported. The tumor had grown into the IIIrd and lateral ventricles as found on the necropsy. The original site of the tumor and the possible physiopathological mechanisms for the precocious puberty are discussed.

Intracranial arterial aneurysms in infancy and childhood

Eleven cases of intracranial arterial aneurysms in patients under 15 years of age, treated from 1959 to 1976, are presented. The preponderance of aneurysms at the internal carotid artery bifurcation and the peculiarities of the defects in this location are remarkable.

Carotid-ophthalmic aneurysms

Carotid-ophthalmic aneurysms have intimate relationships with the ipsilateral optic nerve and other neighboring structures. Direct operation for treatment of these aneurysms has been considered particularly hazardous and difficult. Therefore, some authors have recommended an indirect operation (carotid artery ligation in the neck) as the procedure of choice. A Consecutive series of eight patients with carotid-ophthalmic aneurysms in presented; a direct operation was performed in seven instances. There was no operative mortality and the morbidity was very low. The direct attack seems to be reliable, and is recommended.

[Surgical treatment of syringomyelia by gardner's technic]

O tratamento cirúrgico da siringomielia é, em geral, considerado decepcionante. Vários tipos de drenagem da cavidade siringomiélica não têm fornecido resultados satisfatórios. Gardner, em magnífica série de trabalhos, mostrou que a siringomielia e as várias malformações associadas à hidrocefalia têm fisiopatogenia única. Baseado em sua teoria, Gardner propôs, em 1958, o bloqueio da comunicação entre o IV ventrículo e o canal central da medula, para o tratamento da siringomielia. Esta técnica não tem sido realizada com muita freqüência. Empregamos o método proposto por Gardner em 4 pacientes, os quais melhoraram após a intervenção cirúrgica.

[Bilateral ventricular and subdural shunt with a Holter valve: a new surgical technic]

É relatada uma adaptação da ventrículo-auriculostomia, com válvula de Holter, para casos de bloqueios bilaterais dos orifícios de Monro e de coleções subdurais bilaterais. A técnica consiste na colocação de dois catéteres de borracha siliconiza-da nos ventrículos laterais ou espaços subdurais, mediante trepanações para-medianas na região parietal posterior; êstes catéteres são conectados a uma sonda em forma de T (sonda de Kehr) que, por sua vez, é ligada à uma válvula de Holter, sendo os demais tempos cirúrgicos idênticos aos da ventrículo-auriculostomia convencional. Foram operados, com esta técnica, três pacientes: dois com craniofaringiomas e um com coleção subdural bilateral. Os resultados foram satisfatórios.