Infectious complications and optimising infection prevention for children with cochlear implants.

AIM: To describe the clinical epidemiology of children receiving cochlear implants, as well as the management and outcomes of cochlear implant infections and adherence to infection prevention measures. METHODS: A retrospective observational study was conducted in children ≤18 years who received cochlear implants in Western Australia's tertiary paediatric hospital. Information was obtained from medical and laboratory records regarding demographics, indication for implant, implant infection and preoperative Staphylococcus aureus screening/decolonisation. Immunisation history was examined using the Australian Immunisation Register. RESULTS: Overall, 118 children received cochlear implants, with 158 devices inserted (599 cochlear implant insertion-years). An implant infection rate of 3.8% (6/158) was identified during the study period (four pneumococcal and two community-acquired methicillin resistant S. aureus infections). All required surgical management, with an overall median duration of antibiotic therapy of 37 days (interquartile range (IQR) 29-48) and median length of stay of 8 days (IQR 8-9.5). All devices were retained and there were no relapses or deaths. Half of the children who developed cochlear implant infections (50%, 3/6) were up-to-date with additional pneumococcal vaccinations and no children (0%, 0/118) received S. aureus screening/decolonisation before implant insertion. CONCLUSIONS: Favourable outcomes were achieved with cochlear implant retention; however, the treatment was burdensome for families. We demonstrate significant scope to improve adherence to existing infection prevention strategies and provide direction for optimising preventative measures in the future. These include ensuring parental education, additional pneumococcal vaccinations and S. aureus decolonisation which are delivered as an infection prevention bundle to the growing population of infants receiving cochlear implants.

Gold nanoparticles reduce inflammation in cerebral microvessels of mice with sepsis.

BACKGROUND: Sepsis is an emergency medical condition that can lead to death and it is defined as a life-threatening organ dysfunction caused by immune dysregulation in response to an infection. It is considered the main killer in intensive care units. Sepsis associated-encephalopathy (SAE) is mostly caused by a sepsis-induced systemic inflammatory response. Studies report SAE in 14-63% of septic patients. Main SAE symptoms are not specific and usually include acute impairment of consciousness, delirium and/or coma, along with electroencephalogram (EEG) changes. For those who recover from sepsis and SAE, impaired cognitive function, mobility and quality of life are often observed months to years after hospital discharge, and there is no treatment available today to prevent that. Inflammation and oxidative stress are key players for the SAE pathophysiology. Gold nanoparticles have been demonstrated to own important anti-inflammatory properties. It was also reported 20 nm citrate-covered gold nanoparticles (cit-AuNP) reduce oxidative stress. In this context, we tested whether 20 nm cit-AuNP could alleviate the acute changes caused by sepsis in brain of mice, with focus on inflammation. Sepsis was induced in female C57BL/6 mice by cecal ligation and puncture (CLP), 20 nm cit-AuNP or saline were intravenously (IV) injected 2 h after induction of sepsis and experiments performed 6 h after induction. Intravital microscopy was used for leukocyte and platelet adhesion study in brain, blood brain barrier (BBB) permeability carried out by Evans blue assay, cytokines measured by ELISA and real time PCR, cell adhesion molecules (CAMs) by flow cytometry and immunohistochemistry, and transcription factors, by western blotting. RESULTS: 20 nm cit-AuNP treatment reduced leukocyte and platelet adhesion to cerebral blood vessels, prevented BBB failure, reduced TNF- concentration in brain, and ICAM-1 expression both in circulating polymorphonuclear (PMN) leukocytes and cerebral blood vessels of mice with sepsis. Furthermore, 20 nm cit-AuNP did not interfere with the antibiotic effect on the survival rate of mice with sepsis. CONCLUSIONS: Cit-AuNP showed important anti-inflammatory properties in the brain of mice with sepsis, being a potential candidate to be used as adjuvant drug along with antibiotics in the treatment of sepsis to avoid SAE.

Mitochondrial DNA: A new driver for sex differences in spontaneous hypertension.

The prevalence of arterial hypertension (AH) is higher in men than in premenopausal women of the same age. AH has been characterized as a chronic inflammatory disease and activation of Toll-like receptors (TLR) by damage-associated molecular patterns (DAMPs) is involved. Mitochondrial DNA (mtDNA) may be released by end-organ damage, which is recognized and activates TLR9. The serum level of mtDNA is increased in AH. The aim of this study was to compare the serum mtDNA levels between male and female spontaneously hypertensive rats (SHR) and to evaluate the sex differences in the effect of mtDNA on the function, inflammation and signaling pathway related to TLR9 in the vasculature. Male and female 15-week-old SHR and Wistar rats were used to evaluate the arterial blood pressure, serum mtDNA, contractile response, inflammatory markers and signaling pathway related to TLR9. Male SHR had higher arterial blood pressure values and serum mtDNA compared to female SHR and to male and female normotensive Wistar rats. In male SHR aorta, mtDNA incubation increased the contractile response to phenylephrine, which was blunted by inhibition of TLR9, and also increased pro-inflammatory molecules IL-6 and TNF-α. However, in female SHR aorta, mtDNA incubation did not change the contractile response, reduced pro-inflammatory molecules and prevented oxidative stress. mtDNA incubation did not change the expression of TLR9, MyD88 and eNOS neither in male nor in female SHR aorta, but it increased the phosphorylation of ERK1/2 in male and reduced in female SHR aorta. The mtDNA differential modulation of vascular response in male and female SHR might contribute to sex differences in AH. This study contributes to the understanding of a need for more personalized therapeutic strategies for men and women with hypertension. Keywords: Sex differences, Arterial hypertension, Mitochondrial DNA, Toll-Like receptor 9.

Hyaluronidase decreases neutrophils infiltration to the inflammatory site.

OBJECTIVE: To evaluate the in vivo anti-inflammatory potential of bovine hyaluronidase (HYAL) using two different models of acute inflammation. METHODS: Air pouches were produced in the dorsal subcutaneous of mice and injected with phosphate saline solution or HYAL. The antiinflammatory action of HYAL was evaluated in carrageenan (Cg)-inflamed air pouches. After 4 and 24 h the cellular influx, protein exudation, cytokines and lipid mediators were evaluated. The action of HYAL on the rolling and adhesion of leukocytes was investigated in the LPS-stimulated mesenteric microcirculation by intravital microscopic. RESULTS: Treatment with HYAL reduced the cellular influx and protein exudation in non-inflamed and inflamed air pouches. HYAL treatment of Cg-inflamed air pouch reduced the production of tumor necrosis factor-alpha (TNF-α), interleukin-8 (IL-8), leukotriene B4 (LTB4) and LTC4, whereas prostaglandins E2 (PGE2) and D2 (PGD2) concentrations were unchanged. Histological analyses showed that HYAL administration diminished cell infiltration in the air-pouch lining. In LPS-stimulated mesenteric microcirculation, HYAL usage decreased rolling and adhesion of leukocytes, but did not affect the blood vessels diameters. CONCLUSION: The results demonstrate that HYAL inhibited cellular recruitment, edema formation and pro-inflammatory mediators production, resulting in decreased adherence of leukocytes to blood vessels and tissue infiltration. Our data suggest that HYAL may be considered an effective candidate to ameliorate acute inflammation.

Effects of low-dose rapamycin on lymphoid organs of mice prone and resistant to accelerated senescence.

Aging is a complex, natural, and irreversible phenomenon that subjects the body to numerous changes in the physiological process, characterized by a gradual decline in the organism's homeostatic mechanisms, closely related to immunosenescence. Here, we evaluated the regulation of immunosenescence in lymphoid organs of senescence-accelerated prone 8 (SAM-P8) and senescence-accelerated resistant 1 (SAM-R1) mice treated with a low dose of rapamycin (RAPA). Mice were treated with a dose of 7.1 µg/kg RAPA for 2 months and had body mass and hematological parameters analyzed prior and during treatment. Cellular and humoral parameters of serum, bone marrow, thymus, and spleen samples were evaluated by ELISA, histology, and flow cytometry. Changes in body mass, hematological parameters, cell number, and in the secretion of IL-1ß, IL-6, TNF-α, IL-7, and IL-15 cytokines were different between the 2 models used. In histological analyses, we observed that SAM-P8 mice showed faster thymic involution than SAM-R1 mice. Regarding the T lymphocyte subpopulations in the spleen, CD4+ and CD8+ T cell numbers were higher and lower, respectively, in SAM-P8 mice treated with RAPA, with the opposite observed in SAM-R1. Additionally, we found that the low dose of RAPA used did not trigger changes that could compromise the immune response of these mice and the administered dose may have contributed to changes in important lymphocyte populations in the adaptive immune response and the secretion of cytokines that directly collaborate with the maturation and proliferation of these cells.

Effect of coronaviruses on blood vessel permeability: potential therapeutic targets.

Coronavirus-induced diseases have afflicted humanity for several decades. This scenario was aggravated by the emergence of the coronavirus disease 2019 (named COVID-19) in Wuhan, China, in December 2019. Since then, COVID-19 has killed millions of people worldwide, probably the most devastating pandemic since HIV/AIDS. This review aimed to bring together important updated aspects related to coronavirus-induced diseases and the enhanced vascular permeability observed mainly in the lungs of affected people. The dysregulated vascular permeability in the lungs is of fundamental importance for coronaviruses-caused morbidity and mortality. Thus, as described in this review, it is a target of new and old drugs.

Immune spleen cells attenuate the inflammatory profile of the mesenteric perivascular adipose tissue in obese mice.

The perivascular adipose tissue (PVAT) differs from other fat depots and exerts a paracrine action on the vasculature. The spleen has an important role in the immune response, and it was observed to have either a protective role or a contribution to obesity-related diseases. However, the relation between spleen and PVAT is elusive in obesity. We investigated the role of spleen in the inflammatory profile of the mesenteric PVAT (mPVAT) from mice fed a high-fat diet (HFD) for 16 weeks. Male C57Bl/6 mice were sham-operated or splenectomized (SPX) and fed a HFD for 16 weeks. mPVAT morphology was evaluated by hematoxylin and eosin staining, infiltrated immune cells were evaluated by flow cytometry, inflammatory cytokines were evaluated by ELISA and the splenic cell chemotaxis mediated by mPVAT was evaluated using a transwell assay. In SPX mice, HFD induced adipocyte hypertrophy and increased immune cell infiltration and proinflammatory cytokine levels in mPVAT. However, none of these effects were observed in mPVAT from sham-operated mice. Spleen from HFD fed mice presented reduced total leukocytes and increased inflammatory markers when compared to the spleen from control mice. Chemotaxis of spleen cells mediated by mPVAT of HFD fed mice was reduced in relation to standard diet fed mice. The spleen protects mPVAT against the effects of 16-week HFD. This information was missing, and it is important because PVAT is different from other fat depots and data cannot be extrapolated from any type of adipose tissue to PVAT.

Matrix metalloproteinases cleave the beta2-adrenergic receptor in spontaneously hypertensive rats.

We recently observed the enhanced serine and matrix metalloproteinase (MMP) activity in the spontaneously hypertensive rat (SHR) compared with its normotensive Wistar-Kyoto (WKY) rat and the cleavage of membrane receptors in the SHR by MMPs. We demonstrate in vivo that MMP-7 and MMP-9 injection leads to a vasoconstrictor response in microvessels of rats that is blocked by a specific MMP inhibitor (GM-6001, 1 microM). Multiple pathways may be responsible. Since the beta(2)-adrenergic receptor (beta(2)-AR) is susceptible to the action of endogenous MMPs, we hypothesize that MMPs in the plasma of SHRs are able to cleave the extracellular domain of the beta(2)-AR. SHR arterioles respond in an attenuated fashion to beta(2)-AR agonists and antagonists. Aorta and heart muscle of control Wistar rats were exposed for 24 h (37 degrees C) to fresh plasma of male Wistar and WKY rats and SHRs with and without doxycycline (30 microM) and EDTA (10 mM) to reduce MMP activity. The density of extracellular and intracellular domains of beta(2)-AR was determined by immunohistochemistry. The density of the extracellular domain of beta(2)-AR is reduced in aortic endothelial cells and cardiac microvessels of SHRs compared with that of WKY or Wistar rats. Treatment of the aorta and the heart of control Wistar rats with plasma from SHRs, but not from WKY rats, reduced the number of extracellular domains, but not intracellular domains, of beta(2)-AR in aortic endothelial cells and cardiac microvessels. MMP inhibitors (EDTA and doxycycline) prevented the cleavage of the extracellular domain. Thus MMPs may contribute to the reduced density of the extracellular domain of beta(2)-AR in blood vessels and to the increased arteriolar tone of SHRs compared with normotensive rats.

Microvascular responses to cardiovascular risk factors.

Hypertension, hypercholesterolemia, diabetes, and obesity are among a growing list of conditions that have been designated as major risk factors for cardiovascular disease (CVD). While CVD risk factors are well known to enhance the development of atherosclerotic lesions in large arteries, there is also evidence that the structure and function of microscopic blood vessels can be profoundly altered by these conditions. The diverse responses of the microvasculature to CVD risk factors include oxidative stress, enhanced leukocyte- and platelet-endothelial cell adhesion, impaired endothelial barrier function, altered capillary proliferation, enhanced thrombosis, and vasomotor dysfunction. Emerging evidence indicates that a low-grade systemic inflammatory response that results from risk factor-induced cell activation and cell-cell interactions may underlie the phenotypic changes induced by risk factor exposure. A consequence of the altered microvascular phenotype and systemic inflammatory response is an enhanced vulnerability of tissues to the deleterious effects of secondary oxidative and inflammatory stresses, such as ischemia and reperfusion. Future efforts to develop therapies that prevent the harmful effects of risk factor-induced inflammation should focus on the microcirculation.

3 Tesla MRI brain scanning under general anaesthesia in a paediatric 3 Tesla-compatible cochlear implant recipient, first reported case: Clinical considerations and implications for future practice.

OBJECTIVES: To demonstrate the safety and feasibility of the first reported case of a 3 Tesla MRI scan in a paediatric 3 Tesla-compatible cochlear implant recipient under general anaesthesia. MATERIALS AND METHODS: A three-year-old child with bilateral optic pathway glioma treated with chemotherapy, who subsequently received a right sided 3 Tesla-compatible cochlear implant for sensorineural hearing loss was examined. The CI device chosen was implanted due to its purported MRI compatibility. Following informed consent and hospital executive approval, the child underwent a 3 Tesla MRI scan to assess for growth of the optic pathway glioma. RESULTS: A 3 Tesla MRI scan of the brain was performed under general anaesthesia. There was expected artefact due to the magnet of the receiver stimulator. There was no malfunction of the implant noted after the procedure, and no neurological or otological complications. The child had five more uneventful 3 Tesla MRI scans of the brain without complications. CONCLUSION: This is the first reported case of a child with a 3 Tesla-compatible cochlear implant undergoing a 3 Tesla MRI scan of the brain under general anaesthesia. Provided manufacturer guidelines are adhered to, 3 Tesla MRI scanning should not be contraindicated in paediatric cochlear implant recipients with a compatible device.

Gold nanoparticles carrying or not anti-VEGF antibody do not change glioblastoma multiforme tumor progression in mice.

AIMS: Glioblastoma multiforme (GBM) is the most devastating malignant primary brain tumor known. Life expectance is around 15 months after diagnosis. Several events contribute to the GBM progression such as uncontrolled genetic cancer cells proliferation, angiogenesis (mostly vascular endothelial growth factor (VEGF)-mediated), tissue invasion, glioma stem cell activity, immune system failure, and a hypoxic and inflammatory tumor microenvironment. Tumor cells antiproliferative effect of 20 nm citrate-covered gold nanoparticles (cit-AuNP) has been reported, along with anti-inflammatory and anti-oxidative effects. We aimed to test whether either chronic treatment with 20 nm cit-AuNP or anti-VEGF antibody (Ig)-covered AuNP could reduce GBM progression in mice. MAIN METHODS: Effect of the gold nanoparticles on the GL261 glioblastoma cells proliferation in vitro, and on the GL261-induced glioblastoma cell growth in C57BL/6 mice in vivo were tested. Besides, fluorophore-conjugated gold nanoparticles penetration through the GL261 plasma cell membrane, gold labelling in brain parenchyma of glioblastoma-carrying mice, and VEGF expression into the tumor were evaluated. KEY FINDINGS: We observed cit-AuNP did no change the GL261 cells proliferation. Similarly, we demonstrated chronic treatment with either cit-AuNP or anti-VEGF Ig-covered AuNP did not modify the GL261 cells-induced GBM progression in mice. By the end, we showed AuNPs did not trespass in appreciable amount both the GL261 plasma cell membrane and the tumoral blood brain barrier (BBB), and did not change the VEGF expression into the tumor. SIGNIFICANCE: 20 nm cit-AuNP or anti-VEGF Ig covered-AuNP are not good tools to reduce GBM in mice, probably because they do not penetrate both tumor cells and BBB in enough amount to reduce tumor growing.

Insulin Modulates Inflammatory Cytokine Release in Acute Stages and Augments Expression of Adhesion Molecules and Leukocytes in Lungs on Chronic Stages of Paracoccidioidomycosis.

Type 1 diabetesmellitus (T1D) is caused by partial destruction of the insulin-producing beta cells in the pancreas and is a major issue for public health care worldwide. Reduced or impaired immunological responses, which render patients more susceptible to infections, have been observed in T1D, and this dysfunction is often related to a lack of insulin in the blood. Paracoccidioidomycosis is an important systemic mycosis endemic in Latin America. To evaluate the effects of T1D on this fungal infection and the modulatory effects of insulin, we induced diabetes in C57Bl/6 male mice (alloxan, 60 mg/kg), infected the mice (Pb18, 1 x 106 cells), and treated the mice with neutral protamine Hagedorn (NPH) insulin (2 IU/600 mg/dL blood glucose). Twenty-four hours after infection, infected diabetic mice showed reduced secretion of interferon (IFN)-γ and interleukine (IL)-12 p70 compared to infected nondiabetic controls. On the 45th day of infection, infected diabetic mice presented higher IFN-γ levels, a higher tumor necrosis factor (TNF)-α:IL-10 ratio, and lower adhesion molecule expression levels than nondiabetic mice. In the in vitro experiments, alveolar macrophages from diabetic animals showed reduced phagocytic activity compared to those from control animals at 4, 12, and 24 h. In infected diabetic mice, treatment with insulin restored IL-12 p70 levels at 24 h of infection, reduced IFN-γ levels and the TNF-α:IL-10 ratio at 45 days, and restored vascular cell adhesion molecule (VCAM)-1 expression in pulmonary blood vessels, and this treatment reduced the diminished phosphorylation of extracellular signal-regulated kinases (ERK) and increased nuclear factor-kappa-B(iκb)-α and jun amino-terminal kinases (JNK) p46 levels in infected nondiabetic mice. In addition, insulin promoted increased phagocytic activity in the alveolar macrophages of diabetic mice. These data suggest that T1D mice are more susceptible to Pb18 infection and that insulin modulates this inflammation in diabetic mice by augmenting the expression of adhesion molecules and leukocytes in the lungs and by reducing chronic inflammation.

Systemic arterial hypertension leads to decreased semen quality and alterations in the testicular microcirculation in rats.

Arterial hypertension is a cardiovascular disease that leads to important systemic alterations and drastically impairs normal organ function over time. Hypertension affects around 700 million men of reproductive age and hypertensive men present increased risk for reproductive disorders, such as erectile dysfunction. However, the link between arterial hypertension and male reproductive disorders is associative at best. Moreover, many studies have reported associations between decreased male fertility and/or semen quality and alterations to general male health. In this study we aim to investigate the effect of systemic high blood pressure in sperm quality, sperm functional characteristics and testicular physiology in a rat model. Hypertensive rats presented altered testicular morphology - mainly vascular alterations and impaired testicular vasomotion. Hypertensive rats also presented decrease in sperm concentration, DNA integrity and increased percentages of sperm with dysfunctional mitochondria, intracellular superoxide anion activity and abnormal morphology. This study provides mechanistic insights by which arterial hypertension affects the testes, evidencing the testes as another target organ for hypertension as well as its impact on sperm quality.

Hydralazine reduces leukocyte migration through different mechanisms in spontaneously hypertensive and normotensive rats.

In addition to reducing blood pressure, hydralazine can reduce the production of inflammatory cytokines and reduce the expression of leukocyte adhesion molecules. Differences in leukocyte behavior and leukocyte adhesion molecule expression in spontaneously hypertensive rats (SHR) compared to normotensive rats have been reported. However, whether hydralazine can reduce leukocyte migration in vivo in hypertension and in normotension remains unknown. To address this question, male SHR and Wistar rats were treated for 15 days with hydralazine at a dose of ~3.5 mg/kg or ~14 mg/kg in their drinking water. The numbers of rollers and adherent and migrated cells were determined by direct vital microscopy, and blood pressure was assessed by tail plethysmography. In addition, following treatment with the higher dose, immunohistochemistry was used to measure the expression of intercellular adhesion molecule-1 (ICAM-1), P-selectin, and platelet-endothelial cell adhesion molecule-1 (PECAM-1) in endothelial cells, while flow cytometry was used to evaluate the expression of leukocyte CD18 and L-selectin. Hydralazine reduced leukocyte adherence and migration in SHR either at the higher, that reduced blood pressure levels, or lower dose, which did not reduce it. Reduced ICAM-1 expression might be involved in the reduced migration observed in SHR. In Wistar rats, only at the higher dose hydralazine reduced blood pressure levels and leukocyte migration. Reduced P-selectin expression might be involved. We therefore conclude that hydralazine reduces leukocyte migration by different mechanisms in SHR and Wistar rats, specifically by reducing ICAM-1 expression in the former and P-selectin expression in the latter.

Bilateral stapedectomy: association between first- and second-ear surgical findings and their effects on the second-ear outcome.

OBJECTIVES: We assessed the association between first-ear and second-ear surgical findings in patients undergoing second-ear stapedectomy for bilateral otosclerosis and the impact of such findings on the audiometric outcome of the second ear. METHODS: A retrospective chart review of all stapedectomy patients who underwent stapes surgery by one of two surgeons in a single tertiary referral institution from 1962 to 2001 was performed, and those patients who underwent bilateral stapedectomy were identified. Patient demographic data, surgical findings, procedure performed, and preoperative and postoperative audiometric data were recorded. RESULTS: A total of 459 patients (918 ears) underwent bilateral stapedectomy for bilateral otosclerosis during the study period, of whom 426 had complete data for analysis. The finding of a white or obliterated footplate in the second ear was significantly higher if the first ear had this disease manifestation (p < .001, chi2 test). The association between a second drill-out's being performed and a drill-out in the first operation was significant (p < .001, chi2 test). Statistical analysis identified that those who underwent a drill-out procedure had a 2.9-fold increase in unsuccessful outcome in comparison to those who did not have a drill-out (odds ratio, 2.89; 95% confidence interval, 1.41 to 5.89). Facial nerve anomalies were infrequently encountered, affecting only 23 patients, of whom 3 had bilateral abnormalities. The finding of an overhanging or dehiscent facial nerve in the second ear was significantly more likely if such an abnormality was identified during the first procedure (23% versus 2.5%; p = .005, Fisher's exact test). CONCLUSIONS: Second-ear hearing results are poorer in those who require a drill-out of this ear, and this is more likely to be required if a drill-out was required in the first ear, regardless of a successful outcome of the first procedure. Patients should be aware of the reduced likelihood of success in these cases and be counseled regarding risks and benefits of second-ear surgery based, in part, on the findings from the first ear. This study confirms that bilateral advanced footplate obliteration and overhanging or dehiscent facial nerves may be anticipated in patients found to have these abnormalities during first-ear stapedectomy.

Mechanisms of the effectiveness of poly(ε-caprolactone) lipid-core nanocapsules loaded with methotrexate on glioblastoma multiforme treatment.

PURPOSE: The low penetration of drugs across the blood-brain barrier (BBB) compromises the delivery of chemotherapeutic agents to the brain parenchyma and contributes to the poor prognosis of glioblastoma multiforme (GBM). We investigated the efficacy of methotrexate-loaded lipid-core nanocapsules (MTX-LNC) administered by the oral route to treat murine GBM, its ability to cross the BBB, and the mechanisms of MTX-LNC uptake by cultured GL261 glioma and BV2 microglia cells. MATERIALS AND METHODS: Female C57B/6 mice were used in intravital microscopy assays to investigate the penetrance of rhodamine B-label MTX-LNC (RhoB/MTX-LNC) in the brain after oral or IV administration, and to evaluate the BBB integrity. Intracranial implantation of GL261 cells was undertaken to induce a murine GBM model, and the effectiveness of oral MTX or MTX-LNC treatments (started on Day 10 of GBM, every 2 days for 12 days) was quantified by tumor size, body weight, and leukogram. Pharmacological blockade of endocytic pathways was done to investigate the mechanisms of MTX-LNC uptake by cultured GL261 and microglia BV2 cells by using fluorescence microscopy. The effect of MTX-LNC or MTX on GL261 and BV2 proliferation was evaluated to compare the cytotoxicity of such compounds. RESULTS: RhoB/MTX-LNC was detected in brain parenchyma of mice after IV or oral administration, without any damage on BBB. Oral treatment with MTX-LNC reduced tumor volume and prevented weight loss and leukopenia in comparison to MTX-treated mice. MTX-LNC uptake by GL261 is caveolae-dependent, whereas endocytosis of MTX-LNC by BV2 occurs via phagocytosis and macropinocytosis. Both MTX-LNC and MTX reduced GL261 and BV2 proliferation; however, MTX-LNC showed higher efficacy in the inhibition of glioma proliferation. CONCLUSION: Together, we infer that the higher ability of MTX-LNC to cross the BBB and be captured by cancer and immune brain cells by different mechanisms is responsible for the higher efficacy of oral MTX-LNC treatment in GBM.

Differential effects of chloral hydrate- and ketamine/xylazine-induced anesthesia by the s.c. route.

The proper use of anesthetics in animal experimentation has been intensively studied. In this study we compared the use of chloral hydrate (500 mg kg(-1)) and ketamine (167 mg kg(-1)) combined with xylazine (33 mg kg(-1)) by the s.c. route in male Wistar rats. Chloral hydrate and ketamine/xylazine produced a depth of anesthesia and analgesia sufficient for surgical procedures. The decrease of systolic and diastolic blood pressure was of a higher magnitude in rats anesthetized with chloral hydrate than with ketamine/xylazine. The initial microvascular diameter and blood flow velocity did not differ between both agents. On the other hand, ketamine/xylazine reduced the heart rate more intensively than chloral hydrate. Both anesthetics promoted an increase in arterial pCO(2) and a decrease in pH levels compared to unanesthetized animals. The blood glucose levels were of a higher magnitude in rats after ketamine/xylazine anesthesia than after chloral hydrate. In mesenteric arterioles studied in vivo, ketamine/xylazine anesthesia reduced the constrictive effect of noradrenaline and the dilator effect of bradykinin. However, both anesthetics did not modify the vasodilator effect promoted by acetylcholine. Based on our data, we concluded that both anesthetics alter metabolic and hemodynamic parameters, however the use of chloral hydrate in studies of microvascular reactivity in vivo is more appropriate since ketamine/xylazine reduces the responses to vasoactive agents and increases blood glucose levels.

Differential effect of losartan in female and male spontaneously hypertensive rats.

We demonstrated that the decreased response to acetylcholine observed in aorta of male and female spontaneously hypertensive rats is corrected after sustained (15 days) reduction of blood pressure levels by losartan. In order to verify if the same occurs in resistance vessels, vascular diameter changes induced by topical application of acetylcholine and bradykinin (endothelium-dependent vasodilators) and sodium nitroprusside (endothelium-independent vasodilator) to mesenteric arterioles studied in vivo, in situ were determined in rats treated with losartan for 24 h (acute) or 15 days (chronic). Rats that presented similar reduction (in %) of the blood pressure levels after losartan treatment were chosen. Sodium nitroprusside induced similar responses in losartan-treated and untreated male or female SHR. Whereas in female SHR, losartan corrected the diminished arteriolar response to endothelium-dependent vasodilators after acute and chronic treatment, in male SHR this correction only occurred after chronic treatment. Thus, losartan corrected the endothelial dysfunction more easily in female than in male SHR and independently of the normalization or the magnitude of the reduction of the blood pressure levels. In an attempt to explain the difference, we evaluated the losartan effect on nitric-oxide synthase (NOS) activity and angiotensin II AT1 and AT2 receptor gene expression in these animals. In male and female SHR, NOS activity and AT1 receptor expression were not altered by acute or chronic treatment. On the other hand, AT2 receptor expression was augmented only in female SHR by these treatments. Therefore, augmented AT2 receptor expression, but not alteration of NOS activity or AT1 receptor expression, might explain the difference observed.