Gold nanoparticle-coated apoferritin conductive nanowires

Gold-metallic nanofibrils were prepared from three different iso-apoferritin (APO) proteins with different Light/Heavy (L/H) subunit ratios (from 0% up to 100% L-subunits). We show that APO protein fibrils have the ability to in situ nucleate and grow gold nanoparticles (AuNPs) simultaneously assembled on opposite strands of the fibrils, forming hybrid inorganic-organic metallic nanowires. The AuNPs are arranged following the pitch of the helical APO protein fiber. The mean size of the AuNPs was similar in the three different APO protein fibrils studied in this work. The AuNPs retained their optical properties in these hybrid systems. Conductivity measurements showed ohmic behavior like that of a continuous metallic structure.

Understanding the Formation of Apoferritin Amyloid Fibrils

We present the optimization of experimental conditions to yield long, rigid apoferritin protein amyloid fibrils, as well as the corresponding fibrillation pathway. Fibril growth kinetics was followed using atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), circular dichroism (CD), fourier-transform infrared spectroscopy (FTIR), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Among the morphologies identified, we show that the conditions result in small aggregates, as well as medium and long fibrils. Extended incubation times led to progressive unfolding and hydrolysis of the proteins into very short peptide fragments. AFM, SDS-PAGE, and CD support a universal common fibrillation mechanism in which hydrolyzed fragments play the central role. These collective results provide convincing evidence that protein unfolding and complete hydrolysis of the proteins into very short peptide sequences are essential for the formation of the final apoferritin amyloid-like fibrils.

Apoferritin Amyloid-Fibril Directed the In Situ Assembly and/or Synthesis of Optical and Magnetic Nanoparticles

The coupling of proteins that can assemble, recognise or mineralise specific inorganic species is a promising strategy for the synthesis of nanoscale materials with a controllable morphology and functionality. Herein, we report that apoferritin protein amyloid fibrils (APO) have the ability to assemble and/or synthesise various metal and metal compound nanoparticles (NPs). As such, we prepared metal NP-protein hybrid bioconjugates with improved optical and magnetic properties by coupling diverse gold (AuNPs) and magnetic iron oxide nanoparticles (MNPs) to apoferritin amyloid fibrils and compared them to the well-known β-lactoglobulin (BLG) protein. In a second approach, we used of solvent-exposed metal-binding residues in APO amyloid fibrils as nanoreactors for the in situ synthesis of gold, silver (AgNPs) and palladium nanoparticles (PdNPs). Our results demonstrate, the versatile nature of the APO biotemplate and its high potential for preparing functional hybrid bionanomaterials. Specifically, the use of apoferritin fibrils as vectors to integrate magnetic MNPs or AuNPs is a promising synthetic strategy for the preparation of specific contrast agents for early in vivo detection using various bioimaging techniques.

High power ultrasounds: A powerful, non-thermal and green technique for improving the phenolic extraction from grapes to must during red wine vinification

Wine color is one of the main organoleptic characteristics influencing its quality. It is of especial interest in red vinifications due to the economic resources that wineries have to invest for the extraction of the phenolic compounds. To increase this extraction, some chemical (maceration enzymes) or physical technologies (thermovinification, criomaceration, flash-expansion) can be applied. In this work, the results of the application of high power ultrasounds to the crushed grapes to increase the extraction of phenolic compounds are presented. Crushed grapes (400 kg) from the 2017 harvest were treated with ultrasound, and three different lengths of skin maceration period (2, 3 or 7 days) and the results were compared with a control vinification, where grapes were not subjected to any treatment and were skin macerated during 7 days. The wine chromatic characteristics and the individual phenolic compounds were followed during all the maceration period, at the end of alcoholic fermentation and after bottle storage. The wines made with ultrasound treated grapes presented differences with control wine, especially as regard color and total phenol and tannin content, the wines with three days of maceration time presenting similar chromatic characteristics than control wines with 7 days of maceration time.

Hybrid Nanoscopy of Hybrid Nanomaterials

The combination of complementary techniques to characterize materials at the nanoscale is crucial to gain a more complete picture of their structure, a key step to design and fabricate new materials with improved properties and diverse functions. Here it is shown that correlative atomic force microscopy (AFM) and localization-based super-resolution microscopy is a useful tool that provides insight into the structure and emissive properties of fluorescent β-lactoglobulin (βLG) amyloid-like fibrils. These hybrid materials are made by functionalization of βLG with organic fluorophores and quantum dots, the latter being relevant for the production of 1D inorganic nanostructures templated by self-assembling peptides. Simultaneous functionalization of βLG fibers by QD655 and QD525 allows for correlative AFM and two-color super-resolution fluorescence imaging of these hybrid materials. These experiments allow the combination of information about the topography and number of filaments that compose a fibril, as well as the emissive properties and nanoscale spatial distribution of the attached fluorophores. This study represents an important step forward in the characterization of multifunctionalized hybrid materials, a key challenge in nanoscience.

Apoferritin fibers: a new template for 1D fluorescent hybrid nanostructures

Recently, research in the field of protein amyloid fibers has gained great attention due to the use of these materials as nanoscale templates for the construction of functional hybrid materials. The formation of apoferritin amyloid-like protein fibers is demonstrated herein for the first time. The morphology, size and stiffness of these one-dimensional structures are comparable to the fibers formed by β-lactoglobulin, a protein frequently used as a model in the study of amyloid-like fibrillar proteins. Nanometer-sized globular apoferritin is capable of self-assembling to form 1D micrometer-sized structures after being subjected to a heating process. Depending on the experimental conditions, fibers with different morphologies and sizes are obtained. The wire-like protein structure is rich in functional groups and allows chemical functionalization with diverse quantum dots (QD), as well as with different Alexa Fluor (AF) dyes, leading to hybrid fluorescent fibers with variable emission wavelengths, from green to near infrared, depending on the QD and AFs coupled. For fibers containing the pair AF488 and AF647, efficient fluorescence energy transfer from the covalently coupled donor (AF488) to acceptor tags (AF647) takes place. Apoferritin fibers are proposed here as a new promising template for obtaining hybrid functional materials.

Apomaghemite as a doxorubicin carrier for anticancer drug delivery

Protein cages have well-defined structures and can be chemically and biologically engineered in many ways, making them useful platforms for drug delivery applications. Taking advantage of the unique structure feature of apoferritin, a new theranostic nanocarrier is proposed herein. The apoferritin protein is effective for the encapsulation of maghemite nanoparticles and for loading a significant dose of doxorubicin (DOX) drug. This simultaneous loading of maghemite nanoparticles and DOX has been achieved using either co-encapsulation or surface-binding approaches. Maghemite nanoparticles coated with the protein apoferritin are an effective long-term MRI liver contrast agent and we report here that additionally they can serve as an anticancer drug-delivery system. In particular we show that maghemite-containing apoferritin can sustain the DOX delivery under period of 10 to 25 days depending on the environmental conditions.

Laboratory paradigms of impulsivity and alcohol dependence: a review

Impulsivity can be defined as choosing a smaller, immediate reward over a larger, delayed reward. From this perspective, addictive behaviors such as substance abuse and pathological gambling reflect a series of impulsive choices. However, impulsivity is not a homogeneous construct. Laboratory measures of impulsivity reflect two types of processes. The first is related to behavioral inhibition and refers to an individual's ability to appropriately inhibit thoughts or actions. The second is the delay of reward dimension, namely the degree to which immediate (rewarding) consequences have more control over an individual's behavior than consequences that are delayed. In this review, we describe how alcohol is associated with significant impairments in these paradigms. We also suggest that they may have a role in the development of alcohol dependence. These results are in agreement with a model in which delay of gratification might be a marker for early use and/or abuse of alcohol, whereas impairment in behavioral inhibition might be a marker for maintained use in time and, therefore, for progression towards alcohol dependence.

Effects of 17beta-estradiol on the cytotoxicity of etoposide in a lung carcinoma cell line and its bioavailability in ovariectomized Sprague-Dawley rats

BACKGROUND

The activity of steroid hormones for the efficacy of antineoplastic drugs used in lung cancer treatment has not been explored. We evaluated the influence of 17beta-estradiol on the cytotoxicity of etoposide in a lung cancer cell line (A-549) and determined systemic levels of etoposide in vivoafter pretreatment with this hormone.

METHODS

The effect of 17beta-estradiol alone and combined with etoposide on cellular proliferation was evaluated. Blood levels of etoposide were studied in ovariectomized female rats previously treated with 17beta-estradiol. Etoposide levels were determined by high-performance liquid chromatography, and a pharmacokinetic analysis was performed.

RESULTS

17beta-Estradiol showed a tendency towards an increase in cellular proliferation but did not change the cytotoxic effect of etoposide. This in vivo study demonstrated that the blood levels of etoposide significantly decreased in the 17beta-estradiol-treated group.

CONCLUSION

The clear reduction in the in vivo systemic levels of etoposide in the presence of 17beta-estradiol suggests a possible role of this hormone in drug resistance. However, as these data cannot be extrapolated to clinic situations, more research is necessary to understand the interaction between hormonal compounds and antineoplastic drugs.

A high-performance liquid chromatographic assay for determination of cisplatin in plasma, cancer cell, and tumor samples

A method for determination of cis-diaminedichloroplatinum (II) (cisplatin) in ultrafiltered plasma, cell, and tumour samples is described. Cisplatin separation was carried out on a reversed-phase column using methanol-acetonitrile-water as the mobile phase. The flow rate was maintained constant at 1.6 mL/min and analysis was performed at 23 degrees C. Detection was carried out by absorbance at 254 nm. The method was linear in the range of 0.2-10 microg/mL, and the coefficients of variation were <10%. Using this technique, we measured the intracellular accumulation of cisplatin in cancer cells and in tumours of mice receiving treatment with cisplatin and evaluated the pharmacokinetics of cisplatin in nu/nu mice after intraperitoneal (i.p.) administration. The method proved to be adequate for measuring cisplatin both in vitro and in vivo and could be suitable for studies of cisplatin pharmacokinetics in animal models.

Possible role of systemic inflammatory reaction in vascular access thrombosis

BACKGROUND

Vascular devices are an integral part of modern medicine. Catheter thrombosis is a frequent complication that interferes with their use.

METHOD

We have observed a series of patients in whom vascular access thrombosis occurred in close temporal association with infectious or inflammatory processes.

RESULTS

Laboratory and clinical evidence suggests that activation of the coagulation system may be triggered by certain infectious or inflammatory disorders. Patients with vascular devices are prone to infections that could lead to a transient hypercoagulable state.

CONCLUSIONS

We are proposing that infections or other inflammatory processes may be involved in some vascular access thrombotic events. On the basis of our observations, we believe further studies are warranted regarding a possible association between infections or inflammatory disorders and vascular devices thrombosis. If an association is proven to exist, patients with vascular devices and infectious or inflammatory processes may be candidates for short-term anticoagulation during acute episodes of infection or inflammation.

The decreased serum urea nitrogen-creatinine ratio

Sometimes, readily available laboratory data can provide valuable hidden information. Such is the case with the serum urea nitrogen-creatinine ratio. A normal ratio is 8:1 to 10:1. It is well known that an elevated ratio is seen in cases of prerenal or postrenal uremia. Less appreciated are the diagnostic possibilities suggested by a decreased serum urea nitrogen-creatinine ratio (ie, <8). Several clinical circumstances can lead to a decreased serum urea nitrogen-creatinine ratio.

Case reports: trimethoprim-sulfamethoxazole-induced meningitis in patients with HIV infection

Meningitis is a frequent complication of the human immunodeficiency infection. Possible causes include bacterial, fungal, mycobacterial, syphilitic, and vital pathogens (including the human immunodeficiency virus). Drugs must also be considered in the differential diagnosis. Two patients with probable trimethoprim-sulfamethoxazole-induced meningitis are described in the setting of human immunodeficiency virus infection.

Human herpesvirus-6 and the course of human immunodeficiency virus infection

The aim of this study is to investigate the relationship between human herpesvirus type 6 (HHV-6) and cytomegalovirus (CMV) infection and progression of AIDS disease. A group of 52 HIV-1-seropositive patients was examined for HHV-6 DNA expression in peripheral blood mononuclear cells and for CMV DNA in serum. We found that 21.1% (n = 52) and 12% (n = 25) of them tested positive for HHV-6 and CMV DNA, respectively. In contrast, only 3.3% (n = 29) and 0% (n = 29) of control healthy HIV-1-seronegative donors tested positive for HHV-6 and CMV, respectively. In light of these results, the possible role of HHV-6 as a cofactor in AIDS development has also been assessed by closely following, over 6 years, the course of an HIV-1-seropositive person who had a dramatic loss in the total number of CD4+ cells along with a spontaneous production of HIV-1 p24 antigen in vitro and who also showed progression to AIDS when coinfected with HHV-6. These observations have spurred our prospective analysis of the possible clinical significance of coinfection with HHV-6 and HIV.

[Anticardiolipin antibodies in parenteral drug addicts: relationship with HIV]

The IgG isotype of anticardiolipin antibodies (aCL) and its possible relationship with the immunodeficiency virus (HIV) were studied in 65 parenteral drug addicts (PDA). Thirty-seven patients were infected in the present study. Nineteen (51%) fulfilled diagnostic criteria of AIDS. Thirty-two of these 37 HIV-positive patients (86%) were IgG-aCL positive. Fourteen (50%) of the 28 HIV-negative patients were IgG-aCL positive. Our study reveals a lack of correlation between aCL and thrombocytopenia. None of the patients had thromboembolic complications. In AIDS patients no relationship was found between IgG-aCL levels and the presence of Pneumocystis carinii, other infections by opportunist microorganism, and clinical deterioration. Highly increased levels of IgG-aCL (> 80 GPL) were observed in three patients with AIDS and infectious endocarditis. In conclusion, given the non-specificity of aCL en PDA, it is our opinion that its measurement is of little help in daily clinical praxis.

Leishmania esophagitis in an AIDS patient: an unusual form of visceral leishmaniasis

Esophageal disease is a common cause of morbidity in patients infected by human immunodeficiency virus (HIV). Although gastrointestinal involvement of leishmaniasis has been previously reported, we believed that we describe the first case of leishmania esophagitis. Clinical data and the endoscopic and histologic hallmarks are described.

Successful treatment of antimony-resistant visceral leishmaniasis with liposomal amphotericin B in patients infected with human immunodeficiency virus

We describe two cases of visceral leishmaniasis in patients infected with human immunodeficiency virus (HIV); both cases were resistant to antimony compounds but were cured with liposomal amphotericin B, with no significant toxicity. A review of the previous reported cases of antimony-resistant visceral leishmaniasis in HIV-infected patients confirmed the effectiveness of treatment with liposomal amphotericin B, which directly targets infected macrophages and reaches high levels in plasma and tissue.

Selective decrease of CD26 expression in T cells from HIV-1-infected individuals

The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.

Selective decrease of CD26 expression in T cells from HIV-1-infected individuals

The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.

Cardiovascular effects of a nifedipine infusion during fentanyl-nitrous oxide anesthesia in dogs

The hemodynamic effects of a nifedipine infusion were investigated in eight dogs given fentanyl/pancuronium/nitrous oxide/oxygen anesthesia. Nifedipine (20 micrograms/kg) was given intravenously over two minutes immediately prior to each 30-minute infusion at 2 micrograms/kg/min, 4 micrograms/kg/min, and 6 micrograms/kg/min. The range of plasma nifedipine levels obtained was 52.1 to 113.7 ng/mL. The predominant hemodynamic effects were significant reductions in systemic vascular resistance (SVR) and mean aortic pressure (MAP), accompanied by a rise in cardiac index and heart rate (HR). Administration of calcium chloride (20 mg/kg) after the nifedipine infusion had no effect on SVR or MAP, but HR was significantly reduced. Serum epinephrine and norepinephrine levels increased after the infusion of nifedipine and suggested that fentanyl did not completely overcome the sympathetic response to the profound vasodilatation. The resulting tachycardia in combination with diastolic hypotension from nifedipine could have a detrimental effect on the myocardial oxygen balance.

Reversal of the adverse cardiovascular effects of intravenous diltiazem in anesthetized dogs

Intravenous diltiazem can be used to treat myocardial ischemia, hypertension, and supraventricular dysrhythmias, but significant adverse effects including atrioventricular block and hypotension have been reported. At the present time, there is controversy as to which drug is most effective in reversing these sequelae. This study was designed to assess the effectiveness of calcium chloride v epinephrine in reversing these side effects. The hemodynamic and electrophysiologic effects of diltiazem infusion were investigated in eight dogs anesthetized with fentanyl and nitrous oxide/oxygen. This study confirmed that diltiazem infusions in high concentrations produced predominantly atrioventricular conduction depression followed by profound hypotension. Epinephrine infusion proved to be most effective in attenuating and eliminating each of these deleterious side effects. In contrast, calcium chloride did not significantly increase heart rate or blood pressure or reverse atrioventricular block. In two instances calcium chloride produced further depression of atrioventricular conduction, leading to severe bradycardia and sinus arrest. Although calcium chloride increased left ventricular contractile force (LV dP/ dt) and cardiac index (CI), mean arterial pressure was not affected and SVR was further decreased. This study indicates that calcium chloride should not be given to reverse the side effects of diltiazem in the presence of atrioventricular conduction block or profound hypotension. Calcium chloride is indicated only when isolated myocardial depression is present and after the calcium channels have been reopened by epinephrine.