A Ferrofluid with Surface Modified Nanoparticles for Magnetic Hyperthermia and High ROS Production

A ferrofluid with 1,2-Benzenediol-coated iron oxide nanoparticles was synthesized and physicochemically analyzed. This colloidal system was prepared following the typical co-precipitation method, and superparamagnetic nanoparticles of 13.5 nm average diameter, 34 emu/g of magnetic saturation, and 285 K of blocking temperature were obtained. Additionally, the zeta potential showed a suitable colloidal stability for cancer therapy assays and the magneto-calorimetric trails determined a high power absorption density. In addition, the oxidative capability of the ferrofluid was corroborated by performing the Fenton reaction with methylene blue (MB) dissolved in water, where the ferrofluid was suitable for producing reactive oxygen species (ROS), and surprisingly a strong degradation of MB was also observed when it was combined with H2O2. The intracellular ROS production was qualitatively corroborated using the HT-29 human cell line, by detecting the fluorescent rise induced in 2,7-dichlorofluorescein diacetate. In other experiments, cell metabolic activity was measured, and no toxicity was observed, even with concentrations of up to 4 mg/mL of magnetic nanoparticles (MNPs). When the cells were treated with magnetic hyperthermia, 80% of cells were dead at 43 °C using 3 mg/mL of MNPs and applying a magnetic field of 530 kHz with 20 kA/m amplitude.

Munchausen by proxy syndrome mimicking childhood-onset systemic lupus erythematosus

Childhood-onset systemic lupus erythematosus (cSLE) is a chronic inflammatory multisystem autoimmune disease that requires multiple differential diagnoses. Munchausen by proxy syndrome (MBPS) is a form of child abuse, where a caregiver intentionally creates a medical history and induces or fabricates signs or disease in a patient. To our knowledge, there is no case report of MBPS mimicking cSLE diagnosis. We reported herein a 9-year-old male patient, with a history of multiple hospitalizations due to seizures with altered levels of consciousness. The mother reported malar rash, photosensitivity, alopecia, arthralgia, arterial hypertension, macroscopic hematuria, seizure and positive antinuclear antibodies. In the other service, he was treated with intravenous methylprednisolone, prednisone and mycophenolate mofetil. At 8 years and 8 months, he was admitted to our tertiary center with history of fever and macroscopic hematuria. Laboratory examinations were normal, including negative for antinuclear antibodies, anti-double stranded DNA, anticardiolipin, anti-Ro/SSA, anti-La/SSB, anti-RNP and anti-Sm antibodies. Multiple urine cultures revealed the presence of Enterococcus faecium, Acinetobacter sp., Stenotrophomonas maltophilia and Serratia marcescens, without any association with pyuria. At 8 years and 9 months, he was readmitted at emergency room with history of severe fever, headache, vomiting, photophobia, phonophobia and dizziness. The physical examination showed agitation, confusion, ataxic gait, slurred speech, horizontal nystagmus, painful facial expressions, tachycardia and weight loss. Brain magnetic resonance angiography and cerebrospinal fluid analysis were normal. During hospitalization, he had an acute episode of epistaxis and otalgia with excoriation in the auditory canal. At that moment, the suspicion of MBPS mimicking cSLE was raised and phenytoin intoxication was confirmed (peak phenytoin concentration was 45.4 mcg/mL, therapeutic range 10-20 mcg/mL). The mother and the patient were immediately separated, and she was replaced by another legal guardian. One week later, the neurological and other signs and symptoms were completely resolved. The child was placed under paternal custody with a court order and moved to another state. After that, the mother reported phenytoin use for her child and was referred to psychiatric follow-up. In conclusion, the first case of MBPS mimicking cSLE, resulting in multiple unnecessary examinations and treatments with delayed diagnosis was reported.

A high-resolution frequency variable experimental setup for studying ferrofluids used in magnetic hyperthermia

A scanning system for specific absorption rate of ferrofluids with superparamagnetic nanoparticles is presented in this study. The system contains an induction heating device designed and built with a resonant inverter in order to generate magnetic field amplitudes up to 38 mT, over the frequency band 180-525 kHz. Its resonant circuit involves a variable capacitor with 1 nF of capacitance steps to easily select the desired frequency, reaching from 0.3 kHz/nF up to 5 kHz/nF of resolution. The device performance is characterized in order to compare with the theoretical predictions of frequency and amplitude, showing a good agreement with the resonant inverters theory. Additionally, the setup is tested using a synthetic iron oxide with 10 ± 1 nm diameter suspended in liquid glycerol, with concentrations at 1%. Meanwhile, the temperature rise is measured to determine the specific absorption rate and calculate the dissipated power density for each f. This device is a suitable alternative to studying ferrofluids and analyzes the dependence of the power absorption density with the magnetic field intensity and frequency.

A 17q21.31 microdeletion encompassing the MAPT gene in a mentally impaired patient

About 15% of patients with a clinical phenotype of Angelman syndrome (AS) have an unknown etiology. We report a patient with features reminiscent of AS, including a pattern of characteristic facial anomalies as well as speech impairment, developmental delay and frequent laughter. In addition, the patient had features not commonly associated with AS such as heart malformations and scoliosis. She was negative in SNURF-SNRPN exon 1 methylation studies and the G-banded karyotype was normal. Array-based comparative genomic hybridization disclosed a deletion of maximally 1 Mb at 17q21.31. The deleted region contains the MAPT gene, implicated in late onset neurodegenerative disorders, and the STH and NP_056258.1 genes. Another gene, such as CRHR1, might also be included based on maximum possible size of the deletion. We suggest that microdeletions within the 17q21.31 segment should be considered as a possible cause of phenotypes resembling AS, particularly when easily controlled seizures and/or cardiac abnormalities are also present.

Vaccine-associated paralytic poliomyelitis: a case report of domiciliary transmission

Poliomyelitis associated with live strain vaccine is defined as the paralytic form of the acute anterior poliomyelitis related to the vaccine strain. Since these strains behave similarly to the wild-type virus, we can differentiate, epidemiologically, two types of vaccine-associated poliomyelitis: cases in which the patient was vaccinated and cases in which the patient had had contact with vaccinated individuals. We herein present the case of an unvaccinated child, with a clinical picture of an acute anterior poliomyelitis associated with the live strain vaccine, whose brother received the Sabin vaccine 20 days before the onset of the symptoms. Vaccine strain of the type 3 poliovirus was isolated in fecal culture and a presented mutation in nucleotide 472 (C-->U) in the 5' non-coding region, which is strongly related to the higher strain virulence.

[An experimental model of hepatointestinal transplant in the pig with clinical applications]

A model of experimental hepatointestinal transplant in pigs, with clinical applications is presented. Ten animals received a graft composed by the liver and the full length of the small bowel. Two pigs died during the transplant and in eight the surgical procedure was well tolerated with a good revascularization of the grafts. The coagulation parameters were normal after the transplant and only minor biochemical disturbances were found. The main difficulties of the surgical technique are related with the poor tolerance of the pig to the portal and caval clamping, and the close relationships of the duodenum, pancreas and distal colon, produced by the 360 degrees anti-clockwise bowel rotation around the mesenteric vessels. Clamping the supraceliac aorta during the implant of the graft keeps the animal hemodynamically stable and makes unnecessary the use of the more complicated veno venous shunt.

[Physiopathologic implications of the anesthesiologic management of pediatric laparoscopic surgery]

We study gas exchange and hemodynamic repercussions during pediatric laparoscopic surgery. We provided balanced anesthesia with muscle relaxation while ventilation was maintained with FiO2 at 0.4 and flow volume between 10-15 ml/kg-1 during abdominal laparoscopic procedures performed in 10 ASA I-II children (4-14 years). Pneumoperitoneum was produced with CO2 insufflated up to a pressure of 15 mmHg. Airways pressure (PIP), PaO2, PaCO2, heart rate (HR), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) were measured before insufflation and 5, 30 and 60 minutes afterwards. We calculated the ratio of dead space to flow volume (VD/VT), thoracic distensibility and metabolic production of CO2 (VCO2). Insufflation caused an immediate reduction (29-33%) in dynamic thoracic distensibility (p = 0.0004), but no hypoventilation or increases in VD/VT. The decrease in PaO2 was small (5-6%) but statistically significant (p = 0.0188). Hypercapnia (14-21%) was due to an increase in VCO2 caused by gradual peritoneal absorption of CO2 (24-32%, p = 0.0013). We also found increases in SAP (10%, p = 0.02) and DAP (32%, p = 0.0001) at 5 min, along with an increase in HR (8%, p = 0.0163) at 60 min. Arterial CO2 levels were held within physiological limits by compensatory hyperventilation (+25% of physiological VT). Capnography proved to be an excellent guide. Any clinical repercussion of hemodynamic effects was blocked by a dose of atropine given before insufflation and by the excess loading volume (10 ml/kg of crystalloids). Laparascopic surgery in children diminishes thoracic distensibility and causes hypercapnia, making it necessary to measure PefCO2 to regulate ventilation.

[Biochemical indicators of primary graft dysfunction in experimental orthotopic liver transplantation]

Aiming at investigating biochemical markers of Primary Graft Nonfunction (PNF) in Orthotopic Liver Transplantation (OLT) an experimental work is made on 21 Large-White pigs randomly distributed in three groups of seven, and two additional groups of seven donors each. In Group I the supra and infrahepatic cava, the portal vein and the hepatic artery were clamped. After 30 minutes the caval and portal clamps were released and 30 minutes later the arterial clamp was also removed. In Group II (viable), OLT was performed. The Collins solution was used as preservation fluid, keeping the cold ischemia time under 2 hours. In Group III (Non-Viable), an OLT was carried out 24 hours of cold ischemia with Collins solution. Blood samples are taken in 8 different moments along the procedure to determinate the values of AST, ALT, LDH, FA, Bilirubin, Uric Acid, Cholesterol, Triglycerides, Urea, Creatinine, Glucose, Total Protein, Calcium, Phosphorus, CPK and Aldolase. The last 5 samples were drawn after reperfusion. In the Group III we found, in the samples drawn after reperfusion of the graft, significant increases in 5 of these parameters, AST, ALT LDH, Aldolase and Uric Acid. We consider that these 5 parameters may be of value in the early diagnosis of PNF of the graft, being the AST and ALT the most reliable, with the higher specificity for the same sensitivity.

Seizure recurrence in infants with neonatal convulsions. A follow-up study

Twenty three infants with neonatal seizures were followed prospectively to a mean age of 11 months. Only 2 were pre-term and birth weight ranged from 1700 to 4230 grams, with 17 male and 6 female infants. Hypoxic-ischemic encephalopathy was the most common etiology (82.6%). Focal clonic convulsions were the predominant seizure type, present in 7/16 infants in which the seizure type could be identified. All infants had a neurological examination and EEG, and 18 had a cranial ultrasonography performed at the follow-up. Anticonvulsant medication was discontinued, if follow-up EEG and neurological examination were normal. At the follow-up, seizure recurrence was observed in 7/23 (30%) infants. Abnormal EEG, neurological examination and cranial ultrasonography were statistically correlated with seizure recurrence. We conclude that infants with neonatal seizures can remain free of anticonvulsant medication provided they have normal neurological examination, EEG and cranial ultrasonography.