485 research outputs found
Recursive Least Squares Filtering Algorithms for On-Line Viscoelastic Characterization of Biosamples
The mechanical characterization of biological samples is a fundamental issue in biology
and related fields, such as tissue and cell mechanics, regenerative medicine and diagnosis of diseases.
In this paper, a novel approach for the identification of the stiffness and damping coefficients
of biosamples is introduced. According to the proposed method, a MEMS-based microgripper
in operational condition is used as a measurement tool. The mechanical model describing the
dynamics of the gripper-sample system considers the pseudo-rigid body model for the microgripper,
and the KelvinâVoigt constitutive law of viscoelasticity for the sample. Then, two algorithms based
on recursive least square (RLS) methods are implemented for the estimation of the mechanical
coefficients, that are the forgetting factor based RLS and the normalised gradient based RLS
algorithms. Numerical simulations are performed to verify the effectiveness of the proposed approach.
Results confirm the feasibility of the method that enables the ability to perform simultaneously two
tasks: sample manipulation and parameters identification
No effect of albumin infusion on the prevention of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt
Hepatic encephalopathy (HE) is a major problem in patients submitted to TIPS. Previous studies identified low albumin as a factor associated to post-TIPS HE. In cirrhotics with diuretic-induced HE and hypovolemia, albumin infusion reduced plasma ammonia and improved HE. Our aim was to evaluate if the incidence of overt HE (grade II or more according to WH) and the modifications of venous blood ammonia and psychometric tests during the first month after TIPS can be prevented by albumin infusion. Twenty-three patients consecutively submitted to TIPS were enrolled and treated with 1Â g/Kg BW of albumin for the first 2Â days after TIPS followed by 0,5Â g/Kg BW at day 4th and 7th and then once a week for 3Â weeks. Forty-five patients included in a previous RCT (Riggio et al. 2010) followed with the same protocol and submitted to no pharmacological treatment for the prevention of HE, were used as historical controls. No differences in the incidence of overt HE were observed between the group of patients treated with albumin and historical controls during the first month (34 vs 31Â %) or during the follow-up (39 vs 48Â %). Two patients in the albumin group and three in historical controls needed the reduction of the stent diameter for persistent HE. Venous blood ammonia levels and psychometric tests were also similarly modified in the two groups. Survival was also similar. Albumin infusion has not a role in the prevention of post-TIPS HE
The impact of lockdown on sleep patterns of children and adolescents with ADHD
STUDY OBJECTIVES: The current study examined the impact of home confinement (lockdown) due to the COVID-19 pandemic on sleep patterns of children and adolescents with ADHD.METHODS: Nine hundred ninety-two parents of children and adolescents with ADHD filled out an anonymous online survey through the ADHD family association website. The survey investigated the sleep patterns and disturbances (using a modified version of the Sleep Disturbance Scale for Children) and screen exposure time before and during the lockdown.RESULTS: During the lockdown, 59.3% of children and 69.4% of adolescents with ADHD reported a change of bedtime with significant increase of ADHD patients that went to sleep at 11pm or later. Sleep duration, in contrast, resulted in two opposing processes with more children and adolescent sleeping either less than 6 hours/night or 10-11 hours/night. Among children and adolescents, respectively, 19.9% and 22% slept less than they did before lockdown, while 21.4% and 27.4% slept more hours. Bedtime delay and decreased sleep duration were associated with an increase in the screen time exposure. Moreover, ADHD patients reported an increase in sleep disturbances when compared to previous condition, including mainly difficulties falling asleep, anxiety at bedtime, night awakenings, nightmares and daytime sleepiness.CONCLUSIONS: The lockdown impacted on sleep-wake rhythms by strengthening the maladaptive sleep patterns reported in usual life conditions in ADHD children
A rare case report of hypertrophic cardiomyopathy induced by catecholamine-producing tumor
RATIONALE: Catecholamine-producing tumors are rare, occurring in less than 0.2% of patients with hypertension, but can have relevant cardiovascular morbidity and mortality.
PATIENT CONCERNS: A 37-year-old woman presented with a history of dyspnea, chest pain, palpitations, and paroxysmal hypertension. Electrocardiogram, echocardiogram, and cardiac magnetic resonance showed severe LVH with a prevalent involvement of the anterior portion of interventricular septum. Endomyocardial biopsy found severe hypertrophy with disarray of cardiomyocytes and ultrastructural evidence of contraction and necrosis of myocytes. Hormone investigations revealed high values of 24-hours urinary metanephrines. Abdominal computed tomography (CT) showed an enlarged left adrenal gland with a strong uptake of I-metaiodobenzylguanidine at scintigraphy scan.
INTERVENTIONS:Thus, the adrenal tumor was surgically removed.
OUTCOMES: At follow-up examination, the patient's metanephrines levels were normalized and the transthoracic echocardiogram showed a reduction of LVH.
DIAGNOSIS AND LESSONS: We report a rare case of catecholamine-induced cardiomyopathy due to an adrenal adenoma mixed with nodules enriched in epinephrine-types secreting granules
High CTLA-4 expression correlates with poor prognosis in thymoma patients
Thymomas, tumors that arise from epithelial cells of the thymus gland, are the most common neoplasms of the anterior mediastinum, with an incidence rate of approximately 2.5 per million/year. Cytotoxic T Lymphocyte Antigen 4 (CTLA-4 or CD152) exerts inhibitory activity on T cells, and since its oncogenic role in the progression of different types of tumors, it has emerged as a potential therapeutic target in cancer patients. In this study, we assessed the expression of CTLA-4 both at mRNA and protein levels in paraffin embedded-tissues from patients with thymomas. Furthermore, we evaluated the relationship between CTLA-4 expression and the clinical-pathologic characteristics and prognosis in patients with thymomas. Sixty-eight patients with median age corresponding to 62 years were included in this analysis. Thymomas were classified accordingly to the WHO and Masaoka-Koga for histochemical analysis and for prognostic significance. A statistical difference was found between CTLA-4 mRNA levels in human normal thymus compared with thymoma specimens. CTLA-4 expression was statistically found to progressively increase in A, B1, B2, AB and it was maximal in B3 thymomas. According to Masaoka-Koga pathological classification, CTLA-4 expression was lower in I, IIA and IIB, and higher in invasive III and IV stages. By confocal microscopy analysis we identified the expression of CTLA-4 both in tumor cells and in CD45+ tumor-infiltrating leukocytes, mainly in B3 and AB thymomas. Finally, CTLA-4 overexpression significantly correlates with reduced overall survival in thymoma patients and in atypical thymoma subgroup, suggesting that it represents a negative prognostic factor
Cross-talk between microRNAs, long non-coding RNAs and p21Cip1 in glioma: diagnostic, prognostic and therapeutic roles
Glioblastoma multiforme is considered one of the most common malignant primary intracranial tumors. Despite
treatment with a combination of surgery, chemotherapy and radiotherapy, patients with glioblastoma multiform
have poor prognosis. It has been widely accepted that the occurrence, progression, and even recurrence of
glioblastoma multiforme strictly depends on the presence of glioma cancer stem cells. The presence of glioma
stem cells reduces the efficacy of standard therapies, thus increasing the imperative to identify new targets
and therapeutic strategies in glioblastoma patients. In this regard, the p21Cip1 pathway has been found to play an
important role in the maintenance of the glioma stem cells. It has been shown that this pathway regulates cancer
stem cell pool by preventing hyperproliferation and exhaustion. MicroRNAs, endogenous small non-coding RNAs,
and long non-coding RNAs, regulate post-transcription gene expression. These are not only altered in glioma, but
also in other cancer types, and are involved in tumor development and progression. Notably, they have also been
shown to modulate the expression of proteins in the p21Cip1 signaling pathway. This review highlights the extent and
complexity of cross-talk between microRNAs, long non-coding RNAs and the p21Cip1 pathway, and demonstrates
how such interplay orchestrates the regulation of protein expression and functions in glioma and glioma stem cells
Design and Synthesis of a cADPR Mimic as a Novel Tool for Monitoring the Intracellular Ca2+ Concentration
Cyclic ADP-ribose (cADPR, 1, Figure 1) is a naturally occurring metabolite of NAD+
capable of mobilizing Ca2+ ions from intracellular stores. It was firstly isolated from sea
urchin egg extract, but it was later established that it is also produced in many other
mammalian cells, including pancreatic ÎČ-cells, T-lymphocytes, smooth and cardiac muscle
cells, and cerebellar neurons, acting as a Ca2+-mobilizing agent. For this activity, cADPR
has been classified as a second messenger that, by activating the ryanodine receptors of
the sarcoplasmatic reticulum, is able to mobilize the calcium ions from intracellular stores.
cADPR is involved in many physiological processes related to variation in the Ca2+
concentration, such as synaptic homeostasis in neurons as well as fertilization and cellular
proliferation. This cyclic nucleotide, characterized by a very labile glycosidic bond at N1,
is also rapidly hydrolysed in neutral aqueous solutions to inactive ADP-ribose. Matsuda
and co-workers [1] were the first to synthesize new analogues of cADPR in which the
adenine base is replaced by a hypoxanthine ring. This kind of modification produced the
cyclic inosine diphosphate ribose (cIDPR), which proved to be stable in hydrolytic
physiological conditions and showed significant Ca2+ mobilizing activity. Many
modifications regarding the northern and southern ribose, as well as the purine base of
cADPR, have been proposed so far. In our laboratories, we have synthesized several
analogues of cIDPR [2â7]. In particular, the analogue with the northern ribose replaced
by a pentyl chain (cpIDP) showed interesting Ca2+ mobilizing activity on the neuronal
PC12 cell line [2]. Starting from these results, we report here the synthesis of the novel
analogue 2, in which the ânorthernâ ribose of cIDPR is replaced by a 2âł,3âł-dihydroxy
pentyl chain. The effect of the presence of the diol moiety on the intracellular Ca2+ release
will be assessed in due course
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