Vladimir Jovanovic

Neuroendocrine dysfunction in patients recovering from subarachnoid hemorrhage.

OBJECTIVE: Subarachnoid hemorrhage (SAH) is a recently identified risk factor for hypopituitarism, particularly growth hormone (GH) and corticotrophins deficiencies. The aim of our study was to identify possible predictor(s) for neuroendocrine dysfunction in SAH survivors. DESIGN: Pituitary function was evaluated in 93 patients (30 males, 63 females), aged 48.0±1.1 years (mean±SE), and with a Glasgow Outcome Scale score of 4.6±0.6 (mean±SE) more than one year following SAH. In the acute phase, SAH was complicated by vasospasm (VS) in 18 and by hydrocephalus (HDC) in 9 patients. Baseline serum values of Insulin Growth Factor 1 (IGF-I), cortisol, Thyroxine (T4), Thyroid Stimulating Hormone (TSH), Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), testosterone (in males), estradiol (in females) and prolactin were determined. RESULTS: According to the results of baseline hormonal evaluation, 47 patients (50.5%) had no hormonal abnormalities. Seven patients (7.5%) had multiple pituitary hormone deficiencies: Four patients (4.3%) had two (GH and cortisol), one patient had three (gonadal, adrenal and GH) and two patients had deficiency of all pituitary axes. Thirty-nine patients (42%) had one abnormal axis (13 adrenal, 2 thyroid, 4 gonadal and 20 GH). None of the subjects was treated with desmopressin or exhibited symptomatic polyuria. The VS and HDC during the acute phase of SAH were related to abnormal pituitary status (VS with low IGF-I levels and HDC with low cortisol levels). CONCLUSION: Through a screening procedure, neuroendocrine dysfunction was identified in a substantial number of asymptomatic patients with previous SAH. Cerebral VS and HDC at the time of SAH emerged as risk factors possibly predicting development of pituitary dysfunction. Low basal levels of IGF 1 and cortisol may help in selecting patients requiring further evaluation of pituitary function.

Joint effect of ADARB1 gene, HTR2C gene and stressful life events on suicide attempt risk in patients with major psychiatric disorders

Abstract Objectives. Adenosine to inosine RNA editing, serotonin 2C receptor (HTR2C), and stressful life events (SLEs) have all been implicated in suicidal behaviour. We examined the main and moderating effects of RNA editing (ADAR, ADARB1) and HTR2C genes, childhood trauma (CT), recent SLEs and psychiatric disorders as contributors to suicide attempt (SA) vulnerability. Methods. Study included 165 suicide attempters and 188 suicide non-attempters, all diagnosed with one of major psychiatric disorders. CT and recent SLEs were assessed using Early Trauma Inventory–Self Report and List of Threatening Experiences Questionnaire, respectively. Selected ADAR and ADARB1 tag-variants, and HTR2C rs6318 were pre-screened for association with SA, while generalized linear models and backward selection were applied to identify individual and interacting SA risk factors. Results. ADARB1 rs9983925 and rs4819035 and HTR2C rs6318 were associated with SA. The best minimal model found emotional abuse, recent SLEs, rs9983925 and rs6318 as independent SA risk factors, and general traumas as a factor moderating the effect of psychiatric disorders and emotional abuse. Conclusions. SA vulnerability in psychiatric patients is related to the joint effect of ADARB1 and HTR2C variants, the existing mood disorder and the cumulative exposures to a various childhood and recent stressful experiences.

TGA-DSC-MS Analysis of Pyrolysis Process of Various Biomasses with Isoconversional (Model-Free) Kinetics

Slow pyrolysis characteristics of different biomasses (hazelnut shell (HS), sawdust (Beech), and sawdust chemically treated (SDCT)) were investigated by simultaneous thermal analysis (STA), coupled with mass spectrometry (MS). Thermal decomposition of these samples was divided into three stages corresponding to removal of water, devolatilization, and formation of bio-char. It was found that differences in thermal behavior of the samples are due to differences in their composition. Mass spectrometry results showed that H2, CH4, H2O, CO2 (C3H8), CO, and C2H6 were the main gaseous products released during pyrolysis. It was shown that HS could be a good fuel, since during its pyrolysis at high temperature, more gaseous products are released compared to other systems. Isoconversional (model-free) method was used in order to determine variation magnitudes of effective activation energy (Ea) values on conversion fraction (α) during pyrolysis. It was found that identified variations of Ea with α arise from the different chemical structures among cellulose, hemicelluloses and lignin in tested samples that may affect on their effective activation energies.

Thermogravimetric kinetic study of solid recovered fuels pyrolysis

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co–combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900°C. Two sample sizes x <0.25 mm and 0.25 < x <0.5 mm of each SRF were used in experiments, in order to obtain reliable Thermal Gravimetric Analysis (TGA) data for estimation of kinetic parameters for SRF pyrolysis. Experimental results were used for determination of pre-exponential factor and activation energy according to methods presented in the literature. Presented research provide valuable data of coffee and tire waste, that can be used for the burners design.

Intracerebral hemorrhage as a first sign of pheochromocytoma: case report and review of the literature

Pheochromocytomas and sympathetic paragangliomas are rare catecholamine-secreting tumors and represent very rare causes of intracerebral hemorrhage in young, with only few cases reported. A 32-year-old man presented to our emergency department because of sudden onset of severe headache. He had a six months history of paroxysmal headache, palpitations and sweating. During examination he became somnolent and developed left-sided hemiplegia. A computed tomographic (CT) scan of the brain showed a right temporoparietal hematoma. He was admitted to the Clinic for Neurosurgery and hematoma was evacuated. The patient was comatous, on assisted respiration, with frequent hypertensive crises. An examination for possible secondary causes of hypertension was undertaken. Plasma metanephrine value was elevated (414 pg/ml, reference values < 90pg/ml). Abdominal CT scans revealed a large mass (6cm) in the right adrenal gland. After adequate control of the hypertension was achieved with an nonselective α and β adrenergic blockers, the tumor was excised. The histopathologic findings confirmed the diagnosis of pheochromocytoma. The genetic analysis demonstrated a duplication in exon 1 of VHL gene. We reported a rare, potentially fatal complication of pheochromocytoma, an intracerebral hemorrhage. This case and review of the similar rare cases in the literature illustrate the importance of early recognition of the characteristic symptoms of catecholamine excess in young patients with hypertension.

Investigations of combustion process in combined cooker-boiler fired on solid fuels

The aim of the investigation was to make some reconstructions on the existing stove used for cooking and baking and to obtain the combined cooker-boiler which will fulfill the demands of European standard EN 12815. Implementation of modern scientific achievements in the field of combustion on stoves and furnaces fired on solid fuels was used. During the investigations four various constructions were made with different fresh air inlet and secondary air supply with the intention to obtain more complete combustion with increased efficiency and reduced CO emission. Three different fuels were used: firewood, coal, and wood briquette. A numerous parameters were measured: fuel weight changes during the combustion process, temperature of inlet and outlet water, flue gas composition (O2, CO, SO2, CO2, NOx), flue gas temperature, ash quantity etc. The result of the investigations is the stove with the efficiency of more than 75% - boiler Class 1 (according EN 12815) and CO emission of about 1% v/v. The results obtained during the measurements were used as parameters for modeling of combustion process. .