A Targeted Mass Spectrometry Approach to Identify Peripheral Changes in Metabolic Pathways of Patients with Alzheimer's Disease.

Alzheimer's disease (AD), a neurodegenerative disorder, is the most common cause of dementia in the elderly population. Since its original description, there has been intense debate regarding the factors that trigger its pathology. It is becoming apparent that AD is more than a brain disease and harms the whole-body metabolism. We analyzed 630 polar and apolar metabolites in the blood of 20 patients with AD and 20 healthy individuals, to determine whether the composition of plasma metabolites could offer additional indicators to evaluate any alterations in the metabolic pathways related to the illness. Multivariate statistical analysis showed that there were at least 25 significantly dysregulated metabolites in patients with AD compared with the controls. Two membrane lipid components, glycerophospholipids and ceramide, were upregulated, whereas glutamic acid, other phospholipids, and sphingolipids were downregulated. The data were analyzed using metabolite set enrichment analysis and pathway analysis using the KEGG library. The results showed that at least five pathways involved in the metabolism of polar compounds were dysregulated in patients with AD. Conversely, the lipid pathways did not show significant alterations. These results support the possibility of using metabolome analysis to understand alterations in the metabolic pathways related to AD pathophysiology.

Results from a survey in healthy blood donors in South Eastern Italy indicate that we are far away from herd immunity to SARS-CoV-2.

Here we present results from a survey on anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in healthy blood donors from a low incidence coronavirus disease 2019 area (Apulia region, South Eastern Italy). Among 904 subjects tested, only in nine cases (0.99%) antibodies against SARS-CoV-2 were demonstrated. All the nine seropositive patients were negative for the research of viral RNA by reverse transcription polymerase chain reaction in nasopharyngeal swabs. These data, along with those recently reported from other countries, clearly show that we are very far from herd immunity and that the containment measures are at the moment the only realistic instrument we have to slow the spread of the pandemic.

Challenges in LC-MS-based metabolomics for Alzheimer's disease early detection: targeted approaches versus untargeted approaches.

BACKGROUND: Alzheimer's disease (AD) is one of the most common causes of dementia in old people. Neuronal deficits such as loss of memory, language and problem-solving are severely compromised in affected patients. The molecular features of AD are Aß deposits in plaques or in oligomeric structures and neurofibrillary tau tangles in brain. However, the challenge is that Aß is only one piece of the puzzle, and recent findings continue to support the hypothesis that their presence is not sufficient to predict decline along the AD outcome. In this regard, metabolomic-based techniques are acquiring a growing interest for either the early diagnosis of diseases or the therapy monitoring. Mass spectrometry is one the most common analytical platforms used for detection, quantification, and characterization of metabolic biomarkers. In the past years, both targeted and untargeted strategies have been applied to identify possible interesting compounds. AIM OF REVIEW: The overall goal of this review is to guide the reader through the most recent studies in which LC-MS-based metabolomics has been proposed as a powerful tool for the identification of new diagnostic biomarkers in AD. To this aim, herein studies spanning the period 2009-2020 have been reported. Advantages and disadvantages of targeted vs untargeted metabolomic approaches have been outlined and critically discussed.

Low Prevalence of Antibodies to SARS-CoV-2 and Undetectable Viral Load in Seropositive Blood Donors from South-Eastern Italy.

Recently, a significant cluster of pneumonia caused by a novel betacoronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) was described initially in China and then spread throughout the world. Like other coronaviridae, the viral transmission occurs mainly through droplets. In addition, the virus has been detected in different clinical specimens, suggesting a potential transmission by other routes, including blood transfusion. However, the potential risk of transmission of SARS-CoV-2 via blood products is still unclear. The aim of our study was to investigate the prevalence of antibodies against SARS-CoV-2 among blood donors from South-Eastern Italy. Moreover, in the seropositive donors, we searched for the presence of the virus in nasopharyngeal swabs and in plasma samples. Overall, 1,797 blood donors from the Apulia region were tested for anti-SARS-CoV-2 antibodies, using a commercially available assay. Only 18/1,797 donors (1.0%) tested positive for anti-SARS-CoV-2 antibodies; in none of them SARS-CoV-2 viral RNA was detected in nasopharyngeal swabs and in plasma samples. Our results indicate that most of the blood donors in Apulia remained uninfected during this wave of the pandemic; further, none had detectable virus both in nasopharyngeal swabs and in blood samples. The risk to carry and transmit the virus by healthy and asymptomatic blood donors is probably very low.

Influence of pancreatic status on circulating plasma sterols in patients with cystic fibrosis.

Background Patients with cystic fibrosis (CF) have a reduced intestinal absorption of cholesterol and in a preliminary study we observed differences in plasma sterol profile between patients with pancreatic sufficiency (PS) and those with pancreatic insufficiency (PI). Therefore, we hypothesized that the sterol analysis may contribute to study the digestion and absorption state of lipids in patients with CF. To this aim we evaluated plasma sterols in a significant number of adult patients with CF in relation to the pancreatic status. Methods Beside cholesterol, we measured phytosterols and lathosterol as markers of intestinal absorption and hepatic biosynthesis, respectively, by gas-chromatography in plasma of adult CF patients with pancreatic sufficiency (PS-CF, n = 57), insufficiency (PI-CF, n = 97) and healthy subjects (control group, CT, n = 71). Results PI-CF patients had cholesterol and phytosterols levels significantly lower than PS-CF and CT (p < 5 × 10-10) suggesting a reduced intestinal absorption of sterols related to PI. Instead, lathosterol was significantly higher in PI-CF patients than PS-CF and CT (p < 0.0003) indicating an enhanced cholesterol biosynthesis. In PI-CF patients, phytosterols positively correlate with vitamin E (p = 0.004). Both the classes of molecules need cholesterol esterase for the intestinal digestion, thus the reduced levels of such lipids in serum from PI-CF patients may depend on a reduced enzyme activity, despite the pancreatic enzyme supplementation in all PI-CF patients. Conclusions A plasma sterols profile may be useful to evaluate the metabolic status of lipids in adult patients with CF and could help to manage the pancreatic enzyme supplementation therapy.

Short-Term Physiological Effects of a Very Low-Calorie Ketogenic Diet: Effects on Adiponectin Levels and Inflammatory States.

Adipose tissue is a multifunctional organ involved in many physiological and metabolic processes through the production of adipokines and, in particular, adiponectin. Caloric restriction is one of the most important strategies against obesity today. The very low-calorie ketogenic diet (VLCKD) represents a type of caloric restriction with very or extremely low daily food energy consumption. This study aimed to investigate the physiological effects of a VLCKD on anthropometric and biochemical parameters such as adiponectin levels, as well as analyzing oligomeric profiles and cytokine serum levels in obese subjects before and after a VLCKD. Twenty obese subjects were enrolled. At baseline and after eight weeks of intervention, anthropometric and biochemical parameters, such as adiponectin levels, were recorded. Our findings showed a significant change in the anthropometric and biochemical parameters of these obese subjects before and after a VLCKD. We found a negative correlation between adiponectin and lipid profile, visceral adipose tissue (VAT), C-reactive protein (CRP), and pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), which confirmed the important involvement of adiponectin in metabolic and inflammatory diseases. We demonstrated the beneficial short-term effects of a VLCKD not only in the treatment of obesity but also in the establishment of obesity-correlated diseases.

Prospective evaluation of pregnancy outcome in an Italian woman with late-onset combined homocystinuria and methylmalonic aciduria.

BACKGROUND: Cobalamin metabolism disorders are rare, inherited diseases which cause megaloblastic anaemia and other clinical manifestations. Early diagnosis of these conditions is essential, in order to allow appropriate treatment as early as possible. CASE PRESENTATION: Here we report the case of a patient who was apparently healthy until the age of 20, when she presented with impaired renal function and normocytic anaemia. At the age of 34, when her first pregnancy resulted in an intrauterine death of a morphologically normal growth-restricted foetus, she was diagnosed with homocystinuria and methylmalonic aciduria due to cyanocobalamin C (cblC) defect, which was confirmed by molecular investigation. Consequently, hydroxocobalamin was administered to correct homocysteine plasma levels. This treatment was efficacious in lowering homocysteine plasma levels and restored anaemia and renal function. During a second pregnancy, the patient was also administered a prophylactic dose of low molecular -weight heparin. The pregnancy concluded with a full-term delivery of a healthy male. CONCLUSIONS: This case emphasises the importance of awareness and appropriate management of rare metabolic diseases during pregnancy. We suggest that women with late-onset cblC defect can have a positive pregnancy outcome if this metabolic disease is treated adequately.

Age-related changes of cholestanol and lathosterol plasma concentrations: an explorative study.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) and Lathosterolosis represent two treatable inherited disorders of cholesterol metabolism that are characterized by the accumulation of cholestanol and lathosterol, respectively. The age of the patients suspected of having these disorders is highly variable due to the very different phenotypes. The early diagnosis of these disorders is important because specific therapeutic treatment could prevent the disease progression. The biochemical diagnosis of these defects is generally performed analyzing the sterol profile. Since age-related levels of these sterols are lacking, this study aims to determine a preliminary comparison of plasma levels of cholestanol and lathosterol among Italian unaffected newborns, children and healthy adults. METHODS: The sterols were extracted from 130 plasma samples (24 newborns, 33 children and 73 adults) by a liquid-liquid separation method and quantified by gas chromatography coupled with a flame ionization detector. RESULTS: Cholesterol, cholestanol and lathosterol levels together with the cholestanol/cholesterol and lathosterol/cholesterol ratios are statistically different among the three groups. Cholesterol levels progressively increased from newborns to children and to adults, whereas cholestanol/cholesterol and cholestanol/lathosterol ratios progressively decreased from newborns to children and to adults. Lathosterol levels were higher in adults than in both newborns and children. In the total population a positive correlation was observed between cholesterol levels and both cholestanol (correlation coefficient = 0.290, p = 0.001) and lathosterol levels (correlation coefficient = 0.353, p <  0.0001). CONCLUSIONS: Although this study can only be considered an explorative experience due to the low number of analyzed samples, we revealed several differences of plasma cholestanol and lathosterol levels and their ratios to cholesterol levels among newborns, children and adults. These evidences indicate the need of age-related reference values of cholestanol and lathosterol concentrations, including also newborns and children.

Adiponectin Expression Is Modulated by Long-Term Physical Activity in Adult Patients Affected by Cystic Fibrosis.

Cystic fibrosis (CF) is a genetic disease characterized by progressive decline of lung function and chronic airway inflammation. Adipose tissue, through adiponectin and leptin, exerts several effects on energy metabolism and inflammatory processes. This study evaluated the levels of adiponectin and leptin in adult healthy subjects, in patients with CF and their correlation with long-term physical activity. CF patients were divided into two groups (sedentary versus active) based on their regular physical activity over 3 years. Anthropometric and serum biochemical profiles of CF patients and controls were evaluated and compared. Total serum adiponectin and leptin levels were measured by ELISA; adiponectin oligomeric profiles were analysed by western blot. Adiponectin levels were significantly higher while leptin levels were lower in patients with CF than in healthy controls. Furthermore, adiponectin was significantly lower in active compared to sedentary CF (p = 0.047), while leptin was slightly increased in active compared to sedentary CF. In addition, C-reactive protein levels were significantly lower in active than in sedentary CF patients (p = 0.048). Interestingly, only in the active group adiponectin levels were inversely correlated with forced expiratory volume (FEV) 1% decrease/year and FEV1% decrease. Moreover, adiponectin levels negatively correlated with lipid profiles. Our findings indicated that regular, long-term physical activity in CF improves respiratory function, metabolism, and inflammation status. These improvements in patients' conditions are associated with immunometabolic processes involving adiponectin, leptin, and C-reactive protein. Therefore, we propose that both adipokines may be a useful biomarker in the evaluation of metabolic and inflammatory status in patients with CF.

A rare case of sterol-C4-methyl oxidase deficiency in a young Italian male: Biochemical and molecular characterization.

Inborn defects of cholesterol biosynthesis are metabolic disorders presenting with multi-organ and tissue anomalies. An autosomal recessive defect involving the demethylating enzyme C4-methyl sterol (SC4MOL) has been reported in only 4 patients so far. In infancy, all patients were affected by microcephaly, bilateral congenital cataracts, growth delay, psoriasiform dermatitis, immune dysfunction, and intellectual disability. Herein, we describe a new case of SC4MOL deficiency in which a 19-year-old Italian male was affected by bilateral congenital cataracts, growth delay and learning disabilities, behavioral disorders and small stature, but not microcephaly. Our patient had abundant scalp dandruff, without other skin manifestations. Analysis of the blood sterol profile showed accumulation of C4-monomethyl and C4-dimethyl sterols suggesting a deficiency of the SC4MOL enzyme. Sequencing of the MSMO1 gene (also known as the "SC4MOL" gene) confirmed mutations in each allele (c.731A>G, p.Y244C, which is already known, and c.605G>A, p.G202E, which is a novel variant). His father carried c.731A>G mutation, whereas his mother carried c.605G>A. Thus, the combination of multiple skills and methodologies, in particular, blood sterol profiling and genetic analysis, led to the diagnosis of a new case of a very rare defect of cholesterol biosynthesis. Consequently, we suggest that these two analyses should be performed as soon as possible in all undiagnosed patients affected by bilateral cataracts and developmental delay.

Reduced absorption and enhanced synthesis of cholesterol in patients with cystic fibrosis: a preliminary study of plasma sterols.

BACKGROUND: Low cholesterol is typically observed in the plasma of patients with cystic fibrosis (CF) contrasting with the subcellular accumulation of cholesterol demonstrated in CF cells and in mice models. However, the homeostasis of cholesterol has not been well investigated in patients with CF. METHODS: We studied the plasma of 26 patients with CF and 33 unaffected controls campesterol and ß-sitosterol as markers of intestinal absorption and lathosterol as a marker of de novo cholesterol biosynthesis by gas chromatography (GC-FID and GC-MS). RESULTS: Plasma campesterol and ß-sitosterol results were significantly (p=0.01) lower while plasma lathosterol was significantly higher (p=0.001) in patients with CF as compared to control subjects. Plasma cholesterol results were significantly lower (p=0.01) in CF patients. CONCLUSIONS: Our data suggest that the impaired intestinal absorption of exogenous sterols in patients with CF stimulates the endogenous synthesis of cholesterol, but the levels of total cholesterol in plasma remain lower. This may be due to the CFTR dysfunction that reduces cholesterol blood excretion causing the accumulation of cholesterol in liver cells and in other tissues contributing to trigger CF chronic inflammation.

Cerebrotendinous xanthomatosis, a metabolic disease with different neurological signs: two case reports.

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive inborn error of bile acids synthesis and lipid accumulation caused by a deficiency of the mitochondrial cytochrome P450 sterol 27-hydroxylase enzyme encoded by CYP27A1. Pathogenic variants in CYP27A1 cause elevated cholestanol levels in the body, which leads to a variable clinical presentation that often includes cataracts, intellectual disability, neurological features, tendon xanthomas, and chronic diarrhea. Herein we describe the cases of two unrelated adult CTX patients. Case 1 is a patient with neurological dysfunction, including moderate intellectual disability, cataract of right eye, and xanthomas; Case 2 is a patient with tendon xanthomas without neurological symptoms. Plasma sterols profile obtained from both cases showed higher levels of cholestanol and cholesterol biosynthetic precursors compared to unaffected subjects. Case 1 and Case 2 were homozygous for the c.1263 + 5G > T (p.Leu396Profs29X) and c.1435C > G (p.Arg479Gly) pathogenic variants, respectively, in the CYP27A1 gene. Interestingly, for the first time, Case 2 variant has been identified in a homozygous state. Our results highlight that the sterol profile and genetic analyses are essential to make the diagnosis of CTX and to exclude other dyslipidemias.

Development and Validation of an Enzymatic Method for Total Cholesterol Analysis Using Whole Blood Spot.

BACKGROUND: High serum cholesterol represents a risk factor for cardiovascular disease. This study aims to quantify total cholesterol in dried blood spot (DBS) by direct enzymatic method. METHODS: Three hundred seventeen blood samples with serum cholesterol level ranging from 81 to 337 mg/dl were collected. DBS were manually prepared, cholesterol was extracted using methanol and analyzed by a manual enzymatic method. DBS cholesterol method was validated for imprecision and extraction efficacy. DBS cholesterol values were correlated (training test) with serum values measured by automated enzymatic method (reference method). The obtained correlation was used for predicting serum cholesterol from DBS analysis of a new sample group (validation test, n = 58). RESULTS: Within-day and between-day coefficient of variation (CV%) were lower than 7.69 and 6.32, respectively. Residual cholesterol in DBS after extraction was 16%. DBS cholesterol and serum cholesterol showed a linear correlation (slope = 0.5217; r = 0.9139) and a bias of -28%. Furthermore, DBS cholesterol values of validation test (n = 58), converted using the training test correlation, were not statistically different compared to the corresponding plasma values (P = 0.9487), and the comparison by Passing and Bablok showed a linear regression with a slope of 1.068 (r = 0.611) and a bias of -0.22%. CONCLUSIONS: The results show that this enzymatic method is suitable to analyze cholesterol in DBS and it could be automated and used for population screening of total blood cholesterol.

NMR metabolomic analysis of exhaled breath condensate of asthmatic patients at two different temperatures.

Exhaled breath condensate (EBC) collection is a noninvasive method to investigate lung diseases. EBC is usually collected with commercial/custom-made condensers, but the optimal condensing temperature is often unknown. As such, the physical and chemical properties of exhaled metabolites should be considered when setting the temperature, therefore requiring validation and standardization of the collecting procedure. EBC is frequently used in nuclear magnetic resonance (NMR)-based metabolomics, which unambiguously recognizes different pulmonary pathological states. Here we applied NMR-based metabolomics to asthmatic and healthy EBC samples collected with two commercial condensers operating at -27.3 and -4.8 °C. Thirty-five mild asthmatic patients and 35 healthy subjects were included in the study, while blind validation was obtained from 20 asthmatic and 20 healthy different subjects not included in the primary analysis. We initially analyzed the samples separately and assessed the within-day, between-day, and technical repeatabilities. Next, samples were interchanged, and, finally, all samples were analyzed together, disregarding the condensing temperature. Partial least-squares discriminant analysis of NMR spectra correctly classified samples, without any influence from the temperature. Input variables were either integral bucket areas (spectral bucketing) or metabolite concentrations (targeted profiling). We always obtained strong regression models (95%), with high average-quality parameters for spectral profiling (R(2) = 0.84 and Q(2) = 0.78) and targeted profiling (R(2) = 0.91 and Q(2) = 0.87). In particular, although targeted profiling clustering is better than spectral profiling, all models reproduced the relative metabolite variations responsible for class differentiation. This warrants that cross comparisons are reliable and that NMR-based metabolomics could attenuate some specific problems linked to standardization of EBC collection.

The Onset of Antinuclear Antibodies (ANAs) as a Potential Risk Factor for Mortality and Morbidity in COVID-19 Patients: A Single-Center Retrospective Study.

The immune system's amplified response to SARS-CoV-2 may lead to the production of autoantibodies, but their specific impact on disease severity and outcome remains unclear. This study aims to assess if hospitalized COVID-19 patients face a worse prognosis based on ANA presence, even without autoimmune diseases. We performed a retrospective, single-center, observational cohort study, enrolling 638 COVID-19 patients hospitalized from April 2020 to March 2021 at Hospital "Policlinico Riuniti" of Foggia (Italy). COVID-19 patients with a positive ANA test exhibited a significantly lower 30-day survival rate (64.4% vs. 83.0%) and a higher likelihood of severe respiratory complications during hospitalization than those with negative ANA screening (35.4% vs. 17.0%) (p < 0.001). The association between poor prognosis and ANA status was identified by calculating the HALP score (Hemoglobin-Albumin-Lymphocyte-Platelet), which was lower in COVID-19 patients with a positive ANA test compared to ANA-negative patients (108.1 ± 7.4 vs. 218.6 ± 11.2 AU; p < 0.011). In detail, COVID-19 patients with a low HALP showed a lower 30-day survival rate (99.1% vs. 83.6% vs. 55.2% for high, medium, and low HALP, respectively; p < 0.001) and a higher incidence of adverse respiratory events compared to those with high and medium HALP (13.1% vs. 35.2% vs. 64.6% for high, medium, and low HALP, respectively; p < 0.001). In summary, ANA positivity in COVID-19 patients appears to be linked to a more aggressive disease phenotype with a reduced survival rate. Furthermore, we propose that the HALP score could serve as a valuable parameter to assess prognosis for COVID-19 patients.

Analysis of annual distributions of hemoglobin A2 values as a method to test for HbA2 standardization.

BACKGROUND AND AIMS: The monitoring of yearly distributions of HbA2 measured has been indicated as a reliable indicator of worldwide standardization. MATERIALS AND METHODS: Measurements/year of HbA2 have been collected over three consecutive years in 15 Italian laboratories each using the same analytical method over three years period. HbA2 distributions, cleaned of replicated measurements, were compared by the overlapping area of the raw probability density functions expressed by coefficient eta (η), and by comparing the reference intervals for the central part of each distribution estimated by the indirect method refineR using the R package "refineR". RESULTS: According to the overlapping areas analysis the distributions/year of the data provided by 4 centers able to perform at least 1000 measurements/year were similar in 2 consecutive years. Moreover, the reference intervals provided by 2 centers using the same analytical methods in two separate locations over the three consecutive years, were very similar. The highest overlap (99.7 %) was observed in one center over two consecutive years. The overlapping areas were very high (93.6-95.7%) in 8 out of 9 inter-comparisons. CONCLUSION: Despite the limitations of this study the yearly distribution of the HbA2 measured in various centers appears a reliable tool to test HbA2 standardization over different centers using different analytical methods.

Profiling of acylcarnitines and sterols from dried blood or plasma spot by atmospheric pressure thermal desorption chemical ionization (APTDCI) tandem mass spectrometry.

Free carnitine and acylcarnitines play an important role in the metabolism of fatty acids. Sterols are structural lipids found in the membranes of many eukaryotic cells, and they also have functional roles such as the regulation of membrane permeability and fluidity, activity of membrane-bound enzymes and signals transduction. Abnormal profiles of these compounds in biological fluids may be useful markers of metabolic changes. In this review, we describe the subset of the lipidome represented by acylcarnitines and sterols, and we summarize how these compounds have been analyzed in the past. Over the last 50years, lipid mass spectrometry (MS) has evolved to become one of the most useful techniques for metabolic analysis. Today, the introduction of new ambient ionization techniques coupled to MS (AMS), which are characterized by the direct desorbing/ionizing of molecules from solid samples, is generating new possibilities for in situ analysis. Recently, we developed an AMS approach called APTDCI to desorb/ionize using a heated gas flow and an electrical discharge to directly analyze sterols and indirectly investigate acylcarnitines in dried blood or plasma spot samples. Here, we also describe the APTDCI method and some of its clinical applications, and we underline the common complications and issues that remain to be resolved.

Polar and non-polar organic binder characterization in Pompeian wall paintings: comparison to a simulated painting mimicking an "a secco" technique.

The use of Fourier transform infrared spectromicroscopy and mass spectrometry (MS) allowed us to characterize the composition of polar and non-polar binders present in sporadic wall paint fragments taken from Pompeii's archaeological excavation. The analyses of the polar and non-polar binder components extracted from paint powder layer showed the presence of amino acids, sugars, and fatty acids but the absence of proteinaceous material. These results are consistent with a water tempera painting mixture composed of pigments, flours, gums, and oils and are in agreement with those obtained from a simulated wall paint sample made for mimicking an ancient "a secco" technique. Notably, for the first time, we report the capability to discriminate by tandem MS the presence of free amino acids in the paint layer.

Characterization of pigments and ligands in a wall painting fragment from Liternum archaeological park (Italy).

Spectroscopic and MS techniques were used to characterize the pigments and the composition of polar and nonpolar binders of a stray wall painting fragment from Liternum (Italy) archaeological excavation. X-ray fluorescence and diffraction analysis of the decorations indicated mainly the presence of calcite, quartz, hematite, cinnabar, and cuprorivaite. Infrared spectroscopy, GC coupled to flame-ionization detector, and MS analysis of the polar and nonpolar components extracted from paint layers from three different color regions revealed the presence of free amino acids, sugars, and fatty acids. Interestingly, LC-MS shotgun analysis of the red painting region showed the presence of αS1-casein of buffalo origin. Compared to our previous results from Pompeii's wall paintings, even though the Liternum painting mixture contained also binders of animal origin, the data strongly suggest that in both cases a tempera painting technique was utilized.