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Summary: We evaluated the effect of parathyroid hormone (PTH) on Wnt10b production by immune system cells in humans. We showed that bone anabolic effect of intermittent PTH treatment may be amplified by T cells through increased production of Wnt10b. Chronic increase in PTH as in primary hyperparathyroidism does not increase Wnt10b expression. Introduction: The aim of this study is to assess the effect of PTH on Wnt10b production by immune system cells in humans. We assessed both the effect of intermittent PTH administration (iPTH) and of chronic PTH hypersecretion in primary hyperparathyroidism (PHP). Methods: Eighty-two women affected by post-menopausal osteoporosis were randomly assigned to treatment with calcium and vitamin D alone (22) or plus 1-84 PTH (42), or intravenous ibandronate (18). Wnt10b production by unfractioned blood nucleated cells and by T, B cells and monocytes was assessed by real-time RT-PCR and ELISA at baseline, 3, 6, 12 and 18 months of treatment. The effect of chronic elevation of PTH was evaluated in 20 patients affected by PHP at diagnosis and after surgical removal of parathyroid adenoma. WNT10b from both osteoporotic and PHP patients was compared to healthy subjects matched for age and sex. Results: iPTH increases Wnt10b production by T cells, whereas PHP does not. After surgical restoration of normal parathyroid function, WNT10b decreases, although it is still comparable with healthy subjects' level. Thus, chronic elevation of PTH does not significantly increase WNT10b production as respect to control. Conclusions: This is the first work showing the effect of both intermittent and chronic PTH increase on Wnt10b production by immune system cells. We suggest that, in humans, T cells amplified the anabolic effect of PTH on bone, by increasing Wnt10b production, which stimulates osteoblast activity. [ABSTRACT FROM AUTHOR]

Hair analysis plays an important role in the determination of drugs of abuse in both forensic and clinical toxicology investigations. The analysis of different substances often requires the use of different sample preparation methods, thereby increasing the amount of hair sample and time required. In the present study, a fast method involving a combination of a single 25 mg hair extraction procedure and four liquid chromatography-tandem mass spectrometry methods using the same chromatographic phases and column was developed and validated. The target was the identification and quantification of various commonly abused drugs and their metabolites, including amphetamines, cocaine, opioids, cannabinoids, THC-COOH and EtG, and more than 140 new psychoactive substances, including synthetic cannabinoids, phenethylamines, synthetic opioids, methylphenidate, cathinone, piperidine, and tryptamines., (© 2024 John Wiley & Sons Ltd.)

The aim was the comparison between the Society of Hair Testing (SoHT) consensus for the use of alcohol markers which powdering hair for the extraction of ethylglucuronide (EtG) in water and extraction using the patented M3 Reagent Test kit on cut hair. Hair samples were cut into small segments and washed twice with methanol and diethyl ether. The SoHT-Consensus entails the extraction of pulverised hair in water. This is obtained by incubation of 25 mg of hair at room temperature overnight and 2 h sonication, even if the overnight incubation is not mandatory. The M3 method entails incubation of 25 mg of cut hair with the M3-Reagent at 100°C for 60 min. After centrifugation, the supernatant is injected into a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples (191) were collected in the APSS laboratory in Trento, Italy, between 2021 and 2022. The limit of quantification (LOQ) was set at 5 pg/mg for the pulverised and M3-Reagent methods. Assays showed good linearity above the range of LOQ-300 pg/mg. Precision (within 20%) values were also obtained using both methods. In the Passing-Bablock linear regression, the final regression curve between M3 (y) and the pulverising method (x) showed good agreement; the Bland-Altman analysis did not show any significant bias between the two methods. The M3-Reagent method, due to cut hair use, is easy to perform, saves time and allows for a smaller sample quantity loss with use of nondisposable grinding jars for the ball mill to obtain the extraction of EtG., (© 2023 John Wiley & Sons Ltd.)

Purpose: Critical illness is a life threatening condition inducing a severe acute physical stress. The aim of the study was to investigate the activation of pituitary axis early after ICU admission in patients with critical illnesses of different etiology and its association with outcome., Materials and Methods: Patients admitted for acute respiratory distress syndrome (ARDS), severe traumatic brain injury (TBI), subarachnoid hemorrhage (SAH) and neurocritically ill patients at the moment of brain death (BD) diagnosis were included in the present post-hoc analysis. On day 1, 2-3 and 4-5 after admission the following pituitary axes were assessed: hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, somatotroph, prolactin and copeptin. ICU mortality was used as outcome measure., Results: One hundred-thirteen critical ill patients were studied. Thyroid axis suppression and activation of copeptin axis were the most frequent pituitary hormone alterations, present in almost 60% of patients. Activation of the hypothalamic pituitary adrenal axis was a predictor of ICU mortality independently from the underlying critical illness [OR 3.952 (C.I.95% 1.129-13.838)]., Conclusions: Pituitary axis function is frequently altered early after ICU admission, the magnitude of hormonal response being different according to the underlying critical illness. The activation of the hypothalamic pituitary adrenal axis was a strong predictor of ICU mortality., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Developed countries have a high prevalence of vitamin D deficiency. In previous studies, 25(OH)D was predominantly measured by immunoassays. The present study assessed serum 25(OH)D in a very large Southern European outpatient cohort by liquid chromatography tandem mass spectrometry (LC-MS/MS)., Materials and Methods: 74,235 serum 25(OH)D results generated under routine conditions between 2015 and 2016 were extracted from the laboratory information system of the Department of Clinical Pathology at Bolzano Hospital (Italy). In 3801 cases, parathyroid hormone (PTH) was requested in parallel. Serum 25(OH)D was measured by a NIST-972 aligned commercial LC-MS/MS method. The distribution of serum 25(OH)D concentrations in males and females of different age groups, the prevalence of 25(OH)D 2 and seasonal variability were studied., Results: The average 25(OH)D concentration in the entire cohort was 68.6 nmol/L (7.5-1880 nmol/L). Females had a 7 nmol/L higher average 25(OH)D concentration than males, which increased significantly with age. 37.9 and 28.3% of males and females, respectively, had a deficient 25(OH)D concentration of < 50 nmol/L. 620 samples (0.84%) had measureable amounts of 25(OH)D 2 . In samples with a normal PTH, 25(OH)D was 11 nmol/L higher than in the entire cohort. Seasonal variation ranged between 20 and 30% and was most pronounced in young individuals. 25(OH)D 2 remained constant throughout the year., Conclusion: Average serum 25(OH)D in South Tyrol is higher than in other parts of Europe. 25(OH)D and PTH show a continuous inverse relationship. Seasonal variation of serum 25(OH)D is an important aspect in young and middle-aged adults, but becomes less relevant in elderly subjects. 25(OH)D 2 is of minor practical importance in South Tyrol.

Background and Aims: NTproBNP and BNP levels are reduced in obese subjects, but population-based data comparing the pattern of this relationship in the full spectrum of insulin-resistance mediated conditions, overweight/obesity, metabolic syndrome and diabetes, are limited., Methods: The study-base were 3244 individuals aged 45-74 years, none of whom had heart failure, 1880 without diabetes and 1364 with diabetes, identified as part of two surveys of the population-based Casale Monferrato Study. All measurements were centralized. We examined with multiple linear regression and cubic regression splines the relationship between NTproBNP and BMI, independently of known risk factors and confounders. A logistic regression analysis was also performed to assess the effect of overweight/obesity (BMI ≥ 25 kg/m 2 ), diabetes and metabolic syndrome on NTproBNP values., Results: Out of the overall cohort of 3244 people, overweight/obesity was observed in 1118 (59.4%) non-diabetic and 917 (67.2%) diabetic subjects, respectively. In logistic regression, compared to normal weight individuals, those with a BMI ≥ 25 kg/m 2 had a OR of 0.70 (95% CI 0.56-0.87) of having high NTproBNP values, independently of diabetes. As interaction between diabetes and NTproBNP was evident (p < 0.001), stratified analyses were performed. Diabetes either alone or combined with overweight/obesity or metabolic syndrome enhanced fourfold and over the OR of having high NTproBNP levels, while the presence of metabolic syndrome alone had a more modest effect (OR 1.54, 1.18-2.01) even after having excluded individuals with CVD. In the non-diabetic cohort, obesity/overweight and HOMA-IR ≥ 2.0 decreased to a similar extent the ORs of high NTproBNP [0.76 (0.60-0.95) and 0.74 (0.59-0.93)], but the association between overweight/obesity and NTproBNP was no longer significant after the inclusion into the model of HOMA-IR, whereas CRP > 3 mg/dl conferred a fully adjusted OR of 0.65 (0.49-0.86)., Conclusions: NT-proBNP levels are lower in overweight/obesity, even in those with diabetes. Both insulin-resistance and chronic low-grade inflammation are involved in this relationship. Further intervention studies are required to clarify the potential role of drugs affecting the natriuretic peptides system on body weight and risk of diabetes.

Objectives: To study the concentrations of thrombopoietin (TPO), a growth factor recently involved in the pathogenesis of experimental acute pancreatitis (AP), and its potential role as an early diagnostic and prognostic biomarker in patients with AP., Methods: Thrombopoietin was measured in 44 AP patients, 18 patients with nonpancreatic acute abdominal pain, and 18 healthy volunteers. Acute pancreatitis severity was classified on the basis of the 2012 International Atlanta Symposium on Acute Pancreatitis criteria., Results: Thrombopoietin levels did not differ between AP patients and control subjects, whereas these were higher in patients with moderately severe or severe AP compared with those with mild AP. Receiver operating characteristic curve analysis of TPO for severe AP diagnosis showed an area under the curve of 0.80. A cutoff value of 31.48 pg/mL showed the highest sensitivity, allowing to rule out severe AP when TPO was lower, whereas TPO higher than 98.23 pg/mL was associated with severe AP with high specificity (93.5%). Furthermore, TPO levels were greater in AP patients developing organ dysfunction or sepsis and in nonsurvivors compared with survivors., Conclusions: Our data provide the first evidence for TPO as potential early prognostic biomarker in AP patients. High TPO levels at hospital admission may predict organ dysfunction, sepsis, and fatal outcome in AP patients.

Objective: Up to 50% of hypertensive patients should be screened for primary aldosteronism, using the aldosterone to renin (or plasma renin activity) ratio [aldosterone to active renin ratio (AARR) and aldosterone to plasma renin activity ratio (ARR), respectively]. Aim of the study was to prospectively compare the diagnostic accuracy of AARR (measured by chemiluminescent immunoassay) and ARR (measured by radioimmunoassay) as screening tests for primary aldosteronism and aldosterone assays (measured by chemiluminescence and radioimmunoassay) during confirmatory testing., Methods: One hundred patients were screened for primary aldosteronism and 34 underwent confirmatory testing. The cut-offs for ARR and AARR were 30 ng/dl/ng/ml/h and 3.7 ng/dl/mU/l, respectively. Patients with positive confirmatory test underwent subtype diagnosis., Results: Seventy-five patients were essential hypertensive patients, 15 had idiopathic hyperaldosteronism, five aldosterone-producing adenoma (APA) and five with undefined diagnosis. The AARR displayed a sensitivity of 90% and a specificity of 99%, the ARR had a sensitivity of 100% and a specificity of 73%. Of the two of 20 primary aldosteronism patients missed by AARR, none resulted affected by APA. All primary aldosteronism patients were correctly diagnosed by chemiluminescence at confirmatory testing. In the total sample of 168 measurements both the correlation for plasma renin activity with renin and for aldosterone in chemiluminescence and radioimmunoassay were highly significant (ρ = 0.70, P < 0.001 and ρ = 0.78, P < 0.001, respectively). On receiver operator characteristics curves, the area under the curve for AARR was 0.989 [95% confidence interval (CI) 0.97-1] and 0.934 for ARR (95% CI 0.89-0.98), which were not significantly different., Conclusion: The automated aldosterone and renin chemiluminescent assay is a reliable alternative to the radioimmunometric method, especially for APA detection.

Objective: To assess if tenofovir (TFV) clearance is associated with urinary retinal-binding protein (RBP) in HIV-positive patients with normal estimated filtration rate., Design: A cross-sectional diagnostic study., Methods: HIV-positive patients with estimated creatinine clearance above 60 ml/min, on tenofovir disoproxil fumarate (TDF)-containing combination since at least 6 months, taking TDF at night, and without significant comorbidities (diabetes, untreated hypertension, known renal malformations, recurrent nephrolithiasis) and nephrotoxic drugs were included. TFV plasma and urinary concentrations were measured 12 h after drug intake (C12). RBP was measured through enzyme immunoassay kit on spot urines and corrected per urinary creatinine (uRBP/uCr); normality ranges were below 130 μg/g (in patients aged <50 years) and below 172 μg/g (in patients aged ≥50 years)., Results: Two hundred and eighty-nine patients were included (median age of 45.8 years, 71.6% male and 85.4% whites); patients were concomitantly treated with nonnucleoside reverse transcriptase inhibitors (155, 53.6%), protease inhibitors (118, 40.8%), or integrase inhibitors (16, 5.5%)-containing regimens. Estimated creatinine clearance was 89.4 ml/min (78.6-105.9). Urinary RBP (uRBP) and uRBP/uCr were 204.6 ng/ml (92-380) and 169.7 μg/g (85.8-318.3), respectively; abnormally high uRBP/uCr was observed in 157 patients (54.3%). A multivariate binary logistic regression confirmed that both ethnicity (P = 0.004, β 2.93, 95% confidence interval 1.41-6.10) and TFV urinary C12 less than 21 mg/ml (P = 0.006, β 2.04, 95% confidence interval 1.12-3.41) were significantly associated with abnormal uRBP/uCr., Conclusion: HIV-positive TDF-treated patients showed a high prevalence of proximal tubular impairment: ethnicity (whites) and low urinary TFV concentrations were significantly associated with elevated uRBP. SDC VIDEO:: http://links.lww.com/QAD/A852.

In patients with Addison's disease (AD), a dual-release preparation of hydrocortisone (Plenadren, PLEN) has been demonstrated to maintain cortisol levels in a more physiological range than conventional glucocorticoid therapy, and to exert positive effects. This study aimed to assess variations of anthropometric, metabolic, and hormonal parameters in patients with AD after switching from conventional hydrocortisone (HC) treatment to PLEN. In nineteen AD patients (15 F and 4 M, age 27-65 years) treated with HC 20 mg/day thrice daily, body weight, BMI, waist circumference, fasting glucose, HbA1c, serum lipids, plasma renin activity, electrolytes, and blood pressure were evaluated at baseline, and 1, 3, 6, and 12 months after switching from HC to PLEN. At baseline, and after 1 and 12 months of PLEN, blood ACTH and cortisol (at 0800 h at fasting, and 30, 60, 90, 120, and 240 min after drug ingestion), and health-related quality of life (HRQoL), using 30-AddiQoL questionnaire, were evaluated. During PLEN, waist and serum lipid progressively decreased. After 12 months of PLEN, a significant difference was observed in waist circumference (P = 0.007), HbA1c (P = 0.002), total and LDL-cholesterol levels (P < 0.05). ACTH levels at 240 min and the area under the curve (AUC) were lower (P < 0.05) during PLEN than HC, while cortisol peaks and AUC were similar. 30-AddiQoL total score also improved (P = 0.04) during PLEN. In AD patients, PLEN reduces central adiposity, and improves glucose and metabolism parameters and HRQoL.

The diagnostic and prognostic usefulness of copeptin were evaluated in septic patients, as compared to procalcitonin assessment. In this single centre and observational study 105 patients were enrolled: 24 with sepsis, 25 with severe sepsis, 15 with septic shock, and 41 controls, divided in two subgroups (15 patients with gastrointestinal bleeding and 26 with suspected SIRS secondary to trauma, acute coronary syndrome, and pulmonary embolism). Biomarkers were determined at the first medical evaluation and thereafter 24, 48, and 72 hours after admission. Definitive diagnosis and in-hospital survival rates at 30 days were obtained through analysis of medical records. At entry, copeptin proved to be able to distinguish cases from controls and also sepsis group from septic shock group, while procalcitonin could distinguish also severe sepsis from septic shock group. Areas under the ROC curve for copeptin and procalcitonin were 0.845 and 0.861, respectively. Noteworthy, patients with copeptin concentrations higher than the threshold value (23.2 pmol/L), calculated from the ROC curve, at admission presented higher 30-day mortality. No significant differences were found in copeptin temporal profile among different subgroups. Copeptin showed promising diagnostic and prognostic role in the management of sepsis, together with its possible role in monitoring the response to treatment.

Sepsis, severe sepsis and septic shock are among the most common conditions handled in the emergency department (ED). According to new Sepsis Guidelines, early diagnosis and treatment are the keys to improve survival. Plasma C-reactive protein (CRP) and procalcitonin (PCT) levels, when associated with documented or suspected infection, are now part of the definitions of sepsis. Blood culture is the gold standard method for detecting microorganisms but it requires too much time for results to be known. Sensitive biomarkers are required for early diagnosis and as indexes of prognosis sepsis. CRP is one of the acute phase proteins synthesized by the liver: it has a great sensitivity but a very poor specificity for bacterial infections. Moreover, the evolution of sepsis does not correlate with CRP plasma changes. In recent years PCT has been widely used for sepsis differential diagnosis, because of its close correlation with infections, but it still retains some limitations and false positivity (such as in multiple trauma and burns). Soluble CD14 subtype (sCD14-ST), also known as presepsin, is a novel and promising biomarker that has been shown to increase significantly in patients with sepsis, in comparison to the healthy population. Studies pointed out the capability of this biomarker for diagnosing sepsis, assessing the severity of the disease and providing a prognostic evaluation of patient outcome. In this mini review we mainly focused on presepsin: we evaluate its diagnostic and prognostic roles in patients presenting to the ED with systemic inflammatory response syndrome (SIRS), suspected sepsis or septic shock.

Introduction: Sepsis, severe sepsis and septic shock are common conditions with high mortality. Their early diagnosis in the Emergency Department (ED) is one of the keys to improving survival. Procalcitonin (PCT) has been used as a biomarker in septic patients but has limited specificity and can be elevated in other scenarios of systemic inflammatory response syndrome (SIRS). Soluble CD14 (sCD14) or presepsin is the free fragment of a glycoprotein expressed on monocytes and macrophages. Preliminary reports suggest that levels of presepsin are significantly higher in septic patients than in healthy individuals. The aim of this study is to investigate the diagnostic and prognostic value of presepsin compared to PCT in people presenting at the ED with SIRS and suspected sepsis or septic shock., Methods: This study was conducted in two major hospitals in Turin, Italy. One hundred six patients presenting to the EDs with suspected sepsis or septic shock were included, and another eighty-three patients affected by SIRS, but with no clinical evidence of infection, were recruited as controls. Blood samples were collected at first medical evaluation and for some patients after 24 and 72 h. The samples were analyzed using the PATHFAST Presepsin assay for sCD14, and commercial kits were used for other determinations (for example, PCT). Definitive diagnosis and survival rates were obtained afterward by analysis of digital medical records., Results: Elevated concentrations of presepsin at presentation were observed in septic patients compared to control patients. The same trend was observed for mean values of PCT. Higher values of presepsin were observed in septic patients at presentation (time 0). The diagnostic accuracy of PCT was generally higher, and areas under the curve (AUCs) were 0.875 for PCT and 0.701 for presepsin. Mean presepsin values were significantly higher in nonsurvivor septic patients (60-day mortality) than in survivors. No significant correlation was noted between PCT and survival., Conclusions: In our experience, presepsin was useful in the early diagnosis of infection in a complex population of patients with SIRS, sepsis, severe sepsis and septic shock who presented to the ED. Presepsin showed a significant prognostic value, and initial values were significantly correlated with in-hospital mortality of patients affected by sepsis, severe sepsis or septic shock.

Introduction: Matrix metalloproteinases (MMPs) are involved in aortic pathophysiology. Preliminary studies have detected increased plasma levels of MMP8 and MMP9 in patients with acute aortic dissection (AAD). However, the performance of plasma MMP8 and MMP9 for the diagnosis of AAD in the emergency department is at present unknown., Methods: The levels of MMP8 and MMP9 were measured by ELISA on plasma samples obtained from 126 consecutive patients evaluated in the emergency department for suspected AAD. All patients were subjected to urgent computed tomography (CT) scan for final diagnosis., Results: In the study cohort (N = 126), AAD was diagnosed in 52 patients and ruled out in 74 patients. Median plasma MMP8 levels were 36.4 (interquartile range 24.8 to 69.3) ng/ml in patients with AAD and 13.2 (8.1 to 31.8) ng/ml in patients receiving an alternative final diagnosis (P <0.0001). Median plasma MMP9 levels were 169.2 (93.0 to 261.8) ng/ml in patients with AAD and 80.5 (41.8 to 140.6) ng/ml in patients receiving an alternative final diagnosis (P = 0.001). The area under the curve (AUC) on receiver-operating characteristic (ROC) analysis of MMP8 and MMP9 for the diagnosis of AAD was respectively 0.75 and 0.70, as compared to 0.87 of D-dimer. At the cutoff of 3.6 ng/ml, plasma MMP8 had a sensitivity of 100.0% (95% CI, 93.2% to 100.0%) and a specificity of 9.5% (95% CI, 3.9% to 18.5%) and ruled out AAD in 5.6% of patients. Combination of plasma MMP8 with D-dimer increased the AUC on ROC analysis to 0.89. Presence of MMP8 <11.0 ng/ml and D-dimer <1.0 or <2.0 µg/ml provided a negative predictive value of 100% and ruled out AAD in 13.6% and 21.4% of patients respectively., Conclusions: Low levels of plasma MMP8 can rule out AAD in a minority of patients. Combination of plasma MMP8 and D-dimer at individually suboptimal cutoffs could safely rule out AAD in a substantial proportion of patients evaluated in the emergency department.

The sonochemical degradation rate of Methylene Blue (MB) is markedly increased in the presence of Fe(Ill), a rather inexpensive reagent for the application of sonochemistry to wastewater treatment. The effect of Fe(lll) is due to a sonochemically induced Fenton reaction, where both reactants (Fe(ll) and H2O2) are sonochemically synthesized. Hydroperoxide/superoxide, generated upon sonochemical processes in aerated solution, is a key species involved in both Fe(lll) reduction to Fe(ll) and in the production of H2O2. The Fenton reaction between Fe(ll) and H2O2 then produces hydroxyl radicals, enhancing the degradation of MB. A further enhancement of the degradation of the substrate in the presence of Fe(lll) takes place upon addition of H2O2, which is likely to favor the Fenton process. Interestingly, H2O2 alone, in the absence of Fe(lll), has a very limited effect on the sonochemical degradation rate.

This paper studies the nitration and hydroxylation of benzene in the presence of nitrite/nitrous acid in aqueous solution, both in the dark upon addition of hydrogen peroxide and under 360 nm irradiation. In both cases the detected transformation intermediates were phenol (P), nitrobenzene (NB), 2-nitrophenol (2NP) and 4-nitrophenol (4NP). P and NB directly form from benzene, and the initial formation rate of P is at least an order of magnitude higher than that of NB. In our experiments nitrophenols arise from P nitration, as can be inferred by their time evolution and isomer ratio (2NP:4NP = 60:40, 3NP below detection limit). Nitrophenols may also form upon hydroxylation of NB, but in a different ratio (2NP:3NP:4NP = 45:30:25). The detection of 3NP is thus a marker for the hydroxylation of NB, since this isomer is not formed in P nitration processes. The formation rates of P and NB increase with decreasing pH, both in the presence of HNO(2) + H(2)O(2) in the dark (which produce HOONO) and in the presence of NO(2)(-)/HNO(2) under irradiation. In the former case the pH dependence reflects the formation rate of HOONO. In the case of the irradiation experiments the pH effect can be accounted for by the higher molar absorbivity and photolysis quantum yield of nitrous acid when compared with nitrite. Interestingly, benzene does not react with HNO(2) alone in the dark. An important feature of benzene nitration in the presence of NO(2)(-)/HNO(2) under irradiation is that the process is not inhibited by the addition of hydroxyl scavengers, differently from the case of phenol nitration. This finding indicates that nitrite irradiation might lead to the nitration of certain aromatic compounds in natural waters even in the presence of natural hydroxyl scavenging agents, which are usually thought to limit the environmental role of many photochemical processes.

The oxidation of nitrite and nitrous acid to *NO2 upon irradiation of dissolved Fe(III), ferric (hydr)oxides, and nitrate has previously been shown to enhance phenol nitration. This allowed the proposal of a new role for nitrite and nitrous acid in natural waters and atmospheric aerosols. This paper deals with the interaction between hydrogen peroxide, a key environmental factor in atmospheric oxidative chemistry, and nitrite/nitrous acid. The reaction between nitrous acid and hydrogen peroxide yields peroxynitrous acid, a powerful nitrating agent and an important intermediate in atmospheric chemistry. The kinetics of this reaction is compatible with a rate-determining step involving either H3O2+ and HNO2 or H2O2 and protonated nitrous acid. In the former case the rate constant between the two species would be 179.6 +/- 1.4 M(-1) s(-1), in the latter case it would be as high as (1.68 +/- 0.01) x 10(10) M(-1) s(-1) (diffusion-controlled reaction). Due to the more reasonable value of the rate constant, the reaction between H3O2+ and HNO2 seems more likely. In the presence of HNO2 + H2O2 the nitration of phenol is strongly enhanced when compared with HNO2 alone. The nitration rate of phenol in the presence of peroxynitrous acid decreases as pH increases, thus HOONO is a potential source of atmospheric nitroaromatic compounds in acidic water droplets. The mixture Fe(II) + H2O2 (Fenton reagent) can oxidize nitrite and nitrous acid to nitrogen dioxide, which results in phenol nitration. The nitration in the presence of Fe(II) + H2O2 + NO2-/HNO2 occurs more rapidly than the one with H2O2 + NO2-/HNO2 at pH 5, where little HNO2 is available to directly react with hydrogen peroxide. Both systems, however, are more effective than NO2-/HNO2 alone in producing nitrophenols from phenol. Another process leading to the oxidation of nitrite to nitrogen dioxide is the photo-Fenton one. It can be relevant at pH > or = 6, as nitrite does not react with H2O2 at room temperature. Under such conditions the source of Fe(II) is the photolysis of ferric (hydr)oxides (heterogeneous photo-Fenton reaction). In the presence of nitrite this reaction induces very effective nitrophenol formation from phenol.

Major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL) recognize peptide epitopes of protein antigens in a hierarchical fashion. We investigated whether proteolytic cleavage, in particular by proteasomes, is important in determining epitope hierarchy. Using highly purified 20S proteasomes, we find preferred cleavage sites directly adjacent to the N- and C-terminal ends of the immunodominant epitope of chicken ovalbumin, Ova257-264, while most of the subdominant epitope, Ova55-62, is destroyed by a major cleavage site located within this epitope. Moreover, we show that variations in amino acid sequences flanking these epitopes influence proteasomal cleavage patterns in parallel with the efficacy of their presentation. The results suggest that proteasomal cleavage within and adjacent to class I-restricted epitopes contributes to their level of presentation.

The immune response of peripheral blood lymphocytes (PBL) of non-exposed human individuals to the Nef protein of HIV-1 was studied. Nef is a regulatory protein of HIV which is immediately expressed after infection and which seems to be important in the pathogenicity of HIV. Nef may therefore serve as a potential target for effective immunity against HIV infection. Epstein-Barr (EBV)-transformed lymphoblastoid B cell lines (LCL) were established from four healthy young seronegative adults and transfected with the Nef gene. These cells served as stimulator cells for autologous PBL in vitro and as target cells for CTL. CTL responses were readily generated against Nef-transfected LCL, consisting of Nef-specific and putative EBV-specific CTL. Nef-specific CTL were generated exclusively from CD8+ cells and were MHC class I restricted. Since a vigorous Nef-specific CTL response in non-infected individuals was unexpected, CTL precursor frequencies were determined by limiting dilution analyses in non-fractionated PBL and in PBL separated into the CD45RO- (naive) and CD45RO+ (memory) T cell populations. As expected, the putative EBV-specific CTL precursors were predominantly found in the CD45RO+ subset at frequencies typical for memory T cells. Nef-specific CTL precursors, in contrast, were found predominantly in the CD45RO- population, at even higher frequencies of approximately 1/1000-1/3000. Nef may thus display either an unusually high number of immunogenic peptides or a limited number of peptides presented in a very efficient way, so that many T cells including low affinity cells, would be triggered.

1. After MHV3 infection, only macrophages from resistant A/J mice partially restricted virus growth compared to those from susceptible BALB/c mice (2 logs of difference in virus titer). 2. Cellular ribosomal ribonucleic acid (rRNA) synthesis by MHV3-infected macrophages was decreased only in A/J mouse macrophages as indicated by accumulation of the 28S rRNA fraction. 3. The accumulation of viral messenger ribonucleic acids (mRNAs) in MHV3-infected macrophages was also reduced in A/J mouse macrophages compared to BALB/c mice. 4. In pulse-chase experiments of viral protein synthesis, the appearance, glycosylation and cleavage of glycoprotein S, as well as the metabolism of nucleoprotein N were delayed in A/J mouse macrophages. 5. These data show that MHV3 infection of A/J mouse macrophages induced an imbalanced accumulation of the 28S fraction of rRNA. Furthermore the synthesis of mRNAs correlated with viral protein synthesis in both A/J and BALB/c macrophages, but was delayed in A/J mice. 6. These results suggest that the partial restriction of MHV3 replication in macrophages of resistant A/J mice may take place during or before the mRNA synthesis, although it is correlated with the appearance, glycosylation, cleavage and metabolism of viral proteins.

Macrophages have been described to be important in determining the resistance of A/J mice or the susceptibility of BALB/c mice to the experimental infection with Mouse Hepatitis Virus 3 (MHV3). The interferon gamma (IFN gamma) activation of A/J and BALB/c mouse macrophages was shown to partially restrict the MHV3 replication only in macrophages from the resistant A/J mice. The activation by IFN gamma and/or infection with MHV3 showed that BALB/c mouse macrophages were capable of releasing tumor necrosis factor alpha (TNF alpha), interleukin 1 (IL-1) and anion superoxide (O2-), and A/J mouse macrophages were capable of releasing TNF alpha and IL-1 but not O2-. Comparable amounts of TNF alpha or IL-1 were released by IFN gamma-activated A/J or BALB/c mouse macrophages. Following MHV3 infection or IFN gamma activation and MHV3 infection, BALB/c mouse macrophages were always capable of releasing higher amounts of TNF alpha, IL-1 or O2- than A/J mouse macrophages, which correlated with their susceptibility to the virus infection. The data indicate that the anti-MHV3 effect induced by IFN gamma in A/J mouse macrophages is not related to the studied extrinsic activities of these cells.

The activation of bone-marrow-derived macrophages by IFN-gamma (IFN gamma) partially inhibits mouse hepatitis virus 3 (MHV3) replication only in cells from resistant A/J mice, and not in cells originating from susceptible BALB/c mice. The computer image analysis of gels obtained from 2D-SDS-PAGE of extracted proteins of IFN gamma-activated A/J or BALB/c macrophages enabled us to identify and tag several gene products that were synthesized at elevated or diminished levels. Comparisons of the patterns of non-activated and IFN gamma-activated A/J macrophages revealed 3 gene products which increased, 1 which newly appeared, 6 which decreased and 20 which disappeared upon IFN gamma activation. The protein pattern of BALB/c macrophages revealed 13 gene products which increased, 8 which decreased and 8 which disappeared in IFN gamma-activated BALB/c macrophages. Whether these proteins are involved in the induction of an antiviral state against MHV3 growth remains to be investigated. Macrophages from mice with different genetic background (A/J and BALB/c), upon IFN gamma activation, behave differently at a molecular level, and this observation is consistent with their distinct expression of antiviral state against MHV3.