An LC-MS/MS method for the determination of drugs of abuse included THC-COOH, EtG, and NPS, using a single hair extraction sample

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.

Sterile inflammation via TRPM8 RNA-dependent TLR3-NF-kB/IRF3 activation promotes antitumor immunity in prostate cancer

Inflammation is a common condition of prostate tissue, whose impact on carcinogenesis is highly debated. Microbial colonization is a well-documented cause of a small percentage of prostatitis cases, but it remains unclear what underlies the majority of sterile inflammation reported. Here, androgen- independent fluctuations of PSA expression in prostate cells have lead us to identify a prominent function of the Transient Receptor Potential Cation Channel Subfamily M Member 8 (TRPM8) gene in sterile inflammation. Prostate cells secret TRPM8 RNA into extracellular vesicles (EVs), which primes TLR3/NF-kB-mediated inflammatory signaling after EV endocytosis by epithelial cancer cells. Furthermore, prostate cancer xenografts expressing a translation-defective form of TRPM8 RNA contain less collagen type I in the extracellular matrix, significantly more infiltrating NK cells, and larger necrotic areas as compared to control xenografts. These findings imply sustained, androgen-independent expression of TRPM8 constitutes as a promoter of anticancer innate immunity, which may constitute a clinically relevant condition affecting prostate cancer prognosis.

Comparison of two methods for the extraction of ethylglucuronide from hair

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.

Rhamnolipid 89 Biosurfactant Is Effective against Streptococcus oralis Biofilm and Preserves Osteoblast Behavior: Perspectives in Dental Implantology

Biofilm-related peri-implant diseases represent the major complication for osteointegrated dental implants, requiring complex treatments or implant removal. Microbial biosurfactants emerged as new antibiofilm coating agents for implantable devices thanks to their high biocompatibility. This study aimed to assess the efficacy of the rhamnolipid 89 biosurfactant (R89BS) in limiting Streptococcus oralis biofilm formation and dislodging sessile cells from medical grade titanium, but preserving adhesion and proliferation of human osteoblasts. The inhibitory activity of a R89BS coating on S. oralis biofilm formation was assayed by quantifying biofilm biomass and microbial cells on titanium discs incubated up to 72 h. R89BS dispersal activity was addressed by measuring residual biomass of pre-formed biofilms after rhamnolipid treatment up to 24 h. Adhesion and proliferation of human primary osteoblasts on R89BS-coated titanium were evaluated by cell count and adenosine-triphosphate quantification, while cell differentiation was studied by measuring alkaline phosphatase activity and observing mineral deposition. Results showed that R89BS coating inhibited S. oralis biofilm formation by 80% at 72 h and dislodged 63-86% of pre-formed biofilms in 24 h according to concentration. No change in the adhesion of human osteoblasts was observed, whereas proliferation was reduced accompanied by an increase in cell differentiation. R89BS effectively counteracts S. oralis biofilm formation on titanium and preserves overall osteoblasts behavior representing a promising preventive strategy against biofilm-related peri-implant diseases.

In-vivo evaluations of bone regenerative potential of two novel bioactive glasses

Due to the aging of population, materials able to repair damaged tissues are needed. Among others, bioactive glasses (BGs) have attracted a lot of interest due to their outstanding properties both for hard and soft tissues. Here, for the first time, two new BGs, which gave very promising results in preliminary in vitro-tests, were implanted in animals in order to evaluate their regenerative potential. The new BGs, named BGMS10 and Bio_MS and containing specific therapeutic ions, were produced in granules and implanted in rabbits' femurs for up to 60 days, to test their biocompatibility and osteoconduction. Additionally, granules of 45S5 Bioglass® were employed and used as a standard reference for comparison. The results showed that, after 30 days, the two novel BGs and 45S5 displayed a similar behavior, in terms of bone amount, thickness of new bone trabeculae and affinity index. On the contrary, after 60 days, 45S5 granules were mainly surrounded by wide and scattered bone trabeculae, separated by large amounts of soft tissue, while in BGMS10 and Bio_MS the trabeculae were thin and uniformly distributed around the BG granules. This latter scenario could be considered as more advantageous, since the features of the two novel BG granules allowed for the neo-formation of a uniformly distributed bony trabeculae, predictive of more favorable mechanical behavior, compared to the less uniform coarse trabeculae, separated by large areas of soft tissue in 45S5 granules. Thus, BGMS10 and Bio_MS could be considered suitable products for tissue regeneration in the orthopedic and dental fields.

Mosaicism of a novel variant in the ANKRD11 gene in a child with a mild KBG phenotype: A case report

BACKGROUND

KBG syndrome is likely underdiagnosed because of mild and non-specific features in some affected patients especially before the upper permanent central incisors eruption at about the age of 7-8 years. Somatic mosaicisms are usually recognized in the parents only after a typically affected son is diagnosed with KBG syndrome. We describe for the first time the mosaicism of a novel variant in a child with a mild KBG phenotype.

CASE SUMMARY

Our patient presented at 24 mo of age with short stature, hand abnormalities, facial dysmorphism and mild developmental delay. Pituitary hypoplasia and central hypothyroidism were also detected. By next generation sequencing (NGS) analysis we found a novel deletion in the ANKRD11 gene (c.4880_4893del.), that can be classified as likely pathogenic for the syndrome, with the percentage of mutated allele of 36%. We considered this finding as causative of the mild and non-specific phenotype for KBG syndrome in our patient, as previously reported in adults. A heterozygous variant in HESX1 gene, classified as variant of uncertain significance, but suspected of causing pituitary hypoplasia and hormonal deficiency, was also found. The patient started levothyroxine and growth hormone treatment.

CONCLUSION

The increased use of NGS analysis may expand the phenotypic spectrum of KBG syndrome because it allows genetic diagnosis of somatic mosaicisms also in children.

Counter-Acting Candida albicans-Staphylococcus aureus Mixed Biofilm on Titanium Implants Using Microbial Biosurfactants

This study aimed to grow a fungal-bacterial mixed biofilm on medical-grade titanium and assess the ability of the biosurfactant R89 (R89BS) coating to inhibit biofilm formation. Coated titanium discs (TDs) were obtained by physical absorption of R89BS. Candida albicans-Staphylococcus aureus biofilm on TDs was grown in Yeast Nitrogen Base, supplemented with dextrose and fetal bovine serum, renewing growth medium every 24 h and incubating at 37 °C under agitation. The anti-biofilm activity was evaluated by quantifying total biomass, microbial metabolic activity and microbial viability at 24, 48, and 72 h on coated and uncoated TDs. Scanning electron microscopy was used to evaluate biofilm architecture. R89BS cytotoxicity on human primary osteoblasts was assayed on solutions at concentrations from 0 to 200 μg/mL and using eluates from coated TDs. Mixed biofilm was significantly inhibited by R89BS coating, with similar effects on biofilm biomass, cell metabolic activity and cell viability. A biofilm inhibition >90% was observed at 24 h. A lower but significant inhibition was still present at 48 h of incubation. Viability tests on primary osteoblasts showed no cytotoxicity of coated TDs. R89BS coating was effective in reducing C. albicans-S. aureus mixed biofilm on titanium surfaces and is a promising strategy to prevent dental implants microbial colonization.

The epidemiology of central venous catheter-related bloodstream infection in our renal units is changing

Recent reports have shown an increase in the rate of Gram-negative bacteremia in several settings, including catheter-related bloodstream infections (CRBSI). To analyze if the epidemiology of CRBSI is also changing in hemodialysis patients, we revisited the etiology of CRBSIs in our renal unit over 8 years. During the observed periods, 149 episodes of CRBSIs were reported and the CRBSI incidence rate, ranged between 0.67 and 0.82 episodes/1000 tCVC days. Of these 149 episodes, 84 (56.3%) were due to Gram-positive bacteria, 62 (41.6%) to Gram-negative bacteria, and 3 (2.1%) to polymicrobial flora, no episodes of fungi were found. There was a trend, but not statistically significative, increase over time in the number of Gram-negative CRBSIs among the total CRBSIs, rising from 37.8% in the first period to 41.2% in the second period and to 44.3% in the last period, with a parallel decrease in the percentage of Gram-positive CRBSIs (from 59.5% to 56.9% and subsequently to 54.1%). Between Gram-negative, we reported an intensification of CRBSI due to Enterobacterales, particularly Escherichia coli. Among the Gram-negative, we have isolated germs rarely reported in the literature, such as Burkholderia cepacia, Pantoea agglomerans, and Rhizobium radiobacter. Regarding Gram-positive bacteria, a triplicate incidence of Staphylococcus aureus was reported with MRSA accounting for 42% in the third period. Among the Gram-positive bacteria, we reported two episodes of Kocuria kristinae and two of Bacillus spp.Our data demonstrated that the epidemiology of CRBSI in the same center, will change over time and Gram-negative strains are an increasing cause of CRBSI. The limitation of the present report is that statistical significance has not been reached, probably due to the limited number of CRBSI. New bacteria, both Gram-negative and Gram-positive, are emerging. Collaboration with the Microbiology Department appears essential to an appropriate diagnosis.

Laboratory predictors of death from coronavirus disease 2019 (COVID-19) in the area of Valcamonica, Italy

Background Comprehensive information has been published on laboratory tests which may predict worse outcome in Asian populations with coronavirus disease 2019 (COVID-19). The aim of this study is to describe laboratory findings in a group of Italian COVID-19 patients in the area of Valcamonica, and correlate abnormalities with disease severity. Methods The final study population consisted of 144 patients diagnosed with COVID-19 (70 who died during hospital stay and 74 who survived and could be discharged) between March 1 and 30, 2020, in Valcamonica Hospital. Demographical, clinical and laboratory data were collected upon hospital admission and were then correlated with outcome (i.e. in-hospital death vs. discharge). Results Compared to patients who could be finally discharged, those who died during hospital stay displayed significantly higher values of serum glucose, aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), urea, creatinine, high-sensitivity cardiac troponin I (hscTnI), prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (APTT), D-dimer, C reactive protein (CRP), ferritin and leukocytes (especially neutrophils), whilst values of albumin, hemoglobin and lymphocytes were significantly decreased. In multiple regression analysis, LDH, CRP, neutrophils, lymphocytes, albumin, APTT and age remained significant predictors of in-hospital death. A regression model incorporating these variables explained 80% of overall variance of in-hospital death. Conclusions The most important laboratory abnormalities described here in a subset of European COVID-19 patients residing in Valcamonica are highly predictive of in-hospital death and may be useful for guiding risk assessment and clinical decision-making.

High success rate in salvage of catheter-related bloodstream infections due to Staphylococcus aureus, on behalf of project group of Italian society of nephrology

BACKGROUND

Catheter-related bloodstream infections caused by Staphylococcus aureus represent one of the most fearful infections in chronic haemodialysis patients with tunnelled central venous catheters. Current guidelines suggest prompt catheter removal in patients with positive blood cultures for S. aureus. This manoeuvre requires inserting a new catheter into the same vein or another one and is not without its risks.

METHODS

A protocol based on early, prompt diagnosis and treatment has been utilized in our renal unit since 2012 in an attempt to salvage infected tunnelled central venous catheters. We prospectively observed 247 tunnelled central venous catheters in 173 haemodialysis patients involving 167,511 catheter days.

RESULTS

We identified 113 catheter-related bloodstream infections (0.67 episodes per 1000 days/tunnelled central venous catheter). Forty were caused by S. aureus, including 19 by methicillin-resistant S. aureus (79% saved) and 21 by methicillin-sensitive S. aureus (90% saved), of which 34 (85%) were treated successfully. Eight recurrences occurred and six (75%) were successfully treated. A greater than 12 h time to blood culture positivity for S. aureus was a good prognostic index for successful therapy and tunnelled central venous catheter rescue.

CONCLUSION

Our data lead us to believe that it is possible to successfully treat catheter-related bloodstream infection caused by S. aureus and to avoid removing the tunnelled central venous catheter in many more cases than what has been reported in the literature. On the third day, it is mandatory to decide whether to replace the tunnelled central venous catheter or to carry on with antibiotic therapy. Apyrexia and amelioration of laboratory parameters suggest continuing systemic and antibiotic lock therapy for no less than 4 weeks, otherwise, tunnelled central venous catheter removal is recommended.

Multicenter prospective study on the prevalence of colistin resistance in Escherichia coli: relevance of mcr-1-positive clinical isolates in Lombardy, Northern Italy

Background

The emergence of the plasmid-mediated colistin resistance mechanism in Escherichia coli has raised concern among public health experts as colistin is a last-line antimicrobial resort. The primary aim of the study was to investigate the prevalence of this resistance trait in E. coli isolates circulating in the Lombardy region, Northern Italy. The presence of mcr-type genes and their genetic relationship were also studied.

Materials and methods

A prospective study was performed during a 4-month period (May to August, 2016) in six acute care Hospitals. Consecutive nonduplicate clinical isolates of E. coli from any type of clinical specimen, with the exception of rectal swabs, were included in the study. Isolates that exhibited MIC values for colistin >2 mg/L were further investigated. Bacterial identification was obtained by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Amplification of mcr-type genes (−1 to −5 variants) and microarray analysis were accomplished. Repetitive sequence-based PCR (Rep-PCR) and multilocus sequence typing (MLST) analysis were used for genotyping.

Results

Overall, 3,902 consecutive E. coli isolates (2,342 from outpatients, 1,560 from inpatients) were evaluated during the study period. Of them, 18/3,902 (0.5%), collected from 4/6 centers, showed resistance to colistin. These isolates were mostly obtained from urine of both outpatients (n=12) and inpatients (n=6). Colistin MIC values ranged from 4 to 8 mg/L. The mcr-1 gene was detected in 10/18 isolates (7 from outpatients, 3 from inpatients). Rep-PCR and MLST analysis revealed the presence of nine different clusters. Further mcr-type genes were not detected.

Conclusion

Resistance to colistin in E. coli clinical isolates appears low in our geographic area. With regard to mcr-1-positive isolates, they accounted for approximately 50% of colistin-resistant E. coli isolates, thus representing a relevant resistance mechanism in this context. Although overall limited, the presence of mcr-1 determinant in our region should not be ignored and great concern should be given to the continuous surveillance.

Multiple lung abscesses caused by Streptococcus constellatus

Despite numerous descriptions of body abscesses produced by Streptococcus milleri group bacteria, lung abscesses caused by this group remain under-reported and the clinical and laboratory features have yet to be fully characterised. We present the case of a patient admitted with lung multiple abscesses produced by Streptococcus constellatus.

The importance of an early alert from the Microbiology Laboratory and multidisciplinary collaboration during a suspected salmonellosis outbreak

<em>Background and aims.</em> Salmonellosis is one of the most common and widely distributed food-borne diseases. The increasing complexity and globalization of the food industry are causing an increase of some of these large-scale food-borne illnesses, thus there is a need for improvements in public health signal detection and communication streams between laboratories and regulatory agencies. The aim of this study is to show how the early reporting of salmonellosis cases directly from the Laboratory of Microbiology to the Local Health Service Infectious Diseases Office along with the prompt response of the ASL, and the rapid involvement of the Local Veterinary Prevention Department resulted in an improved individuation and investigation of a suspected food-borne outbreak with anomalous manifestation. <br /><em>Materials and methods.</em> From August to November 2014 the early warning from the Laboratory of Microbiology regarding <em>Salmonella</em> spp. isolates with the identical serogroup and antibiotic resistance phenotype, allowed for prompt identification of a food-borne infection. <br /><em>Results and conclusions.</em> The genotyping analysis suggested that over the period considered there was more than a single monophasic <em>Salmonella</em> <em>typhimurium</em> isolate: one responsible for the sporadic cases that occurred in September and October, and another in November.

Guided folding takes a start from the molecular imprinting of structured epitopes

A biomimetic route towards assisted folding was explored. Molecularly imprinted polymeric nanoparticles (MIP NPs), i.e. biomimetics with entailed molecular recognition properties made by a template assisted synthesis, were prepared to target a structured epitope: the cystine containing peptide CC9ox, which corresponds to the apical portion of the β-hairpin hormone Hepcidin-25. The structural selection was achieved by the MIP NPs; moreover, the MIP NPs demonstrated favouring the folding of the linear random peptide (CC9red) into the structured one (CC9ox), anticipating the future role of the MIP NPs as in situ nanomachines to counteract folding defects.

Staphylococcus aureus toxic shock syndrome toxin-1 endocarditis with muscular metastatic abscesses

A 42-year-old woman, living in a nursing home for the mentally disabled, with congenital ventricular septal defect and multiple comorbidities, developed endocarditis with vegetations of the interventricular septum and the right coronary aortic leaflet. The main feature of this case was the metastatic embolism leading to multiple and muscular abscesses. Methicillin-sensitive S. aureus, spa type 253 and ST30, producing toxin shock syndrome toxin-1 was isolated from blood cultures. The patient was initially treated with beta-lactam antibiotics without showing clinical response and subsequently with daptomycin and linezolid that improved the patient's clinical symptoms. The effectiveness of treatment with daptomycin and linezolid was partly due to the ability of linezolid to reduce TSST-1 secretion. The portal of entry of the infection was not recognized. TSST-1 production by the strain might have favoured the formation of large cardiac vegetations and the subsequent metastatic dissemination to the muscles.

Mandibular ameloblastic fibroma in 6-years-old girl: a case report

Ameloblastic fibroma (AF) is defined in WHO classification as a ''neoplasm composed of proliferating odontogenic epithelium embedded in a cellular ectomesenchymal tissue that resembles dental papilla, and with varying degrees of inductive change and dental hard tissue formation''. AF is a rather uncommon tumor, accounting for only 2.5% of all odontogenic tumors. AF is a true mixed tumor, in which the epithelial and ectomesenchymal elements are neoplastic. AF raises at any age, ranging from 6 months to 42 years (mean 14.6 to 15.5 years); it does not show sex predilection. The lesion occurs in nearly 70% of cases in posterior areas of the mandible. Patients exhibit swelling of the jaw; pain is not usually described. Authors present a clinical and surgical management of an early onset of a large mandibular ameloblastic fibroma in a 6-year-old girsl.

Increased erythrocyte glutathione peroxidase activity and serum tumor necrosis factor-alpha in HIV-infected patients: relationship to on-going prothrombotic state

A condition of oxidative stress, due to perturbation of oxidant/antioxidant balance, has been suggested to play a role not only in the pathogenesis of human immunodeficiency virus (HIV) infection, but also in the promotion of a thrombophilic condition. Because various hemostatic dysfunctions usually considered as risk factors for thrombotic events were reported in HIV infection, this study was undertaken to investigate whether the oxidative phenomenon could promote a prothrombotic state in such condition. Erythrocyte glutathione peroxidase (GSH-Px), the major free-radical scavenger enzyme, and serum tumor necrosis factor-alpha (TNF-alpha) were evaluated in 33 consecutive HIV-infected out-patients and 35 matched HIV-negative healthy controls at a distance of any acute episode. Thrombin generation was explored by measuring the plasma levels of prothrombin fragment 1 + 2 (F1 + 2), whereas fibrin degradation products (D-dimer) and plasminogen activator inhibitor (PAI-1) activity were evaluated as indices of plasmin activity and fibrinolytic derangement. The anticoagulant pathway was investigated by measuring the plasma levels of antithrombin and protein C. Erythrocyte GSH-Px activity and serum TNF-alpha were significantly higher in HIV-infected patients when compared to controls. F1 + 2, D-dimer, and PAI-1 activity were increased in HIV-infected patients by comparison with controls. Normal antithrombin, but decreased protein C, was instead detected in HIV-infected patients. In the latter patients, serum TNF-alpha negatively correlated with both erythrocyte GSH-Px activity and plasma D-dimer. On the other hand, a positive correlation was shown between F1 + 2 and D-dimer and between D-dimer and GSH-Px activity. Furthermore, a trend toward increasing levels of GSH-Px with increasing PAI-1 activity was reported. These findings suggest a relationship between erythrocyte oxidative stress and the hypercoagulable condition during HIV infection.

Biological variability of myoglobin in healthy elderly and younger subjects

To study the effect of age on serum myoglobin more clearly, the analytical, intra-individual and inter-individual components of variation were estimated from duplicate analyses of specimens collected from 18 healthy elderly subjects [ages 74-97 years; 9 men (EM)], and 14 healthy younger subjects [ages 25-31 years; 7 men (YM)] over a period of 6 weeks. The mean values (microgram/L) were EM: 53.7; EW: 44.9; YM: 34.2; YW:24.8. Estimated analytical (CVA), intra- (CVI) and inter-individual (CVG) variations as CV% were: CVA: 2.2. CVI: EM: 13; EW: 9.9; YM: 12.4; YW: 9.6. CVG: EM: 37.6; EW: 28; YM: 18.5; YW: 13.4. The data obtained were used to derive the desirable analytical goal for imprecision (i.e., < or = 6.5% in EM; < or = 4.9% in EW and < or = 6.2% in YM; < or = 4.8% in YW); inaccuracy (i.e., < or = 9.9% in EM; < or = 7.7 in EW and < or = 5.5% in YM; < or = 4.12% in YW); the change required for serial results to be significantly different (i.e., 36% in EM; 28% in EW and 34% in YM; 27.2% in YW), the numbers of specimen collections required to produce a more precise estimate of the homeostatic set point of an individual within 5% (i.e., 26 in EM; 16 in EW and 24 in YM; 15 in YW), and the index of individuality (i.e., 0.34 in EM; 0.35 in EW and 0.67 in YM; 0.71 in YW). This study shows that intra-individual biological variation of myoglobin in healthy elderly subjects is not different from that in young subjects. Inter-individual variation, instead, is greatly influenced by differences in age and sex.

Altered oxidative stress in healthy old subjects

To understand the magnitude of oxidative phenomena during senescence, we evaluated, as antioxidant, the activity of glutathione peroxidase (GSH-Px) in erythrocytes and plasma uric acid (UA) levels together with the malondialdehyde (MDA) levels in plasma, as an index of lipid peroxidation, in 46 apparently healthy elderly subjects (87 +/- 6 years old; mean +/- SD), and 49 young subjects (29 +/- 4 years old). The elderly subjects had lower erythrocyte GSH-Px activity (15.7 +/- 4.8 vs 20.2 +/- 7.0 U/g Hb, p < 0.001; mean +/- SD) and plasma UA levels (192 +/- 46 vs 240 +/- 54 mmol/L, p < 0.001), but higher MDA levels (5.3 +/- 0.8 vs 4.1 +/- 0.8 mmol/L, p < 0.001) than the young subjects. Of additional interest was the finding of a positive correlation between age and erythrocyte GSH-Px activity (r = 0.74, p < 0.001), and a negative correlation between age and plasma MDA levels (r = -0.83, p < 0.001) in the elderly group. Although erythrocyte (GSH-Px activity was significantly less in the elderly than in the young group, the oldest subjects showed the greatest erythrocyte GSH-Px activity and had lower MDA levels.

Biological variation in protein C, protein S and antithrombin concentrations in plasma of healthy subjects

The analytical, intra- and inter-individual components of biological variation were estimated for protein C, protein S and antithrombin over a period of 6 weeks in a cohort of 17 apparently healthy subjects. Expressed as percentage activity (protein C and antithrombin) as a percentage concentration in normal human plasma (protein S), the mean values for men and women show no significant differences (p > 0.05) for any of the analytes studied. Calculated analytical goals (CV, %) for precision required for optimal patient care are: protein C, 2.9; protein S, 2.9 and antithrombin 2.7. A single numerical index, called "index of fiduciality", was also calculated to demonstrate that the analytical performance of our method was satisfactory. The generally applicable differences (% activity or % concentration) required for two results to be significantly different (p < or = 0.05) were calculated as: protein C, 17; protein S, 16 and antithrombin, 16. The usefulness of critical differences as guidelines for the interpretation of changes in serial results was investigated using an "index of heterogeneity" of intra-individual variation. The marked degree of individuality demonstrated for all the quantities indicates that, if conventional population-based ranges are used uncritically, major changes in analyte concentration may not be correctly identified for some patients, because observed values continue to lie within the reference range. The utility of conventional population-based reference intervals was determined by calculating a single numerical index, called "index of individuality". For protein C, protein S and antithrombin we found that five of a patient's specimens are required to achieve a 95% chance that the mean is within +/- 5% of the true value.

Reference values of neuroactive amino acids in the cerebrospinal fluid by high-performance liquid chromatography with electrochemical and fluorescence detection

Sampling and HPLC analysis procedures for CSF amino acid determinations were evaluated. In order to increase sensitivity, a precolumn derivatization of amino acids by o-phthalaldehyde-mercaptoethanol reagent was used. By using fluorimetric and electrochemical detection in series, positive peak identification can be obtained in a single chromatographic run. It is recommended to analyze freshly collected CSF. Amino acids are stable for short periods over a wide range of temperature, but storage at -80 degrees C is recommended. The CSF samples for the calculation of the reference values were taken from 40 healthy subjects, hospitalized for lumbar disk herniation, placed on the same diet and kept drug-free for at least 1 week. The mean values (mumol/l) and the ranges (in parentheses) were: 0.27 (0.09-0.63), 0.62 (0.18-1.15), 5.32 (3.05-11.50), 6.16 (2.90-13.30), 0.16 (0.03-0.22) for aspartic acid, glutamic acid, glycine, taurine and gamma-aminobutyric acid respectively.

PHA-stimulated cellular immune function and T-lymphocyte subsets in major depressive disorders

We measured some immunological parameters in 20 hospitalized patients with major depression and 20 age- and sex-matched healthy controls. Both enumeration of immune cells, including T-lymphocyte subpopulations, and assay of T-cell function were studied. White blood cells were evaluated with an automated cell counter, T-cell subsets with an immunobead technique, and T-cell function with a phytohemagglutinin-induced proliferation in vitro assay. We found that T-lymphocyte responses to the mitogen were significantly lower in depressed patients than in controls. All the other parameters were normal. These findings suggest that functional but not numerical changes in T-lymphocytes characterize major depressive disorders.