Analytical study on the primary and secondary organic carbon and elemental carbon in the particulate matter at the high-altitude Monte Curcio GAW station, Italy

This study provides a thorough investigation of the trends of organic carbon (OC) and elemental carbon (EC) in particulate matter (PM)₁₀ and PM_2.5 samples collected at the Monte Curcio Observatory (1780 m a.s.l.), a station of the Global Atmosphere Watch (GAW) program and Global Mercury Observation System (GMOS) network. Although the drawn attention toward these pollutants, there is still a lack of data for southern Italy, and this work is a contribution toward the filling of this gap. PM was sampled daily in 2016 and analyzed by thermo-optical transmittance method, while equivalent black carbon (eBC) concentrations in PM₁₀ were simultaneously measured using a multiangle absorption photometer. The results showed that in PM₁₀, the average values of OC and EC were 1.43 μgC/m³ and 0.12 μgC/m³, whereas in PM_2.5, these concentrations were 1.09 μgC/m³ and 0.12 μgC/m³, respectively. We detected a clear seasonal variability in OC and EC with higher concentrations during the warm period. Moreover, the analysis of the OC/EC ratio revealed that most of the carbonaceous aerosol was transported by long-range air masses, as further confirmed by the use of the concentration-weighed trajectory (CWT) model. The mass absorption cross-section at 632 nm of EC (MAC_EC) over the entire period was 9.67 ± 4.86 m²/g and 8.70 ± 3.18 m²/g in PM_2.5 and PM₁₀, respectively, and did not exhibit a clear seasonal variation. The concentrations for OC and EC were also used for the computation of the secondary organic carbon (SOC) content, whose outcomes resulted in a seasonal trend similar to those obtained for OC and EC. As regards the eBC, its weekly pattern showed a slight increase during the weekend in the warm period, consistent with the anthropic activities in the touristic area surrounding the observatory.

Potential involvement of GRIN2B encoding the NMDA receptor subunit NR2B in the spectrum of Alzheimer's disease

Increasing evidence links dysregulation of NR2B-containing N-methyl-D-aspartate receptor remodelling and trafficking to Alzheimer's disease (AD). This theme offers the possibility that the GRIN2B gene, encoding this selective NR2B subunit, represents a potential molecular modulating factor for this disease. Based on this hypothesis, we carried out a mutation scanning of exons and flanking regions of GRIN2B in a well-characterized cohort of AD patients, recruited from Southern Italy. A "de novo" p.K1293R mutation, affecting a highly conserved residue of the protein in the C-terminal domain, was observed for the first time in a woman with familial AD, as the only genetic alteration of relevance. Moreover, an association study between the other detected sequence variants and AD was performed. In particular, the study was focused on five identified single nucleotide polymorphisms: rs7301328, rs1805482, rs3026160, rs1806191 and rs1806201, highlighting a significant contribution from the GRIN2B rs1806201 T allele towards disease susceptibility [adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI) 1.40-2.63, p < 0.001, after correction for sex, age, and APOE ε4 genotype]. This was confirmed by haplotype analysis that identified a specific haplotype, carrying the rs1806201 T allele (CCCTC), over-represented in patients versus controls (adjusted OR = 6.03; p < 0.0001). Although the pathogenic role of the GRIN2B-K1293R mutation in AD is not clear, our data advocate that genetic variability in the GRIN2B gene, involved in synaptic functioning, might provide valuable insights into disease pathogenesis, continuing to attract significant attention in biomedical research on its genetic and functional role.

Presenilin enhancer-2 gene: identification of a novel promoter mutation in a patient with early-onset familial Alzheimer's disease

γ-Secretase proteins complex cleaves the amyloid precursor protein (APP) to generate amyloid-β (Aβ) peptides. Considerable evidence suggests that alterations in genes encoding these proteins exert their influence on the pathogenesis of familial Alzheimer's disease (FAD). Presenilin enhancer-2 gene (PEN-2) is a necessary component of the γ-Secretase complex. Recently, it has been shown that PEN-2 mutations could be involved in Alzheimer's disease (AD). We performed a mutational screening of all PEN-2 coding and promoter regions in a FAD cohort derived from Southern Italy. Four hundred and fifty-two subjects (FAD: 97;

CONTROLS

355) were recruited for this study. We identified for the first time in a key region necessary for the promoter activity a novel 3 bp deletion in a subject with early-FAD. Our genetic data demonstrate that the mutant allele may influence the transcriptional activity of the PEN-2 gene. Although the effective role of the PEN-2 promoter deletion in AD is not entirely clear, these findings might lead to more studies on its functional and genetic role.

Leber’s hereditary optic neuropathy associated with a multiple-sclerosis-like picture in a man

A 35-year-old young man displayed Leber’s optic neuropathy (LHON) due to T14484C and multiple sclerosis (MS) phenotype that was dominated by symptoms and signs of spinal cord impairment. Magnetic resonance imaging (MRI) revealed demyelinating lesions extending from D6 to D11 in the spinal cord with gadolinium enhancement, while only three linear demyelinating lesions were seen on brain MRI. In the literature, a major involvement of the spinal cord was already reported in three of four male patients with the 14484 LHON mutation who developed MS, but the reasons of this peculiar association remain unknown, and further research in this area is needed.

CASP-9: A susceptibility locus for multiple sclerosis in Italy

Caspase-9 is a primary effector CASP that executes programmed cell death, which plays an important role in the development of multiple sclerosis (MS). Polymorphisms in the CASP-9 gene may influence its activity, thereby modulating the susceptibility to MS. To test this hypothesis, we evaluated a SNP in the CASP-9 gene in a set of Italian patients from Southern Italy and healthy control subjects. Our results suggest that the presence of the G/G genotype represents a higher risk factor in our MS population and a differential production of CASP-9 might be a contributory factor in determining the severity of MS.

The role of VLA4 polymorphisms in multiple sclerosis: An association study

Lymphocyte and monocyte brain infiltration determines inflammation in multiple sclerosis. The trafficking of these cells into the CNS results from the VLA-4 binding with its ligand on brain endothelial cells. MS patients treated with an antibody against the alpha-4 subunit, which inhibits this interaction, prevents brain lesion development. We investigated the association between VLA-4 gene polymorphisms and MS in a study on 275 patients and 255 controls. No differences were detected, thus suggesting that these polymorphisms are not a significant genetic risk factor for susceptibility to MS in Italy.

Fas antigen and sporadic Alzheimer's disease in Southern Italy: evaluation of two polymorphisms in the TNFRSF6 gene

Tumor Necrosis Factor Receptor Super Family 6 gene (TNFRSF6), also known as FAS, encodes the Fas antigen, a cell surface receptor mediating cell apoptosis, situated on chromosome 10q located near the region of linkage to sporadic Alzheimer's disease (sAD). FAS levels have been reported elevated in the brain of AD patients. Due to both positional and pathobiological criteria, the association of the FAS antigen with this pathology is of great interest. We have tested two SNPs in the FAS gene in 223 Italian patients with non-familial AD from Southern Italy (Calabria region) and 211 healthy control subjects. No significant differences in allelic and genotypic distributions were found between cases and controls, or late and early-onset AD patients, thus suggesting that these polymorphisms do not represent an AD risk factor in our population.

Genetic variation in the myeloperoxidase gene and cognitive impairment in multiple sclerosis

There is evidence that multiple sclerosis (MS) may associated with cognitive impairment in 25 to 40% of cases. The gene encoding myeloperoxidase (MPO) is involved in molecular pathways leading to beta-amyloid deposition. We investigated a functional biallelic (G/A) polymorphism in the promoter region (-463) of the MPO gene in 465 patients affected by MS, divided into 204 cognitively normal and 261 impaired. We did not find significant differences in allele or genotype distributions between impaired and preserved MS patients. Our findings suggest that MPO polymorphism is not a risk factor for cognitive impairment in MS.

Gender-related effect of clinical and genetic variables on the cognitive impairment in multiple sclerosis

BACKGROUND

Cognitive impairment may occur at any time during the course of multiple sclerosis (MS), and it is often a major cause of disability in patients with the disease. The APOE-epsilon4 allele is the major known genetic risk factor for late onset familial and sporadic Alzheimer's Disease (AD), and it seems to be implicated in cognitive decline in normal elderly persons.

OBJECTIVE

To investigate the clinical and genetic variables that can be associated with the cognitive decline in patients with MS.

METHODS

Five-hundred and three patients with clinically definite MS underwent a battery of neuropsychological tests and, according to the number of failed tests, were divided into cognitively normal and impaired. All patients were genotyped for APOE gene polymorphisms.

RESULTS

Fifty-six percent of MS patients showed, to different extents, cognitive impairment. Cognitive decline was predominant in men and was associated with disease duration, Kurtzke Expanded Disability Status Scale (EDSS) score, a low level of education, and, interestingly, the epsilon4 allele of the APOE gene. By contrast, cognitive impairment in women was independent of any investigated variable.

CONCLUSION

The findings demonstrate that clinical and genetic factors play a role in men affected by MS developing cognitive impairment.

Association between Synapsin III gene promoter polymorphisms and multiple sclerosis

Although multiple sclerosis (MS) is considered to be an inflammatory demyelinating disease, increasing evidence indicates that it is also an axonal pathology; indeed, studies of experimental allergic encephalitis showed that several neuronal proteins such as synapsins take part in the pathogenesis of the axonal dysfunction. Synapsins are a family of abundant neuron-specific phosphoproteins with crucial roles in synaptogenesis and neuronal plasticity. Distinct genes encode the three different isolated proteins (I, II and III); of interest, the gene of synapsin III (SYN3) is located in the chromosome 22q12-q13, a locus close to one of the candidate susceptibility regions (22q13.1) for MS. In the present study we selected two polymorphisms (g.-631C > G and g.-196A > G) within the SYN3 5'-promoter region because of the protein's role and genetic location; we analysed the allele and genotype distributions of these polymorphisms in a selected MS population of southern Italy. An inverse association between MS and the g-631C > G polymorphism was found; indeed, the two polymorphisms were in almost complete linkage disequilibrium and the haplotype analysis showed that the C631/A196 haplotype seemed to confer a significant protection against MS.

Increased Risk for Alzheimer Disease With the Interaction of MPO and A2M Polymorphisms

BACKGROUND

The genes encoding myeloperoxidase (MPO) and alpha(2)-macroglobulin (A2M) are involved in molecular pathways leading to beta-amyloid deposition. Two polymorphic sites in these genes (MPO-G/A and A2M-Ile/Val) have been associated with Alzheimer disease (AD), but conflicting findings have been reported in populations with different ethnic backgrounds.

OBJECTIVES

To study the association of MPO-G/A and A2M-Ile/Val polymorphisms with sporadic AD and to investigate the interactions among the MPO, A2M, and apolipoprotein E (APOE) gene polymorphisms in determining the risk of the development of AD.

DESIGN

Case-control study.

SETTING

Referral center for AD in Calabria, southern Italy.

PARTICIPANTS

One hundred forty-eight patients with sporadic AD and 158 healthy control subjects.

RESULTS

The MPO-G and A2M-Val alleles were found more frequently in cases than in controls, as were the MPO-G/G and A2M-Val/Val genotypes. The odds ratio (OR) for the MPO-G/G genotype was 1.78 (95% confidence interval [CI], 1.13-2.80); for the A2M-Val/Val genotype, 3.81 (95% CI, 1.66-8.75). The presence of MPO-G/G and A2M-Val/Val genotypes synergistically increased the risk of AD (OR, 25.5; 95% CI, 4.65-139.75). Stratification of cases by sex, age at onset of AD, and APOE-epsilon 4 status did not show significant differences in the distribution of MPO or A2M polymorphisms.

CONCLUSIONS

The MPO and A2M polymorphisms are associated with sporadic AD in southern Italy. Moreover, a genomic interaction between these polymorphisms increases the risk of the development of AD.

Apolipoprotein E genotype does not influence the progression of multiple sclerosis

OBJECTIVE

To investigate the association between apolipoprotein E (APOE) polymorphisms and the progression of MS.

METHODS

We investigated 428 subjects affected by clinically defined MS, with a disease duration of at least three years. We collected data concerning the age at onset of MS, clinical type, disease duration and disability according to the expanded disability status scale (EDSS). We also calculated the progression index (PI) to evaluate disease progression. APOE genotyping and the -491 A/T polymorphism of the APOE promoter were determined.

RESULTS

No association was observed between the APOE epsilon4 allele and clinical characteristics of our study population. We also investigated the -491 A/T APOE promoter polymorphism in 236 MS subjects and did not find any association between the -491 A/T polymorphism and the selected clinical variables.

CONCLUSIONS

In our population the APOE epsilon4 allele and the -491 A/T APOE promoter polymorphism are not associated with a more rapid course of MS.

CD45 and multiple sclerosis: the exon 4 C77G polymorphism (additional studies and meta-analysis) and new markers

We re-evaluated the association with multiple sclerosis (MS) of the C77G splicing regulatory variation in the CD45 gene and screened for new mutations the three alternatively spliced exons (#4, 5 and 6). No association with C77G was detected in two groups of patients (total=448) and controls (total=559) from Northern and Southern Italy. When excluding the first published study indicating a positive association, a meta-analysis of the five further studies conducted to date (including the present one) led to a non-significant combined odds ratio (OR) of 1.11. None of the four newly identified nucleotide substitutions, namely C77T (Pro59Pro) in exon 4, G69C (Asp121His) in exon 5, T127A (Ile187Asn) and A138G (Thr191Ala) in exon 6, was significantly associated to MS.

GABA(B) receptor 1 polymorphism (G1465A) is associated with temporal lobe epilepsy

BACKGROUND

Dysfunction of gamma-aminobutyric acid (GABA) (B) receptors has been implicated in the pathogenesis of temporal lobe epilepsy (TLE).

OBJECTIVE

To evaluate the genetic contribution of cloned human GABA(B) receptors to TLE.

METHODS

The authors genotyped 141 patients (78 women and 63 men; mean age = 49.1 +/- 18.0 years) with nonlesional TLE and 372 age- and sex-matched normal individuals for the known polymorphism G1465A in the human GABA(B) receptor 1 [GABA(B[1])] gene.

RESULTS

There was a highly significant overrepresentation of the G1465A heterozygote in patients with TLE compared with controls. The A/G genotype was found in 17% of the 141 patients with TLE and in only 0.5% of the 372 controls (p < 0.0001). The authors also found that patients carrying the A allele had a significantly higher risk (p = 0.003, OR = 6.47, 95% CI = 2.02 to 20.76) of developing drug-resistant TLE. Furthermore, the age at onset of seizures tended to be lower in patients with A/G genotype, but the difference was not significant.

CONCLUSIONS

The results of this study indicate that the GABA(B[1]) polymorphism (G1465A) confers a highly increased susceptibility to TLE. Moreover, it seems to influence the severity of this common epileptic disorder.

Genetic association of alpha2-macroglobulin polymorphisms with AD in southern Italy

The authors investigated the segregation of two polymorphisms of the alpha2-macroglobulin gene (A2M-I/D and A2M-Ile1000Val) in patients with sporadic AD from southern Italy. The A2M-I and A2M-Val1000 alleles were more frequent in cases than in controls, and this effect was independent from the APOE-epsilon4 status as well as from the age at onset of AD. Moreover, subjects carrying the A2M genotype I/I-Val/Val had a threefold increase of risk for AD. These data support a population-based susceptibility for AD linked to A2M polymorphisms.

Lack of association between estrogen receptor 1 gene polymorphisms and multiple sclerosis in southern Italy in humans

Estrogen receptor 1 gene polymorphisms (ESR1) have been found to be associated with multiple sclerosis (MS) in both Japanese and Finnish populations. We investigated the association between ESR1 polymorphisms (PvuII and XbaI) and MS in a study of 132 MS patients and 129 controls from the same geographic background (southern Italy). Allelic and genotypic frequencies were not different between MS patients and population controls for either the PvuII or XbaI polymorphism. This result suggests that the association between a given disease and a genomic characteristic must be confirmed by separate investigations in different populations.

Reboxetine in the treatment of depression in the elderly: pilot study

Elderly patients are particularly susceptible to the potential side effects of current antidepressants due to agerelated physiologic changes. We report a pilot study to examine the tolerability of increasing doses of reboxetine, a selective noradrenaline reuptake inhibitor (selective NRI), in elderly depressed patients. Twelve elderly female patients (75-87 years) with either major depression or dysthymia received reboxetine titrated to 8 mg/day over a 4-week period. Tolerability was assessed and included the measurement of vital signs. Electrocardiograms were recorded at baseline and on days 14 and 28. Newly emergent signs and symptoms were recorded throughout the study. Efficacy was assessed using four rating scales, including the Clinical Global Impression (CGI) scale and Hamilton Depression Rating Scale (HAM-D). Eleven patients completed the study, nine received the maximal dose of reboxetine 8 mg/day, and two received maximum doses of reboxetine 6 mg/day due to cardiac rhythm changes in week 3. A total of five patients experienced tachycardia (including two with cardiac rhythm changes in week 3). At the end of the study, seven patients were "much" to "very much" improved on the CGI scale with a concomitant decrease in HAM-D total score of 22% to 41%. Reboxetine was well tolerated by the majority of patients and efficacy outweighed side effects in 75% of patients. Reboxetine 4 mg/day, increasing to 6 mg/day on the basis of individual patient tolerability, may be considered as a safe dose range for testing the efficacy and tolerability of reboxetine in long-term controlled clinical trials in elderly patients with depression.

Serine base exchange enzyme in porcine lyophilised platelets: enzyme properties and modulation by AlF4- and different types of heparin

Phosphatidylserine is one of the PKC modulators and thus it may play an important role in signal transduction. Regulation of the synthesis of this phospholipid is not yet clarified. The contrasting reports are possibly related to the existence of different enzymes which, in mammalian tissues, catalyse the exchange between free serine and the nitrogen base of a membrane phospholipid. This study demonstrates that serine base exchange reactions of commercially available lyophilised porcine platelets exhibit similar pH optima, temperature and Ca2+ dependence as observed in fresh tissues. Analysis of fatty acids composition of the three phospholipid classes involved in base exchange reactions also demonstrated a similarity with fresh platelets. Serine and ethanolamine base exchange enzyme activities were assayed in parallel in platelet lysate subjected to preincubation at various temperatures (30-60 degrees C). When dithioerithrol was omitted from the incubation medium, the two base exchange reactions were inhibited with a similar temperature-dependent pattern. Addition of the reducing agent enhanced the sensitivity to preincubation only for the serine base exchange reaction which was inhibited by 80% after preincubation at 45 degrees C. With respect to its regulation, porcine platelet serine base exchange enzyme(s) was inhibited by fluoroalluminate, a widely used G-protein activator, and stimulated by unfractionated heparin. Low mol. wt. heparin did not influence enzyme activity. Unfractionated heparin greatly stimulated SBEE activity assayed at pH 7.4, a pH value far from the optimal pH.

APOE and risk of cognitive impairment in multiple sclerosis

OBJECTIVES

The APOE gene polymorphism and the -491 A/T polymorphism in its regulatory region have been associated with an increased risk for developing Alzheimer's disease. We examined these polymorphisms in multiple sclerosis (MS) patients, to determine if a genetic predisposition may explain the risk for developing cognitive decline in MS.

MATERIAL AND METHODS

Eighty-nine relapsing-remitting and secondary progressive MS patients underwent to a full neuropsychological battery as well as to determination of APOE and -491 A/T polymorphisms. Genetic analysis was also performed in 107 population controls.

RESULTS

The APOE polymorphism was not associated with the risk of cognitive impairment in MS patients. The AA genotype of the -491 A/T polymorphism in the APOE regulatory region was more frequent in cognitively impaired than in cognitively preserved MS subjects.

CONCLUSION

The AA homozygous state of the -491 A/T polymorphism of the APOE regulatory region is associated with cognitive impairment in patients with MS.

Dopamine D2 receptor gene polymorphism and the risk of levodopa-induced dyskinesias in PD

OBJECTIVE

To investigate whether polymorphisms in the genes for dopamine receptors D1 and D2 are associated with the risk of developing peak-dose dyskinesias in PD.

BACKGROUND

Peak-dose dyskinesias are the most common side effects of levodopa therapy for PD. The identified predictors may only partially account for the risk of developing peak-dose dyskinesias because a substantial proportion of patients never develop peak-dose dyskinesias. Genetic factors could play a role in determining the occurrence of peak-dose dyskinesias.

METHODS

A case-control study of 136 subjects with sporadic PD and 224 population control subjects. We studied three polymorphisms involving the dopamine receptor D1 gene and one intronic short tandem repeat polymorphism of the dopamine receptor D2 gene.

RESULTS

The polymorphisms of the dopamine receptor D1 gene were not associated with the risk of developing PD or peak-dose dyskinesias. The 15 allele of the polymorphism of the dopamine receptor D2 gene was more frequent in parkinsonian subjects than in control subjects. More important, the frequency of both the 13 allele and the 14 allele of the dopamine receptor D2 gene polymorphism was higher in nondyskinetic than in the dyskinetic PD subjects. The risk reduction of developing peak-dose dyskinesias for PD subjects carrying at least 1 of the 13 or 14 alleles was 72% with respect to the PD subjects who did not carry these alleles.

CONCLUSIONS

Certain alleles of the short tandem repeat polymorphism of the dopamine receptor D2 gene reduce the risk of developing peak-dose dyskinesias and could contribute to varying susceptibility to develop peak-dose dyskinesias during levodopa therapy.

Severe erythrocyte adenylate kinase deficiency due to homozygous A-->G substitution at codon 164 of human AK1 gene associated with chronic haemolytic anaemia

A child of Italian origin with a congenital haemolytic anaemia had spectrophotometrically undetectable erythrocyte adenylate kinase (AK) activity. Her parents and brother had approximately 50% normal AK activity, and AK electrophoresis of red blood cell (RBC) crude extract on cellulose acetate strips showed the presence of the normal allele AK1-1. No AK band was detected in the AK electrophoresis of the proband, in whom the erythrocyte 2,3-diphosphoglycerate (2,3DPG) and glutathione (GSH) concentrations were normal whereas adenosine triphosphate (ATP) concentration, pyruvate kinase (PK) and glucose-6P-dehydrogenase (G6PD) activities were increased, reflecting the high reticulocyte count (6.9%). No other evident enzymatic defect was detected by standard procedures. Analysis of AK gene exons, based on polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP), clearly showed an abnormality in the fragment containing exon 6. The subsequent sequence analysis of this abnormal fragment revealed homozygous and heterozygous A-->G substitutions in the proband and in the parents and brother respectively at codon 164, corresponding to a tyrosine-->cysteine substitution in the AK protein.

Synthesis of ethanolamine phosphoglycerides in rat cerebral cortex subjected in vitro to experimental hypoxia with and without hypocapnia

Slices and homogenates from rat cerebral cortex were used to study the effect of hypoxia, with or without hypocapnia, on phosphatidylethanolamine synthesis. The incorporation of [1-3H]ethanolamine into the corresponding phospholipid was greatest in slices treated with pure nitrogen, intermediate when the nitrogen contained 5% CO2, and least in slices treated with 95% O2-5% CO2. The role of hypocapnia in reinforcing the effect due to hypoxia did not require the integrity of the cell because similar results were obtained by treating homogenates with pure nitrogen or nitrogen plus 5% CO2. In both cases the synthesis of phosphatidylethanolamine was abolished by the addition of EGTA and the degradation of newly synthesized phospholipid by phospholipases was similar to that obtained in controls. When the homogenate was not buffered, changes in the pH due to experimental treatment influenced the response to Ca2+ and to hypoxia plus hypocapnia. Intracellular calcium ions are thought to play a role in the response of cerebrocortical slices to N2-treatment. In fact, although the incorporation was greater in complete medium that contains 2 mM Ca2+ than in the same medium prepared without the addition of this ion, the relative increase of incorporation due to N2-treatment was greater in the medium lacking added Ca2+.

Different mechanisms regulate phosphatidylserine synthesis in rat cerebral cortex

Transduction of extracellular signals through the membrane involves both the lipid and protein moiety. Phosphatidylserine participates to these processes as a cofactor for protein kinase C activity and thus the existence of a regulatory mechanism for its synthesis ought to be expected. In plasma membranes from rat cerebral cortex, the activity of serine base exchange enzyme, that is mainly responsible for phosphatidylserine synthesis in mammalian tissues, was reduced by the addition to the incubation mixture of AlF4- or GTP-gamma-S, known activators of G proteins, whereas ATP was almost uneffective. GTP-gamma-S inhibited the enzyme activity only at relatively high concentration (> 0.5 mM). When the synthesis of phosphatidylserine in the same cerebral area was investigated by measuring the incorporation of labelled serine into the phospholipid in the homogenate buffered at pH 7.6, ATP had an inhibitory effect as GTP-gamma-S and AlF4-. Heparin activated both serine base exchange enzyme in plasma membranes and phosphatidylserine synthesis in the homogenate. The preincubation of plasma membranes in the buffer without any other addition at 37 degrees C for 15 min reduced by 30% serine base exchange enzyme activity. The remaining activity responded to the addition of GTP-gamma-S but was insensitive to 5 mM AlF-4, a concentration that inhibited by 60% the enzyme assayed without preincubation. These results indicate the existence of different regulatory mechanisms, involving ATP and G proteins, possibly acting on different enzymes responsible for the synthesis of phosphatidylserine. Since previous studies have shown that hypoxia increases the synthesis of this phospholipid in brain slices or homogenate (Mozzi et al. Mol Cell Biochem 126: 101-107, 1993), it is possible that hypoxia may interfere with at least one of these mechanisms. This hypothesis is supported by the observation that in hypoxic homogenate 20 mM AlF-4 was not able to reduce the synthesis of phosphatidylserine as in normoxic samples. A similar difference between oxygenated and hypoxic samples, concerning their response to AlF4-, was observed when the incorporation of ethanolamine into phosphatidylethanolamine was studied. The incorporation of choline into phosphatidilcholine was, on the contrary, inhibited at a similar extent in both experimental conditions.

Phosphatidylserine synthesis in rat cerebral cortex: effects of hypoxia, hypocapnia and development

Phosphatidylserine, which is necessary for protein kinase C activity, is synthesized in mammalian tissues by the Ca(2+)-dependent base exchange enzyme. The synthesis of phosphatidylserine is greater in slices or homogenates of rat cerebral cortex subjected to hypoxia by N2 treatment when compared with O2 plus 5% CO2. An intermediate effect was observed when the treatment was done with N2 plus 5% CO2. Incorporation rates were dependent on Ca2+ in Krebs-Henseleit Ringer bicarbonate medium, being greater with 2 mM Ca2+ than with the same medium prepared without Ca2+. The increase of phosphatidylserine synthesis, due to hypoxia, was, on the contrary, more evident in the medium lacking added Ca2+. Similar results were obtained with the homogenates. This suggests that elevation of intracellular Ca2+, caused by hypocapnia and hypoxia, may be responsible for the greater incorporation of serine into phosphatidylserine. In both cerebrocortical slices and homogenate, [14C]serine incorporation decreased with development both in O2 plus 5% CO2 and N2-treated preparations. However, in younger rats (14-18 days) hypoxia induced a lesser increase of phosphatidylserine than in 40 day old animals. We suggest that a regulatory mechanism for phosphatidylserine synthesis is established during development and that N2-treatment can increase phosphatidylserine synthesis by interfering with this regulatory mechanism.

The complexity of psychiatric nosography and the "simplicity" of molecular genetics

Are molecular genetic approaches, related at the present time to psychiatric categories, mostly conventional? If the psychiatric field is to be related with the plasticity of the brain, and then to its ability to be reorganized relative to experiences, it seems to be more important to study the relation between genetics and brain plasticity. It therefore seems more significant today, to be raising questions rather than gathering data.

Affective disorders and S-adenosylmethionine: a new hypothesis

S-Adenosyl-L-methionine (AdoMet) is a safe and probably effective antidepressant agent in certain forms of clinical depression. This article presents a new hypothesis to account for the mechanism of action of S-adenosylmethionine in such illnesses, based upon the known biochemistry of this compound, and upon current knowledge of clinical and genetic aspects of affective disorders. Giulio Cantoni, S. Harvey Mudd and V. Andreoli postulate that at least some major mood disorders are due to abnormalities affecting the AdoMet-dependent methylation of a substance in the CNS. For convenience and without prejudging the chemical structure of this substance, they call it 'barinine'. The model requires that barinine be subject to AdoMet-dependent methylation and that methylbarinine be subject to metabolic demethylation to regenerate the original barinine. Methylbarinine should be mood elevating, whereas barinine itself should not be. Depression is a result of abnormalities lowering the normal steady-state concentration of methylbarinine, whereas mania results from an abnormal elevation of methylbarinine.

Promazine. A major plasma metabolite of chlorpromazine in a population of chronic schizophrenics

N-Demethylation and dehalogenation of chlorpromazine (CPZ) were compared in six psychotic inpatients and in rats orally treated for 4 weeks with a daily CPZ dose of 5.4 (mean value) and 20 mg X kg-1 body weight, respectively, by measuring drug and metabolite plasma levels by means of a gas-liquid chromatography-nitrogen/phosphorus detector method. In patients the major plasma metabolite was found to be promazine (PZ), as identified by capillary GC-MS analysis. In rats, on the contrary, PZ represented only a small proportion of the compounds detected in plasma. The mean [PZ]/[CPZ] ratio after 4 weeks of treatment was 1.64 in patients and 0.08 in rats. The relative frequency of the N-demethyl metabolites in plasma, however, was similar in the two species. The mean [N-monodemethylated CPZ]/[CPZ] and [N-didemethylated CPZ]/[CPZ] ratios after 4 weeks of treatment were 0.45 and 0.24 in patients and 0.56 and 0.25 in rats, respectively. These findings suggest that dechlorination of CPZ in psychotic patients represents an important metabolic pathway.

Facilitation of social interaction through deindividuation of the target

It was hypothesized that actors want their perception of a target to be consistent with the type of interaction they expect. It was predicted that subjects expecting to aggress would deindividuate their target through the selective recall of deindividuating information. Conversely, subjects expecting a prosocial interaction should individuate the target. Further, angry subjects should deindividuate the individual who angered them. Male subjects were either angered or not angered by an experimental confederate and then given the opportunity to either shock, reward, or have no interaction with him. Subjects recalled information about the confederate either prior to or after the learning task. Subjects expecting to aggress deindividuated the target, whereas subjects expecting a prosocial interaction individuated him. Angry subjects deindividuated the target, nonangry subjects did not. Since the selective recall of information occurred prior to the interaction, the deindividuation (individuation) was aimed at facilitating future behavior rather than justifying it.

Facilitation of social interaction through deindividuation of the target

It was hypothesized that actors want their perception of a target to be consistent with the type of interaction they expect. It was predicted that subjects expecting to aggress would deindividuate their target through the selective recall of deindividuating information. Conversely, subjects expecting a prosocial interaction should individuate the target. Further, angry subjects should deindividuate the individual who angered them. Male subjects were either angered or not angered by an experimental confederate and then given the opportunity to either shock, reward, or have no interaction with him. Subjects recalled information about the confederate either prior to or after the learning task. Subjects expecting to aggress deindividuated the target, whereas subjects expecting a prosocial interaction individuated him. Angry subjects deindividuated the target, nonangry subjects did not. Since the selective recall of information occurred prior to the interaction, the deindividuation (individuation) was aimed at facilitating future behavior rather than justifying it.

Double-blind cross-over clinical comparison of two 2'-chloro benzodiazepines: 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one (chlordesmethyldiazepam) versus 7-chloro-5-(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) in neurotic anxiety

A group of 20 female neurotic inpatients has been treated with 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one-(chlordesmethyldiazepan)- 7-chloro-5(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) according to a double-blind cross-over design. For each drug clinical evaluations were performed by means of Hamilton's rating scale for anxiety states and of Overall and Gorham's brief psychiatric rating scale, at the beginning, after the first week and at the end of the two-week period of treatment, in opposite sequence. A statistically greater efficacy of chlordesmethyldiazepam in comparison to lorazepam was observed. Results are discussed with regard to benzodiazepine structure-activity relationships.

Plasma tryptophan transport in normal and depressed subjects

Depressed patients have a delayed clearance of i.v. injected labelled 1-tryptophan. A high affinity binding for the amino acid and a derangement of transport or distribution to tissues in the depressed are suggested as possible mechanisms.