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Profile and burden of the family caregiver: the caring experience in multiple sclerosis. An observational study. BMC Psychol 2024; 12:173. [PMID: 38528601 DOI: 10.1186/s40359-024-01678-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 03/20/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND The broad implications of caring for a family member with a chronic medical condition, such as MS, can lead caregivers to experience a high burden of care. The aim of the study was to describe profile of MS caregivers and their burden and to explore potential factors influencing this burden. METHODS 200 family caregivers of a person with MS completed survey questionnaires across a cross-sectional study. Many information were collected: caregiver socio-demographic and health-related data, caregiving activities, knowledge of MS, coping strategies, mood, social support received and care recipient information. Caregiving burden was measured by the ZBI (Zarit Burden Interview). The extent to which the variables explained caregiver burden was analyzed using a hierarchical approach. RESULTS 68% of the caregivers reported a perceived burden of care (ZBI score > 20). Our results show that physical and mental related-health variables are important predictive factors of the care burden, explaining much of the observed variance (40.9%). CONCLUSION Family caregivers in MS continue to make up the shortfall produce by national health and welfare systems. We highlighted the importance of good physical and mental health in decreasing perceived burden. Working to alleviate psychological distress through mechanisms focus on reducing worries and perceived burden may be a valid approach.
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Work Difficulties in People with Multiple Sclerosis. JOURNAL OF OCCUPATIONAL REHABILITATION 2023:10.1007/s10926-023-10149-9. [PMID: 37921967 DOI: 10.1007/s10926-023-10149-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/17/2023] [Indexed: 11/05/2023]
Abstract
PURPOSE This study identifies potential predictors of unemployment and describes specific work difficulties and their determinants in a subgroup of employed people with multiple sclerosis (PwMS). The specific work difficulties were evaluated using a validated tool that measures the impact of respondents' symptoms and of workplace features. METHODS A cross-sectional study was carried out in Italy during 2021-2022. The subjects included were adults (18-65 years) with a diagnosis of MS, currently employed or unemployed. Logistic regression models were used to determine the association between each potential determinant and employment status, while linear regression models were used to determine the association between determinants and specific work difficulties. RESULTS The main risk factors associated with a higher risk of being unemployed were being older, living in the South of Italy/islands, and having a higher disability level, while protective factors against unemployment were having a high level of education and 'stable' employment (an open-ended contract). Fatigue was found to be associated with all work difficulties analyzed; mood disorders emerged as the main predictors of mental health-related work difficulties; level of disability and comorbidity significantly impacted physical health-related ones, and a good quality of life was found to improve both workplace-related and mental health-related difficulties at work. CONCLUSION Identifying the most significant difficulties is a crucial step in the development of vocational rehabilitation interventions tailored to maximize the ability of PwMS to handle their job-related duties and demands.
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Development and psychometric properties of a self-assessed knowledge questionnaire for caregivers of people with multiple sclerosis (CareKoMS): a cross-sectional study. BMJ Open 2023; 13:e071657. [PMID: 37399437 DOI: 10.1136/bmjopen-2023-071657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/05/2023] Open
Abstract
OBJECTIVES Knowledge about multiple sclerosis (MS) is crucial for those who provide care and support as caregivers. However, despite the key benefits of acquiring relevant information to properly assume the caregiving role, caregivers' knowledge of MS is poorly investigated. The aim of this study was to develop and validate the Caregivers' Knowledge of Multiple Sclerosis (CareKoMS), a self-assessed questionnaire, to test MS knowledge in caregivers of people with MS. DESIGN Cross-sectional study. SETTING Italy. PARTICIPANTS Two-hundred caregivers (female: 49%) were asked to self-administer the 32-item CareKoMS questionnaire; they had a median age of 60 years (IQR: 51-68 years) and a medium-high educational level (36.5% primary school and 63.5% high school/university). Item analysis using item difficulty index, item discrimination index, Kuder-Richardson-20 coefficient and item-total correlation were assessed. Once excluding less useful items, reliability, floor and ceiling effects and construct validity were calculated on the 21-item CareKoMS final version. RESULTS Psychometric evaluation indicates that the 21-item CareKoMS was a good questionnaire with no ceiling or floor effects registered. Internal consistency was satisfactory and acceptable as indicated by the mean value of 0.74 of Kuder-Richardson-20. No ceiling or floor effects have been observed. Interestingly, educational level and disease duration correlated with MS knowledge. CONCLUSION CareKoMS is a valid self-assessed questionnaire on MS knowledge for caregivers that may be used in clinical practice and research. Assessing knowledge of MS among caregivers is essential to facilitate their caregiving role and thus decrease the burden of disease management.
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[Epidemiological analysis on the hospitalization from neurological diseases in the Province of Pavia (Lombardy Region, Northern Italy)]. EPIDEMIOLOGIA E PREVENZIONE 2019; 43:286-294. [PMID: 31650784 DOI: 10.19191/ep19.4.p286.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
OBJECTIVES to evaluate time and spatial distribution of hospitalization due to neurological diseases in the province of Pavia (Lombardy Region, Northern Italy). DESIGN ecological study. SETTING AND PARTICIPANTS the study was performed on aggregate data of people residing in the province of Pavia in the period 2005-2014. MAIN OUTCOME MEASURES hospital discharge records of neurological diseases and raw and standardized hospitalization rates. RESULTS hospitalization due to neurological diseases in the Province of Pavia showed a slight decreasing trend in time. For the year 2014, the spatial analysis of hospitalizations highlights excesses of risk in the Lomellina district, both in males and in females. CONCLUSION spatial analysis confirms previous results on specific neurological diseases and suggests more detailed analysis on hospitalization excesses in Lomellina area.
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756. Resection of primary leiomyosarcoma of the inferior vena cava (IVC) with reconstruction: A case series. Eur J Surg Oncol 2016. [DOI: 10.1016/j.ejso.2016.06.376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Novel automated system for magnetic resonance imaging quantification of the inflamed synovial membrane volume in patients with juvenile idiopathic arthritis. Arthritis Care Res (Hoboken) 2012; 64:1657-64. [DOI: 10.1002/acr.21739] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Reply to "Ethical concerns surrounding the conception of an HLA-compatible child for medical purposes" Haematologica 2012;97(9):e33. Haematologica 2012. [DOI: 10.3324/haematol.2012.070318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Abstract
SUMMARYObjective – The study investigated eating disordered behaviours and life-habits correlated in a large sample of Northern Italian adolescents of both sexes. Methods – The study had a cross-sectional design. 2595 students (2,146 responders; mean age 17.2±1.7 years) attending high schools in Savona (Italy) in April and May 2001 were sampled. To assess eating attitudes, the Inventory for the Screening of Eating Disorders (ISED) was self-administered. Inquiries regarding possible risk factors for eating disorders were also made: socio-economic status, body weight, smoking and alcohol drinking habits, illegal drugs use. Results – Females scored significantly higher than males at ISED (13.4±7.7 vs. 7.6±5.8). 28.5% of females had a total ISED score above the cut-off point (18/19). Unhealthy eating behaviours were strongly associated with higher BMI, body image disturbance and illegal drugs use in both sexes; age had significant role only in males. No significant association between disordered eating behaviours and socio-economic status, smoking habit and alcohol consumption were found. Conclusions – Symptoms of eating disorders are quite spread in the Northern Italian female adolescents and associate with illegal drugs use. These data, with not negligible frequency of unhealthy eating behaviours and attitudes in males too, suggest that primary and secondary preventive interventions for teen-agers should be got ready.Declaration of Interest: 1) the study received the financial support by Regione Liguria and ASL 2 of Savona; 2) the study didn't receive any forms of financing by pharmaceutical company support and any honoraria for consultancies or interventions was received by each author in the last two years; 3) any other involvements that might be considered a conflict of interest in connection with the submitted article. The authors state that if and when the manuscript accepted for publication, they automatically agree to transfer the copyright to the publisher
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Abstract
We discuss how a large class of regularization methods, collectively known as spectral regularization and originally designed for solving ill-posed inverse problems, gives rise to regularized learning algorithms. All of these algorithms are consistent kernel methods that can be easily implemented. The intuition behind their derivation is that the same principle allowing for the numerical stabilization of a matrix inversion problem is crucial to avoid overfitting. The various methods have a common derivation but different computational and theoretical properties. We describe examples of such algorithms, analyze their classification performance on several data sets and discuss their applicability to real-world problems.
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Inverse relationship between multiple sclerosis and allergic respiratory diseases. Neurol Sci 2009; 30:115-8. [PMID: 19259620 DOI: 10.1007/s10072-009-0036-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 02/05/2009] [Indexed: 11/24/2022]
Abstract
Th1 up-regulation seems to favour autoimmunity, while Th2 up-regulation seems to favour humoral immunity. Accordingly, subjects affected by atopic diseases (such as allergic respiratory diseases, ARDs) should be less prone to autoimmune diseases (such as multiple sclerosis, MS), and vice versa. The recent identification of Th17 cells, which seem to favour the development of both autoimmunity and allergy, led to the revision of the classic Th1/Th2 paradigm. We studied 200 MS patients and 200 controls to analyze the relationships between ARDs and MS. MS patients had less probability to suffer from ARDs (OR = 0.30, p < 0.001) and allergic rhinitis (OR = 0.25, p < 0.001), after adjusting for environmental factors. MS tended to be less severe when associated to ARDs. Our findings add some elements for the comprehension of immune mechanisms involved in MS pathogenesis and suggest to analyze other MS cohorts, in order to evaluate if MS patients affected by allergic diseases show particular clinical findings.
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Motorcycle accidents in forensic pathology. Human factors, and injury and crash tipologies. EMERGENCY CARE JOURNAL 2008. [DOI: 10.4081/ecj.2008.5.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Quantitative assessment of synovitis in juvenile idiopathic arthritis using Dynamic Contrast-Enhanced Magnetic Resonance Imaging. Pediatr Rheumatol Online J 2008. [PMCID: PMC3334159 DOI: 10.1186/1546-0096-6-s1-p94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Motorcycle accident in a forensic-pathological perspective. EMERGENCY CARE JOURNAL 2008. [DOI: 10.4081/ecj.2008.1.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Early haemoglobin-independent increase of plasma erythropoietin levels in patients with acute myocardial infarction. Eur Heart J 2007; 28:1805-13. [PMID: 17412728 DOI: 10.1093/eurheartj/ehm065] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
AIMS We studied plasma erythropoietin (EPO) levels and their relation with CD34(+)VEGFR-2(+) (mature and progenitor endothelial cells) and CD34(+) CD133(+)VEGFR-2(+), or CD34(+) CD117(+)VEGFR-2(+) (early/immature endothelial progenitors) cells in patients with acute myocardial infarction (AMI). METHODS AND RESULTS Fifty AMI patients undergoing percutaneous coronary intervention (PCI) within 6 h of symptom onset were enrolled. EPO, measured by ELISA, and cell subsets, by cytofluorimetric analysis, were evaluated before PCI, 24 h and 7 days afterwards. Forty-five healthy subjects (CTRLs) were studied. Plasma EPO levels were higher in AMI patients at admission, 24 h, and 7 days (P = 0.04, P = 0.0001, P = 0.001, respectively) than in CTRLs. No correlation was evidenced between EPO and haemoglobin (Hb) or haematocrit at admission or 24 h after AMI. Differently, both Hb and haematocrit inversely correlated with EPO at day 7 (P = 0.0016, P = 0.029, respectively). Plasma EPO levels correlated with CD34(+)CD133(+)VEGFR-2(+) cells at day 7 (P = 0.03). CONCLUSION AMI patients have increased plasma EPO levels until day 7. In the early phase, plasma EPO levels are Hb-independent; at day 7, an Hb-modulated increase of EPO correlates with the percentage of CD34(+)CD133(+)VEGFR-2(+) cells.
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[Preliminary analysis of indoor pollution from nitrogen dioxide in an area of Northern Italy]. EPIDEMIOLOGIA E PREVENZIONE 2006; 30:85-90. [PMID: 16909956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE The aims of this work are to describe the annual mean concentration of NO2 and to identify the home features and "habits" of its occupants related to NO2 levels. Both indoor and outdoor NO2 concentrations were measured in 114 dwellings in Pavia (Northern Italy). DESIGN The study is in the frame of European Community Respiratory Health Survey II. Data were collected in the period 2001-2002 during home visits by trained fieldworkers. PARTICIPANTS 116 subjects gave the consent to home visits. MAIN OUTCOME MEASURE NO2 concentration measured using passive samplers. RESULTS Indoor NO2 concentration is in average 47.1 microg/m3 (+/- 24.5 microg/m3) and outdoor NO2 concentration is 44.3 microg/m3 (+/- 14.5 microg/m3). The gas oven is the only domestic gas appliance associate with high levels of NO2 when measuring in homes. The outdoor pollution affects NO2 indoor concentrations and contribute to store NO2 in homes. CONCLUSION the study is the first step in the evaluation of NO2 exposure effect on respiratory health.
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Molecular basis for the antiviral and anticancer activities of unnatural L-beta-nucleosides. Expert Opin Investig Drugs 2005; 7:1285-300. [PMID: 15992031 DOI: 10.1517/13543784.7.8.1285] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
As a general rule, enzymes act on only one enantiomer of a chiral substrate and only one of the enantiomeric forms of a chiral molecule may bind effectively at the catalytic site, displaying biological activity. In recent years, some exceptions have been found among viral and cellular enzymes involved in the synthesis of deoxynucleoside triphosphates and in their polymerisation into DNA. Examples are: herpes virus thymidine kinases, cellular deoxycytidine kinase and deoxynucleotide kinases, human immunodeficiency virus type 1 (HIV-1) reverse transcriptase, hepatitis B virus (HBV) DNA polymerase and, to a lesser extent, some cellular DNA polymerases. The lack of enantioselectivity allows herpes simplex virus (HSV) thymidine kinase and cellular deoxycytidine kinase to phosphorylate the unnatural L-beta-enantiomers of D-thymidine and D-deoxycytidine, respectively, or of their analogues to monophosphate. This phosphorylation represents the first and often the rate-limiting step of their activation to triphosphates. The L-triphosphates can then exert antiviral (anti-HSV, anti-Human cytomegalovirus, anti-HIV-1, anti-HBV) and anticancer activities. Although only one L-nucleoside (3TC) has so far gained United States of America Food and Drug Administration (USA FDA) approval for clinical use against HIV-1, other L-enantiomers of nucleoside analogues, which have shown antiviral or anticancer activity in cell cultures are in clinical trials. Their resistance to enantioselective enzymes, such as thymidine phosphorylase, thymidylate synthase, (deoxy)-cytidine and dCMP deaminases, and their lower affinity for the mitochondrial thymidine kinase can ensure a higher selectivity and lower cytotoxicity with respect to those exerted by their corresponding natural D-enantiomers and might be exploited to solve problems arising during chemotherapy, such as metabolic inactivation, cytotoxicity and drug-resistance.
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Molecular characteristics of small intestinal and renal brush border thiamin transporters in rats. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1558:187-97. [PMID: 11779568 DOI: 10.1016/s0005-2736(01)00430-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The molecular characteristics of thiamin (T) transport were studied in the small intestinal and renal brush border membrane vesicles of rats, using [(3)H]T at high specific activity. The effects of various chemical modifiers (amino acid blockers) on T uptake were examined and their specificity assessed. Treatment with the carboxylic specific blockers 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluene sulfonate, (1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide hydrochloride and N-ethyl-5-phenylisoaxolium-3'-sulfonate (Woodward's Reagent K) and with the sulfhydryl specific blocker p-chloromercuribenzene sulfonate inhibited T transport in both types of vesicles. Phenylglyoxal, but not ninhydrin, both reagents for arginine residues, and diethylpyrocarbonate, a reagent for histidine residues, specifically decreased T transport only in renal and small intestinal vesicles respectively. Similarly 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole reacted, but not N-acetylimidazole, both of which are reagents for tyrosine residues. However, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole inhibition was aspecific. Acetylsalicylic acid, a reagent for lysine and serine residues, decreased T transport, but the lysine effect was aspecific. Acetylsalicylic acid serine blockage also eliminated T/H(+) exchange in small intestinal vesicles. Taken together, these results suggest that for T transport carboxylic and sulfhydryl groups and serine residues are essential in both renal and small intestinal brush border membrane vesicles. In addition, arginine and histidine residues are also essential respectively for renal and small intestinal transporters. Serine was essential for the T/H(+) antiport mechanism.
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5-(Trifluoromethyl)-beta-l-2'-deoxyuridine, the L-enantiomer of trifluorothymidine: stereospecific synthesis and antiherpetic evaluations. Bioorg Med Chem 2001; 9:1731-8. [PMID: 11425574 DOI: 10.1016/s0968-0896(01)00062-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
As a part of our ongoing work on beta-L-nucleoside analogues as potential antiviral drugs, we have synthesized 5-(trifluoromethyl)-beta-L-2'-deoxyuridine (L-TFT), the hitherto unknown L-enantiomer of trifluorothymidine (CF(3)dUrd, TFT). We have also studied the effect of L-TFT on human and herpes simplex virus (HSV) type 1 and 2 thymidine kinases, and human thymidine phosphorylase, as well as its anti-HSV-1 and anti-HSV-2 activities in cell cultures. L-TFT has been found: (i) to inhibit HSV-1 TK with activity comparable to TFT, with no effect on human TK, (ii) to be phosphorylated by the viral enzyme with similar efficiency to TFT, (iii) to be resistant, in contrast to TFT, to hydrolysis by human thymidine phosphorylase. Unfortunately, when evaluated in cell cultures, L-TFT did not show any anti-HSV-1 and anti-HSV-2 activities.
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Synthesis and in vitro activity of D- and L-enantiomers of 5-(trifluoromethyl)uracil nucleoside derivatives. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:1123-5. [PMID: 11562969 DOI: 10.1081/ncn-100002502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Recently, beta-L-nucleoside analogues have emerged as a new class of sugar modified nucleosides with potential antiviral and/or antitumoral activity. As a part of our ongoing research on this topic, we decided to synthesize 5-CF3-beta-L-dUrd (7), the hitherto unknown L-enantiomer of Trifluridine, an antiherpetic drug approved by FDA but only used in topical applications due to concomitant cytotoxicity. 5-CF3-beta-L-dUrd (7) as well as some other related L-nucleoside derivatives were stereospecifically prepared and tested in vitro against viral (HSV-1 and HSV-2) and human thymidine kinases (TK).
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Anti-(herpes simplex virus) activity of 4'-thio-2'-deoxyuridines: a biochemical investigation for viral and cellular target enzymes. Biochem J 2000; 351 Pt 2:319-26. [PMID: 11023816 PMCID: PMC1221366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The antiviral activity of several nucleoside analogues is often limited by their rapid degradation by pyrimidine nucleoside phosphorylases. In an attempt to avoid this degradation, several modified nucleosides have been synthesized. A series of 4'-thio-2'-deoxyuridines exhibits an anti-[herpes simplex virus (HSV)] activity significantly higher (20-600 times) than that shown by the corresponding 4'-oxy counterpart. We investigated the mode of action of these compounds and we found that: (i) several 4'-thio-2'-deoxyuridines are phosphorylated to the mono- and di-phosphates by HSV-1 thymidine kinase (TK) more efficiently than their corresponding 4'-oxy counterpart; (ii) both are inhibitors of cellular thymidylate synthase; (iii) 4'-thio-2'-deoxyuridines are resistant to phosphorolysis by human thymidine phosphorylase; (iv) both 4'-oxy- and 4'-thio-2'-deoxyuridines are phosphorylated to deoxyribonucleotide triphosphate in HSV-1-infected cells and are incorporated into viral DNA; (v) 4'-thio-2'-deoxyuridines are better inhibitors than their 4'-oxy counterparts of [(3)H]thymidine incorporation in HSV-1-infected cells; (vi) 4'-thio-2'-deoxyuridines are not recognized by HSV-1 and human uracil-DNA glycosylases. Our data suggest that 4'-thio-2'-deoxyuridines, resistant to pyrimidine phosphorylase, can be preferentially or selectively phosphorylated by viral TK in HSV-infected cells, where they are further converted into triphosphate by cellular nucleotide kinases. Once incorporated into viral DNA, they are better inhibitors of viral DNA synthesis than their corresponding 4'-oxy counterpart, either because they are not recognized, and thus not removed, by viral uracil-DNA glycosylase, or because they preferentially interfere with viral DNA polymerase.
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Cl/HCO3 antiport affects H-lactate symport activity at the basolateral pole of jejunum enterocyte. Cell Physiol Biochem 2000; 8:151-7. [PMID: 9617477 DOI: 10.1159/000016278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Under normal conditions the jejunal tract of the rat intestine absorbs HCO3. A basolateral Cl/HCO3 exchange, evidenced by means of membrane vesicles, could be involved in this process. Aim of this study was to investigate the anion exchange activity in the whole jejunal tract, where various transport systems could interact. METHODS In the jejunal tract of rat intestine everted and incubated in vitro, the experimental conditions set up minimized loss of CO2 from the serosal solution, where pH and pCO2 were determined together with fluid and electrolyte transintestinal transport. RESULTS The serosal pCO2 increase and pH decrease, evident during the experiment, could be antagonized by enhancing the 4,4-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) concentrations in the serosal fluid. Moreover high DIDS concentration affected fluid, sodium, lactate, bicarbonate and, although in the opposite direction, chloride transport, whilst they were ineffective on K flux. CONCLUSION These results give evidence that in the basolateral membrane the inhibition of Cl/HCO3 antiport causes a diminution of lactic acid movement. Therefore we can hypothesize that Cl/HCO3 antiport facilitates basolateral H-lactate symport in order to carry endogenous lactic acid towards the blood stream.
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Riboflavin phosphorylation is the crucial event in riboflavin transport by isolated rat enterocytes. J Nutr 2000; 130:2556-61. [PMID: 11015489 DOI: 10.1093/jn/130.10.2556] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In isolated rat enterocytes, both normoenergized (normal) and de-energized with rotenone, riboflavin intracellular metabolic processes, operating in association with a membrane-specific transport mechanism, were investigated. The contents of unlabeled (endogenous) and labeled (exogenous) flavins [riboflavin (RF), flavin mononucleotide (FMN), flavin adenindinucleotide (FAD)] were determined by HPLC before and after incubation with tritiated RF. In normoenergized enterocytes, total labeled RF content (i.e., total uptake, the sum of RF membrane transport and intracellular metabolism) increased steadily to a plateau after 20 min incubation; FMN and FAD contents reached a plateau between 3 and 20 min, whereas free RF content increased constantly. The phosphorylated forms prevailed over the free form ( approximately 60% of total flavins). In de-energized enterocytes, RF total uptake was significantly lower than in normoenergized enterocytes and reached a plateau after only 3 min incubation. FMN and FAD contents were significantly lower than in normoenergized enterocytes, and free RF represented the prevailing form of flavins (70% of total RF ). In both normoenergized and de-energized enterocytes, the contents of unlabeled total RF, FMN and FAD decreased significantly after 20 min incubation, whereas free RF increased significantly only in normoenergized enterocytes. After 20 min incubation, the RF structural analog 8-dimethyl-amino-8-demethyl-RF caused a significant decrease of all flavin contents, whereas 5'-deoxy-RF decreased only the total and free RF contents. Results directly confirmed the leading role of metabolic processes such as phosphorylation in RF transport by isolated small intestinal enterocytes.
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Abstract
BACKGROUND Unlike intestinal absorption, renal transport of thiamin has received little attention. This study was designed to investigate the reabsorptive steps of thiamin transport in brush border membrane vesicles (BBMVs) from rat kidney proximal tubules using tritiated thiamin with a high specific activity. METHODS BBMVs prepared from the cortex kidney of rats were suspended in different media, controlling the composition of the intravesicular fluid by prolonged equilibration at 4 degrees C in preincubation buffers of desired composition. Then they were held on ice until used, when they were warmed at 25 degrees C for the uptake experiments. The amount of radioactivity taken up by the vesicles was measured radiometrically after separation with a rapid-filtration procedure. RESULTS The time course profile of thiamin uptake was Na+ independent; 53% of thiamin taken up was membrane bound. The concentration curve had a biphasic course that was nonlinear (saturable) at physiological concentrations (<1.25 micromol/L) and linear at higher ones. Thiamin uptake was stimulated several-fold by an outwardly directed H+ gradient (pHin 6:pHout 7.5), which caused a transient accumulation of thiamin inside BBMVs against a concentration gradient. The enhanced thiamin uptake was only due to the H+ gradient, which made thiamin binding virtually negligible compared with translocation, and maintained the biphasic course of the concentration curve. The saturable component, however, had kinetic constants 12-fold higher than those in the absence of gradient. Moreover, the saturable component was inhibited by nonlabeled thiamin and its structural analogues, by inhibitors of intestinal thiamin/H+, renal guanidine/H+, and Na+/H+ antiporters, while it remained unmodified by some typical organic cations transported in renal BBMVs. CONCLUSION The results provide strong evidence for the presence in renal BBMVs of a thiamin/H+ antiport having a 1:1 stoichiometric ratio.
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Oral self-mutilation in a patient with rhombencephalosynapsys. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2000; 44 ( Pt 1):86-90. [PMID: 10711654 DOI: 10.1046/j.1365-2788.2000.00242.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Rhombencephalosynapsis (RS) is a rare cerebellar malformation. Its essential features are the absence of the incisura cerebelli posterior, fusion of the cerebellar hemispheres, the absence of the velum medullare anterius and nuclei fastigii, and fusion of the dentate nuclei, which are shifted towards the mid-line. Clinically, affected patients present with signs of cerebellar and motor disturbances. The present report describes a new patient affected by RS. The subject first presented at the age of 22 years because of a psychiatric symptomatology which was characterized by obsessive oral self-mutilation associated with an intellectual disability. Objective evaluation documented dysmorphic features, while neurological examination showed only a slight truncal ataxia. The subject's IQ was 74 on the Wechsler Scale (verbal IQ = 79, performance IQ = 74). Psychiatric evaluation with DSM-IV criteria documented an obsessive-compulsive personality disorder associated with emotional instability and oral self-mutilation. The typical picture of rhombencephalosynapsis was evident on magnetic resonance imaging. Both chromosomal analysis and routine biochemical investigations were normal. The relationship between oral self-injurious behaviour and cerebellar malformations is discussed with particular regard to the behavioural aspects of cerebellar congenital pathology in affective disorders and in autism.
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An Italian-Australian comparison of quality of life among people with intellectual disability living in the community. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 1999; 43 ( Pt 6):513-522. [PMID: 10622368 DOI: 10.1046/j.1365-2788.1999.00241.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper reports the measurement of both objective and subjective quality of life in samples of people either with intellectual disability or from the general adult population, drawn from Australia and Italy. Measures were made using the Comprehensive Quality of Life Scale. Generally, it was found that the scores for all groups were comparable. This finding is consistent with the provision of generally decent objective living conditions in both countries and subjective well-being homeostasis, wherein subjective quality of life is held within a predictable range. These results are discussed in the context of measurement difficulties imposed by the need for simple Likert scales and subjective data which are strongly negatively skewed.
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Molecular modeling and synthesis of inhibitors of herpes simplex virus type 1 uracil-DNA glycosylase. J Med Chem 1999; 42:2344-50. [PMID: 10395474 DOI: 10.1021/jm980718d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We recently reported the properties of the first selective inhibitors of herpes simplex virus type 1 (HSV1) uracil-DNA glycosylase (UDG), an enzyme of DNA repair that has been proposed to be required for reactivation of the virus from latency. 6-(4-Octylanilino)uracil (octAU) was the most potent inhibitor among a series of 6-(4-alkylanilino)uracils, acting in the micromolar range and without effect against human UDG. A 28.5-kDa catalytic fragment of HSV1 UDG has been crystallized in the presence of uracil, and the structure was recently solved. We have used the coordinates of this structure in order to study interaction of our inhibitors with the enzyme, and a model of binding between octAU and UDG has been derived. Starting with the optimized model, the activity of several octAU analogues was predicted, and the values compared favorably with experimental results found for the synthetic compounds. Several hydrophilic derivatives were predicted and found to be active as UDG inhibitors. These compounds will be useful to determine if UDG, like the viral thymidine kinase, is required for reactivation of HSV1 from latency in nerve cells.
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Contingent negative variation indicates phasic arousal for externally cued unilateral eye blink in human subjects. Neurosci Lett 1999; 266:57-60. [PMID: 10336183 DOI: 10.1016/s0304-3940(99)00261-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The contingent negative variation (CNV) as a slow cortical potential was used to investigate cortical processing of externally cued, voluntary unilateral eye blink. Probands blinked as a response within a modified two-stimulus reaction time paradigm. Reaction time and amplitudes of CNV were determined. The activity of the orbicularis oculi muscles (OO) was registered by surface electromyography (EMG). Probands who performed unilateral eye blinks with accurately inhibiting contralateral OO activity showed a significantly higher negativity of the early CNV component compared with the bilateral eye blink condition. This effect was confined to the beginning of unilateral blinking performance. It is suggested that the unilateral eye blink is a challenging motor task, initially requiring an increased cortically driven arousal and attention as revealed by increased early CNV components.
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Synthesis and molecular modeling of novel HSV1 uracil-DNA glycosylase inhibitors. NUCLEOSIDES & NUCLEOTIDES 1999; 18:709-11. [PMID: 10432670 DOI: 10.1080/15257779908041549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In a recent paper the first selective inhibitors of HSV1 uracil-DNA glycosylase (UDG) acting in the micromolar range have been reported. A 28.5 kDa catalytic fragment of HSV1 UDG has been crystallized in the presence of uracil, and the structure was recently solved. Starting with the optimized model of binding between 6-(4'-n-octylanilino)uracil (octAU) and UDG some new derivatives have been predicted to be active. In vitro studies with the novel synthetized compounds confirm the plausibility of the model and define the structure features for UDG inhibitors.
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Interaction of beta-L-adenosine-5'-triphosphate (L-ATP) with human deoxycytidine kinase, human DNA primase and T4 DNA ligase: does the chance direct enzymatic enantioselectivity? NUCLEOSIDES & NUCLEOTIDES 1999; 18:867-9. [PMID: 10432697 DOI: 10.1080/15257779908041585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We demonstrate that L-ATP: 1) as well as its natural D-enantiomer, acts as a phosphate donor in the reaction catalysed by human deoxycytidine kinase; 2) inhibits human DNA-primase and the ATP-dependent T4 DNA ligase. Thus, the lack of enantioselectivity of the enzymes is more frequent than it was believed a few years ago and we suggest that it would depend on chance more than on an evolutionary strategy.
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L-ATP is recognized by some cellular and viral enzymes: does chance drive enzymic enantioselectivity? Biochem J 1999; 337 ( Pt 3):585-90. [PMID: 9895305 PMCID: PMC1220013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We demonstrate that l-ATP is recognized by some enzymes that are involved in the synthesis of nucleotides and nucleic acids. l-ATP, as well as its natural d-enantiomer, acts as a phosphate donor in the reaction catalysed by human deoxycytidine kinase, whereas it is not recognized by either enantioselective human thymidine kinase or non-enantioselective herpes virus thymidine kinase. l-ATP strongly inhibits (Ki 80 microM) the synthesis of RNA primers catalysed by DNA primase associated with human DNA polymerase alpha, whereas RNA synthesis catalysed by Escherichia coli RNA polymerase is completely unaffected. Moreover, l-ATP competitively inhibits ATP-dependent T4 DNA ligase (Ki 25 microM), suggesting that it interacts with the ATP-binding site of the enzyme. Kinetic studies demonstrated that l-ATP cannot be used as a cofactor in the ligase-catalysed joining reaction. On the other hand, l-AMP is used by T4 DNA ligase to catalyse the reverse reaction, even though a high level of intermediate circular nicked DNA molecules accumulates. Our results suggest that a lack of enantioselectivity of enzymes is more common than was believed a few years ago, and, given the absence of selective constraints against l-nucleosides in Nature, this may depend on chance more than on evolutionary strategy.
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Cerebellar dysgenesis and mental retardation associated with a complex chromosome rearrangement. ANNALES DE GENETIQUE 1999; 42:210-4. [PMID: 10674160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Cerebellar hypoplasia, mild mental retardation, skeletal abnormalities, and ataxia were present in a 40 years old patient with a complex chromosome rearrangement (CCR). Chromosomes 2, 5, 16, and 17 were involved in the CCR. For the definition of the eight breakpoints leading to the rearrangement FISH with whole chromosomes paintings and specific telomeric probes was employed. Gene disruption, positional effect variegation, and sub-microscopic deletions are all possible causes for the abnormal phenotype observed in the patient.
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Carotid endoarterectomy in the presence of contralateral carotid occlusion. Minerva Cardioangiol 1998; 46:429-34. [PMID: 10207290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
BACKGROUND The purpose of this study was to define a correct anesthesiological and surgical approach in patient who present a significant carotid stenosis with contralateral carotid occlusion. METHODS Between 1996 and 1998 in our Department of Vascular Surgery of the Hospital S. Giovanni Battista has been executed 337 Carotid Endoarterectomies (CEA). Of these, 44 patient (13%) had a contralateral internal carotid occlusion. Forty was male (91%), and 4 female (9%). Echo Doppler, angiography, angioTC or angio-RMN and TCD were performed in all patients. In all cases was executed a traditional CEA. RESULTS Because of the presence of a large ischaemic cerebral lesion or clamping intolerance 12 operation were performed under general anesthesia (27%). Shunt was used in 15 patients (34%) and patch was used in 10 cases (23%). In 2 cases (4.5%) there was be a thrombosis of the operated internal carotid artery and one patient died (2.3%). CONCLUSIONS The presence of contralateral internal carotid occlusion with carotid stenosis > 70% increase the risk of peroperative stroke because of the difficulty of collateral cerebral blood flow. The execution of echo Doppler, angiography, angioTC or angioRM and TCD and their evaluation permit to choice the best anesthesiological and surgical treatment. The utilization of narcosis with thiopental protection and shunting reducing the rate of perioperative stroke, but the local anesthesia allows the best monitoring of intraoperative cerebral function. This behaviour was correctly when in patient with contralateral internal carotid occlusion there is an insufficient intracranic vascularization or an extensive ischaemic lesion or clamping intolerance.
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Abstract
OBJECTIVE The present study aimed to investigate the relationship between secondary amenorrhea due to different etiologic mechanisms, eating disorders, and psychiatric morbidity in a nonpsychiatric population observed in a gynecological department. METHOD Amenorrheic women (n = 95) with hypogonadotropic, hyperandrogenic, and hyperprolactinemic features were interviewed individually using the SCID-R (Structured Clinical Interview for DSM-III-R) to diagnose Axis I disorders including mood disorders, anxiety disorders, somatoform disorders, adjustment disorders, and eating disorders. Binge eating disorder was diagnosed according to DSM-IV criteria. RESULTS The incidence of eating disorders was significantly higher in hypogonadic women than in hyperandrogenic and hyperprolactinemic subjects (chi 2 = 23.03, p < .003). However, we also found a high percentage of hyperandrogenic women suffering from an eating disorder (40.9%) with a prevalence of binge eating disorder (27.2%), while the only eating disorder described in the hyperprolactinemic group was the not otherwise specified. In addition, a marked psychiatric comorbidity was found in amenorrheic women suffering from an eating disorder but a similar trend of pathologies was also found in amenorrheic women, without any positive SCID diagnosis for an abnormal eating disorder. DISCUSSION Our study demonstrated that a high incidence of eating disorders, mainly anorexia and binge eating, characterizes hypogonadic and hyperandrogenic women, respectively. In addition, secondary amenorrhea displays a wide spectrum of Axis I diagnoses, without a significant comorbidity with eating disorders. Whether or not the endocrine findings related to the amenorrheic condition constitute a common background for the occurrence of psychopathology or, alternatively, the presence of psychiatric disturbances may contribute to the development of menstrual dysfunction remain to be clarified.
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Neurological symptoms of the sick building syndrome: analysis of a questionnaire. FUNCTIONAL NEUROLOGY 1998; 13:225-30. [PMID: 9800149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Sick building syndrome (SBS) is an excess of work-related irritations of the skin and mucous membranes and of symptoms such as headache and fatigue in those working in modern air-conditioned buildings. We aimed to analyse the neurological symptoms, especially headache, in workers with potential SBS. The most frequent symptoms were headache and dry eyes. Sex was a major factor of difference: women report more symptoms than men. A positive correlation emerged between the number of symptoms and the asthenia scale score. Only 11 (8.2% of the whole sample) and 37 (27.4%) workers met all the IHS criteria for migraine and tension-type headache respectively. At least one symptom of SBS was present in 92.6% of workers. A negative correlation emerges between air conditioning and headache during working hours. No correlation emerges between the workplace comfort indicator and SBS and asthenic symptoms while a negative correlation was found between migraine and tension-type headache and comfort in the workplace. SBS symptoms are very frequent among all workers but headache is the primary symptom.
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Abstract
Support vector machines (SVMs) perform pattern recognition between two point classes by finding a decision surface determined by certain points of the training set, termed support vectors (SV). This surface, which in some feature space of possibly infinite dimension can be regarded as a hyperplane, is obtained from the solution of a problem of quadratic programming that depends on a regularization parameter. In this article, we study some mathematical properties of support vectors and show that the decision surface can be written as the sum of two orthogonal terms, the first depending on only the margin vectors (which are SVs lying on the margin), the second proportional to the regularization parameter. For almost all values of the parameter, this enables us to predict how the decision surface varies for small parameter changes. In the special but important case of feature space of finite dimension m, we also show that m + 1 SVs are usually sufficient to determine the decision surface fully. For relatively small m, this latter result leads to a consistent reduction of the SV number.
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Some 6-aza-5-substituted-2'-deoxyuridines show potent and selective inhibition of herpes simplex virus type 1 thymidine kinase. NUCLEOSIDES & NUCLEOTIDES 1998; 17:187-206. [PMID: 9708347 DOI: 10.1080/07328319808005169] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The synthesis and X-ray crystal structures of a series of 5-substituted-6-aza-2'-deoxyuridines is reported. These nucleoside analogues inhibit the phosphorylation of thymidine by HSV-1 TK but have no effect on the corresponding human enzyme. Detailed examination of one analogue proves it to be a competitive inhibitor of thymidine with a Ki of 0.34 microM and is a very poor substrate. The analogues are not substrates for the enzyme and also do not inhibit the degradation of thymidine by thymidine phosphorylase. Molecular modelling showed that the inhibitors fit well in the active site of HSV-1 TK, provided the conformation of the sugar moiety is the same for thymidine in the complex.
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Abstract
UNLABELLED Premenstrual Dysphoric Disorder (PMDD) can be differentiated from Premenstrual Syndrome (PMS) by the use of the research criteria provided by the Diagnostic and Statistical Manual (DSM) IV. Indeed, PMS corresponds to mild clinical symptoms, such as breast tenderness, bloating, headache and concomitant minor mood changes, while premenstrual magnification occurs when physical and psychological symptoms of a concurrent axis I disorder get worse during the late luteal phase. Changes in appetite and eating behavior have been documented in women suffering from PMS, with an increased food intake occurring during the luteal phase. Moreover, in women with PMS, a major effect of the phase of the menstrual cycle on appetite has been documented and a high correlation with self-ratings of mood, particularly depression, has been described only in such disturbance. The aim of the present study was to analyse the clinical similarities between PMDD and Eating Disorders (in particular Bulimia Nervosa and Binge Eating Disorder). Thus, we compared the DSM III-R comorbidity, the personality dimensions and the eating attitudes in these patients, attempting to identify any relationship between groups. Twelve PMDD women (mean age 28 years), diagnosed using DSM IV criteria and premenstrual assessor form, were compared with 10 eating disorder (ED) women (6 Bulimia Nervosa, 4 Binge Eating Disorder) (mean age 25 years) and with 10 control women matched for age. The following instruments were used: (i) clinical interview with DSM III-R criteria (SCID); (ii) a psychometric study with TPQ for the evaluation of three personality dimensions (novelty seeking, harm avoidance and reward dependence); (iii) EAT/26 for the evaluation of eating attitudes. Results show that a high comorbidity for mood and anxiety disorders in PMDD and ED is well documented. Our PMDD patients share a 16.6% of comorbidity with ED, whereas such an association is present only in 2.3% of the general population. In addition, as a common clue, the personality dimension, harm avoidance, linked to a serotonin mediation is significantly more frequent in PMDD and ED than in normal controls. IN CONCLUSION from the present study it seems clear that a certain degree of similarity exists between the PMDD and ED. However, whether or not these two disorders really share common ground from a physiopathological point of view still has to be clarified by more extensive studies.
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Relaxed enantioselectivity of human mitochondrial thymidine kinase and chemotherapeutic uses of L-nucleoside analogues. Biochem J 1997; 328 ( Pt 1):317-20. [PMID: 9359870 PMCID: PMC1218923 DOI: 10.1042/bj3280317] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Our discovery that Herpes virus thymidine kinase (TK) and cellular deoxycytidine kinase lack enantioselectivity, being able to phosphorylate both D- and L-enantiomers of the substrate, suggested the use of unnatural L-nucleoside analogues as antiviral drugs (Herpes, hepatitis and immunodeficiency viruses). Several L-nucleoside analogues have displayed a short-term cytotoxicity much lower than their corresponding D-counterpart. Since the delayed cytotoxicity of a drug often depends on its effects on mitochondrial metabolism, we have investigated the degree of enantioselectivity of human mitochondrial thymidine kinase (mt-TK). We demonstrate that mt-TK does not show an absolute enantioselectivity, being able to recognize, although with lower efficiency, the L-enantiomers of thymidine, deoxycytidine and modified deoxyuridines, such as (E)-5-(2-bromovinyl)-2'-deoxyuridine and 5-iodo-2'-deoxyuridine. Interestingly, the reported negative co-operativity of mt-TK phosphorylating beta-D-2'-deoxythymidine (D-Thd), disappears when the deoxyribose moiety has the inverted configuration, resulting in the preferential phosphorylation of d-Thd even in the presence of high concentrations of the L-enantiomer. This, coupled with the higher Km for beta-L-2'-deoxythymidine (L-Thd), makes mt-TK resistant to high concentrations of L-Thd and L-Thd analogues, minimizing the mitochondria-dependent delayed cytotoxicity that might be caused by the administration of L-nucleoside analogues as antivirals.
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Exclusion of an internal carotid aneurysm by a covered stent. THE JOURNAL OF CARDIOVASCULAR SURGERY 1997; 38:301-3. [PMID: 9219482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The authors report a case of a patient with thromboembolic strokes caused by a high internal carotid artery aneurysm. Considering the position and the anatomic structure of this aneurysm the sac was excluded transluminally by placing an endovascular covered stent.
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Combined surgical and endovascular treatment of a traumatic pseudo-aneurysm of the brachiocephalic trunk with anatomical anomaly. THE JOURNAL OF CARDIOVASCULAR SURGERY 1997; 38:173-6. [PMID: 9201131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The authors report a case of combined surgical and endovascular treatment of a traumatic pseudo-aneurysm of the innominate artery in which the left common carotid artery originated from the brachiocephalic trunk. After a conventional surgical intervention with the implantation of the left common artery on the left subclavian artery, to correct the anatomic anomaly, a safe and effective endovascular stent-graft placement excluded the aneurysm. This new technique proposes a good chance for polytraumatized patients to receive a better prognosis and a much faster rehabilitation.
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Lack of enantiospecificity of human 2'-deoxycytidine kinase: relevance for the activation of beta-L-deoxycytidine analogs as antineoplastic and antiviral agents. Mol Pharmacol 1997; 51:132-8. [PMID: 9016355 DOI: 10.1124/mol.51.1.132] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We demonstrate that human 2'-deoxycytidine kinase (dCK) is a nonenantioselective enzyme because it phosphorylates beta-D-2'-deoxycytidine (D-dCyd), the natural substrate, and beta-L-2'-deoxycytidine (L-dCyd), its enantiomer, with the same efficiency. Kinetic studies showed that L-dCyd is a competitive inhibitor of the phosphorylation of D-dCyd with a Kl value of 0.12 microM, which is lower than the K(m) value for D-dCyd (1,2 microM). Chemical modifications of either the base or the pentose ring strongly decrease the inhibitory potency of L-dCyd, L-dCyd is resistant to cytidine deaminase and competes in cell cultures with the natural D-dCyd as substrate for dCK, thus reducing the incorporation of exogenous [3H]dCyd into DNA. L-dCyd had no effect on the pool of dTTP deriving from the salvage or from the de novo synthesis, does not inhibit short term RNA and protein syntheses, and shows little or no cytotoxicity. Our results indicate a catalytic similarity between human dCK and herpetic thymidine kinases, enzymes that also lack stereospecificity. This functional analogy underlines the potential role of dCK as activator of L-deoxycytidine analogs as antiviral and antineoplastic agents and lends support to the hypothesis that herpesvirus thymidine kinase might have evolved from a captured cellular dCK gene, developing the ability to phosphorylate thymidine and retaining that to phosphorylate deoxycytidine.
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Computational aspects of motion perception in natural and artificial vision systems. Philos Trans R Soc Lond B Biol Sci 1997; 337:429-43. [PMID: 1359590 DOI: 10.1098/rstb.1992.0119] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this paper a computational scheme for motion perception in artificial and natural vision systems is described. The scheme is motivated by a mathematical analysis in which first-order spatial properties of optical flow, such as singular points and elementary components of optical flow, are shown to be salient features for the computation and analysis of visual motion. The fact that different methods for the computation of optical flow produce similar results is explained in terms of the simple spatial structure of the image motion of rigid bodies. Singular points and elementary flow components are used to compute motion parameters, such as time-to-collision and angular velocity, and also to segment the visual field into areas which correspond to different motions. Then a number of biological implications are discussed. Electrophysiological findings suggest that the brain perceives visual motion by detecting and analysing optical flow components. However, the cortical neurons, which seem to detect elementary flow components, are not able to extract these components from more complex flows. A simple model for the organization of the receptive field of these cells, which is consistent with anatomical and electrophysiological data, is described at the end of the paper.
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Long-term exposure to zidovudine affects in vitro and in vivo the efficiency of phosphorylation of thymidine kinase. AIDS Res Hum Retroviruses 1996; 12:223-8. [PMID: 8835200 DOI: 10.1089/aid.1996.12.223] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The purpose of this study was to investigate the mechanism of acquired cellular resistance to AZT, a mechanism that has been described as a potential source of drug resistance in addition to viral mutations. To study this phenomenon the kinetics parameters of thymidine kinase (TK) activity have been defined in CEMazt, a cell line previously selected for resistance to AZT, in comparison with the parental AZT-sensitive CEM cells. The results revealed that the value of the maximum velocity (Vmax) of TK activity for deoxythymidine (dThd) phosphorylation is decreased in CEMazt as compared to the wild-type cell line (Vmax: CEM = 105.3 +/- 17.6 nmol/hr/mg of protein; CEMazt = 0.3 +/- 0.02 nmol/hr/mg of protein; p < 0.001). Furthermore, the enzyme affinity versus dThd is lower in CEMazt as compared to CEM (Km: CEM = 0.9 +/- 0.2 microM; CEMazt = 1.6 +/- 0.2 microM; p < 0.01). Consequently phosphorylation efficiency, expressed as the ratio between Vmax and Km, is also reduced in CEMazt (p < 0.001). To evaluate whether such a phenomenon may also occur in patients, ex vivo experiments were carried out by using PBMCs from HIV-infected patients, treated or not treated with AZT. The results (mean values from 10 patients for each group) indicate that a prolonged treatment (> 6 months) with AZT may modify the enzymatic kinetics of TK, leading to a significant reduction in the phosphorylation efficiency of the enzyme (4.07 +/- 1.7 in treated patients versus 13.5 +/- 1.7 in untreated patients; p < 0.001). These results indicate that AZT treatment can also induce a defect in TK activity in patients.
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Herpes simplex virus type 1 (HSV-1) uracil-DNA glycosylase: functional expression in Escherichia coli, biochemical characterization, and selective inhibition by 6-(p-n-octylanilino)uracil. Virology 1995; 211:307-11. [PMID: 7645226 DOI: 10.1006/viro.1995.1406] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Herpes simplex virus type 1 (HSV-1) uracil-DNA glycosylase (UDG) is encoded by the UL2 gene. The translation from the first putative start codon of UL2 predicts a polypeptide of 334 residues, while the translation from the second start codon predicts a polypeptide of 244 residues. We have cloned and expressed the two forms of UDG, by means of the prokaryotic expression vector pMAL-c2, and both of them were enzymatically active. Furthermore, the enzymatic properties of the recombinant UDGs and of the enzyme purified from HSV-1-infected cells were similar. The two UDG polypeptides have molecular weights of 27 and 37 kDa, respectively. The 37-kDa form of recombinant UDG is consistent with the reported molecular mass of 37 kDa for the enzyme purified from HSV-1-infected cells. Both recombinant UDGs were as sensitive as UDG purified from HSV-1-infected cells to 6-(p-n-octylanilino)uracil, the most potent of a series of uracil analogs that inhibit the viral enzyme.
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5-Iodo-2'-deoxy-L-uridine and (E)-5-(2-bromovinyl)-2'-deoxy-L-uridine: selective phosphorylation by herpes simplex virus type 1 thymidine kinase, antiherpetic activity, and cytotoxicity studies. Mol Pharmacol 1995; 47:1231-8. [PMID: 7603465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
5-Iodo-2'-deoxy-L-uridine (L-IdU) and (E)-5-(2-bromovinyl)-2'-deoxy-L-uridine (L-BVdU) have been prepared and found to inhibit herpes simplex virus type 1 (HSV-1) thymidine kinase (TK) with activities comparable to those of their analogs with the natural D-sugar configuration. The mechanism of inhibition is purely competitive for L-IdU (Ki = 0.24 microM) and mixed-type for L-BVdU (Ki = 0.13 microM). High performance liquid chromatographic analysis of the reaction products demonstrated that the viral enzyme phosphorylates both L-enantiomers to their corresponding monophosphates with efficiency comparable to that for D-enantiomers. Neither L-enantiomer inhibits the human cytosolic TK. In contrast to their D-enantiomers, L-IdU and L-BVdU have no effect on human thymidylate synthase, either in HeLa cells or in TK-deficient HeLa cells transformed with the HSV-1 TK gene. Both L-enantiomers (i) have no effect on HeLa cell growth, (ii) are 1000-fold less cytotoxic toward TK-deficient HeLa cells transformed with the HSV-1 TK gene than are their D-enantiomers, (iii) in contrast to their D-enantiomers, are fully resistant to hydrolysis by nucleoside phosphorylase, and, (iv) in spite of their much lower cytotoxicity, most probably due to the very low affinity of L-BVdU monophosphate and L-IdU monophosphate for thymidylate synthase, are only 1 or 2 orders of magnitude less potent than their D-enantiomers in inhibiting viral growth, with potency comparable to that of acyclovir.
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Alteration of thymidine kinase activity in cells treated with an antiviral agent. J BIOL REG HOMEOS AG 1995; 9:47-51. [PMID: 9127632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A lymphoblastoid cell line, CEM, was rendered resistant to zidovudine (AZT) in vitro by exposure to low but gradually increasing concentrations of the drug. This type of cellular resistance seems to be due to a defect of thymidine kinase (TK) activity that is acquired by cells grown in the presence of AZT. In fact, enzymatic studies with extracts from AZT-resistant cells (CEMazt), have shown that the value of the maximum velocity (Vmax) of TK activity measured with AZT and for deoxythymidine (dThd) is decreased as compared to sensitive CEM cells. Furthermore, the enzyme affinity for AZT and dThd is reduced in CEMazt. Further experiments have shown that such cells do not show resistance to other nucleoside analogs, such as ddI, ddC, AraT and D4T, suggesting that the phosphorylation pathways different from those involving TK are unaltered. Ex vivo experiments performed by using peripheral blood mononuclear cells (PBMC) from HIV infected individuals revealed that a prolonged treatment with AZT may modify the affinity of TK for dThd, thus suggesting that the aforementioned phenomenon may occur also in vivo.
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48
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Characterization of a cellular line expressing a defect of thymidine kinase activity and displaying resistance to the antiviral activity of AZT. Antiviral Res 1995. [DOI: 10.1016/0166-3542(95)94780-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Lack of stereospecificity of some cellular and viral enzymes involved in the synthesis of deoxyribonucleotides and DNA: molecular basis for the antiviral activity of unnatural L-beta-nucleosides. Biochimie 1995; 77:861-67. [PMID: 8824765 DOI: 10.1016/0300-9084(95)90004-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Among enzymes involved in the synthesis of nucleotides and DNA, some exceptions have recently been found to the universal rule that enzymes act only on one enantiomer of a chiral substrate and that only one of the enantiomeric forms of chiral molecules may bind effectively at the catalytic site, displaying biological activity. The exceptions include: herpes virus thymidine kinases, cellular deoxycytidine kinase and deoxynucloside mono- and diphosphate kinases, cellular and viral DNA polymerases, such as DNA polymerase alpha, terminal transferase and HIV-1 reverse transcriptase. The ability of these enzymes to utilize unnatural L-beta-nucleosides or -nucleotides as substrate may be exploited from chemotherapeutic point of view.
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50
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Aphidicolin inhibits in vitro the activity of pseudorabies virus (PRV) DNA polymerase and in vivo the viral proliferation. In Vivo 1994; 8:1041-6. [PMID: 7772734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have purified and characterized Pseudorabies virus (PRV) DNA polymerase from infected TK- mouse cells. PRV DNA polymerase has a 3'- > 5' exonuclease activity; it is stimulated by ionic strength, requires magnesium for optimal activity and it is more sensitive to aphidicolin than eukaryotic and HSV-1 replicative DNA polymerases. Aphidicolin inhibits in vitro PRV DNA polymerase competitively with respect to dCTP with a Ki of 0.06 microM and completely blocks viral growth in vivo at 4.4 microM. The high sensitivity to aphidicolin of animal herpesvirus DNA polymerases might allow a topical use of this drug in the treatment of animal herpesvirus keratitis and stomatitis.
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