Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
Med Oral Patol Oral Cir Bucal ; 28(6): e545-e552, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37330956

RESUMO

BACKGROUND: The use of graphic novels is a trending topic in health communication as a new form of visual storytelling which explores narratives of health care, cancer, healing, and disability. The objective of the present study was to evaluate - for the first time in the literature - the effect of graphic novels in reducing the anxiety of patients waiting for an incisional biopsy in an oral oncology setting. MATERIAL AND METHODS: This open-label randomized clinical trial comprised 50 patients with a clinical suspicion of oral potentially malignant disorders. Twenty-five patients were randomly allocated to the test group, and a colourful graphic novel was provided. Subsequently, the Beck Depression Inventory and the Depression Anxiety Stress Scales-21 were administered to all 50 recruited patients, after which a biopsy was performed on each patient. RESULTS: No statistically significant difference was observed between the test and control groups for the variables regarding the demographic data (p>0.2). There was a significant difference after the introduction of the graphic novel, regardless of which questionnaire was used. The graphic novel demonstrated an improvement in the ability of the test group to tolerate anxiety while waiting for an oral biopsy in both psychological tests (p<0.05). CONCLUSIONS: In light of these initial positive results, the authors of this study would like to suggest the use of graphic novels in oral oncology, dentistry, and medicine with the aim of reducing patient anxiety.


Assuntos
Ansiedade , Lesões Pré-Cancerosas , Humanos , Ansiedade/etiologia , Ansiedade/prevenção & controle , Transtornos de Ansiedade
2.
Acta Psychiatr Scand ; 141(3): 254-264, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797353

RESUMO

OBJECTIVE: To identify factors associated with a history of suicide attempt in medical students. METHODS: A Web-based survey was sent out to a sample of medical students. A multi-predictor Poisson regression was performed to identify factors associated with a history of suicide attempt. In addition, an elastic net regularization was used to build a risk calculator to identify students at risk for attempted suicide. RESULTS: A total of 4,840 participants were included in the study. Prevalence of suicide attempts in the sample was 8.94%. Risk factors associated with past suicide attempt in the multi-predictor Poisson regression were as follows: female gender (P < 0.001); homosexuality (P < 0.001); low income (P = 0.026); bullying by university peers (P = 0.006); childhood (P = 0.001) or adult (P = 0.001) trauma; family history of suicide (P = 0.005); suicidal ideation within the last month (P < 0.001); daily tobacco use (P = 0.037); and being at severe risk for alcohol abuse (P = 0.023). Our elastic net model performed well with an AUC of 0.83. CONCLUSIONS: This study identifies a number of key factors associated with a history of suicide attempts among medical students. Future longitudinal studies should assess the causal relationship between these factors and suicide attempts. Additionally, these results demonstrate that current available data on suicide attempts among medical students can be used to develop an accurate risk algorithm.


Assuntos
Estudantes de Medicina/psicologia , Ideação Suicida , Tentativa de Suicídio/estatística & dados numéricos , Adolescente , Adulto , Brasil/epidemiologia , Bullying/estatística & dados numéricos , Feminino , Humanos , Masculino , Prevalência , Fatores de Risco , Fatores Sexuais , Inquéritos e Questionários , Adulto Jovem
3.
Neurology ; 70(17): 1549-54, 2008 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-18427071

RESUMO

BACKGROUND: Mutations of presenilin 2 gene are a rare cause of familial Alzheimer disease (AD). We describe an Italian family with hereditary dementia associated with a novel mutation in the presenilin 2 gene. METHODS: Clinical investigations of the diseased subjects; interviews with relatives; studies of medical records; pedigree analysis; and neuroradiologic, neuropathologic, and molecular genetic studies were carried out in the pedigree. RESULTS: Genetic analysis showed a novel PSEN2 A85V mutation present in the proband and in all analyzed affected members, in a subject presenting with an amnesic mild cognitive impairment, and in a young, still asymptomatic subject. The proband showed a clinical phenotype indicative of Lewy body dementia and the neuropathologic examination demonstrated the presence of unusually abundant and widespread cortical Lewy bodies in addition to the hallmark lesions of AD. Other affected members exhibited a clinical phenotype typical of AD. CONCLUSIONS: Our findings add complexity to the spectrum of atypical phenotypes associated with presenilin mutations and should then be taken into account when considering the nosography of neurodegenerative diseases. They also support previous data that specific mutations of genes associated with familial Alzheimer disease may influence the presence and extent of Lewy bodies.


Assuntos
Demência/genética , Mutação Puntual , Presenilina-2/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Mutacional de DNA , Demência/patologia , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Presenilina-2/metabolismo
6.
J Neurol ; 252(9): 1033-6, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16170650

RESUMO

Genetic evidence indicates a central role of cerebral accumulation of beta-amyloid (Abeta) in the pathogenesis of Alzheimer's disease (AD). Beside presenilin 1 and 2, three other recently discovered proteins (Aph 1, PEN 2 and nicastrin) are associated with gamma-secretase activity, the enzymatic complex generating Abeta. Alterations in genes encoding these proteins were candidates for a role in AD. The PEN 2 gene was examined for unknown mutations and polymorphisms in sporadic and familial Alzheimer patients. Samples from age-matched controls (n=253), sporadic AD (SAD, n=256) and familial AD (FAD, n=140) were screened with DHPLC methodology followed by sequencing. Scanning the gene identified for the first time a missense mutation (D90N) in a patient with FAD. Three intronic polymorphisms were also identified, one of which had a higher presence of the mutated allele in AD subjects carrying the allele epsilon4 of apolipoprotein E than controls. The pathogenic role of the PEN-2 D90N mutation in AD is not clear, but the findings might lead to new studies on its functional and genetic role.


Assuntos
Doença de Alzheimer/genética , Predisposição Genética para Doença , Proteínas de Membrana/genética , Mutação , Idoso , Secretases da Proteína Precursora do Amiloide , Sequência de Bases , Western Blotting , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Masculino , Linhagem , Polimorfismo Genético , Reação em Cadeia da Polimerase Via Transcriptase Reversa
7.
Infect Immun ; 73(7): 4198-204, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15972510

RESUMO

Vaccination against Brucella infections in animals is usually performed by administration of live attenuated smooth B. abortus strain S19 and B. melitensis strain Rev1. They are proven effective vaccines against B. abortus in cattle and against B. melitensis and B. ovis in sheep and goats, respectively. However, both vaccines have the main drawback of inducing O-polysaccharide-specific antibodies that interfere with serologic diagnosis of disease. In addition, they retain residual virulence, being a cause of abortion in pregnant animals and infection in humans. To overcome these problems, one approach is to develop defined rough mutant Brucella strains lacking O antigen of lipopolysaccharide. B. abortus rough strain RB51, a rifampin-resistant mutant of virulent strain B. abortus 2308, is used as a vaccine against B. abortus infection in cattle in some countries. However, RB51 is not effective in sheep, and there is only preliminary evidence that it is effective in goats. In this study, we tested the efficacies of six rifampin-resistant rough strains of B. melitensis in protecting BALB/c mice exposed to B. melitensis infection. The protective properties, as well as both humoral and cellular immune responses, were assessed in comparison with those provided by B. melitensis Rev1 and B. abortus RB51 vaccines. The results indicated that these rough mutants were able to induce a very good level of protection against B. melitensis infection, similar to that provided by Rev1 and superior to that of RB51, without inducing antibodies to O antigen. In addition, all B. melitensis mutants were able to stimulate good production of gamma interferon. The characteristics of these strains encourage further evaluation of them as alternative vaccines to Rev1 in primary host species.


Assuntos
Vacina contra Brucelose/imunologia , Brucella melitensis/imunologia , RNA Polimerases Dirigidas por DNA/genética , Rifampina/farmacologia , Animais , Anticorpos Antibacterianos/sangue , Brucella melitensis/efeitos dos fármacos , Brucella melitensis/genética , Farmacorresistência Bacteriana , Feminino , Genótipo , Interferon gama/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Vacinação
8.
Biol Psychiatry ; 50(6): 472-5, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11566166

RESUMO

BACKGROUND: The aim of this study is to analyze the segregation of the 102T/C polymorphism in the serotonin 2A receptor gene in patients affected by sporadic and familial Alzheimer's disease (FAD) with and without psychotic symptoms. METHODS: The polymorphism was analyzed in 275 subjects. A semistructured interview was used to obtain information about delusions, hallucinations, and other specific behavioral signs occurring during the disease. RESULTS: Fifty-two percent of AD patients with psychotic symptoms were homozygous for the C102 allele, as compared with 6.9% of AD patients without psychosis. Similarly, the C102/C102 genotype was significantly more frequent in FAD patients with psychosis than in FAD patients without (46.5% vs. 7.8%). CONCLUSIONS: Our data strongly confirm and extend to FAD previous studies suggesting that the genetic variation at this locus is associated with prominent psychotic features in AD and that the 102C allele could play an important role in late-onset AD.


Assuntos
Doença de Alzheimer/genética , Polimorfismo Genético/genética , Transtornos Psicóticos/genética , Transtornos Psicóticos/metabolismo , Receptores de Serotonina/genética , Receptores de Serotonina/metabolismo , Idoso , Doença de Alzheimer/psicologia , Apolipoproteínas E/genética , Feminino , Amplificação de Genes , Expressão Gênica/genética , Frequência do Gene , Genótipo , Homozigoto , Humanos , Masculino , Mutação Puntual/genética , Transtornos Psicóticos/etiologia
9.
J Refract Surg ; 17(2): 110-2, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11310759

RESUMO

PURPOSE: To report four cases of corneal interface complications that occurred after excimer laser in situ keratomileusis (LASIK). METHODS: Four eyes of three patients underwent technically uneventful LASIK. RESULTS: One day after LASIK, patients presented with severe pain, blurred vision, conjunctival infection, and diffuse opacity at the interface. Two days after LASIK, significant features were central opacity, striae in the flap, loss of uncorrected and best spectacle-corrected visual acuity, and corneal sensitivity. The findings did not improve by using drugs or by lifting the flap and irrigating the bed. The central opacity partially resolved over 8 to 12 months, leaving a hyperopic shift (one patient), striae (one patient), and loss of two or more lines of best spectacle-corrected visual acuity (three patients). CONCLUSION: This severe central inflammation after LASIK could be an extreme manifestation of diffuse lamellar keratitis.


Assuntos
Córnea/patologia , Ceratite/etiologia , Ceratomileuse Assistida por Excimer Laser In Situ/efeitos adversos , Administração Tópica , Adulto , Antibacterianos , Anti-Inflamatórios/uso terapêutico , Conjuntivite Bacteriana/tratamento farmacológico , Conjuntivite Bacteriana/etiologia , Córnea/efeitos dos fármacos , Opacidade da Córnea/diagnóstico , Opacidade da Córnea/tratamento farmacológico , Opacidade da Córnea/etiologia , Quimioterapia Combinada/uso terapêutico , Glucocorticoides , Humanos , Hiperopia/diagnóstico , Hiperopia/etiologia , Hiperopia/terapia , Ceratite/diagnóstico , Ceratite/tratamento farmacológico , Necrose , Dor/etiologia , Manejo da Dor , Transtornos da Visão/diagnóstico , Transtornos da Visão/tratamento farmacológico , Transtornos da Visão/etiologia , Acuidade Visual
10.
Biochem Biophys Res Commun ; 281(2): 352-60, 2001 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-11181054

RESUMO

DNA represents the primary target for platinum antitumor metal complexes and is the probable target for newly developed cytotoxic gold(III) complexes. To test this hypothesis the reactions with calf thymus DNA of five representative gold(III) complexes--namely [Au(en)(2)]Cl(3), [Au(dien)Cl]Cl(2), [Au(cyclam)](ClO(4))(2)Cl, [Au(terpy)Cl]Cl(2) and [Au(phen)Cl(2)]Cl--were analyzed in vitro through various physicochemical techniques including circular dichroism, absorption spectroscopy, DNA melting, and ultradialysis. It is shown that all tested complexes interact with DNA and modify significantly its solution behavior. The solution conformation of DNA is affected to variable extents by the individual complexes as shown by CD titration experiments. Notably, in all cases, the gold(III) chromophore is not largely perturbed by addition of calf thymus DNA ruling out occurrence of gold(III) reduction. Ultradialysis experiments point out that the binding affinity of the various complexes for the DNA double helix is relatively low; in most cases the gold(III)/DNA interaction is electrostatic in nature and reversible. The implications of these findings for the mechanism of action of antitumor gold(III) complexes are discussed.


Assuntos
DNA/química , Ouro/química , Compostos Organometálicos/química , Animais , Bovinos , Dicroísmo Circular , Adutos de DNA/química , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , Espectrofotometria , Temperatura , Timo
11.
Mol Med ; 6(10): 816-24, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11126197

RESUMO

BACKGROUND: The pattern of platelet amyloid precursor protein (APP) forms is altered in sporadic Alzheimer's disease patients, compared with both control subjects and non-Alzheimer's disease-demented patients. The aims of this study were to evaluate in platelets of symptomatic and presymptomatic patients carrying the mutation Met239Val in presenilin 2 (PS2) whether: i) PS2 and presenilin 3 (PS1) were expressed in platelets; ii) an altered expression of different APP isoforms mRNAs could be related to the presence of the mutation; and iii) an abnormal pattern of APP forms was associated to the mutation. MATERIALS AND METHODS: Reverse transcriptionpolymerase chain reaction (RT-PCR) of APP isoforms, PS1 and PS2 was performed on RNA extracted from platelets of three PS2 Met239Val mutated subjects, seven sporadic Alzheimer's patients and nine control subjects. The pattern of platelet APP forms at protein level was evaluated in the same population of subjects by means of Western blots analysis with specific antibody. RESULTS: We found that PS1 and PS2 were expressed correctly in human platelets. When the relative amount of expression of mRNA coding for APP 771/ 751-695 was measured, a similar ratio of expression was found in PS2-mutated subjects, compared with both sporadic Alzheimer's patients and to control subjects. Furthermore, when APP forms were evaluated in platelet homogenates by means of Western blots analysis with appropriate antibody, no difference was found in the pattern of APP forms in presence of PS2 mutation in platelets, compared with control subjects. CONCLUSIONS: These results indicated that PS2 was expressed in human platelets and that PS2 mutation did not affect APP forms pattern, thus, suggesting that in this peripheral cell the pathological effect of PS2 mutation might occur upstream of the amyloid cascade.


Assuntos
Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas de Membrana/genética , Mutação , Idoso , Doença de Alzheimer/genética , Sequência de Bases , Estudos de Casos e Controles , Primers do DNA , Humanos , Presenilina-2 , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
Psychother Psychosom ; 69(6): 335-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11070447

RESUMO

BACKGROUND: The identification of the premorbid manifestation of Alzheimer's disease (AD) usually is carried out retrospectively by eliciting information from caregivers. However, the study of subjects with familial Alzheimer's disease (FAD) not yet affected by AD allows the direct identification of premorbid characteristics of the disease. METHODS: This is a psychometric assessment of 3 mutated and 5 control subjects, belonging to an Italian family associated with a missense mutation linked to the presenilin 2 gene. The assessment included an evaluation of personality traits, cognitive and affective condition, social disabilities, experiential and familial context. RESULTS: According to the MMPI, the mutated subjects did not show consistent personality traits. Also other questionnaires (HADS, WAIS, BDQ) were negative for definite cognitive or behavioural patterns. ApoE genotypes did not differentiate mutated from control subjects. CONCLUSIONS: Our results may be considered important for a better understanding of the pathogenesis of AD. The heuristic and practical importance of longitudinal prospective studies is emphasised.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/psicologia , Transtornos da Personalidade/genética , Transtornos da Personalidade/psicologia , Adulto , Doença de Alzheimer/etiologia , Feminino , Predisposição Genética para Doença , Humanos , Linhagem , Transtornos da Personalidade/complicações , Inventário de Personalidade , Psicometria , Fatores de Risco
13.
J Med Chem ; 43(19): 3541-8, 2000 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-11000008

RESUMO

Gold(III) complexes generally exhibit interesting cytotoxic and antitumor properties, but until now, their development has been heavily hampered by their poor stability under physiological conditions. To enhance the stability of the gold(III) center, we prepared a number of gold(III) complexes with multidentate ligands - namely [Au(en)(2)]Cl(3), [Au(dien)Cl]Cl(2), [Au(cyclam)](ClO(4))(2)Cl, [Au(terpy)Cl]Cl(2), and [Au(phen)Cl(2)]Cl - and analyzed their behavior in solution. The solution properties of these complexes were monitored by visible absorption spectroscopy, mass spectrometry, and chloride-selective potentiometric measurements; the electrochemical properties were also studied by cyclic voltammetry and coulometry. Since all the investigated compounds exhibited sufficient stability under physiological conditions, their cytotoxic properties were tested in vitro, via the sulforhodamine B assay, on the representative human ovarian tumor cell line A2780, either sensitive or resistant to cisplatin. In most cases the investigated compounds showed relevant cell-killing properties with IC(50) values falling in the 0.2-10 microM range; noticeably most investigated gold(III) complexes were able to overcome, to a large extent, resistance to cisplatin when tested on the corresponding cisplatin-resistant cell line. The cytotoxic properties of the free ligands were also determined under the same solution conditions. Ethylenediamine, diethylenetriamine, and cyclam were virtually nontoxic (IC(50) values > 100 microM) so that the relevant cytotoxic effects observed for [Au(en)(2)]Cl(3) and [Au(dien)Cl]Cl(2) could be quite unambiguously ascribed to the presence of the gold(III) center. In contrast the phenanthroline and terpyridine ligands turned out to be even more cytotoxic than the corresponding gold(III) complexes rendering the interpretation of the cytotoxicity profiles of the latter complexes less straightforward. The implications of the present findings for the development of novel gold(III) complexes as possible cytotoxic and antitumor drugs are discussed.


Assuntos
Antineoplásicos/síntese química , Ouro , Compostos Organometálicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Eletroquímica , Humanos , Espectrometria de Massas , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Potenciometria , Soluções , Relação Estrutura-Atividade , Células Tumorais Cultivadas
14.
Chem Biol Interact ; 125(1): 29-38, 2000 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-10724364

RESUMO

The chloro glycylhistidinate gold(III) complex (GHAu) is shown to be fairly cytotoxic towards the established A2780 ovarian carcinoma human cell line either sensitive or resistant to cisplatin. Remarkably, GHAu is far more cytotoxic than the corresponding zinc(II), palladium(II), platinum(II) and cobalt(II) complexes implying that cytotoxicity is essentially to be ascribed to the presence of a gold(III) center. Circular dichroism (CD) spectra, atomic absorption measurements and DNA melting profiles suggest that GHAu in vitro is able to bind DNA, the presumed target for several antitumor metal complexes, and to modify its conformation, even if the observed changes are generally small. Implications of these findings for the mechanism of action of cytotoxic gold(III) complexes are discussed.


Assuntos
Antineoplásicos/toxicidade , DNA/metabolismo , Dipeptídeos/toxicidade , Compostos Organometálicos/toxicidade , Neoplasias Ovarianas/tratamento farmacológico , Animais , Antineoplásicos/metabolismo , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Cisplatino/toxicidade , DNA/efeitos dos fármacos , Dipeptídeos/metabolismo , Resistência a Medicamentos , Feminino , Humanos , Compostos Organoáuricos , Compostos Organometálicos/metabolismo , Espectrofotometria Atômica , Células Tumorais Cultivadas/efeitos dos fármacos
15.
Oncol Res ; 12(9-10): 361-70, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11697815

RESUMO

The gold(III) complexes [Au(phen)Cl2]Cl and [Au(dien)Cl]Cl2 were recently shown to exert important cytotoxic effects in vitro on human tumor cell lines. To elucidate the biochemical mechanisms leading to cell death, the effects produced by these gold(III) complexes on the leukemic CCRF-CEM cell line--either sensitive (CCRF-CEM) or resistant to cisplatin (CCRF-CEM/CDDP)--were analyzed in detail by various techniques. For comparison purposes the effects produced by equitoxic concentrations of cisplatin were also analyzed. First, the dependence of the IC50 values of either complex on the incubation time was investigated. Cytotoxicity experiments confirmed that both gold(III) compounds retain their efficacy against the cisplatin-resistant line: only minimal cross-resistance with cisplatin was detected. Notably, [Au(phen)Cl2]Cl is more cytotoxic than [Au(dien)Cl]Cl2, with IC50 values of 7.4 and 6.0 M at 24 and 72 h, respectively, on the resistant line. Results of the COMET assay point out that both gold(III) complexes directly damage nuclear DNA. Remarkably, DNA damage inferred by either gold(III) complex in the two cell lines is larger than that produced by equitoxic cisplatin concentrations. Finally, the effects that either gold(III) complex produces on the cell cycle were investigated by flow cytometry. It was found that both complexes cause only moderate and transient cell cycle perturbations. Larger cell cycle perturbations are induced by equitoxic concentrations of cisplatin. The implications of the present results for the mechanism of action of cytotoxic gold(III) complexes are discussed.


Assuntos
Ciclo Celular/efeitos dos fármacos , Cisplatino/farmacologia , Dano ao DNA , Ouro/farmacologia , Ouro/uso terapêutico , Leucemia/tratamento farmacológico , Antineoplásicos/farmacologia , Linhagem Celular , Ensaio Cometa , DNA , Citometria de Fluxo , Humanos , Concentração Inibidora 50 , Modelos Químicos , Fatores de Tempo , Células Tumorais Cultivadas
16.
Met Based Drugs ; 7(4): 195-200, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-18475945

RESUMO

Some biological aspects of the new complex imidazolium bisimidazole tetrachloro iridate(III)-IRIM- the iridium(III) analogue of ICR, were considered. More in detail the conformational effects produced by IRIM on DNA and the cytotoxic properties of IRIM on some selected human cell lines were measured. Dialysis experiments and DNA thermal denaturation studies are suggestive of poor binding of IRIM to DNA; formation of interstrand crosslinks is not observed. In any case CD measurements suggest that addition of increasing amounts of IRIM to calf thymus DNA results into significant spectral changes, that are diagnostic of a direct interaction with DNA. A number of experiments carried out on the A2780 human ovarian carcinoma, B16 murine melanoma, MCF7 and TS mammary adenocarcinoma tumor cell lines strongly point out that IRIM does not exhibit significant growth inhibition effects within the concentration range 10(-4)-10(-6) M. It is suggested that the lower biological effects of IRIM compared to ICR are a consequence of the larger kinetic inertness of the iridium(III) center with respect to ruthenium(III).

17.
Met Based Drugs ; 7(5): 253-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-18475953

RESUMO

Reactions of the complexes bisethylendiammine gold(III) and bisethylendiammine platinum(II) with calfthymus DNA were comparatively analysed. Both complexes bind DNA non-covalently most probably on the basis of electrostatic interactions. Binding of either complex at low ratios results into modest modifications of B-type DNA conformations, as detected by CD. Far larger CD alterations are observed at high ratios. The gold(III) chromophore is scarcely perturbed by DNA addition Binding of [Au(en)(2)]Cl(3) to calf thymus DNA is reversed by sodium cyanide. By analogy with the case of [Pt(en)(2)]Cl(2) it is suggested that Auen acts as a minor groove binder.

18.
Neuromuscul Disord ; 9(4): 257-61, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10399754

RESUMO

We describe a patient with congenital hypomyelination neuropathy. The pathological and morphometrical findings in the sural nerve biopsy were consistent with a defect of myelin formation and maintenance. Direct sequence analysis of the genomic regions coding the peripheral myelin proteins P0 and PMP22 disclosed a heterozygous missense point mutation that leads to a Ser72Leu substitution in the second transmembrane of PMP22. Codon 72 mutations of PMP22 are associated with different phenotypes encompassing the Dejerine-Sottas syndrome and including congenital hypomyelination neuropathy.


Assuntos
Substituição de Aminoácidos/genética , Doenças Desmielinizantes/congênito , Doenças Desmielinizantes/genética , Mutação de Sentido Incorreto/fisiologia , Proteínas da Mielina/genética , Mutação Puntual/fisiologia , Substituição de Aminoácidos/fisiologia , DNA/análise , DNA/genética , Doenças Desmielinizantes/patologia , Eletromiografia , Eletrofisiologia , Humanos , Lactente , Masculino , Mutação de Sentido Incorreto/genética , Mutação Puntual/genética , Nervo Sural/patologia
19.
J Cell Sci ; 112 ( Pt 13): 2137-44, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10362543

RESUMO

Mutations in presenilin 1 and 2 are causative factors for early onset familial Alzheimer's disease and possible roles for presenilins include protein trafficking, regulation of apoptosis and/or calcium homeostasis. Presenilin 2 mRNA is expressed in brain, muscle and pancreas but the role of pancreatic presenilin 2 and its relationship to diabetes are unknown. Presenilin 2 immunoreactivity was localised in human and rodent pancreas to islet cells and found in granules of beta-cells. Presenilin 2 was identified in primitive islet and duct cells of human foetal pancreas and in proliferating exocrine duct cells in human pancreatitis but not found in islet amyloid deposits in Type 2 diabetic subjects. Full length, approximately 50 kDa, and the approximately 30 kDa N-terminal fragment of presenilin 2 were identified by western blotting in extracted rodent pancreas but only the 30 kDa fragment was detected in mouse islets and human insulinoma. Post-mortem pancreatic morphology was normal in a subject with the presenilin 2 Met239Val variant and early onset familial Alzheimer's disease. Oral glucose tolerance tests on subjects with the presenilin 2 Met239Val mutation unaffected by early onset familial Alzheimer's disease (mean age 35 years) and on their first-degree relatives without the mutation demonstrated no evidence of glucose intolerance or increased proinsulin secretion. PS2 is a novel &bgr;-cell protein with potential roles in development or protein processing but pancreatic islet structure and function appear to be unaffected by the Met239Val mutation.


Assuntos
Diabetes Mellitus/genética , Variação Genética , Ilhotas Pancreáticas/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Adulto , Idade de Início , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Linhagem Celular , Diabetes Mellitus/metabolismo , Feminino , Teste de Tolerância a Glucose , Humanos , Imuno-Histoquímica , Ilhotas Pancreáticas/citologia , Masculino , Proteínas de Membrana/química , Camundongos , Pessoa de Meia-Idade , Peso Molecular , Presenilina-2
20.
Am J Pathol ; 154(4): 1001-7, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10233838

RESUMO

Extracellular Abeta-amyloid and intraneuronal paired helical filaments (PHFs) composed of tau protein are the neuropathological hallmark of Alzheimer's disease. Abeta is a 39- to 43-residue peptide derived by cleavage of a 695- to 770-amino-acid membrane-associate glycoprotein (termed beta-protein precursor, betaPP). Following the observation that an antiserum to an epitope located between residues 713 and 723 of betaPP770 (ie, the transmembrane region of the betaPP distal to Abeta) labels PHFs and that a synthetic peptide homologous to residues 713 to 730 of betaPP770 (betaPP713-730) is highly fibrillogenic and interacts with tau in vitro, it has been hypothesized that betaPP fragments other than Abeta may feature in the pathogenesis of Alzheimer's disease concurring with neuronal degeneration. To investigate this issue, we have analyzed the effects of the exposure of primary neuronal cultures to the synthetic peptide betaPP713-730. Cultures were prepared from rat hippocampus on embryonic day 17 and incubated with the peptide at 2.5 to 30 micromol/L concentration for 1 to 4 days. Cell viability was compared with that of control cultures exposed to a scrambled sequence of the peptide. A 4-day exposure to 20 micromol/L betaPP713-730 resulted in almost complete neuronal loss, whereas no changes were observed with the scrambled peptide. Degenerating neurons showed DNA fragmentation by agarose gel electrophoresis and apoptotic changes by light and electron microscopy. These findings support the view that betaPP sequences other than Abeta may play a role in nerve cell degeneration in Alzheimer's disease.


Assuntos
Precursor de Proteína beta-Amiloide/farmacologia , Precursor de Proteína beta-Amiloide/fisiologia , Neurônios/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Animais , Apoptose , Tamanho Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Eletroforese em Gel de Ágar , Feto , Hipocampo/efeitos dos fármacos , Marcação In Situ das Extremidades Cortadas , Microscopia Eletrônica , Mutagênese Sítio-Dirigida , Neurônios/citologia , Neurônios/metabolismo , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...