Serum repressor element-1 silencing transcription factor levels in alzheimer's patients from a national institute of health in mexico city, elderly and young controls

ABSTRACT Background: Decreased levels of repressor element-1 silencing transcription (REST) factor in the brain, plasma, and neuron-derived exosomes are associated with Alzheimer’s disease (AD). Objective: The objective of the study was to test the viability of serum REST as a possible blood-based biomarker for AD, comparing serum REST levels in AD patients from a National Institute of Health in Mexico City (with different levels of severity and comorbidities), with elderly controls (EC) and young controls (YC). Methods: We used an enzyme-linked immunosorbent assay to determine serum REST levels in AD patients (n = 28), EC (n = 19), and YC (n = 24); the AD patients were classified by dementia severity and comorbidities (depression and microangiopathy) using clinimetric tests and magnetic resonance imaging. Results: Mean serum REST levels did not differ between AD patients, EC, and YC. The severity of AD and the presence of depression or microangiopathy were not associated with serum REST levels. Conclusion: Our results differ from previously published patterns found for plasma and cerebral REST levels. Free serum REST levels may not be a viable AD blood-based biomarker. (REV INVEST CLIN. 2021;73(1):17-22)

Association of vitamin d with mild cognitive impairment and alzheimer's dementia in older mexican adults

ABSTRACT Background It has been proposed that Vitamin D helps reduce the accumulation of cerebral β-amyloid-42 by innate immune stimulation and phagocytosis activation. An association between low Vitamin D levels and Alzheimer’s dementia (AD) has been established. We determined the association between Vitamin D, mild cognitive impairment (MCI), and AD in older Mexican adults (> 65 years) Methods Cross-sectional study conducted at the memory clinic in a tertiary-level hospital in Mexico City. We evaluated subjects with MCI, AD, and normal cognition (NC) with available serum Vitamin D [25(OH)D] levels (past 6 months). Three categories were assigned according to 25(OH)D levels: sufficiency (> 30 ng/mL), insufficiency (21-29 ng/mL), and deficiency (≤ 20 ng/mL). Descriptive statistics, means and standard deviations were used. Logistic regression analyses adjusted by age, sex, and educational level were performed Results We evaluated 208 patients. Mean age was 79 ± 1 year, 65% (n = 136) were female; and mean educational level was 6.7 ± 2.3 years. Thirty-one subjects (14%) had NC; 42% (n = 88) had MCI; and 43% (n = 89) had AD. Prevalence of Vitamin D deficiency was 54%, more frequent in the AD group (64%) followed by the MCI (59%) and NC (13%) (p < 0.001) groups. In the multivariate logistic regression analysis, Vitamin D deficiency was associated with MCI (HR 25.02 [confidence interval 95% 4.48-139]; p < 0.001) and AD (HR 41.7 [5.76-301]; p < 0.001) after adjusting for confounders Conclusions Serum Vitamin D deficiency was associated with MCI and dementia; low levels produced a greater effect over executive functions.

Nutritional and hematological factors associated with the progression of Alzheimer's disease: a cohort study

SUMMARY OBJECTIVE: We studied the users of the Specialized Drug Distribution Program of the public health network. METHODS: A prospective cohort examined the elderly at two intervals of three years and included 30 patients in phase I and 16 in phase II. The methodology was composed of home visits, anthropometric, nutritional and hematological evaluation. For the progression of AD, the Clinical Dementia Rating (CDR) scale was used. RESULTS: According to the CDR, the disease evolved, since in 2014 most of the patients were in CDR 3. In the analysis of the micronutrients, only the B vitamins (B1, B2, B3, B5, B6) presented a significant reduction in 2014. The consumption of carbohydrates and lipids increased in the 2014 evaluation, and protein consumption decreased. As for the average weight of the elderly, there was an increase in 2014, 65.9 (± 15.6) Kg, with a BMI of 26.75 (± 4, 5), in 2011 the average weight was 62.44 kg (± 14, 36), BMI 24.64 (± 4.97). CONCLUSION: The hypothesis that patients are likely to be overweight or obese before the development of AD and that this may be associated with an increased risk of dementia is suggested.

RESUMO OBJETIVO: Foram estudados os usuários do programa de distribuição de medicamentos especializados da rede pública de saúde de Guarapuava, Paraná, Brasil. MÉTODOS: Uma coorte prospectiva, em que os idosos foram examinados em dois momentos, com um intervalo de três anos, com 30 pacientes na fase I e 16 na fase II. A metodologia foi composta por visitas domiciliares, avaliação antropométrica; avaliação nutricional e hematológica. Para a progressão da DA, utilizou-se a escala Clinical Demential Rating (CDR). Os testes de Shapiro-Wilk, teste de Wilcoxon e correlações com associações (Δ%), p < 0,05 para as análises estatísticas. RESULTADOS: A progressão da doença, segundo o CDR, evoluiu, pois, em 2014, a maioria dos pacientes encontrava-se em CDR 3. Na análise dos micronutrientes, somente as vitaminas do complexo B (B1, B2, B3, B5, B6) apresentaram redução significativa em 2014. O consumo de carboidratos e lipídeos aumentou na avaliação de 2014, e o consumo de proteínas diminuiu. Quanto ao peso médio dos idosos, houve um aumento em 2014, 65,9 (± 15,6) kg, com IMC 26,75 (± 4, 5); em 2011, o peso médio foi 62,44 kg (± 14,36), IMC 24,64 (± 4,97). CONCLUSÃO: Não foram encontrados pacientes anêmicos ou desnutridos na amostra. A hipótese de que os pacientes provavelmente já apresentavam sobrepeso ou obesidade antes do desenvolvimento da DA, e que isso pode estar associado com um aumento de risco de demência, pode ser sugerida.

OxLDL plasma levels in patients with Alzheimer's disease / Níveis plasmáticos de LDL-ox em pacientes com doença de Alzheimer

ABSTRACT Objective: The objective of this study was to characterize the conventional lipid profile, oxLDL levels and ApoE polymorphism in patients with Alzheimer's disease (AD) and in elderly individuals without cognitive impairment. Methods: Eighty elderly individuals were selected and the levels of oxLDL were determined using the ELISA kit, and ApoE gene polymorphism was investigated using polymerase chain reaction-restriction fragment length polymorphism. Results: Significantly reduced levels of oxLDL were observed in patients with AD compared to the control group. A higher frequency of the ApoE ε4 allele was observed in patients with AD compared to controls. No difference was observed for total cholesterol, HDL-C, and LDL-C levels between the two groups, while triglyceride levels were higher in controls compared with patients with AD. Conclusion: The data analyzed together did not reveal significant differences in lipid profiles, including oxLDL levels. However, the importance of lipid changes in the genesis of the disease cannot be ruled out. Nevertheless, the ApoE ε4 allele was significantly more frequent in patients with Alzheimer's dementia in agreement with previous findings in the literature, but this genetic component did not change the levels of oxLDL.

RESUMO Objetivo: O objetivo deste estudo foi caracterizar o perfil lipídico convencional, os níveis de LDL-ox e o polimorfismo da ApoE em pacientes com doença de Alzheimer (DA) e em indivíduos idosos sem comprometimento cognitivo. Métodos: Foram selecionados oitenta indivíduos idosos. Os níveis de LDL-ox foram determinados usando o kit ELISA e a investigação do polimorfismo do gene da ApoE por PCR-RFLP. Resultados: Níveis significativamente reduzidos de LDL-ox foram observados em pacientes com DA comparado ao grupo controle. Uma maior frequência do alelo ε4 da ApoE foi observada nos pacientes com DA em relação aos controles. Nenhuma diferença foi observada para os níveis de colesterol total, HDL-C e LDL-C entre os dois grupos, enquanto níveis de triglicérides foram mais altos em controles comparados aos pacientes com DA. Conclusão: Os dados analisados em conjunto não revelaram diferenças significativas no perfil lipídico, incluindo os níveis de LDL-ox. No entanto, não se pode excluir a importância de alterações lipídicas na gênese da doença. Não obstante, o alelo ε4 da ApoE foi signicativamente mais frequente nos pacientes com demência de Alzheimer em concordância com achados prévios da literatura, mas esse componente genético não interferiu nos níveis de LDL-ox.

Pharmacogenetic effects of angiotensin-converting enzyme inhibitors over age-related urea andcreatinine variations in patients with dementia due to Alzheimer disease / Efectos farmacogenéticos de inhibidores de la enzima convertidora de la angiotensina en variaciones de urea y creatinina asociadas con el envejecimiento en pacientes con demencia de la enfermedad de Alzheimer

Background: Renal function declines according to age and vascular risk factors, whereas few data are available regarding geneticallymediated effects of anti-hypertensives over renal function. Objective: To estimate urea and creatinine variations in dementia due to Alzheimer disease (AD) by way of a pharmacogenetic analysis of the anti-hypertensive effects of angiotensin-converting enzyme inhibitors (ACEis). Methods: Consecutive outpatients older than 60 years-old with AD and no history of kidney transplant or dialytic therapy were recruited for prospective correlations regarding variations in fasting blood levels of urea and creatinine in one year, considering ACE genotypes of rs1800764 and rs4291 and their respective haplotypes, and treatment with ACEis along with blood pressure variations. Results: For 190 patients, 152 had arterial hypertension, and 122 used ACEis. Minor allele frequencies were 0.492 for rs1800764-C and 0.337 for rs4291-T, both in Hardy-Weinberg equilibrium. There were no overall significant yearly variations in levels of urea and creatinine, but their concurrent variations were positively correlated (ρ <0.0001). Each A allele of rs4291 led to an yearly urea increase of 3.074 mg/ dL, and an yearly creatinine increase of 0.044 mg/dL, while the use of ACEis was protective regarding creatinine variations. The use of ACEis was also protective for carriers of rs1800764-CT/rs4291-AA, while carriers of rs1800764-CT/rs4291-AT had steeper reductions in creatinine levels, particularly when they were treated with ACEis. Conclusions: Effects of ACEis over creatinine variations are genetically mediated and independent of blood pressure variations in older people with AD.

Antecedentes: El deterioro de la función renal depende de la edad y los factores vasculares. La literatura sobre los efectos de fármacos antihipertensivos mediada genéticamente en la función renal es pobre. Objetivo: Estimar las variaciones de urea y creatinina a través del análisis farmacogenético de los efectos antihipertensivos de los inhibidores de la enzima convertidora de angiotensina (iECA) en pacientes con demencia debido a la enfermedad de Alzhaimer. Métodos: Fueron reclutados pacientes consecutivos mayores de 60 años de edad con enfermedad de Alzheimer y sin antecedentes de trasplante renal o diálisis. Se determinaron correlaciones prospectivas durante un año entre los cambios en los niveles sanguíneos de urea y creatinina, considerando genotipos y haplotipos de ACE (rs1800764 y rs4291) y el tratamiento con iECA a y las variaciones en la presión arterial. Resultados: De 190 pacientes, 152 presenaron hipertensión, 122 usaron iECA. Las frecuencias de alelos polimórficos fueron de 0.492 para rs1800764-C y 0.337 para rs4291-T, los dos alelos en equilibrio de Hardy-Weinberg. No se determinaron fluctuaciones anuales significativas en los niveles de urea o creatinina, pero sus variaciones concomitantes se asociaron fuertemente (ρ= <0.0001). Cada alelo A de rs4291 condujo a aumentos anuales de 3.074 mg/dL en urea y 0.044 mg/dL en creatinina, mientras que el uso de iECA fue protector para las variaciones en la creatinina. El uso de iECA también fue protector para las personas con rs1800764-CT/rs4291-AA, mientras que los portadores de rs1800764-CT/rs4291-AT tuvieron reducciones de creatinina más altas, particularmente cuando se usó iECA. Conclusión: Los efectos de iECA en la variación de la creatinina son genéticamente mediadas e independiente de las variaciones en la presión arterial en pacientes de edad avanzada con la enfermedad de Alzheimer.

Reference Intervals for Plasma Amyloid β in Korean Adults Without Cognitive Impairment

Amyloid β (Aβ) peptides are important components of plaques in patients with Alzheimer's disease (AD). Recent studies suggest that a low plasma ratio of Aβ42 to Aβ40 may precede the development of the sporadic form of AD. The aim of this study was to establish reference intervals for plasma Aβ in Korean adults. A total of 370 apparently healthy individuals (181 males and 189 females aged 40-69 yr) without cognitive impairment were enrolled. Plasma concentrations of Aβ40 and Aβ42 were measured by using a human amyloid β assay kit (Immuno-Biological Laboratories, Japan). Reference intervals were established according to the "CLSI guidelines for defining, establishing, and verifying reference intervals in the clinical laboratory". There was no need to partition the data with respect to gender or age group. The 95th percentile reference intervals for Aβ40 and Aβ42 were 127-331 pg/mL and 2.31-19.84 pg/mL, respectively. The reference interval for the Aβ42/Aβ40 ratio was 0.011-0.092. Plasma Aβ concentrations obtained in this study could be used as reference intervals for clinical purposes.

Mild cognitive impairment (part 2): biological markers for diagnosis and prediction of dementia in Alzheimer's disease

Objective: To present a critical review of publications reporting on the rationale and clinical implications of the use of biomarkers for the early diagnosis of Alzheimer's disease (AD). Methods: We conducted a systematic search of the PubMed and Web of Science electronic databases, limited to articles published in English between 1999 and 2012, and based on the following terms: mild cognitive impairment, Alzheimer's disease OR dementia, biomarkers. We retrieved 1,130 articles, of which 175 were reviews. Overall, 955 original articles were eligible. Results: The following points were considered relevant for the present review: a) rationale for biomarkers research in AD and mild cognitive impairment (MCI); b) usefulness of distinct biomarkers for the diagnosis and prediction of AD; c) the role of multimodality biomarkers for the diagnosis and prediction of AD; d) the role of biomarkers in clinical trials of patients with AD and MCI; and e) current limitations to the widespread use of biomarkers in research and clinical settings. Conclusion: Different biomarkers are useful for the early diagnosis and prediction of AD in at-risk subjects. Nonetheless, important methodological limitations need to be overcome for widespread use of biomarkers in research and clinical settings. .

Is anti-cyclic citrullinated peptide antibody a good value biomarker for Alzheimer disease?

Alzheimer's disease [AD] is one of the most important neurodegenerative disorder. Anti-cyclic citrullinated peptide [anti-CCP] may all be involved in the development of vascular disease such as AD. The aim of this study is detection of seropositivity for anti-CCP antibody in AD patients. In our study, 30 patients with AD and 29 healthy controls [age and-sex matched] were recruited. Homocysteine and anti-CCP was measured by spectrophotometrically and immunoassay. Mean +/- SE anti-CCP was higher significantly between AD [13.6 +/- 3] and healthy subjects [4.8 +/- 0.2] [P = 0.006]. In the patients, anti CCP serum level was in high range [32.1%] of abnormal levels, but there was no significant difference in serum homocysteine in AD patients compared with controls. There is no correlation between anti-CCP and homocysteine levels in AD patients [P = 0.75], but between age and anti-CCP level observed a significantly correlation [P = 0.04]. It needs more studies to clarify confirmation the role of anti-CCP antibody production in AD patients

Trabalho de consenso de força-tarefa da WFSBP sobre marcadores biológicos das demências: contribuição da análise do LCR e do sangue para o diagnóstico precoce e diferencial das demências / Consensus Paper of the WFSBP Task Force on Biological Markers of Dementia: The role of CSF and blood analysis in the early and differential diagnosis of dementiaWorld J Biol Psychiatry

O envelhecimento da população e o aumento da expectativa de vida resultam em um número cada vez maior de pacientes com demência. Os déficits cognitivos podem ser manifestações de uma doença curável do sistema nervoso central (por exemplo, neuroinflamação), como também de uma doença atualmente considerada irreversível, como a doença de Alzheimer (DA). Tendo em vista as novas abordagens terapêuticas para a DA, em que se avalia o potencial modificador da patogenia, torna-se necessário o estabelecimento de um diagnóstico confiável em vida. Embora a análise do líquido cefalorraquidiano (LCR) e do soro seja realização de rotina em doenças neuroinflamatórias, ainda necessita de padronização para ser usada como instrumento auxiliar no diagnóstico clínico da DA. Vários parâmetros relacionados à DA (tau total, formas fosforiladas de tau, peptídeos Aβ, genótipo ApoE, p97 etc.) podem ser determinados no LCR. A combinação de alguns desses parâmetros proporciona sensibilidade e especificidade na faixa de 85 por cento para o diagnóstico da DA, um valor usualmente atribuído a um bom instrumento de diagnóstico. Nesta revisão, são discutidas as publicações mais recentes sobre os marcadores neuroquímicos para o diagnóstico clínico das demências, com ênfase no diagnóstico precoce e diferencial da DA. Discutem-se brevemente as novas perspectivas oferecidas por tecnologias recentes, tais como a FCS (fluorescence correlation spectroscopy) e a técnica de espectrometria de massa pelo método SELDI-TOF (surface enhanced laser desorption/ionization time-of-flight mass spectrometry).

Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Aß peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85 percent, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.

Detección de ADN de Chlamydophila Pneumoniae en líquido cefalorraquídeo proveniente de pacientes diagnósticados con enfermedad de alzheimer / DNA detection of chlamydophila Pneumoniae in cerebrospinal fluid of patients diagnosed with alzheimer disease

La enfermedad de alzheimer (EA) es un desorden neurodegenerativo y la isoforma 4 de apolipoproteína E (ApoE) es mundialmente aceptada como un factor de riesgo para el desarrollo de alzheimer esporádico. La EA se ha asociado con infecciones por Chlamydophila pneumoniae (ChP) debido a que inhibe la respuesta inmune del huésped generando infecciones crónicas. El objetivo fue detectar el ADN de ChP en líquido cefalorraquídeo (LCR) de pacientes con diagnóstico clínico de alzheimer provenientes de distrito metropolitano de caracas. Se analizaron (7) muestras de LCR de pacientes con diagnóstico clínico de EA y el grupo control estuvo constituido por (13) muestras de LCR de pacientes con otras enfermedades neurológicas (OND) no demencia. A los cuales se les determino la isoforma de ApoE, se amplificaron los genes para OmcA y 16Sribosomal de ChP. La frecuencia de apoE isoforma 4 en los pacientes con EA fue (0,57) en contrste con el grupo control donde la frecuencia fue de (0,31). En todas las mustras analizadas se obtuvo una ausencia de la banda correspondiente a Chlamydophila pneumoniae. La mayor probabilidad es que la bacteria no se encontrara en el LCR de los pacientes. Pero existe la posibilidad de que ADN de ChP no estuviese en suficiente cantidad como para ser detectado por las técnicas empleadas. Además, debemos considerar que el protocolo de extracción es un punto crítico. Finalmente, los pacientes con diagnóstico clínico de EA y en particular del género femenino tienen mayor frecuencia de tener una copia de ApoE isoforma 4 en su genotipo.

Alzheimer's disease (AD) is a neurodegenerative disorder and the isoform 4 of apoliporotein E (ApoE) is world accepted as a risk factor for developing sporadic alzheimer. The AD has been associated with infections by Chlamydophila pneumoniae (ChP) because it inhibits the host immune response causing chroic infections. To detected ChP DNA in cerebrospinal fluid (CSF) of patients with clinical diagnosis lf alzheimer's from the metropolitan district of caracas. We analyzed (7) CSF samples from patients with clinical diagnsis of AD and control groups consisted of (13) CSF samples from patientes with other neurological diseases (OND) no dementia. To with the determined the isoform of ApoE genes were amplified for OmcA and 16Sribosomal of ChP. The frecuency of ApoE isoform 4 in AD patients was (0.57) in contrast to the control group where the frequency was (0.31). All samples were obtained an absence of the band corresponding to Chlamydophila pneumoniae. The greater likelihood is that the bacteria is not found in the CSF of patients. But there is the possibility that DNA was no ChP insufficient quantity to be detected by the techniques employed. Furthermore, we most consider the extraction protocol is a critical point. Finally, patients with clinical diagnosis of Ad and in particular the female are more often have a copy of ApoE isoform 4 in its genotype.

Alzheimer's disease in Brazilian elderly has a relation with homocysteine but not with MTHFR polymorphisms / A doença de Alzheimer em idosos brasileiros tem relação com homocisteina mas não com polimorfismos MTHFR

OBJECTIVE: To investigate the association between total plasma homocysteine concentration, C677T and A1298C polymorphisms in MTHFR gene and Alzheimer's disease (AD) development. METHOD: Forty-three patients with probable (63 percent) and possible (37 percent) AD and 50 non-demented controls were evaluated. Groups did not differ as to gender, age, scholar years, diabetes, alcohol and coffee intake and physical activity. Total plasma homocysteine (Hcy) levels were determined by HPLC and genotyping for MTHFR by PCR/RFLP. Mann-Whitney "U" test was used to compare quantitative variable, Fisher-Freeman-Halton test to compare genotypes and allele proportions and Chi-square test to other qualitative variables. RESULTS: AD patients presented higher total plasma Hcy levels than controls and the difference was statistically significant. No differences in the C677T and A1298C MTHFR polymorphisms distributions were found between patients and controls. Plasma homocysteine concentration did not change with MTHFR genotypes. CONCLUSION: Our data confirms the association between increased plasma Hcy concentration and AD and suggests that neither C677T nor A1298C MTHFR polymorphisms contributed to genetic susceptibility for AD in elderly individuals in the Northeast of Brazil.

OBJETIVO: Investigar a associação entre a concentração plasmática total de homocisteína (Hcy), os polimorfismos C677T e A1298C do gene MTHFR e o desenvolvimento da Doença de Alzheimer (AD). MÉTODO: Foram avaliados 43 pacientes com doença de Alzheimer possível (37 por cento) e provável (63 por cento) e 50 controles não dementes, não divergentes quanto ao sexo, idade, anos de escolaridade, diabetes, consumo de álcool e de café e vida sedentária. Os níveis plasmáticos de homocisteína foram determinados por HPLC e a genotipagem para MTHFR por PCR/RFLP. A comparação dos níveis de homocisteína foi realizada pelo teste "U" Mann-Whitney, a comparação das proporções dos genótipos e alelos pelo teste de Fisher-Freeman-Halton e as demais variáveis qualitativas, pelo teste do qui-quadrado. RESULTADOS: Os pacientes AD apresentaram níveis mais elevados de Hcy plamática total do que os controles e a diferença entre os grupos foi estatisticamente significante. Não houve diferença nas distribuições genotípicas C677T e A1298C entre pacientes e controles. A concentração de Hcy não variou com os genótipos. CONCLUSÃO: Nossos dados confirmam a associação de concentração elevada de Hcy plasmática com DA e sugerem que os polimorfismos C677T e A1209C não contribuem para a susceptibilidade genética a DA em idosos do Nordeste do Brasil.

Role of anti-oxidant enzymes superoxide dismutase and catalase in the development of cataract : study of serum levels in patients with senile and diabetic cataracts.

Cataract is a universal phenomenon in old age and the most common cause of blindness worldover. Oxidative stress is believed to be a key factor in the gradual loss of transparency of lens. Free radicals formed result in derangement and opacification of lens fibres. Superoxide dismutase, catalase and glutathione peroxidase are major anti-oxidant enzymes, which protect against free radicals. The purpose of this study is to evaluate the role of anti-oxidant enzymes - superoxide dismutase and catalase in the development of cataract in senile and diabetic persons. Serum levels of major anti-oxidant enzymes-superoxide dismutase and catalase were estimated in 20 patients with diabetic cataract, and matched with another 20 patients of senile cataract taken as control. Estimation of superoxide dismutase was done by improved spectrophotometric assay based on epinephrine auto-oxidation at 480nm, while catalase estimation was done by the method of Hugo Aebi. The mean serum levels of superoxide dismutase and catalase were lower as age increased. These enzymes were also significantly lower in diabetic cataracts (9.13 and 16.42 units/ml) as compared to senile cataracts (25.30 and 57.27units/ml). Oxidative stress is one of the major factors contributing to cataract formation. In diabetics where there is increased oxidative stress, the serum levels of the major anti-oxidant enzymes decrease, which lead to early cataract formation. It may be concluded that oxidative stress is an important factor in the development of diabetic cataracts and anti-oxidants may have a role in decreasing the incidence of cataract.

Serum cobalamin levels in dementias.

The present study attempts to find a correlation between low serum B-12 levels and dementias. A total of 178 patients of dementia were seen at the cognitive disorder clinic from 1996 to 1998. Serum B-12 levels were studied in 100 patients. 15 patients (39.5%) of Alzheimer's dementia had reduced B-12 levels, while only 5 patients (13.9%) with vascular dementias and 3 patients (11.5%) with other types of dementias had reduced levels. The incidence of low serum B-12 was statistically significant in the Alzheimer's group when compared with the other groups, individually as well as combined together (p<0.05). The aetiopathogenesis and significance of these findings is discussed and the literature is reviewed.

Oligoelementos en la enfermedad de Alzheimer / Trace elements in Alzheimer's disease

Se investigaron cinco metales, aluminio, calcio, cromo, manganeso y zinc en suero, orina y cabello de enfermos de Alzheimer, comparados con tres testigos sanos de edad similar. La determinación se efectuó por Absorción Atómica en la llama o electrotérmica. No se hallaron diferencias significativas con los testigos. Esto indicaría que estos oligoelementos en especial el aluminio no guardan una relación causal directa con la enfermedad.

Distúrbio do metabolismo de fosfolípides na doença de Alzheimer / Disordered metabolism of membrane phospholipds in Alzheimer's disease

A fosfolipase A2 (PLA2) é uma enzima fundamental no metabolismo dos fosfolípides da membrana celular. A PLA2 influencia o processamento e a secreção da proteína precursora do amilóide, que dá origem ao peptídeo ß-amilóide, o componente principal das placas senis na doença de Alzheimer (DA). Investigamos a atividade da PLA2 em duas amostras: a) num estudo post mortem, em tecido cerebral de 23 pacientes com uma DA e 20 controles não-dementes, e b) em plaquetas de 16 pacientes com uma DA provável, 13 controles sadios e 14 pacientes idosos com uma depressão. No cérebro, a atividade da PLA2 estava significantemente reduzida no córtex parietal e frontal de pacientes com DA. Esta redução estava correlacionada com um início precoce da doença, com um número mais elevado de neurofibrilas e placas senis, e com um óbito mais prematuro. Também nas plaquetas de pacientes com DA encontramos uma redução da atividade da PLA2 em comparação com os controles sadios e deprimidos. A redução da atividade da enzima em plaquetas estava correlacionada com um início precoce da doença, com o grau de atrofia cerebral e com um déficit cognitivo mais acentuado, indicando assim uma relação entre a redução da PLA2 e uma forma mais severa da doença. Nossos resultados indicam um distúrbio do metabolismo de fosfolípides na DA e sugerem que a redução da atividade da PLA2 poderia contribuir para a formação do peptídeo ß-amilóide na doença. Estudos futuros devem esclarecer se a atividade da PLA2 em plaquetas poderia ser útil como um marcador periférico para a DA, ou como preditor para o grau de severidade da doença

Physiology and function of platelets from patients with Alzheimer's disease.

The discovery that intact Alzheimer amyloid precursor protein is present in platelet granules, has created a great interest in the biochemistry, physiology and function of platelets of patients with Alzheimer disease (AD). In this study we monitored various biochemical and physiological parameters, such as serotonin and adenine nucleotide levels, membrane fluidity, agonist-mediated release of arachidonic acid, thromboxane formation, calcium mobilization, as well as irreversible aggregation and secretion of granule contents. Platelets of patients with AD responded poorly when stirred with weak or potent agonists on a platelet aggregometer. Although capable of agonist-mediated calcium mobilization and synthesis of thromboxanes, the aggregation response of platelets of patients with AD to thrombin and archidonate was considerably compromised. In view of the normal biochemistry and signal transduction capabilities, the compromised response of these cells to potent agonists like thrombin suggested an extrinsic defect. The present study has shown that a plasmatic factor is at least in part responsible for the functional abnormalities of AD platelets.