ABSTRACT
BACKGROUND: Regular consumption of fish reduces cardiovascular risks. Here, we investigate if the consumption of products with mackerel (Scomber scombrus) with 8.82 g of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) content per 100 g of product improves parameters of endothelial function in a controlled population. MATERIALS AND METHODS: Subjects maintained a 12-week diet with products with mackerel. The population consisted of 58 senior subjects (12 withdrawals, 25 women), aged 82.08 +/- 8.13 years (Group A). Twenty-three senior subjects (13 women) on a regular diet were used as the control group (Group B). Subjects of Group A received 57 portions throughout 12 weeks (four to five portions a week of products with a mean EPA + DHA content of 2.5 g a day). A continuous follow-up and a final evaluation were performed to determine the level of consumption. Plasma samples were stored at -70 degrees C for a biochemical study. Endothelial function was analysed by reactive hyperemia with a mercury strain gauge plethysmography with measurement of blood flow in the forearm, both baseline and at the end of the 12-week diet. RESULTS: Endothelium-dependent vasodilatation significantly increased in Group A subjects (P < 0.001). No changes were found in Group B. The subgroup analyses showed that improvements were produced in Group A subjects without cardiovascular disease (P < 0.001). Nitrites/nitrates and von Willebrand factor plasma concentrations were higher in participants after the 12-week diet. CONCLUSIONS: The consumption of mackerel meat products improves endothelium-dependent, flow-mediated vasodilatation in a senior population. This finding might explain some of the cardioprotective effects of fish consumption.
Subject(s)
Endothelium, Vascular/drug effects , Fatty Acids, Omega-3/pharmacology , Aged , Aged, 80 and over , Animals , Case-Control Studies , Docosahexaenoic Acids/administration & dosage , Docosahexaenoic Acids/pharmacology , Eicosapentaenoic Acid/administration & dosage , Eicosapentaenoic Acid/pharmacology , Fatty Acids, Omega-3/administration & dosage , Female , Humans , Male , Middle Aged , Perciformes , Statistics as TopicABSTRACT
OBJECTIVE: As vascular endothelial growth factor (VEGF) determines important neurotrophic and neuroprotective actions, we postulated serum VEGF levels could be abnormally low in patients with Alzheimer's disease (AD). METHODS: We measured serum VEGF levels (VEGF(165) isoform by ELISA) in 51 patients with AD by National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorder Association criteria and compared with 66 age- and gender-matched non-demented controls. Patients with AD were stratified into levels of dementia severity by the Clinical Dementia Rating scale. Serum VEGF levels were stratified into upper (>309 pg/ml), middle (207-309 pg/ml), and lower (<207 pg/ml) tertiles. VEGF (-2,578) (rs 699,947) and VEGF (-634) (rs 2,010,963) polymorphisms were genotyped in patients with AD and controls. RESULTS: The mean concentration of VEGF in the serum of patients with AD (215.9 pg/ml, SD 101.5) was significantly lower than that of the controls (308.6 pg/ml, SD 223.9, P = 0.004), and decreased serum VEGF levels were associated with AD in a dose-dependent manner, the lower tertile of serum VEGF levels being associated with a fivefold increased risk for AD when compared with the upper tertile. There was no significant correlation between serum VEGF levels and age, sex, APOE alleles, AD dementia severity nor VEGF gene polymorphisms. CONCLUSION: Decrease in serum VEGF levels could contribute to the neurodegenerative process in AD.
Subject(s)
Alzheimer Disease/blood , Vascular Endothelial Growth Factor A/blood , Age Factors , Aged , Aged, 80 and over , Alzheimer Disease/genetics , Apolipoprotein E4/genetics , Case-Control Studies , Female , Humans , Male , Middle Aged , Polymorphism, Genetic , Severity of Illness Index , Sex Factors , Vascular Endothelial Growth Factor A/geneticsABSTRACT
Normal aging is commonly associated with a decline in memory, mainly for that related with newly acquired information. The hippocampal formation (HF) is a brain region that has been implicated in this dysfunction. Within the HF there are several cellular types, such as pyramidal cells, granule neurons of the dentate gyrus, and astrocytes. CDP-choline is a well-known intermediate in the biosynthesis of phosphatidylcholine, a phospholipid essential for neuronal membrane preservation and function; thus, this compound would attenuate the process of neuronal aging. To test this, three groups of male mice were used in this study. An adult 12-month-old group (ACG), a 24-month-old (OCG), and an old experimental group (OEG) were administered orally a solution of CDP-choline (150 mg/kg per day) from 12 up to 24 months. Experimental observations suggest that CDP-choline has a positive effect on memory (reference errors were attenuated), and hippocampal morphology resembled that of younger animals.
Subject(s)
Aging , Hippocampus/drug effects , Phosphatidylcholines/pharmacology , Animals , Cytidine Diphosphate Choline/pharmacology , Hippocampus/metabolism , Hippocampus/pathology , Male , Memory , Mice , Phosphatidylcholines/metabolism , Phospholipids/metabolismABSTRACT
The purpose of the present study has been to determine, in a population group over 80 years of age in a publicly-funded geriatric institution, the anthropometric parameters that represent reference values for the study of nutritional status. These parameters allow detection of alterations in the nutritional status which, once corrected, will contribute to maintaining an appropriate quality of life in a population group that is highly sensitive to the associated morbidity and mortality processes. In order to carry out this study, a sample of 56 healthy elderly individuals was selected (13 men and 43 women) with a mean age of 86.5 +/- 4.8 years and a range from 80 to 101 years. The parameters measured were: weight, height, tricipital fold, brachial perimeter and the following values calculated on the basis of these figures: body mass index, percentage of body fat, brachial muscular area, brachial muscular perimeter, brachial adipose area and the ratio of muscle to adipose tissue. These values were processed statistically with the assistance of the RSB-SIGMA computer software, with calculation of the percentiles, the mean, and the comparison between the sexes. The criterion for statistical significance was set at p < 0.05. Our results confirm the presence of significant differences in the muscle parameters, which are greater in men than in women, whereas the fat parameters are higher in the latter. Thus, it is concluded that weight, height, brachial muscle area and brachial muscle perimeter are significantly higher in men whereas tricipital fold, percentage of body fat, the brachial adipose area and the muscle to adipose tissue ratio are significantly superior among women. There are no significant differences by gender in the body mass index and the brachial perimeter.
Subject(s)
Anthropometry , Institutionalization , Aged , Aged, 80 and over , Female , Humans , MaleABSTRACT
El objetivo del presente trabajo ha sido determinar, en un grupo de población de más de 80 años de una residencia geriátrica pública, los parámetros antropométricos que constituyen valores de referencia para el estudio del estado nutricional. Estos parámetros permiten detectar alteraciones en el estado nutricional que corrregidas ayudarán a mantener una adecuada calidad de vida en un grupo de población muy sensible a los procesos asociados de morbimortalidad. Para la realización de este estudio se seleccionó una muestra de 56 ancianos sanos (13 varones y 43 mujeres), con una media de edad de 86,5 +/- 4,8 años y un rango comprendido entre 80 y 101 años. Los parámetros medidos fueron: peso, talla, pliegue tricipital, perímetro braquial y los valores calculados a partir de éstos: índice de masa corporal, porcentaje de grasa corporal, área muscular braquial, perímetro muscular braquial, área adiposa braquial y el índice adiposo muscular. Estos valores fueron procesados estadísticamente con ayuda del programa informático RSB-SIGMA y se calcularon los percentiles, la media, y la comparación entre sexos. Se estableció como criterio de diferencias significativas una p<0,05. Nuestros resultados constatan la presencia de diferencias significativas en los parámetros musculares, los cuales son mayores en los varones que en las mujeres, mientras que los parámetros grasos son más elevados en éstas últimas. Así se concluye que, peso, tala, área muscular braquial y perímetro muscular braquial son significativamente más elevados en los varones que en las mujeres. Por otra parte el pliegue tricipital, el porcentaje de grasa corporal, el área adiposa braquial y el índice adiposo muscular lo son en mujeres. No hay diferencias significativas por sexos en el índice de masa corporal y el perímetro braquial (AU)
The purpose of the present study has been to determine, in a population group over 80 years of age in a publicly- funded geriatric institution, the anthropometric parameters that represent reference values for the study of nutritional status. These parameters allow detection of alterations in the nutritional status which, once corrected, will contribute to maintaining an appropriate quality of life in a population group that is highly sensitive to the associated morbidity and mortality processes. In order to carry out this study, a sample of 56 healthy elderly individuals was selected (13 men and 43 women) with a mean age of 86.5 ± 4.8 years and a range from 80 to 101 years. The parameters measured were: weight, height, tricipital fold, brachial perimeter and the following values calculated on the basis of these figures: body mass index, percentage of body fat, brachial muscular area, brachial muscular perimeter, brachial adipose area and the ratio of muscle to adipose tissue. These values were processed statistically with the assistance of the RSB-SIGMA computer software, with calculation of the percentiles, the mean, and the comparison between the sexes. The criterion for statistical significance was set at p < 0.05. Our results confirm the presence of significant differences in the muscle parameters, which are greater in men than in women, whereas the fat parameters are higher in the latter. Thus, it is concluded that weight, height, brachial muscle area and brachial muscle perimeter are significantly higher in men whereas tricipital fold, percentage of body fat, the brachial adipose area and the muscle to adipose tissue ratio are significantly superior among women. There are no significant differences by gender in the body mass index and the brachial perimeter (AU)
Subject(s)
Aged , Aged, 80 and over , Male , Female , Humans , Anthropometry , InstitutionalizationABSTRACT
The low density lipoprotein receptor-related protein (LRP) may influence both the clearance and the production of beta-amyloid peptide and thus plays a role in Alzheimer's disease (AD) pathogenesis. Previous studies, although inconsistent, have suggested that the LRP exon 3 CC genotype contributes to the risk of AD. A case-control study utilizing a clinically well-defined group of 305 sporadic AD patients and 304 control subjects was performed to test this association in an ethnically homogeneous population from Spain. In the current study, the LRP CC genotype was not over-represented in AD patients compared to non-demented controls. A meta-analysis of previous studies revealed a weak correlation of LRP CC genotype with AD (odds ratio of 1.35, P=0.01).
Subject(s)
Alzheimer Disease/genetics , Exons/genetics , Low Density Lipoprotein Receptor-Related Protein-1/genetics , Polymorphism, Genetic/genetics , Aged , Aged, 80 and over , Case-Control Studies , Female , Gene Frequency/genetics , Genotype , Humans , Male , Middle AgedABSTRACT
INTRODUCCION Y OBJETIVO: La HTA en el anciano es un problema de salud relevante, y existe un escaso conocimiento de su prevalencia, así como un bajo grado de control de las cifras de PA. Hemos llevado a cabo un estudio en pacientes ancianos institucionalizados con un objetivo doble: evaluar la prevalencia de HTA esencial y su grado de control en ese medio, y evaluar la eficacia antihipertensiva de una asociación farmacológica de trandolapril y verapamilo en combinación fija en los pacientes no controlados en monoterapia. MATERIAL Y MÉTODOS: Se trata de un estudio abierto, prospectivo, en pacientes ancianos institucionalizados en residencias de Vizcaya y Cantabria, en dos fases: epidemiológica (escrutinio para detectar la población hipertensa) y de intervención (tratar a los hipertensos no controlados en monoterapia con la asociación fija trandolapril más verapamilo), durante seis meses. RESULTADOS: Estudio de prevalencia: de un total de 1.696 ancianos escrutados, 1.053 no recibían tratamiento. Existía HTA en el 31 por ciento (323 pacientes), mientras que en los hipertensos tratados, el 70 por ciento (453 pacientes) mostraban cifras de PA no controladas (prevalencia de un 56,9 por ciento). De los tratados y no controlados, el 81 por ciento recibía monoterapia para la HTA. La cifra global de prevalencia de HTA fue del 56,95 por ciento de la población estudiada. ESTUDIO DE INTERVENCION: En 257 ancianos no controlados con monoterapia, la administración de la asociación de trandolapril y verapamilo durante cuatro meses consiguió que el 45,2 por ciento de los pacientes mostraran cifras de PA controladas, porcentaje que ascendía al 78 por ciento si se definía como control adecuado de la PA cifras inferiores a 145/90 mm Hg. La presión del pulso descendió significativamente de 75 a 58 mm Hg. CONCLUSIONES: En una población anciana institucionalizada, con HTA mal controlada en monoterapia, el empleo de la asociación verapamilo y trandolapril ayuda a conseguir un control estricto en cerca de la mitad de los pacientes, o un control adecuado de la misma en un 78 por ciento de los mismos, disminuyendo la presión del pulso (AU)
Subject(s)
Aged , Aged , Humans , Drug Combinations , Hypertension/epidemiology , Hypertension/drug therapy , Prospective Studies , Cross-Sectional StudiesABSTRACT
INTRODUCTION: Recent reports indicate that the K variant of the butyrylcholinesterase (BCHE) gene may act in synergism with the epsilon4 allele of apolipoprotein E (APOE) to increase the risk of Alzheimer's disease (AD), but this is controversial. MATERIAL AND METHODS: We genotyped for the BCHE-K and APOE epsilon4 alleles in a sample of 249 AD patients and 250 controls derived from the same region in a Spanish population. RESULTS: A protective effect of the K variant of BCHE with an odds ratio of 0.41 (95% confidence interval 0.19-0.86, P=0.02) was observed among non-APOE epsilon4 carriers, but it was limited to women. CONCLUSION: Our study is the first to demonstrate that lower susceptibility to AD determined by the K variant of BCHE is dependent on gender.
Subject(s)
Alzheimer Disease/genetics , Alzheimer Disease/physiopathology , Apolipoproteins E/genetics , Butyrylcholinesterase/genetics , Genetic Predisposition to Disease , Aged , Aged, 80 and over , Case-Control Studies , Female , Humans , Male , Middle Aged , Risk FactorsABSTRACT
An association between cognitive performance in elderly people and variability in the codon 129 of the prion protein gene (PRNP) has been recently described. The authors analyzed this polymorphism in 278 sporadic AD patients and 268 cognitively normal control subjects. Analyses stratifying by APOE genotype, age, and gender failed to reveal any association between homozygosity for the 129 PRNP methionine or valine alleles and AD.
Subject(s)
Alzheimer Disease/genetics , Amyloid/genetics , Polymorphism, Genetic/genetics , Protein Precursors/genetics , Age of Onset , Aged , Aged, 80 and over , Alleles , Alzheimer Disease/epidemiology , Amino Acid Substitution/genetics , Apolipoprotein E4 , Apolipoproteins E/genetics , Female , Genetic Carrier Screening , Genetic Linkage/genetics , Genetic Predisposition to Disease/epidemiology , Homozygote , Humans , Male , Middle Aged , Odds Ratio , Prion Proteins , Prions , Risk Assessment , Spain/epidemiology , White People/geneticsABSTRACT
We examined the possible involvement of polymorphisms of the presenilin 1 (PS1) and presenilin 2 (PS2) genes in the risk for sporadic Alzheimer's disease (AD), either through an independent effect or through interaction with the existing apolipoprotein E (ApoE) risk, in 211 AD cases and 188 age-matched control subjects. No significant differences were obtained in any of the comparisons relating the effect of the PS1 and PS2 polymorphisms; thus, these polymorphisms do not appear to be sufficient risk factors by themselves for sporadic AD. Although the ApoE varepsilon4 genotype is the only definite predictor of risk, homozygosity for either the 1 allele of the PS1 or the C allele of the PS2 genes may increase the risk conferred by the presence of an ApoE epsilon4 allele. Additionally, combination of PS1/11 and PS2/CC genotypes might have a small synergistic effect on the risk for AD.
Subject(s)
Alzheimer Disease/genetics , Membrane Proteins/genetics , Polymorphism, Genetic/genetics , Adult , Aged , Aged, 80 and over , Alleles , Female , Genotype , Humans , Male , Middle Aged , Presenilin-1 , Presenilin-2 , Risk FactorsABSTRACT
INTRODUCTION: The role of gender in Alzheimer's disease (AD), and its possible interaction with apolipoprotein E (apoE), has been controversial. MATERIAL AND METHODS: ApoE allelic frequencies and the effect of apoE epsilon4 allele dosage on risk and age at onset of AD were evaluated, separately for men and women, in 100 patients with sporadic AD and 100 age-matched controls. RESULTS: The distribution of apoE alleles and the odds ratio for AD, when associated with 1 or 2 epsilon4 alleles, were not statistically different between men and women. No effect of the dosage of the epsilon4 allele was found on the age at onset of dementia in the 2 sex groups. CONCLUSION: Our data suggest that the relation of the apoE genotype to AD is not dependent on sex.
Subject(s)
Alzheimer Disease/genetics , Apolipoproteins E/genetics , Alleles , Alzheimer Disease/epidemiology , Apolipoprotein E4 , Female , Humans , Male , Prevalence , Risk Factors , Sex DistributionSubject(s)
Anus, Imperforate/diagnosis , Hip Dislocation, Congenital/diagnosis , Age Factors , Aged , Aged, 80 and over , Female , HumansABSTRACT
The effect of chronic intake of cytidine-5'-diphosphate choline (CDP choline), a precursor of the membrane lipid phosphatidylcholine, was analyzed in secretory cells of the Harderian gland (HG) of aged (26-month-old) female Swiss mice. These mice were treated with the drug from 12 months of age until they were 26 months old. The results obtained were compared with those of an age-matched control group and another adult (12-month-old) control group. In both control groups, the HGs displayed secretory tubules formed by a single squamous epithelium of lipid-secreting cells. The tubule lumens were occupied by numerous small pleomorphic porphyrin accretions. In contrast, the tubules of the CDP-choline-treated animals consisted of a single columnar epithelium, with lipid-secreting cells filled with lipid vacuoles. The most striking feature in the HGs of the CDP-choline group was the absence of prophyrin deposits. These observations indicate that porphyrin biosynthesis in female Swiss mice is maintained even in very old animals, and that chronic administration of CDP choline prevents porphyrin deposition in the HG of aged animals.
Subject(s)
Aging/drug effects , Cytidine Diphosphate Choline/pharmacology , Harderian Gland/drug effects , Nootropic Agents/pharmacology , Animals , Female , Harderian Gland/metabolism , Harderian Gland/ultrastructure , Mice , Microscopy, Electron , Porphyrins/biosynthesisABSTRACT
Co-localization of calretinin immunoreactivity and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity was studied in the rat hippocampus and dentate gyrus. Neurons co-expressing both markers (CR/NADPH-d) were observed throughout the hippocampus and dentate gyrus. However, they were more abundant in the stratum pyramidale and radiatum of CA3, stratum pyramidale of CA1, and in the juxtagranular zone of the hilus. The NADPH-d activity appeared in 37% of the calretinin immunoreactive neurons in CA3, 42% in CA1, and 36% in the dentate gyrus, whereas calretinin immunoreactivity occurred in 41% of the NADPH-d positive neurons in the hippocampus, and 16% in the dentate gyrus. The morphology and location of the double marked cells could not be used as a characteristic of the co-localizing neurons. The heavily stained NADPH-d neurons occurring mainly in CA1 do not show calretinin immunoreactivity. NADPH-d fiber swellings could be observed in close apposition to calretinin immunoreactive neurons and dendrites, suggesting synaptic contacts. It has been reported that calretinin immunoreactivity and NADPH-d activity co-localize infrequently in other areas such as the neocortex, striatum, hypothalamus and tegmental nucleus. The relatively high proportion of double marked cells found in the hippocampus and dentate gyrus could be indicative of the importance of the CR/NADPH-d interneurons in the circuitries of these areas.
Subject(s)
Dentate Gyrus/cytology , NADPH Dehydrogenase/metabolism , Neurons/chemistry , Neurons/enzymology , S100 Calcium Binding Protein G/immunology , Animals , Antibody Specificity , Calbindin 2 , Dentate Gyrus/chemistry , Dentate Gyrus/enzymology , Histocytochemistry , Immunohistochemistry , NADPH Dehydrogenase/analysis , Nerve Tissue Proteins/analysis , Nerve Tissue Proteins/immunology , Nitric Oxide/metabolism , Rats , Rats, Sprague-Dawley , S100 Calcium Binding Protein G/analysisABSTRACT
Since melatonin has direct inhibitory effects on some tumor cells in vitro, the aim of the present work was to study whether the growth and structural characteristics of the human neuroblastoma cell line SK-N-SH in vitro are influenced by this indoleamine. Concentrations of melatonin of 10(-9) and 10(-11) M significantly inhibited (P < 0.05) cell proliferation. Subphysiological (10(-13) M) or supraphysiological (10(-7) and 10(-5) M) concentrations of melatonin lacked this effect. After 8 days of exposure to melatonin (10(-9) M), cells showed significantly smaller cell and nuclear sizes than control cells. Melatonin-treated cells presented greater neurite outgrowth than control cells. These results support the hypothesis that melatonin, at physiological concentrations, exerts a direct antiproliferative effect on SK-N-SH cells, promoting the differentiation of neuroblastoma cells.
Subject(s)
Melatonin/pharmacology , Neuroblastoma , Analysis of Variance , Cell Differentiation/drug effects , Cell Division/drug effects , Cell Nucleus/drug effects , Cell Size/drug effects , Humans , Tumor Cells, Cultured/cytology , Tumor Cells, Cultured/drug effectsABSTRACT
The influence of chronic administration of cytidine-5'-diphosphate choline (CDP-choline), a precursor of the membrane lipid phosphatidylcholine, was studied in neurosecretory neurons (NSNs) of the supraoptic nucleus (SON) of aged mouse hypothalamus. Animals were treated with CDP-choline from 12 months of age until 26 months. They were studied for both morphologic and morphometric features. The results obtained were compared to those of an age-matched control group. There was evidence of differences between NSNs of the control group and those of the CDP-choline group which showed neuronal hypertrophy. This size increase was mainly attributed to the increment of cellular protein synthesis machinery, rough endoplasmic reticulum (RER) and Golgi complexes. Furthermore there was an increase in the number of neurosecretory granules (NSGs) in the CDP-choline group. In addition, there was no tertiary lysosomes in the treated animals. Moreover, the percentage of NSN membrane that was not covered by glial prolongations, increased from about 2% in the control group to 12% in the CDP-Choline treated group. These changes suggested an activation of the cellular processes for neurohormone synthesis in the experimental group. Furthermore, these NSNs displayed lipid droplets in their cytoplasm. The possible relationship between CDP-choline and NSNs activity is discussed.
Subject(s)
Aging/pathology , Cytidine Diphosphate Choline/pharmacology , Neurons/drug effects , Neurosecretory Systems/drug effects , Supraoptic Nucleus/drug effects , Animals , Cell Count , Male , Mice , Mice, Inbred Strains , Neurons/ultrastructure , Supraoptic Nucleus/cytologyABSTRACT
The effects of the retinal ganglion cell (RGC) activity blockage on the early myelination of the rat optic nerve (ON) were investigated at the light and ultrastructural levels. The blockage of the RGC action potential was attained by the use of tetrodotoxin (TTX), a blocker of the voltage-sensitive sodium channels. TTX was either infused directly into the left eye (TON) or injected systematically (SON). These two groups of ONs were compared with the untreated paired right nerves (UON) of the eye-infused group. Our observations showed that the general morphology of the ONs in either treated group was similar to that of the UONs. The most noticeable ultrastructural feature of these nerves was the presence of dimorphic myelin sheaths in 4% of the myelinated fibres (MFs) in the TON group at postnatal day twelve, while they were seldom observed in the other groups (0.5%). These abnormal covers were of two types; long flaps of aberrant myelin or redundant myelin profiles. However, at postnatal day seven, the onset of myelination and the percentage of MFs was similar in the three groups. The morphometric results showed that there were no age-group differences in axon size in unmyelinated and MFs. These results suggest that while the bioelectrical activity of the RGCs could not play any role in maintaining axon calibre it may, to some extent, regulate the process of formation of normal myelin sheaths in the rat ON.
Subject(s)
Animals, Newborn/physiology , Myelin Sheath/ultrastructure , Optic Nerve/ultrastructure , Retinal Ganglion Cells/drug effects , Tetrodotoxin/pharmacology , Animals , Axons/drug effects , Axons/ultrastructure , Male , Microscopy, Electron , Myelin Sheath/drug effects , Nerve Fibers/drug effects , Nerve Fibers/ultrastructure , Optic Nerve/drug effects , Rats , Rats, Sprague-Dawley , Retinal Ganglion Cells/ultrastructureABSTRACT
We used differentiating chick and rat Purkinje cells to investigate in homologous neurons the influence of the number of nucleolar organizer regions (two in the chick and six in the rat) on the behaviour of the nucleolus and coiled bodies. We employed specific silver-staining methods on smear preparations and on semithin and ultrathin sections. In chick Purkinje cells the number of nucleolar silver-staining granules increased from 15.7 +/- 3 (mean +/- SD) at embryonic day 13 to 23.8 +/- 3 at post-hatching day 7. These nucleolar granules were unevenly distributed between the two nucleoli of binucleolated cells. Electron-microscopic cytochemistry showed that nucleolar granules are equivalent to the fibrillar centres with their associated shell of dense fibrillar component. A reduction in the number of nucleoli was found during the differentiation of both chick and rat Purkinje cells, although in mature cells the average number of nucleoli per cell was higher in the chick (1.60) than in the rat (1.07). The number of coiled bodies decreased from 1.33 in newborn rats to 0.47 at postnatal day 90 in the rat. Coiled bodies were not observed in homologous chick Purkinje cells. The dynamic behaviour of nucleoli and coiled bodies during neuronal differentiation and the relationship of these two nuclear organelles with the number of nucleolar organizer regions is discussed.
