Study of the human hippocampal formation: a method for histological and magnetic resonance correlation in perinatal cases

Little information is available on the magnetic resonance imaging (MRI) determination of the hippocampal formation (HF) during the perinatal period. However, this exploration is increasingly used, which requires defining visible HF landmarks on MRI images, validated through histological analysis. This study aims to provide a protocol to identify HF landmarks on MRI images, followed by histological validation through serial sections of the temporal lobe of the samples examined, to assess the longitudinal extent of the hippocampus during the perinatal period. We examined ex vivo MRI images from nine infant control brain samples. Histological validation of the hippocampal formation MRI images was obtained through serial sectioning and examination of Nissl-stained sections at 250 μm intervals along the entire length of the hippocampal formation. Up to six landmarks were identified both in MRI images and the serial histological sections. Proceeding in an anterior to posterior (rostrocaudal) direction, these were as follows: 1) the limen insulae (fronto-temporal junction); 2) the beginning of the amygdaloid complex; 3) the beginning of the lateral ventricle; 4) the caudal limit of the uncus, indicated by the start of the lateral geniculate nucleus (at the level of the gyrus intralimbicus); 5) the end of the lateral geniculate nucleus (beginning of the pulvinar); and 6) the beginning of the fornix. After histological validation of each of these landmarks, the full longitudinal length of the hippocampal formation and distances between landmarks were calculated. No statistically significant differences were found in total length or between landmarks. While the HF is anatomically organized at birth, its annotation is particularly challenging to perform. The histological validation of HF landmarks allows a better understanding of MRI images. The proposed protocol could be useful to assess MRI hippocampal quantification in children and possible variations due to different neurological diseases.

In vitro Validation of Quantitative Light-Induced Fluorescence for the Diagnosis of Enamel Fluorosis in Permanent Teeth

This study aimed to validate quantitative light-induced fluorescence (QLF) as a diagnostic tool for mild and moderate enamel fluorosis in permanent teeth, comparing it to visual diagnosis and histological assessment completed using polarized light microscopy (PLM). The buccal surfaces of 139 teeth were visually classified using the Thylstrup and Fejerskov Index (TFI) into sound (TFI 0; n = 17), mild (TFI 1-2; n = 69), and moderate (TFI 3-4; n = 43) fluorosis. Fluorosis was then assessed with QLF (variables ΔF, A, and ΔQ at 5-, 15-, and 30-radiance thresholds) using as reference areas the entire surface and a region of interest (ROI), identified as the most representative region of a fluorosis lesion. PLM images of longitudinal thin sections including the ROI were assessed for histological changes. Correlations among TFI, PLM, and QLF were determined. A receiver-operating characteristic curve was conducted to determine QLF's diagnostic accuracy when compared to the TFI and PLM assessments. This was used to assess the probability that the images were correctly ranked according to severity as determined by PLM and TFI. A positive correlation was found between QLF and PLM, and between QLF and TFI. QLF showed the highest sensitivity and specificity for the diagnosis of mild fluorosis. There was also a strong agreement between TFI and PLM. The selection of a ROI resulted in a stronger correlation with TFI and PLM than when the entire surface was used. The study results indicate that defining an ROI for QLF assessments is a valid method for the diagnosis of mild and moderate enamel fluorosis.

The ICTUS Study: A Prospective Longitudinal Observational Study of 1,380 AD Patients in Europe

The long-term objective of the ICTUS study is to identify milestones in Alzheimer's disease (AD) progression and to develop a model to predict disease course in individual AD patients in Europe. The secondary objectives are to describe the patterns of prescribing, and the socioeconomic impact of AD in Europe. Between 2003 and 2005 1,380 patients with probable AD were recruited in specialised (secondary care) clinics in 12 European countries. Their mean age was 76 years and they had a mean of 8.0 +/- (SD) 4.6 years of education. Thirty-five percent were male. The mean MMSE score was 20.4 +/- (SD) 4.0. Forty-three percent had very mild dementia (CDR 0.5) and 44% had mild dementia (CDR 1). All patients completed baseline evaluation and biannual follow-up is ongoing. The goals of the current study are to describe the specific methods for recruitment in this crosscultural setting and the characteristics of the inception ICTUS cohort, including clinical features, co-morbidity, neuropsychological performance, neuropsychiatric symptoms, functional impairment and social burden.

Six and 18-month changes in mild to moderate Alzheimer's patients treated with acetylcholinesterase inhibitors: what can we learn for clinical outcomes of therapeutic trials?

BACKGROUND

Clinical trials in Alzheimer's disease (AD) include patients benefiting from recent improvements in AD management.

OBJECTIVE

To observe the progression of Alzheimer's disease (AD) after 6 and 18 months in patients treated with acetylcholinesterase inhibitors (AChEI) in order to determine the best duration of follow-up necessary to demonstrate the impact of new drugs.

METHODS

Six hundred and eleven patients included in the REAL.FR cohort were treated with AChEI at baseline. We describe the cognitive, functional, behavioural, nutritional and global changes in the 509 and 364 patients who completed 6 and 18 months of follow-up, respectively, and who did not discontinue treatment.

RESULTS

After 6 and 18 months, we observed a statistically significant change in the MMSE (-0.54 +/- 3.13 at 6 months and -2.90 +/- 4.10 at 18 months), ADAS-cog (1.58 +/- 5.23 and 4.02 +/- 6.83), ADL (-0.30 +/- 0.79 and -0.84 +/- 1.20), IADL (-0.31 +/- 0.95 and -0.94 +/- 1.20), CDR sum of boxes (0.75 +/- 2.03 and 2.65 +/- 3.18) and MNA scores (-0.42 +/- 2.89 and -0.95 +/- 3.57), demonstrating the progression of AD. But on examining these changes, it appears that even if they were statistically significant at 6 months, they do not appear to be clinically relevant or sufficient to allow the observation of the effect of a new drug at this time, whereas such observation would be possible after 18 months. Similar results were obtained in a subgroup of patients who answer to the inclusion criteria of disease modifying trials which confirms the need for having 18 months of follow-up.

CONCLUSION

Changes in AD in patients under AChEI treatment are not sufficient to demonstrate the effect of a new treatment at 6 months. However, 18-month trials appear to have the potential to demonstrate clearly the effect of a new drug.

Recent data on the natural history of Alzheimer's disease: results from the REAL.FR Study

OBJECTIVES

This paper aims to present the changes observed in the evolution of Alzheimer's disease (AD) in the cohort REAL.FR after one year by taking account new treatments and improved management.

METHODS

Four hundred and ninety-eight patients recruited for the REAL.FR study were followed for one year with a standardized case report filled for each patient every 6 months. Changes in the status of these patients were evaluated on various levels: cognitive, functional, behavioural, global, nutritional, social, medical and caregiver burden. Specific treatments were also recorded.

RESULTS

A high proportion of patients received specific treatment for AD throughout the year (86%), mainly acetylcholinesterase inhibitors (AChEI) . As expected we observed statistically significant changes in cognitive function (MMS: -1.93 +/- 3.74, p < 0.0001 and ADAS-cog: +2.40 +/- 3.74, p < 0.0001), an overall loss of autonomy (ADL: -0.56 +/- 1.05, p < 0.0001 and IADL: -1.00 +/- 1.46, p < 0.0001), worsening of behavioral disturbances (NPI: +1.85 +/- 14.83, p=0.0047) and a deterioration of general status (CDRSB: +1.63 +/- 2.55, p< 0.0001). Even if the MNA score decreased not significantly, the loss was close to the threshold of significativity (MNA: -0.31 +/- 3.07, p=0.0531).

CONCLUSION

We observed a statistically significant change for the worse in most parameters. However, it appears that this deterioration had been relatively slowed by non-pharmacological management and the specific AD treatments. This resulted in stability or improvement of the condition in 63.4% of patient at 1 year. The management proposed (including prescription of AChEI) seemed to have a real impact on the course of the disease during this first year of follow-up.

Long-term cholinergic treatment is not associated with greater risk of weight loss during Alzheimer's disease: data from the French REAL.FR cohort

BACKGROUND

An increased incidence of weight loss has been reported in patients with Alzheimer's disease (AD) treated with higher doses of acetylcholinesterase inhibitors (AChEI) compared with placebo patients in several clinical trials. The proportion of patients losing weight is extremely variable from one study to another and further analysis is necessary to reach a conclusion on the association of weight loss and AChEI.

OBJECTIVE

This observational study was designed to investigate the potential effects of AChEI use on weight loss during AD.

DESIGN

486 patients with AD were followed for one year (initial mean age 77.3 +/- 77 years; initial mean MMS score 20.3 +/- 4.2). Comprehensive geriatric and neuropsychological assessment was conducted every 6 months. Cholinergic treatment was recorded at each visit, as well as any concomitant medication for dementia, psychotropic and other medications. We defined clinically significant weight loss as > or = 4% of the subject's initial weight based on the last measured weight. The data were initially evaluated categorically to identify those who had lost > or = 4% of their initial weight or had remained stable.

RESULTS

Eighty-nine per cent of AD patients were treated with AchEI during the first year of follow-up. Twenty-one per cent experienced clinically significant weight loss during this period. Weight loss was associated with more rapid deterioration of cognitive function (Delta MMSE -2.62 +/- 3.99 versus -1.72 +/- 3.64, P = 0.014) and loss of independence in instrumental activities of daily living (Delta IADL -1.45 +/- 1.50 versus - 0.88 +/- 1.43, P = 0.002). The frequency of weight loss was similar whether AD patients were treated with AChEI or not (respectively 21.1 and 19.5%, P = 0.81). In multivariate analysis, the risk of weight loss was significantly decreased in patients taking AChEI for more than 3 months compared (OR = 0.25, 95% CI = 0.11-0.56, P = 0.0007).

CONCLUSIONS

Our data suggest that long-term cholinergic treatment is not associated with greater risk of weight loss during AD and may be a protective factor. Further analysis is necessary to confirm this relation. It is obvious that the benefit observed might also be partly related to the organised non-pharmacological management provided for our patients, which included a specific care plan for each individual and facilitated response to nutritional problems as they occurred. Global care of AD patients must associate regular pluridisciplinary management with AChEI treatment.

Myosin heavy chain expression in zebrafish and slow muscle composition

In the zebrafish embryo, two distinct classes of muscle fibers have been described in the forming myotome that arise from topographically separable precursor populations. Based entirely on cross-reactivity with antibodies raised against mammalian and chick myosin heavy chain isoforms slow twitch muscle has been shown to arise exclusively from "adaxial" myoblasts, which migrate from their origin flanking the notochord to form a single layer of subcutaneous differentiated muscle cells. The remainder of the myotome differentiates behind this migration as muscle fibers recognized by anti-fast myosin heavy chain (MyHC) antibodies. To identify unambiguous molecular markers of cell fate in the myotome, we have characterized genes encoding zebrafish fast and slow MyHC. Using phylogenetic and expression analysis, we demonstrate that these genes are definitive molecular markers of slow and fast twitch fates. We also demonstrate that zebrafish embryonic slow twitch muscle co-expresses both slow and fast twitch MyHC isoforms, a property that they share with primary fibers of the amniote myotome.

Impact of nutritional status on the evolution of Alzheimer's disease and on response to acetylcholinesterase inhibitor treatment

BACKGROUND

Weight loss is frequently observed in patients with Alzheimer's disease (AD), as observed in clinical practice and reported in the literature. However, information on the evolution of nutritional status and its impact on the prognosis of AD is still scarce.

OBJECTIVE

Our aim was to determine the impact of nutritional status on the evolution of AD and on the response to treatment with acetylcholinesterase inhibitors (AChEI) by prospective one-year follow-up of AD patients living at home.

METHODS

We studied a cohort of 523 patients with Alzheimer's disease referred from 1994 to 2002 to an Alzheimer centre. After diagnosis, they were followed for one year in a prospective observational study in clinical practice. At entry and every 6 months, patients underwent standardised neurocognitive and geriatric evaluation (MMSE, ADAS-cog, IADL, MNA, caregiver burden). These evaluations were accompanied by complete clinical examination, standard paraclinical investigations and recording of treatment received.

RESULTS

Of our patients, 25.8% presented at inclusion a risk of undernutrition with an MNA score of 23.5 or less. During follow-up, the number of patients with rapid loss on the MMSE (3 points or more in one year) was higher in subjects who presented a risk of undernutrition at inclusion (53.6%) than in well-nourished subjects (43.2%) (P = 0.07). Similarly, increased dependence at one year was more frequent in subjects at risk of undernutrition at inclusion (57.7% versus 44.4%, P = 0.0219). The beneficial effect of AChEI treatment on cognitive function was not influenced by initial nutritional status; on the contrary, among the subjects at risk of undernutrition at inclusion, the risk of rapid loss on the MMSE in one year was decreased in subjects treated during follow-up compared with untreated subjects (43.9% versus 73.1% ; OR = 0.29; 95% CI = 0.10-0.83; P = 0.0219). This relationship was not found in subjects whose initial MNA score was greater than 23.5.

CONCLUSION

Our work indicates that AD patients living at home with a caregiver are frequently at risk of undernutrition. Undernourished patients seem to present more rapid aggravation of the disease, but paradoxically, these patients appear to be those who best respond to AChEI treatment.

Five novel RPGR mutations in families with X-linked retinitis pigmentosa

X-linked forms of retinitis pigmentosa (XLRP) are among the most severe because of their early onset, often leading to significant visual impairment before the fourth decade. RP3, genetically localized at Xp21.1, accounts for 70% of XLRP in different populations. The RPGR (Retinitis Pigmentosa GTPase Regulator) gene that was isolated from the RP3 region is mutated in 20% of North American families with XLRP. From mutation analysis of 27 independent XLRP families, we have identified five novel RPGR mutations in 5 of the families (160delA, 789 A>T, IVS8+1 G>C, 1147insT and 1366 G>A). One of these mutations was detected in a family from Chile. Hum Mutat 17:151, 2001.

Both bovine and rabbit lymphocytes conditioned with hydrogen peroxide show an adaptive response to radiation damage

We have carried out experiments to study the possible induction of an adaptive response in cultured bovine and rabbit lymphocytes conditioned with subtoxic doses of hydrogen peroxide after stimulation and subsequently challenged with 1 Gy of X-rays. Peroxide treatment was given at different doses 48 h after the addition of PHA to stimulate the cells. A protective effect of pre-exposure to H2O2 against radiation damage detected as micronuclei in binucleated cells was evident for all the animals tested regardless the dose of H2O2 used, although this effect was in general of greater magnitude in bovine than in rabbit cells. These results lend further support to our previous finding in human lymphocytes that DNA single strand breaks induced by H2O2 (most likely due to the generation of hydroxyl radicals) is the most important lesion to trigger the adaptive response.

An unusual case of ectodermal dysplasia

The syndrome was characterized by striking hypoplasia of nails, malformations of hands and feet, curly hair, small lower teeth and seizures. There were no similarly affected relatives. Death occurred at 31 months with the patient apparently in status epilepticus with terminal hepatorenal syndrome.

Insights on plant chromosome structure provided by the FPG technique

The high resolution afforded by the fluorescence plus Giemsa (FPG) labelling method has allowed us to visualize three main features in BrdU-substituted A. cepa chromosomes. These are (1) exchanged segments smaller than the width of the chromatid detected after BrdU substitution for two S periods; (2) late-replicated chromosome segments (LRS) of similar characteristics; (3) discontinuous or 'step-wise' exchanges (SWE). A variation in longitudinal dimension has not been observed in any case; all these features have a roughly constant longitudinal dimension of about 0.5 microns. These results suggest that arrangements of the chromatin fibres having a diameter detectable under the light microscope following a longitudinal pattern can be ignored. In addition, our observations seem to support the model of a coiled structure of metaphase chromosomes. On the other hand, the analysis of the morphological pattern shown by the SWE along a chromatid and in sister chromatids has provided us with what could be evidence of a direction of the hypothetical gyres.