Analysis of co-isogenic prion protein deficient mice reveals behavioral deficits, learning impairment, and enhanced hippocampal excitability

Background

Cellular prion protein (PrP^C) is a cell surface GPI-anchored protein, usually known for its role in the pathogenesis of human and animal prionopathies. However, increasing knowledge about the participation of PrP^C in prion pathogenesis contrasts with puzzling data regarding its natural physiological role. PrP^C is expressed in a number of tissues, including at high levels in the nervous system, especially in neurons and glial cells, and while previous studies have established a neuroprotective role, conflicting evidence for a synaptic function has revealed both reduced and enhanced long-term potentiation, and variable observations on memory, learning, and behavior. Such evidence has been confounded by the absence of an appropriate knock-out mouse model to dissect the biological relevance of PrP^C, with some functions recently shown to be misattributed to PrP^C due to the presence of genetic artifacts in mouse models. Here we elucidate the role of PrP^C in the hippocampal circuitry and its related functions, such as learning and memory, using a recently available strictly co-isogenic Prnp^0/0 mouse model (Prnp^ZH3/ZH3).

Results

We performed behavioral and operant conditioning tests to evaluate memory and learning capabilities, with results showing decreased motility, impaired operant conditioning learning, and anxiety-related behavior in Prnp^ZH3/ZH3 animals. We also carried in vivo electrophysiological recordings on CA3-CA1 synapses in living behaving mice and monitored spontaneous neuronal firing and network formation in primary neuronal cultures of Prnp^ZH3/ZH3 vs wildtype mice. PrP^C absence enhanced susceptibility to high-intensity stimulations and kainate-induced seizures. However, long-term potentiation (LTP) was not enhanced in the Prnp^ZH3/ZH3 hippocampus. In addition, we observed a delay in neuronal maturation and network formation in Prnp^ZH3/ZH3 cultures.

Conclusion

Our results demonstrate that PrP^C promotes neuronal network formation and connectivity. PrP^C mediates synaptic function and protects the synapse from excitotoxic insults. Its deletion may underlie an epileptogenic-susceptible brain that fails to perform highly cognitive-demanding tasks such as associative learning and anxiety-like behaviors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-021-01203-0.

Modelling the seasonal impacts of a wastewater treatment plant on water quality in a Mediterranean stream using microbial indicators

Faecal pollution modelling is a valuable tool to evaluate and improve water management strategies, especially in a context of water scarcity. The reduction dynamics of five faecal indicator organisms (E. coli, spores of sulphite-reducing clostridia, somatic coliphages, GA17 bacteriophages and a human-specific Bifidobacterium molecular marker) were assessed in an intermittent Mediterranean stream affected by a wastewater treatment plant (WWTP). Using Bayesian inverse modelling, the decay rates of each indicator were correlated with two environmental drivers (temperature and streamflow downstream of the WWTP) and the generated model was used to evaluate the self-depuration distance (SDD) of the stream. A consistent increase of 1-2 log₁₀ in the concentration of all indicators was detected after the discharge of the WWTP effluent. The decay rates showed seasonal variation, reaching a maximum in the dry season, when SDDs were also shorter and the stream had a higher capacity to self-depurate. High seasonality was observed for all faecal indicators except for the spores of sulphite-reducing clostridia. The maximum SDD ranged from 3 km for the spores of sulphite-reducing clostridia during the dry season and 15 km for the human-specific Bifidobacterium molecular marker during the wet season. The SDD provides a single standardized metric that integrates and compares different contamination indicators. It could be extended to other Mediterranean drainage basins and has the potential to integrate changes in land use and catchment water balance, a feature that will be especially useful in the transient climate conditions expected in the coming years.

MicroRNA expression profiling in blood from fragile X-associated tremor/ataxia syndrome patients

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with FMR1 gene premutation alleles (55-200 CGG repeats). Fragile X-associated tremor/ataxia syndrome clinical core features include action tremor, gait ataxia, cognitive deficits progressing to dementia, and frequently parkinsonism. Although the pathogenic molecular mechanism of FXTAS is not completely understood, the restriction of the phenotype to the FMR1 premutation range has given rise to a model based on a RNA toxic gain-of-function. Since the identification of the first microRNAs (miRNAs) and their role in normal development, several studies have associated them with neurodegenerative diseases such as Parkinson, Alzheimer and Huntington diseases, suggesting that they play a key role in brain development, as well as in its morphogenesis. Herein, we present the characterization of miRNA expression profiles in FXTAS male patients using deep sequencing-based technologies and microarray technology. Deep sequencing analysis evidenced 83 miRNAs that were significantly deregulated whereas microarray analysis showed 31. When comparing these results, 14 miRNAs were found deregulated in FXTAS patients. MiR-424 and miR-574-3p showed significant fold change adjusted P-values in both platforms in FXTAS patients. MiR-424 has been founded substantially and specifically enriched in human cerebral cortical white matter of Alzheimer disease patients, which, together with cerebral atrophy, is a prominent imaging finding in individuals with FXTAS. The study provides the first systematic evidence of differential miRNA expression changes in FXTAS blood samples. Although further studies are necessary to better characterize the miRNA function in FXTAS disorder, our results suggest that they might contribute to its pathogenesis.

Jagged2 controls the generation of motor neuron and oligodendrocyte progenitors in the ventral spinal cord

In the developing spinal cord, motor neurons (MNs) and oligodendrocytes arise sequentially from a common pool of progenitors. However, the genetic network responsible for this neurogenesis to gliogenesis switch is largely unknown. A transcriptome analysis identified the Notch ligand Jagged2 (JAG2) as a Sonic hedgehog-regulated factor transiently expressed in MN progenitors (pMNs). In vivo loss- and gain-of-function experiments show that JAG2 schedules the differentiation of the pMN progenitors. At early developmental stages, Olig2 expressing pMN progenitors that enter the differentiation pathway exclusively generate MNs. At these times, the activation of the Notch pathway by JAG2 maintains selected pMN progenitors in an undifferentiated state by two mechanisms; first it inhibits MN generation by reducing Olig2 proteins levels, and second it directly inhibits the premature generation of oligodendrocyte progenitors (OLPs) by maintaining high levels of Hes5. Later, extinction of JAG2 from the pMN results in the loss of Hes5 expression, heralding the gliogenic phase of pMN progenitors. Strikingly, downregulation of JAG2 in pMN progenitors is sufficient to promote the precocious generation of OLPs. Together these data provide evidence that JAG2 is a key regulator of the timely and ordered generation of two of the defining cell types in the spinal cord, MNs and OLPs.

[Conservative treatment of the pectus carinatum]

INTRODUCTION

Pectus carinatum (PC) is a deformity that involves the protrusion of the anterior chest wall. It is 10 times less frequent than pectus excavatum. It has a progressive growth and is more common with men. There are two different types, the lower or condrocorporal which is the most common one, and the upper or condromanubrial. Most of the time there are no cardio-respiratory symptoms.

OBJECTIVE

We present our experience in the orthopedic treatment of the pectus carinatum.

METHOD

Retrospective review of patients treated in our hospital from 2002 until 2009. Patients were treated with observation, aerobic exercises, postural change and/or compression braces. Literature review was performed of the treatment for this pathology.

RESULTS

18 patients have been diagnosed with PC, 16 were men and 2 women. All were treated in a nonoperative way. Only 11 of them used a compression brace. We missed two follow-ups and another has just yet begun to achieve proper results. All the rest have had excellent results with nonoperative treatment. None of them have had a surgical treatment.

CONCLUSION

The PC is a disease that most often is a cosmetic problem, with no impact on a cardio-respiratory level. Classically it has been a surgical entity. In our experience we have found that the orthopedic method is an effective alternative, safe and with a significant reduction in morbidity. But we need the collaboration of the patient to accept and maintain continuity in the use of the prostheses.

[The Spanish Home Enteral Nutrition registry of the year 2009: from the NADYA-SENPE group]

OBJECTIVE

To describe the Home Enteral Nutrition Characteristics (HEN) recorded by the group NADYA-SENPE during 2009.

MATERIAL AND METHOD

collection and analysis of the data voluntary recorded in the HEN registry from the NADYA-SENPE group from January 1st to December 31st.

RESULTS

6.540 HEN patients were registered, 5.11% more than the previous year and 6,649 episodes (3,135 in women, 47,93%) from 32 different hospitals. 6,238 of them (95,38%) were over 14 years. The mean age of the patients under 14 yr was 3,67 ± 2,86 and it was 72,10 ± 16,89 in those over 14 yr group. The base illness registered more frequently was the neurological disorders in 2,732 (41,77%) patients, followed by cancer patients in 1,838; 28,10%. The enteral access route was registered in 1,123 (17,17%) of the episodes, being more frequent the administration by nasogastric tube 562 (50,04%). The mean length of nutritional treatment by episode was 323 days (10,77 months). 606 episodes of HEN ended, being the principal reasons for discontinuing treatment the patient death in 295 (48,68%) occasions. The transition to oral feeding occurred in 219 (36,14%) cases. Patients maintained normal activity in 2162 (32,55%) HEN episodes and 2,468 (37,13%) cases were living "bed-couch". The level of dependence was "total" in 2,598 (39,07%) of the episodes recorded. The nutritional formula was provided by the hospital in 4,183 (62,91%) cases and by the reference pharmacy in 2,262 (el 34,02%). Consumables were provided by the hospital in 3,531 (53,11%) cases.

CONCLUSIONS

The number of HEN patients recorded increased from the year 2008, continuing the gradual growth increase since the start of registration. The characteristics of the patients remain in the same profile as in previous years.

[Transversal study on the prevalence of Metabolic Bone Disease (MBD) and Home Parenteral Nutrition (HPN) in Spain: data from NADYA group]

Patients with intestinal failure who receive HPN are at high risk of developing MBD. The origin of this bone alteration is multifactorial and depends greatly on the underlying disease for which the nutritional support is required. Data on the prevalence of this disease in our environment is lacking, so NADYA-SEMPE group has sponsored this transversal study with the aim of knowing the actual MBD prevalence.

MATERIAL AND METHODS

Retrospective data from 51 patients from 13 hospitals were collected. The questionnaire included demographic data as well as the most clinically relevant for MBD data. Laboratory data (calciuria, PTH, 25 -OH -vitamin D) and the results from the first and last bone densitometry were also registered.

RESULTS

Bone mineral density had only been assessed by densitometry in 21 patients at the moment HPN was started. Bone quality is already altered before HPN in a significant percentage of cases (52%). After a mean follow up of 6 years, this percentage increases up to 81%. Due to retrospective nature of the study and the low number of subjects included it has not been possible to determine the role that HPN plays in MBD etiology. Only 35% of patients have vitamin D levels above the recommended limits and the majority of them is not on specific supplementation.

CONCLUSIONS

HPN is associated with very high risk of MBD, therefore, management protocols that can lead to early detection of the problem as well as guiding for follow up and treatment of these patients are needed.

[Spanish home enteral nutrition (HEN) registry of the year 2008 from the NADYA-SENPE group]

AIM

To present the results of the Spanish home enteral nutrition (HEN) registry of the year 2008 from the NADYA-SENPE group.

MATERIAL AND METHODS

We recorded the HEN registry data from January 1st to December 31st 2008.

RESULTS

The number of patients registered in this period was 6206 (51% male) with up to 6,279 episodes of HEN, from 31 Spanish hospitals. Most of the patients (95%) were older than 14 yr. Mean age was 4.83±3.29 yr in the children group, and 70.75±18.14 yr in the adult group (older than 14 yr). Neurological disorders (39%) and cancer (27%) were the two most prevalent diagnoses. The oral route was the most frequently used (43,4%), followed by nasogastric tube (40,4%), and gastrostomy tube (14,7%). Mean length of treatment was 305,36 days (10 months). The principal reasons for discontinuing treatment were death (43%) and progress to oral diet (40%). Only 33% of the patients had a normal activity level, being limited in different grades in the rest of the patients. Most of the patients required partial (25%) or total help (38%). The enteral formula was provided by the hospital in 65% of the cases and by private pharmacies in 32%. The disposables were provided by the hospital (82,4%) and primary care services (17,2%).

CONCLUSIONS

The number and the age of the patients registered have increased comparing to previous years, with little variations in the rest of analyzed variables. The increase in the length of treatment could reflect misreporting of the weaning process in the registry.

[Treatment of lymphatic malformations with OK-432 sclerosis. Our experience]

INTRODUCTION

The elective treatment of lymphatic malformations has always been surgical resection. However sclerotherapy with a variety of substances is being used as an alternative to surgery specially in the last years. The aim of this essay is to present our results using sclerosis with OK-432.

MATERIALS AND METHODS

We have reviewed all patients affected by lymphatic malformation that have been treated by sclerosis with OK-432. Each procedure was performed under general anesthesia by a radiologist and a pediatric surgeon.

RESULTS

Fifteen patients have been treated. On the whole, 36 procedures have been performed, with a mean of 2.4 for each patient. The mean amount of OK-432 injected was 1.5 milligrams (mg) in each procedure. 73% of the patients showed nearly complete or complete response. There were two complications; one of them was a limited bleeding and the other one, a case of high fever resolved by antipyretics and antibiotics. Microcystic or mixed malformations required a higher number of procedures and presented poorer response.

CONCLUSION

Sclerotherapy with OK-432 is an effective and safe treatment for lymphatic malformation specially the macrocystic ones, therefore it should be considered as first line therapeutic option.

[National registry of home enteral nutrition in Spain 2007]

OBJECTIVE

To communicate the results from the registry of Home-Based Enteral Nutrition of the NADYASENPE group in 2007.

MATERIAL AND METHODS

We included every patient in the registry with home enteral nutrition any time from January 1st to December 31st of 2007.

RESULTS

The number of patients with home enteral nutrition in 2007 was 5,107 (52% male) from 28 different hospitals. 95.4% of them were 15 yr or older, with a mean age of 67.96 +/- 18.12, and 4.2 +/- 3.38 among patients aged 14 yr or less. The most common underlying diseases were neurological (37.8%) and neoplastic diseases (29.3%). Enteral nutrition was administered p.o. in most patients (63.5%), followed by nasogastric tube (25.9%), while gastrostomy was only used in 9.2%. The mean time in enteral nutrition support was 9.4 months and the most common reasons for withdrawal were death (58.7%) and switching to oral intake (32%). Activity was limited in 31.4% of patients and 36.01% were house-bound. Most patients needed partial (26.51%) or total (37.68%) care assistance. Enteral formula was provided by hospitals to 69.14% of patients and by pharmacies to 30.17% of them, while disposable material was provided by hospitals to 81.63% and by Primary Care to the remaining patients.

CONCLUSIONS

In 2007, there has been an increase of more than 30% of patients registered with home enteral nutrition comparing with 2006, without any big difference in other data, but a higher proportion of patients with enteral nutrition p.o.

Measuring in-stream retention of copper by means of constant-rate additions

Human practices entail inputs of nutrients and toxicants such as heavy metals to the fluvial ecosystems. While nutrient dynamics in fluvial ecosystems have been widely studied for over three decades, dynamics of toxicants still remain unclear. In this investigation, the nutrient spiraling concept and associated methodologies to quantify nutrient retention in streams were applied to study copper (Cu) dynamics in streams. The present study aimed to quantify total dissolved Cu retention using a simplified system of indoor channels colonized with fluvial biofilms. Cu retention was studied at sub-toxic concentrations to avoid negative/lethal effects on biota. In addition, Cu retention was compared with retention estimates of a macronutrient, phosphate (PO(4)(3-)), which has been widely studied within the context of the nutrient spiraling concept. The methodology used allowed a successful quantification of Cu and PO(4)(3-) retention. The results showed higher retention efficiency for PO(4)(3-) than for Cu. The biofilm played a key role in retaining both solutes. Although retention efficiency for both solutes was higher in the experiments with colonized substrata compared to uncolonized substrata, we found a positive relationship between uptake rate and chlorophyll-a only for PO(4)(3-). Finally, retention efficiency for both solutes was influenced by water discharge, showing lower retention efficiencies under higher flow conditions. These results suggest that the fate and toxic effects of copper on stream biota may be strongly influenced by the prevailing environmental conditions. Our results indicate that the experimental approach considered can provide new insights into the investigation of retention of toxic compounds in fluvial systems and their controlling mechanisms.

Increased NR2A expression and prolonged decay of NMDA-induced calcium transient in cerebellum of TgDyrk1A mice, a mouse model of Down syndrome

Transgenic mice overexpressing Dyrk1A (TgDyrk1A), a Down syndrome (DS) candidate gene, exhibit motor and cognitive alterations similar to those observed in DS individuals. To gain new insights into the molecular consequences of Dyrk1A overexpression underlying TgDyrk1A and possibly DS motor phenotypes, microarray studies were performed. Transcriptome analysis showed an upregulation of the NR2A subunit of the NMDA type of glutamate receptors in TgDyrk1A cerebellum. NR2A protein overexpression was also detected in TgDyrk1A cerebellar homogenates, in the synaptosome-enriched fraction and in TgDyrk1A primary cerebellar granular neuronal cultures (CGNs). In TgDyrk1A synaptosomes, calcium-imaging experiments showed a higher calcium uptake after NMDA stimulation. Similarly, NMDA administration promoted longer calcium transients in TgDyrk1A CGNs. Taken together, these results show that NMDA-induced calcium rise is altered in TgDyrk1A cerebellar neurons and indicate that calcium signaling is dysregulated in TgDyrk1A mice cerebella. These findings suggest that DYRK1A overexpression might contribute to the dysbalance in the excitatory transmission found in the cerebellum of DS individuals and DS mouse models.

Study of apoptosis-related markers in ram spermatozoa

Certain features of capacitated or frozen-thawed spermatozoa have been considered to be an apoptosis-like phenomenon, and, it has been suggested that the presence of apoptotic sperm in seminal doses could be one of the reasons for poor fertility. The objective of this study was to determine whether phosphatidylserine (PS) translocation, caspase activity and DNA fragmentation, which are considered to be apoptotic markers in somatic cells, occur in ram sperm. Fresh ejaculates and sperm samples in different physiological state (cold-shocked, in vitro capacitated and acrosome-reacted (AR)) were compared. Simultaneous staining with 6-carboxifluorescein diacetate (6-CFDA) and Annexin V-Cy3.18 (AnnV) revealed four different sperm subpopulations in ejaculates. The main subpopulation was composed of viable cells without PS exposure (CFDA+/AnnV-). A total of 40.8% of sperm showed inverted PS, with two levels of alteration: CFDA+/AnnV+ in midpiece ("type I AnnV+"), and in acrosome and midpiece ("type II AnnV+"). The fewest subpopulation contained non-viable cells showing Annexin labelling in the entire cell (CFDA-/AnnV+). Labeling of caspases-3 and -7 by immunocytochemistry revealing different sperm subtypes depending on their localization in apical, equatorial, post-acrosomal regions and tail. The results obtained by western-blot showed, for the first time to our knowledge, that caspase-like proteins are present in fresh ram semen as both inactive and active forms. The proportion of sperm with fragmented DNA [terminal transferase-mediated dUDP nick end-labeling (TUNEL)-positive] were found rarely (2.7+/-0.5%) in all fresh ejaculates involved in this study. The analysis of total activity of both caspases by a fluorometric method showed a decrease in vitro capacitated and acrosome-reacted samples as well as in cryoinjured samples. However, the percentage of TUNEL-positive sperm demonstrating DNA fragmentation was significantly increased after in vitro induced capacitation and acrosome reaction, as well as after cold-shock although this augment was not significant. PS exposure is not totally dependent on caspases in ram spermatozoa as the addition of a caspase inhibitor prevented the increase in PS inversion due to incubation in capacitating conditions but not to the ionophore-induced acrosome reaction or cold-shock.

[Retinal and brain infarctions secondary to acute carotid thrombosis in ovarian hyperstimulation syndrome]

INTRODUCTION

Ovarian hyperstimulation syndrome (OHSS) is an uncommon but potentially life-threatening iatrogenic condition that may appear following ovulation induction in the course of some fertility treatments. This may lead to further complications, some of which may be severe, such as thromboembolic events. Though rarely, it can therefore be a potential cause of stroke.

CLINICAL CASE

We report the case of a 34-year old woman under ovulation induction treatment who developed retinal and brain infarctions secondary to internal carotid occlusion. Oral anticoagulation was administered and recovery was good in spite of the persistence of carotid occlusion in follow-up magnetic ressonance imaging- angiographies.

CONCLUSIONS

This is the first case of carotid occlusion following an OHSS reported in Spain and the eighth one published in the literature. Current literature on cerebrovascular complications in OHSS is also briefly reviewed.

[Registry of home-based enteral nutrition in Spain for the year 2006 (NADYA-SENPE Group)]

OBJECTIVE

To communicate the results obtained from the registry of Home-Based Enteral Nutrition (HBEN) of the NADYA-SENPE group for the year 2006.

MATERIAL AND METHODS

Recompilation of the data from the HBEN registry of the NADYA-SENPE group from January 1st to December 31st of 2006.

RESULTS

During the year 2006, 3,921 patients (51% men) from 27 hospital centers were registered. Ninety-seven percent were older than 14 years. The mean age for those < 14 years was 4.9 +/- 3.9 (m +/- SD) and in those > or = 14 years, it was 68.5 +/- 18.2 years. The most common underlying disease was neurological pathology (42%), followed by cancer (28%). Enteral nutrition was administered p.o. in 44% of the patients, through nasogastric tube in 40%, gastrostomy in 14%, and jejunostomy in 1%. The average time of nutritional support was 8.8 months. The most common reasons for ending the therapy were patient's death (54%) and switching to oral feeding (32%). Thirty-one percent of the patients presented a limited activity and 40% were confined to bed/coach. Most of the patients required partial (25%) or total (43%) care assistance. The nutritional formula was provided by the hospital in 62% of the cases and from the reference pharmacy in 27%. The fungible material was provided by the hospital in 80% of the cases and by primary care in the remaining patients.

CONCLUSIONS

Although the number of registered patients is slightly higher than that from the last years, there are no important changes in the patients characteristics, or way of administration and duration of enteral nutrition.

Intentional replantation for the management of maxillary sinusitis

AIM

To present a case that emphasizes the importance of the use of intentional replantation as a technique to successfully treat a periapical lesion and an odontogenic maxillary sinusitis through the alveolus at the same time.

SUMMARY

This case report presents a patient with odontogenic maxillary sinusitis secondary to periapical disease of a maxillary molar that had previously received root canal treatment. The molar was extracted, with drainage and rinsing of the maxillary sinus. The apices were resected extra-orally, the retrograde cavities prepared with ultrasound and retrograde fillings of silver amalgam placed. The tooth was then replanted. After 2 years, the patient was asymptomatic, periapical radiography showed no evidence of root resorption and computed tomography scanning demonstrated the resolution of maxillary sinusitis.

KEY LEARNING POINTS

*When root canal treatment or periapical surgery cannot be undertaken or has failed, intentional replantation may be considered. *This alternative treatment may be predictable in certain cases.

Trigeminal neuropathy

Trigeminal neuropathies (TNs) are well recognized disorders characterized and manifesting as skin and mucosal numbness in the region innervated by the trigeminal nerve. Facial numbness indicates trigeminal sensory alteration affecting the trigeminal system. TNs always pose differential location difficulties as multiple diseases are capable of producing them: they can be the result of traumatism, tumors, or diseases of the connective tissue, infectious or demyelinating diseases, or may be of idiopathic origin. Their importance is explained by the fact that TN may represent the first manifestation of tumor disease, or of relapse in patients with prior neoplastic processes. As such, these manifestations are ominous, and patient life expectancy is often short. The clinical exploration reveals a loss of sensitivity in the cutaneous territory corresponding to the affected nerve, which can be partial (hypoesthesia) or complete (anesthesia). The sensory defect is occasionally associated with hyperesthesia (i.e., the patient suffers a decrease in sensory perception, but when sensation is perceived, it may cause considerable discomfort). Complementary studies are needed to establish the etiologic diagnosis, with laboratory tests to discard the possible causative diseases underlying the trigeminal neuropathy, and the opportune radiographic examinations in the form of plain X-rays or a routine cranial computed tomography scan.

BDNF up-regulates TrkB protein and prevents the death of CA1 neurons following transient forebrain ischemia

The neurotrophin family of growth factors, which includes Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin-3 (NT3) and Neurotrophin-4/5 (NT4/5) bind and activate specific tyrosine kinase (Trk) receptors to promote cell survival and growth of different cell populations. For these reasons, growing attention has been paid to the use of neurotrophins as therapeutic agents in neurodegeneration, and to the regulation of the expression of their specific receptors by the ligands. BDNF expression, as revealed by immunohistochemistry, is found in the pre-subiculum, CA1, CA3, and dentate gyrus of the hippocampus. Strong TrkB immunoreactivity is present in most CA3 neurons but only in scattered neurons of the CA1 area. Weak TrkB immunoreactivity is found in the granule cell layer of the dentate gyrus. Unilateral grafting of BDNF-transfected fibroblasts into the hippocampus resulted in a marked increase in the intensity of the immunoreaction and in the number of TrkB-immunoreactive neurons in the granule cell layer of the dentate gyrus, pre-subiculum and CA1 area in the vicinity of the graft. No similar effects were produced after the injection of control mock-transfected fibroblasts. Delayed cell death in the CA1 area was produced following 5 min of forebrain ischemia in the gerbil. The majority of living cells in the CA1 area at the fourth day were BDNF/TrkB immunoreactive. Unilateral grafting of control mock-transfected or BDNF fibroblasts two days before ischemia resulted in a moderate non-specific protection of TrkB-negative, but not TrkB-positive cells, in the CA1 area of the grafted side. This finding is in line with a vascular and glial reaction, as revealed, by immunohistochemistry using astroglial and microglial cell markers. This astroglial response was higher in the grafted side than in the contralateral side in ischemic gerbils, but no differences were seen between BDNF-producing and non-BDNF-producing grafts. However, grafting of BDNF-producing fibroblasts two days before ischemia significantly and specifically prevented nerve cells from dying in the CA1 area of the ipsilateral hippocampus. Cell survival was associated with increased TrkB immunoreactivity as the majority of living cells were TrkB immunoreactive. Thus, our results show that BDNF is able to up-regulate the expression of TrkB in control and pathological states, and that BDNF prevention of neuronal death following transient forebrain ischemia is associated with increased expression of its specific receptor.

[The year 2003 National Registry of Home-based Parenteral Nutrition]

OBJECTIVE

To report the results of the Home-based Parenteral Nutrition (HBPN) registry of the NADYA-SENPE working group, for the year 2003.

MATERIAL AND METHODS

Gathering of registry data introduced by all units responsible of HBPN patient care. This an on-line registry available for authorized users of the working group web page (www.nadya-senpe.com). Epidemiological data, diagnosis, access route, complications, hospital admissions, disability degree, and course at December 31st, 2003

RESULTS

Data from 86 patients (62% female and 38% male) from 17 hospitals were gathered. Mean age of adult patients was 50.7 +/- 15.0 years, whereas for patients younger than 14 years was 2.4 +/- 1.5 years (n = 5 patients). Diseases that prone HBPN were neoplasm (21%), followed by mesenteric ischemia (20%), radiation enteritis (16.3%), motility impairments (10.5%), and Crohn's disease (4.6%). Tunneled catheters were used in 66.3% of the cases versus 29.1% of subcutaneous reservoirs. Mean treatment duration has been 8.5 +/- 4.6 months; 67.4% of patients had been on HBPN for a period of time longer than 6 months. Patient follow-up was mostly done from the reference area hospital (88.4%). In no case patient follow-up was done by the primary care team or by specialists other than those prescribing nutritional support. Nutritional support-related complications were seen in 98 occasions. The most frequent complications were infectious ones. They represented 1.60 hospital admissions per patient. The mean number of visits was 7.9 per patient (6.4 for scheduled visits and 1.5 for emergency visits). By the end of the year, we observed that 73.3% of the patients were still on the program, whereas in 23.3% HBPN had been withdrawn. The main reasons for withdrawal were decease (11 patients), and advancing to oral diet (9 patients). As for the disability degree, 13% were confined to a wheelchair or bed, and only 28% had no disability degree or only mild social disability.

CONCLUSIONS

We observed a mild increase in HBPN prevalence rate in Spain (2.15 patients pmp). The main indication was cancer followed by short-bowel syndrome secondary to vascular pathology. Nutritional support-related complications were common, especially those of an infectious origin.

[National registry of Home Enteral Nutrition in 2003]

GOAL

To communicate the information available by the NADYA-SENPE Working Group from patients on Home Enteral Nutrition (HEN) in our country during the year 2003.

MATERIAL AND METHODS

The data were collected through a closed questionnaire included in the web site of the Working Group (www.nadya-senpe.com) available only by the authorized users. Variable included were: epidemiological information, the indication to prescribe this treatment, the access path, the specific nutritional formula used, the treatment duration, the complications and hospital readmission related to the nutritional treatment, the follow-up and the quality of life.

RESULTS

We register 3,858 patients that belong to twenty-one hospitals. Mean age from those adults 66.2 +/- 18.9 years, and from those younger than 14, 6.0 +/- 4.3 years. Neurological and neoplasic diseases were the diagnostics more frequents (38.9% and 37.4%, respectively). Oral nutrition was the preferential rout used for the enteral nutrition (54.7%) followed by naso-enteral tube (26.6%), and only in 17.6% we used ostomy tubes. Polymeric was the enteral formula mainly utilized (80.1%). The mean time on HEN was 6.6 +/- 4.3 months; the 28.8% of patients stayed in the treatment for less than 3 months, 21.2 % between 3 and 6 months, and 50.0% more than 6 months. Patients were followed mainly by Nutritional Support Unit from the reference hospital (73.1%). While the reference hospital supplies the material (62.4%), reference hospital pharmacy (46.8%) and public pharmacies (32.0%) provides the enteral formula. Complications related to enteral nutrition included change of enteral tube (44.5%), gastrointestinal complications (30.5%), mechanical complications (21.7%), and the metabolic one (3.3%). These complications were followed by 0.02 hospitalizations/patient. At the end of the year, 54.7% of patients were in the HEN programme, and in 35.2 % HEN was finish due to accept oral conventional alimentation (49.2%) or by deceased of patients (40.9%). While 26.6% of the patients were confined to bed or armchair, 19.7 % no or light discapacity degree was observed.

CONCLUSIONS

We found a persistence of these treatment in our country. Neurological and neoplasic diseases were the more frequent diagnosis in patients analysed. The high prevalence of cancer patients could be the main cause of oral access for enteral nutrition. Change of enteral tube was the more frequent complication observed during this treatment.

[The year 2002 national registry on home-based enteral nutrition]

GOAL

To communicate the information available by the NADYA-SENPE Working Group from patients on Home Enteral Nutrition (HEN) in our country during the year 2002.

MATERIAL AND METHODS

The data were collected through a closed questionnaire included in the web site of the Working Group (www.nadya-senpe.com) available only by the authorized users. Variable included were: epidemiological information, the indication to prescribe this treatment, the access path, the specific nutritional formula used, the treatment duration, the complications and hospital readmission related to the nutritional treatment, the follow-up and the quality of life.

RESULTS

We register 3967 patients that belong to twenty-one hospitals. Mean age from those adults 69.2 +/- 19.2 years, and from those younger than 14, 5.6 +/- 4.1 years. Neurological and neoplasic diseases were the diagnostics more frequents (39.2% and 34.6%, respectively). Oral nutrition was the preferential rout used for the enteral nutrition (53.6%) followed by naso-enteral tube (30.6%), and only in 15.8% we used ostomy tubes. Polymeric was the enteral formula mainly utilized (81.5%). The mean time on HEN was 5.8 +/- 4.4 months; the 35.7% of patients stayed in the treatment for less than 3 months, 22.4% between 3 and 6 months, and 41.6% more than 6 months. Patients were followed mainly by Nutritional Support Unit from the reference hospital (75.3%). While the reference hospital supplies the material (65.7%), reference hospital pharmacy (43%) and public pharmacies (37.3%) provides the enteral formula. Complications related to enteral nutrition included change of enteral tube (29.7%), mechanical complications (22.9%), gastrointestinal complications (22.9%), and the metabolic one (9.2%). These complications were followed by 0.02 hospitalizations/patient. At the end of the year, 49.3% of patients were in the HEN programme, and in 41.5% HEN was finish due to accept oral conventional alimentation (47.3%) or by deceased of patients. While 31.8% of the patients were confined to bed o armchair, 17.8% no o light discapacity degree was observed.

CONCLUSIONS

We found a persistence of these treatment in our country (96.5 patients/million inhabitants. Neurological and neoplasic diseases were the more frequent diagnosis in patients analysed. The high prevalence of cancer patients could be the main cause of oral access for enteral nutrition. Change of enteral tube was the more frequent complication observed during this treatment.

[Home Enteral Nutrition: National Registry 2001]

GOAL

The NADYA-SENPE Working Group analyzed the registered data of patients on Home Enteral Nutrition (HEN) in our country, during year 2001.

MATERIAL AND METHODS

The data were collected through a closed questionnaire included on our web site (www.nadya-senpe.com). Apart from epidemiological information, the form includes the indication to prescribe this treatment, the specific nutritional treatment used and its duration, access path, complications and readmission rate in hospital, follow-up of the treatment, patient's quality of life and progress. All data were processed and analyzed by the coordinating team.

RESULTS

Twenty two hospitals participated and 3,458 patients, aged 5.6 +/- 4.0 y for those younger than 14 y, and 67.1 +/- 19.5 y for those older than 14 y, were enrolled. Of these patients, 43.4% were diagnosed with neurological diseases and 33.5% with cancer. The mean time on HEN was 6.5 +/- 4.5 months. Oral nutrition was the preferential route (54.5%), followed by nasoenteral tube (32.3%), and in 13.3% ostomy tubes were placed. Polymeric was the formula composition mainly used (85.9%). Patients were followed (71.1%) by the hospital reference Nutritional Support Unit. The complications related to nutrition included mainly the gastrointestinal (0.16 complications/patient), and the mechanical one (0.15 complications/patient). At the end for the year, 48.3% of the patients were in the HEN program, and in 33.3% HEN was finish due to different reasons. In 22.9% of the patients no, o light, discapacity degree was found.

CONCLUSIONS

Neurological diseases and cancer were the more frequent diagnoses in HEN patients. Oral access was the higher feeding route due, probably, to the high prevalence of cancer patients. In spite of the elevated prevalence of neurological diseases, a few number of patients, as previous years, were feed with ostomy tube. Due to the few complications observed, HEN is a safe treatment in our country.

[National Registry of Home Parenteral Nutrition of the year 2001]

AIM

We analyse the registered data of home parenteral nutrition (HPN) in our country during the year 2001.

METHOD

The data were collected through a previously designed questionnaire. Apart from epidemiological information, the form includes the disease to prescribe this treatment, the specific nutritional treatment used and its duration, access path, complications and readmission rate in hospital, follow-up of the treatment, and progress. All data were processed and analysed by the co-ordinating team.

RESULTS

Seventeen hospitals participated, and 66 patients were enrolled. Middle age was 5.5 +/- 4.9 years for patients < 14 years old, and 49.2 +/- 15.8 years for those > or = 14 years old. The more prevalent diagnosis were: ischemic bowel (28.9%), neoplasm (22.7%), radiation enteritis (12.1%), motility disorders (4.5%) and Crohn's disease (4.5%). The mean time on HPN was 8.4 +/- 4.5 months. Tunnelled catheter was the preferential route (62.1%), followed by the implantated one (33.3%). The intermittent method (nocturnal) was preferential (81.8%). Patients receive the formula, mainly from hospital pharmacy (75.7%). The complications related to nutrition (1.3/patient) included the infections (0.46 sepsis/patient, and 0.19 catheter contamination/patients), mechanic (0.15/patient), metabolic (0.1/patient) and electrolytic disorders (0.07/patient). The readmission rate, for nutritional problems, was 1.34/patient. At the end of the year, 74.2% of the patients remained in the HPN program, and 25.8% abandoned the treatment (due to death: 52.9%, and to progress to oral feeding (25.3%).

CONCLUSIONS

This review illustrates that the registration of HPN patients in our country is standing (1.65 patients/10(6) habitants), that vascular pathology is the more frequent diagnoses in HPN patients, and the rate of readmission and complications and the behaviour is similar to other series making this as a safe treatment in our place.

Motor phenotypic alterations in TgDyrk1a transgenic mice implicate DYRK1A in Down syndrome motor dysfunction

Motor deficits are among the most frequent impairments in Down syndrome (DS), but their neuropathological and molecular bases remain elusive. Here we investigate the motor profile of transgenic mice overexpressing Dyrk1a, Tg(Dyrk1a)1Cff (hereafter TgDyrk1a), a candidate gene hypothesized to cause some of the neurological defects associated with DS. We have previously shown DYRK1A expression in the cerebellum and functionally related structures, most brainstem motor nuclei and spinal cord, supporting a role for Dyrk1a in controlling motor function. Here we demonstrate that TgDyrk1a mice present DYRK1A overexpression in these areas along with specific motor dysfunction. The main finding that emerged was impairment of motor learning and alteration of the organization of locomotor behavior, which agrees with reported clinical observations in subjects with DS. These results confirm and extend previous data and provide further insight to the functional domains that might be altered in TgDyrk1a mice and underlying molecular mechanisms of DS motor dysfunction.

Survival rate and antioxidant enzyme activity of ram spermatozoa after dilution with different extenders or selection by a dextran swim-up procedure

The aim of this study was to evaluate the effect of four extenders (Sucrose (S), Galactose (G), milk-yolk (MY), and Fiser (F)) on the motility, membrane integrity, and functional integrity of ram spermatozoa during liquid storage at 15 degrees C. The use of either S or MY for the selection of high quality spermatozoa by a swim-up procedure was comparatively analyzed. Additionally, the activity of three antioxidant enzymes, superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) was evaluated in both swim-up selected samples maintained at 15 degrees C for 6h. Sperm motility was better preserved in MY and was significantly higher after 6h of incubation than in either S or F (P<0.0001) and G (P<0.0005). Likewise, the incidence of spermatozoa with integral and functional membranes was higher in samples diluted in MY, with no significant decrease after 6h of incubation. The comparative analysis of the swim-up procedure performed with either MY or S revealed that not only was total sperm recovery significantly (P<0.001) higher (67.3%+/-3.21 versus 47.6%+/-3.78), but also that the best survival rate of spermatozoa was found in the MY stored sample. Sperm motility, viability and response to a hypoosmotic swelling (HOS) test were also significantly higher in the MY extended sample, maintaining still significantly higher values after 6h of incubation. In addition, this sample showed higher activity values for the antioxidant defense enzyme system.

Characterisation and evolution of a soil affected by olive oil mill wastewater disposal

A location used for 10 years as an uncontrolled olive oil mill wastewater disposal site is studied in this work. Once it was closed the sedimented solid waste on the soil surface was removed. In order to evaluate the influence upon soil characteristics, morphological aspects and analytical parameters of a soil profile from the affected zone are compared to those of a control soil located near the landfill. The residual contamination levels in the underlying soil are determined. The results show that the wastewater infiltration in the soil has caused carbonate dissolution and redistribution and modifications in pH values, electrical conductivity, nutrient contents, phenolic compounds and biological activity of the horizons. Removal of waste, natural leaching and biological activity, in time, led to an effective decrease in electrical conductivity and phenolic compounds, although residual levels can be important even 2 years later.

Control of retinal ganglion cell axon growth: a new role for Sonic hedgehog

Retinal ganglion cell (RGC) axons grow towards the diencephalic ventral midline during embryogenesis guided by cues whose nature is largely unknown. We provide in vitro and in vivo evidence for a novel role of Sonic hedgehog (SHH) as a negative regulator of growth cone movement. SHH suppresses both the number and the length of neurites emerging from the chick retina but not from neural tube or dorsal root ganglia explants, without interfering with their rate of proliferation and differentiation. Similarly, retroviral-mediated ectopic expression of Shh along the chick visual pathway greatly interferes the growth of RGC axons. Upon SHH addition to grown neurites, the intracellular level of cAMP decreases, suggesting that the dampening of growth cone extension mediated by SHH may involve interaction with its receptor Patched which is expressed by RGC. Based on these findings, we propose that Shh expression at the chiasm border defines a constrained pathway within the ventral midline which serves to guide the progression of RGC axons.

Identification of Kir2.1 channel activity in cultured trabecular meshwork cells

PURPOSE

To study the presence of inwardly rectifying K(+) (Kir) channels in cultured bovine (BTM) and human (HTM) trabecular meshwork cells.

METHODS

Cultures of BTM and HTM cells were obtained by an extracellular matrix digestion technique. Whole-cell patch-clamp recordings of BTM cells were performed with the appropriate solutions to detect K(+) currents. Also, Western blot analysis of Kir2.1 protein expression was performed on both cultured BTM and HTM cells.

RESULTS

A strong inwardly rectifying current at negative potentials to the equilibrium potential for K(+) (E(K+)) and highly selective for K(+) was detected in 60% of cultured BTM cells. The slope conductance of the inward rectification was more pronounced when the extracellular [K(+)] was increased and was proportional to [K(+)](0.45). The current was blocked by Ba(2+) and Cs(+) in a voltage- and concentration-dependent manner, with K(d) at 0 mV, of 74.7 microM and 45.6 mM, respectively. Current amplitude was reduced by increasing extracellular [Ca(2+)]. The current was insensitive to 10 microM glibenclamide and 10 nM tertiapin. The application of 100 microM 8-Br-cAMP reduced the current by 50%. Kir2.1 channel expression was detected in confluent monolayers of BTM and HTM cells by Western blot analysis.

CONCLUSIONS

A population of cultured BTM cells expressed an inwardly rectifying K(+) current that illustrates the biophysical and pharmacologic characteristics of the detected Kir2.1 channel protein. Kir2.1 channels are also thought to be present in HTM cells. Kir2.1 channels could be related to TM physiology, because they are involved in contractile and cell volume regulatory responses, two mechanisms that modify TM permeability.

Neurodevelopmental delay, motor abnormalities and cognitive deficits in transgenic mice overexpressing Dyrk1A (minibrain), a murine model of Down's syndrome

Down's syndrome (DS) is a major cause of mental retardation, hypotonia and delayed development. Murine models of DS carrying large murine or human genomic fragments show motor alterations and memory deficits. The specific genes responsible for these phenotypic alterations have not yet been defined. DYRK1A, the human homolog of the Drosophila minibrain gene, maps to the DS critical region of human chromosome 21 and is overexpressed in DS fetal brain. DYRK1A encodes a serine-threonine kinase, probably involved in neuroblast proliferation. Mutant Drosophila minibrain flies have a reduction in both optic lobes and central brain, showing learning deficits and hypoactivity. We have generated transgenic mice (TgDyrk1A) overexpressing the full-length cDNA of Dyrk1A. TgDyrk1A mice exhibit delayed cranio-caudal maturation with functional consequences in neuromotor development. TgDyrk1A mice also show altered motor skill acquisition and hyperactivity, which is maintained to adulthood. In the Morris water maze, TgDyrk1A mice show a significant impairment in spatial learning and cognitive flexibility, indicative of hippocampal and prefrontal cortex dysfunction. In the more complex repeated reversal learning paradigm, this defect turned out to be specifically related to reference memory, whereas working memory was almost unimpaired. These alterations are comparable with those found in the partial trisomy chromosome 16 murine models of DS and suggest a causative role of DYRK1A in mental retardation and in motor anomalies of DS.

Vitronectin regulates Sonic hedgehog activity during cerebellum development through CREB phosphorylation

During development of the cerebellum, Sonic hedgehog (SHH) is expressed in migrating and settled Purkinje neurons and is directly responsible for proliferation of granule cell precursors in the external germinal layer. We have previously demonstrated that SHH interacts with vitronectin in the differentiation of spinal motor neurons. Here, we analysed whether similar interactions between SHH and extracellular matrix glycoproteins regulate subsequent steps of granule cell development. Laminins and their integrin receptor subunit alpha6 accumulate in the outer most external germinal layer where proliferation of granule cell precursors is maximal. Consistent with this expression pattern, laminin significantly increases SHH-induced proliferation in primary cultures of cerebellar granule cells. Vitronectin and its integrin receptor subunits alpha(v) are expressed in the inner part of the external germinal layer where granule cell precursors exit the cell cycle and commence differentiation. In cultures, vitronectin is able to overcome SHH-induced proliferation, thus allowing granule cell differentiation. Our studies indicate that the pathway in granule cell precursors responsible for the conversion of a proliferative SHH-mediated response to a differentiation signal depends on CREB. Vitronectin stimulates phosphorylation of cyclic-AMP responsive element-binding protein (CREB), and over-expression of CREB is sufficient to induce granule cell differentiation in the presence of SHH. Taken together, these data suggest that granule neuron differentiation is regulated by the vitronectin-induced phosphorylation of CREB, a critical event that terminates SHH-mediated proliferation and permits the differentiation program to proceed in these cells.

Brain-derived neurotrophic factor reduces cortical cell death by ischemia after middle cerebral artery occlusion in the rat

Stroke is the major cause of adult brain dysfunction. In an experimental approach to evaluate the possible beneficial effects of administration of neurotrophic factors in stroke, we have used a model of distal middle cerebral artery (MCA) occlusion in adult rats. In this model, we found: (1) a permanent reduction of brain-derived neurotrophic factor (BDNF) and its full-length receptor, TrkB, in the infarcted core; (2) a transient increase in BDNF immunoreactivity in the internal region of the border of the infarct (penumbra area) at 12 h after MCA occlusion; (3) increased truncated TrkB immunoreactivity in astrocytes surrounding the area of the infarction; and (4) increased full-length TrkB immunoreactivity in scattered neurons, distant from the infarct, in ipsilateral and contralateral cortices at 24 and 48 h after MCA occlusion. We next studied the regulation of TrkB expression by BDNF, after ischemia, and its neuroprotective effects in vivo. In control non-ischemic rats, grafting of mock- or BDNF-transfected fibroblasts (F3A-MT or F3N-BDNF cell lines, respectively) in the medial part of the somatosensory cortex increased truncated TrkB immunoreactivity in neighboring astrocytes. Grafting alone also increased full-length TrkB in the vicinity of the mock graft (at 24 and 48 h) and the BDNF-grafted graft (at 4 days). Interestingly, ischemic animals grafted with the mock-transfected cell line did not show any further regulation of TrkB receptors. However, ischemic animals grafted with the BDNF cell line showed an up-regulation of full-length TrkB expression in neurons located in the internal border of the infarct. Analysis of nuclear DNA fragmentation in situ, combined with microtubule-associated protein 2 immunohistochemistry, revealed that most cells dying in the borders of the infarct (penumbra area) at 48 h following MCA occlusion were neurons. No differences in the infarct size were found between MCA occluded, mock-transfected MCA-occluded, and BDNF-transfected MCA-occluded rats. Moreover, cell death was similar in nongrafted and mock-grafted rats subjected to MCA occlusion. However, the number of cells with nuclear DNA breaks was significantly reduced in the penumbra area close to the BDNF graft in ischemic rats. Thus, our results show that BDNF specifically up-regulates its full-length TrkB receptor in cortical neurons of the penumbra area and prevents their death in an in vivo model of focal ischemia.

Differential regulation of chromogranin A, chromogranin B and secretoneurin protein expression after transient forebrain ischemia in the gerbil

The chromogranin/secretogranin family of proteins is widely distributed in the central nervous system, where they are stored in large dense-core vesicles. These proproteins are actively processed into small neuroactive peptides, which influence neurotransmitter release, microglial activation and monocyte migration. These properties suggest a possible role of chromogranins/secretogranins in the response that follows central nervous system injury. In the present study, the temporal pattern of expression and the distribution of chromogranin A, chromogranin B and secretoneurin, the major proteolytic product of secretogranin-II, have been studied by immunohistochemistry after 5 min of transient forebrain ischemia in the Mongolian gerbil. A strong increase in the immunoreactivity for chromogranin A and secretoneurin was found in the CA3 pyramidal cell layer of the hippocampus, starting at 12 h, with a peak at 24 h and decrease at 48 h after transient forebrain ischemia. In the hippocampal formation, a rise in chromogranin A immunoreactivity was detected in neurons of the subiculum and the granule cell layer of the dentate gyrus. In addition, increase in the immunoreactivity for chromogranin A and secretoneurin was found in selected neurons of the neocortex. Chromogranin A and secretoneurin immunostaining patterns were similar in ischemic and control gerbils at 4 and 7 days following the ischemic insult. Chromogranin A and secretoneurin immunoreactivity in consecutive sections showed co-localization of both antigens but also selective overexpression of chromogranin A or secretoneurin in various neurons. No changes in chromogranin B immunoreactivity were detected across the time course following transient forebrain ischemia. These data indicate that changes in the expression of the chromogranin family of proteins after ischemia are selective for chromogranin A and secretoneurin. To our knowledge, this is the first study showing that the expression of the chromogranin family of proteins is differentially regulated after an ischemic insult in selected neuronal populations of the hippocampal formation and the cerebral cortex. Furthermore, the present data suggest a possible implication of chromogranin A and secretoneurin in the pathophysiology of transient forebrain ischemia.

Functional genomics of Down syndrome: a multidisciplinary approach

The availability of the DNA sequence of human chromosome 21 (HSA21) is a landmark contribution that will have an immediate impact on the study of the role of specific genes to Down syndrome (DS). Trisomy 21, full or partial, is a major cause of mental retardation and other phenotypic abnormalities, collectively known as Down syndrome (DS), a disorder affecting 1 in 700 births. The identification of genes on HSA21 and the elucidation of the function of the proteins encoded by these genes have been a major challenge for the human genome project and for research in DS. Over 100 of the estimated 300-500 genes of HSA21 have been identified, but the function of most remains largely unknown. It is believed that the overexpression of an unknown number of HSA21 genes is directly or indirectly responsible for the mental retardation and the other clinical features of DS. For this reason, HSA21 genes that are expressed in tissues affected in DS patients are of special interest.

Prion protein deposition and abnormal synaptic protein expression in the cerebellum in Creutzfeldt-Jakob disease

Prion protein (PrP(C)) is a cell membrane-anchored glycoprotein, which is replaced by a pathogenic protease-resistant, beta-sheet-containing isoform (PrP(CJD) or PrP(SC)) in human and animal prion encephalopathies, including sporadic Creutzfeldt-Jakob disease. Cell fractionation methods show that PrP(C) localizes in presynaptic membrane-enriched fractions. Following infection, abnormal PrP accumulates in nerve cell processes and synaptic regions. The present study examines the possible correlation between abnormal PrP deposition and the expression of synaptic proteins controlling neurotransmission in the cerebellum of six 129 Met/Met sporadic cases of Creutzfeldt-Jakob disease. Aggregates of protease-resistant PrP-positive granules, reminiscent of cerebellar glomeruli, were found in the granular cell layer, whereas fine punctate PrP-immunoreactive deposits occurred in the molecular layer. Small numbers of diffuse, irregular plaque-like PrP deposits in the molecular and granular cell layers were present in every case. The somas of Purkinje cells, and stellate, basket and Golgi neurons, were not immunostained. PrP-immunoreactive fibres were found in the album of the cerebellum and hilus of the dentate nucleus. Punctate PrP deposition decorated the neuropil of the dentate nucleus and the surface of dentate neurons. Synaptic protein expression was examined with synaptophysin, synapsin-1, synaptosomal-associated protein of 25,000 mol. wt, syntaxin-1 and Rab3a immunohistochemistry. Reduced synaptophysin, synapsin-1, synaptosomal-associated protein of 25,000 mol. wt, syntaxin-1 and Rab3a immunoreactivity was noted in the granular cell layer in every case, but reduced expression was inconstant in the molecular layer. Synaptophysin accumulated in axon torpedoes, thus indicating abnormal axon transport. Expression of synaptic proteins was relatively preserved in the dentate nucleus, although synaptophysin immunohistochemistry disclosed large coarse pericellular terminals in Creutzfeldt-Jakob disease, instead of the fine granular terminals in control cases, around the soma of dentate neurons. Finally, Rab3a accumulated in the cytoplasm of Purkinje cells, thus suggesting major anomalies in Rab3a transport. These observations demonstrate, for the first time, abnormal expression of crucial synaptic proteins in the cerebellum of cases with Creutzfeldt-Jakob disease. However, abnormal PrP deposition is not proportional to the degree of reduction of synaptic protein expression in the different layers of the cerebellar cortex and in the dentate nucleus. Therefore, it remains to be elucidated how abnormal PrP impacts on the metabolism of proteins linked to exocytosis and neurotransmission, and how abnormal PrP deposition results in eventual synaptic loss.

Expression of chick BMP-1/Tolloid during patterning of the neural tube and somites

The expression pattern described here is that of the chick BMP-1/Tolloid family of secreted metalloproteinases during early stages of development. BMP-1/Tolloid transcripts are expressed in the blastoderm, at gastrulation stages and as the neural plate forms and neural tube folds, BMP-1/Tolloid is found at the neural plate/ectodermal transition. Expression is maintained in the premigratory neural crest, and transiently in the migrating cephalic neural crest cells. BMP-1/Tolloid is also expressed in the caudal, but not in the anterior notochord, and in the ventral neural tube at the time of dorso-ventral patterning. Further sites of BMP-1/Tolloid expression are the lateral plate mesoderm and the dermotome and the myotome of the somites.

Differential c-Fos and caspase expression following kainic acid excitotoxicity

Caspases play crucial roles in the inflammatory response and in the cell pathway leading to apoptosis. Caspase 1 (ICE), 2 (Nedd2), 3 (CPP32), 6 (Mch2) and 8 (Mch5, FLICE) expression was examined using immunohistochemistry in the brains of rats and gerbils following systemic administration of kainic acid (KA). The distribution of caspase expression was compared with the distribution of c-Fos expression, a transcription factor that is produced in response to the excitotoxic insult. Strong caspase 2 immunoreactivity was found in microglia up to 6 h following KA administration. Focal strong expression of caspases 1, 2, 3, 6 and 8 was observed in astrocytes and neurons, from 12 to 48 h after KA injection, in areas in which a number of neurons were committed to die. This distribution was in contrast with the generalised distribution of c-Fos expression following KA administration. Only a minority of neurons in the entorhinal cortex, amygdala and hilus, but a majority of neurons in selected thalamic nuclei, exhibited strong caspase expression in KA-treated rats. Similar findings, although minimised, were observed in KA-treated gerbils. Double-labelling caspase immunohistochemistry and in situ end-labelling of nuclear DNA fragmentation disclosed co-localisation of strong caspase expression and nuclear DNA breaks in a small percentage of neurons but no co-localisation in astrocytes. Western blots of entorhinal cortex and neocortex homogenates showed cleavage of certain caspase substrates in KA-treated rats. The intensity of the bands corresponding to lamin B and protein kinase C-delta was decreased in the entorhinal cortex following KA administration. Several bands appeared in the entorhinal cortex and neocortex paragraph signin Western blots processed for the demonstration of poly(ADP-ribose) polymerase (PARP), thus indicating that other proteases, in addition to caspases, cleaved PARP following KA administration. Taken together, these findings indicate that KA excitotoxicity triggers caspase expression which, although predominant in regions subjected to irreversible cell damage, has only a weak association with the presence of nuclear DNA breaks and neuron cell death. Although these results suggest caspase activation, further studies have to be performed to elucidate whether caspase activation plays a crucial role in KA excitotoxicity.

Sonic hedgehog synergizes with the extracellular matrix protein vitronectin to induce spinal motor neuron differentiation

Patterning of the vertebrate neural tube depends on intercellular signals emanating from sources such as the notochord and the floor plate. The secreted protein Sonic hedgehog and the extracellular matrix protein Vitronectin are both expressed in these signalling centres and have both been implicated in the generation of ventral neurons. The proteolytic processing of Sonic hedgehog is fundamental for its signalling properties. This processing generates two secreted peptides with all the inducing activity of Shh residing in the highly conserved 19 kDa amino-terminal peptide (N-Shh). Here we show that Vitronectin is also proteolitically processed in the embryonic chick notochord, floor plate and ventral neural tube and that this processing is spatiotemporally correlated with the generation of motor neurons. The processing of Vitronectin produces two fragments of 54 kDa and 45 kDa, as previously described for Vitronectin isolated from chick yolk. The 45 kDa fragment lacks the heparin-binding domain and the integrin-binding domain, RGD, present in the non-processed Vitronectin glycoprotein. Here we show that N-Shh binds to the three forms of Vitronectin (70, 54 and 45 kDa) isolated from embryonic tissue, although is preferentially associated with the 45 kDa form. Furthermore, in cultures of dissociated neuroepithelial cells, the combined addition of N-Shh and Vitronectin significantly increases the extent of motor neuron differentiation, as compared to the low or absent inducing capabilities of either N-Shh or Vitronectin alone. Thus, we conclude that the differentiation of motor neurons is enhanced by the synergistic action of N-Shh and Vitronectin, and that Vitronectin may be necessary for the proper presentation of the morphogen N-Shh to one of its target cells, the differentiating motor neurons.

BDNF and full-length and truncated TrkB expression in Alzheimer disease. Implications in therapeutic strategies

Brain-derived neurotrophic factor (BDNF), and full-length and truncated tyrosin kinase B receptor (TrkB) protein expression were examined by Western blotting and immunohistochemistry in the frontal cortex and hippocampus of individuals affected by long-lasting severe Alzheimer disease (AD) and age-matched controls. Since preliminary processing studies in the brains of rats have shown loss of immunoreactivity depending on the postmortem delay in tissue processing and on the type, duration, and temperature of the fixative solution, only human samples obtained up to 6 hours (h) after death for biochemical and morphological studies and fixed by immersion in 4% paraformaldehyde for 24 h for morphological studies were included in the present series. Decreased BDNF and full-length TrkB expression accompanied by increased truncated TrkB expression, as revealed by Western blotting, was observed in the frontal cortex of patients with AD. Immunohistochemistry disclosed reduced BDNF and full-length TrkB immunoreactivity in neurons. BDNF decrease was equally observed in tangle-bearing and non-tangle-bearing neurons, as revealed with double-labeling immunohistochemistry to BDNF and phosphorylated tau or phosphorylated neurofilament epitopes. Full-length TrkB immunoreactivity was largely decreased in tangle-bearing neurons, whereas only moderate decreases occurred in neurons with granulovacuolar degeneration. Strong BDNF immunoreactivity was observed in dystrophic neurites surrounding senile plaques, whereas strong TrkB expression occurred in reactive glial cells, including those surrounding senile plaques. Finally, truncated TrkB immunoreactivity was observed in individual neurons and in reactive glial cells in the cerebral cortex and white matter in AD. These results show decay in the expression of BDNF and TrkB in AD neurons, accompanied by altered BDNF, and full-length and truncated TrkB expression in dystrophic neurites and reactive glial cells, respectively, in this disease. The present results demonstrate selective decline of the BDNF/TrkB neurotrophic signaling pathway in the frontal cortex and hippocampus in AD and provide supplemental data that may be relevant in discussing the suitability of the use of BDNF as a therapeutic agent in patients with AD.

Expression of synaptic proteins in the developing rat cerebellum following ionizing radiation

Various proteins regulating neurotransmission release and synaptic vesicle exocytosis have been implicated in axonal elongation and synaptic maturation. In the present study, immunohistochemistry to the presynaptic membrane proteins syntaxin-I and synaptosomal-associated protein of 25 kDa (SNAP-25) synaptic vesicle-associated proteins synaptophysin and synapsin-I and the neuronal maturation and axonal growth-related protein GAP-43, has been carried out in the normal developing cerebellum and following a single dose of ionizing radiation (2 Gy gamma-rays) at postnatal day 1. Our aim has been to learn about the morphological and possible functional modalities that occur during the progression of neuronal connectivity in normal and abnormal development. Expression of all these proteins is associated with the arrival of afferents in the subcortical white matter and with the maturation of the internal granule cell layer and molecular layer during normal development. In addition, SNAP-25 and GAP-43 are strongly expressed in granule cells of the external granule cell layer, thus suggesting that these proteins are involved in cell elongation of granule cells. Apoptosis appears at 3 h and peaks at 6 h following ionizing radiation. Radiation-induced apoptosis in the external granule cell layer produces a transient decrease in the expression of SNAP-25 and GAP-43 in the external granule cell layer. The external granule cell layer recovers at 48 h and external granule cells of proliferating cells also express SNAP-25 and GAP-43, thus indicating that proliferating cells in this layer are equipped with proteins involved in cell elongation. Furthermore, expression of synaptophysin, synapsin-I, syntaxin-I and SNAP-25 is the same in the cerebellum of irradiated and normal rats from this time to adulthood (3 months). These results point to the likelihood that recovery of the cerebellar cortex occurs following a single exposure of ionizing radiation during postnatal development.

[The usefulness of a diagnostic study of mental retardation]

INTRODUCTION

The etiological diagnosis of mental retardation is of interest for several reasons, such as being able to inform parents of the risk of recurrence, and offer the possibility of prenatal diagnosis when possible. It is therefore not surprising that doctors use all means available for this, although the real usefulness of this has not been fully studied.

OBJECTIVE

To find the frequency with which an etiological diagnosis is made after relevant investigations.

PATIENTS AND METHODS

We describe a retrospective study of persons aged between 0 and 14 years, who were seen by specialists in the hospitals of Gandia and Denia over a period of 7 years. Cases in which the diagnosis was already known or there was isolated motor or language retardation were excluded from the study.

RESULTS

An etiological diagnosis was established in 15.4% of the 65 children who fulfilled the criteria of inclusion or exclusion.

CONCLUSIONS

The little help obtained from the tests done, and the fact that the number of such tests did not affect the possibility of reaching a diagnosis, made us reconsider the habitual complementary investigations. It would be useful if other centres carried out similar studies so that the results may be compared.