PRNP H187R mutation associated with neuropsychiatric disorders in childhood and dementia.

Described is a large family with an autosomal dominant dementia associated with an H187R mutation in the prion protein gene (PRNP). Clinical features include neuropsychiatric disturbances in childhood and adolescence, dementia in young adulthood with frontotemporal manifestations, and long disease duration. Neuropathology revealed atrophy and mild gliosis, whereas prion protein analysis revealed an abnormal conformer with unusual sensitivity to protease digestion. Mutations in PRNP may cause neuropsychiatric disorders that predate dementia by many years.

Binding of neural cell adhesion molecules (N-CAMs) to the cellular prion protein.

To identify molecular interaction partners of the cellular prion protein (PrP(C)), we sought to apply an in situ crosslinking method that maintains the microenvironment of PrP(C). Mild formaldehyde crosslinking of mouse neuroblastoma cells (N2a) that are susceptible to prion infection revealed the presence of PrP(C) in high molecular mass (HMM) protein complexes of 200 to 225 kDa. LC/MS/MS analysis identified three murine splice-variants of the neural cell adhesion molecule (N-CAM) in the complexes, which isolate with caveolae-like domains (CLDs). Enzymatic removal of N-linked sugar moieties did not disrupt the complexes, arguing that the interaction of PrP with N-CAM occurs through amino acid side-chains. Additionally, similar levels of PrP/N-CAM complexes were found in N2a and prion-infected N2a (ScN2a) cells. With the use of an N-CAM-specific peptide library, the PrP-binding site was determined to comprise beta-strands C and C' within the two consecutive fibronectin type III (FNIII) modules found in proximity of the membrane-attachment site of N-CAM. As revealed by in situ crosslinking of PrP deletion mutants, the PrP face of the binding site is formed by the N terminus, helix A (residues 144-154) and the adjacent loop region of PrP. N-CAM-deficient (N-CAM(-/-)) mice that were intracerebrally challenged with scrapie prions succumbed to disease with a mean incubation period of 122 (+/-4.1, SEM) days, arguing that N-CAM is not involved in PrP(Sc) replication. Our findings raise the possibility that N-CAM may join with PrP(C) in carrying out some as yet unidentified physiologic cellular function.

Inherited prion disease caused by the V210I mutation: transmission to transgenic mice.

OBJECTIVE: To describe the clinical and neuropathologic profile and determine the strain characteristics of familial Creutzfeldt-Jakob disease (fCJD) caused by a point mutation of the PRNP gene at codon 210 that results in a valine-to-isoleucine substitution in the prion protein (PrP). METHODS: The clinicopathologic features of four individuals from the United States who died of fCJD(V210I) were compared. Transgenic (Tg) mice expressing a chimeric human-mouse PrP transgene were inoculated with brain extracts from three fCJD(V210I) cases, sporadic CJD (sCJD), fCJD(E200K), and fatal familial insomnia (FFI), to compare prion strain characteristics. RESULTS: The clinicopathologic profile of fCJD(V210I) was variable among cases but shared similarities with sCJD. The pattern of PrP(Sc) deposition in the brains of Tg mice was similar to that caused by sCJD but different from that associated with fCJD(E200K) or FFI. CONCLUSIONS: Each of these prion diseases is characterized by a rapidly progressive dementia with myoclonus, periodic complexes on EEG, and spongiform change without PrP plaque deposition in the brain. The occurrence of a different PrP(Sc) phenotype with each PRNP mutation argues that each respective amino acid sequence substitution produces a different prion strain.

Cultured cell sublines highly susceptible to prion infection.

Cultured cell lines infected with prions produce an abnormal isoform of the prion protein (PrP(Sc)). In order to derive cell lines producing sufficient quantities of PrP(Sc) for most studies, it has been necessary to subclone infected cultures and select the subclones producing the largest amounts of PrP(Sc). Since postinfection cloning can introduce differences between infected and uninfected cell lines, we sought an approach to generate prion-infected cell lines that would avoid clonal artifacts. Using an improved cell blot technique, which permits sensitive and rapid comparison of PrP(Sc) levels in multiple independent cell cultures, we discovered marked heterogeneity with regard to prion susceptibility in tumor cell sublines. We exploited this heterogeneity to derive sublines which are highly susceptible to prion infection and used these cells to generate prion-infected lines without further subcloning. These infected sublines can be compared to the cognate uninfected cultures without interference from cloning artifacts. We also used susceptible cell lines and our modified cell blot procedure to develop a sensitive and reproducible quantitative cell culture bioassay for prions. We found that the sublines were at least 100-fold more susceptible to strain RML prions than to strain ME7 prions. Comparisons between scrapie-susceptible and -resistant cell lines may reveal factors that modulate prion propagation.

Prion protein of 106 residues creates an artifical transmission barrier for prion replication in transgenic mice.

A redacted prion protein (PrP) of 106 amino acids with two large deletions was expressed in transgenic (Tg) mice deficient for wild-type (wt) PrP (Prnp0/0) and supported prion propagation. RML prions containing full-length PrP(Sc)produced disease in Tg(PrP106)Prnp0/0 mice after approximately 300 days, while transmission of RML106 prions containing PrP(Sc)106 created disease in Tg(PrP106) Prnp0/0 mice after only approximately 66 days on repeated passage. This artificial transmission barrier for the passage of RML prions was diminished by the coexpression of wt MoPrPc in Tg(PrP106)Prnp+/0 mice that developed scrapie in approximately 165 days, suggesting that wt MoPrP acts in trans to accelerate replication of RML106 prions. Purified PrP(Sc)106 was protease resistant, formed filaments, and was insoluble in nondenaturing detergents. The unique features of RML106 prions offer insights into the mechanism of prion replication, and the small size of PrP(Sc)106 should facilitate structural analysis.

[Quality control of general diets served in a county hospital]. / Control de calidad de las dietas generales servidas en un hospital comarcal.

INTRODUCTION: The general diet of a hospital, given to patients who do not require therapeutic modifications, must meet their nutritional demands. MATERIAL AND METHODS: During a 42 consecutive days period, the complete menu of a patient was randomly selected. Using a computer program based on the food composition tables, we verified whether or not the foods the patient received, met the requirements of the theoretical menus of the hospital, designed according to the international recommendations. RESULTS: The provided menus supplied 2,410 kilocalories, of which 900 (37.3%) corresponded to carbohydrates, 1,071 (44.4%) corresponded to lipids, and 439 (18.3%) corresponded to proteins. The level of cholesterol was 422 mg, and the fiber content was 20 g. These values differ significantly from the theoretical values noted previously: 2,200 kilocalories, 55% carbohydrates, 30% lipids, 15% proteins, cholesterol less than 300 mg, and 40 g of fiber (p < 0.001). Within the fats, the monounsaturated fats were the most abundant (45%). With regard to vitamins and minerals, vitamin D was the only deficient vitamin when compared to the international recommendations. CONCLUSION: We have detected that our general menus provide an excess of fats and cholesterol, as well as a deficient supply of carbohydrates, fiber, and vitamin D. We believe it necessary to carry out periodic quality controls to correct the defects that arise on translating the theoretical menus into daily practice.

A PrP gene codon 178 base substitution and a 24-bp interstitial deletion in familial Creutzfeldt-Jakob disease.

Several mutations in the prion protein (PrP) gene are associated with familial Creutzfeldt-Jakob disease (FCJD). We describe a family in which five members in three generations have had FCJD. The proband and some descendants of the affected members carried an abnormal PrP gene allele. This allele contained a 24-bp deletion from the tandem repeat region of the open reading frame and a codon 178 missense substitution. Observations suggest that the codon 178 mutation is involved in the pathogenesis of FCJD in the family described here. The 24-bp deletion may be an uncommon polymorphism.

[Morphology of the posterior colliculus in epileptic hamsters]. / Comportamiento morfológico del colículo posterior en hamsters epilépticos.

In an inbred strain of Golden hamsters with audiogenic seizures, we have studied the collicular participation, planning a morphologic study of posterior colliculus central nucleus. The parameters used have been: number of neurons and glia, neuronal areas and area of all the colliculus. The measurement and the counts have been done in both sides and for to validate the results we have used an A.N.O.V.A.. In the epileptic group, there are a less number of neurons and a major correlation Nucleus/cytoplasm. The left-right correlations are positive for the neurons, while in the control group are for the glia. Although, the number of neurons in the epileptic animals are less, this are more active, which can be related to the participation of the colliculus in the audiogenic seizures.

Effect of vagotomy on the conjugated bile acids in the dog.

The effects of truncal vagotomy and selective gastric vagotomy on the conjugated bile acids and rations T/G and Tri/Di have been studied in twenty dogs. The results show that truncal vagotomy has no effect on the conjugated bile acid values determined in the 4th and 16th week. The ratio T/G increased while the Tri/Di decreased in the 16th week. The selective gastric vagotomy only shows a change of the taurocholic acid levels which are lower than the control levels in the 4th week.

[Effect of vagal denervation on the alkaline phosphatases of the jejunal mucosa of the rat (author's transl)]. / Efecto de la denervación vagal sobre las fosfatasas alcalinas de la mucosa yeyunal de la rata

The results of experiments conducted on the qualitative (histochemical) and quantitative (biochemical) determination of alkaline phosphatase present in rat yeyunum mucosa. Normal and vagal denervated animals were used. Results indicate that there are no significant enzymatical changes after vagal extirpation.