The retinal degeneration (rd) gene seriously impairs spatial cognitive performance in normal and Alzheimer's transgenic mice

To determine the effects of the recessive retinal degeneration (rd) gene on behavioral performance, three Alzheimer's transgenic lines (APPsw, P301L, APPsw + P301L) and non-transgenic littermates were evaluated in a comprehensive behavioral battery between 5 and 8.5 months of age. For all four genotypes collectively, rd homozygosity resulted in profound impairment in spatial cognitive tasks requiring visual acuity (Morris maze, platform recognition, and radial arm water maze). Non-transgenic and P301L mutant tau mice contributed most to this rd effect since heterozygous and wild type mice performed well. By contrast, spatial cognitive performance of both APPsw-expressing lines was often impaired, irrespective of rd status. Sensorimotor performance was unaffected by rd homozygosity, while rd effects on anxiety were genotype-dependent (less anxiety in NT, APPsw; more anxiety in P301L, APPsw + P301L). Our results strongly encourage rd screening of genetically manipulated mouse lines produced from rd-carrying strain backgrounds to avoid serious potential confounds in the interpretation of spatially based cognitive performance.

Mild hypercholesterolemia is an early risk factor for the development of Alzheimer amyloid pathology

BACKGROUND

Epidemiologic and experimental data suggest that cholesterol may play a role in the pathogenesis of AD. Modulation of cholesterolemia in transgenic animal models of AD strongly alters amyloid pathology.

OBJECTIVE

To determine whether a relationship exists between amyloid deposition and total cholesterolemia (TC) in the human brain.

METHODS

The authors reviewed autopsy cases of patients older than 40 years and correlated cholesterolemia and presence or absence of amyloid deposition (amyloid positive vs amyloid negative subjects) and cholesterolemia and amyloid load. Amyloid load in human brains was measured by immunohistochemistry and image analysis. To remove the effect of apoE isoforms on cholesterol levels, cases were genotyped and duplicate analyses were performed on apoE3/3 subjects.

RESULTS

Cholesterolemia correlates with presence of amyloid deposition in the youngest subjects (40 to 55 years) with early amyloid deposition (diffuse type of senile plaques) (p = 0.000 for all apoE isoforms; p = 0.009 for apoE3/3 subjects). In this group, increases in cholesterolemia from 181 to 200 almost tripled the odds for developing amyloid, independent of apoE isoform. A logistic regression model showed consistent results (McFadden rho2 = 0.445). The difference in mean TC between subjects with and without amyloid disappeared as the age of the sample increased (>55 years: p = 0.491), possibly reflecting the effect of cardiovascular deaths among other possibilities. TC and amyloid load were not linearly correlated, indicating that there are additional factors involved in amyloid accumulation.

CONCLUSIONS

Serum hypercholesterolemia may be an early risk factor for the development of AD amyloid pathology.

De novo partial duplications 1p: report of two new cases and review

We describe two de novo intrachromosomal duplications of 1p. One case is a dir ins dup(1)(q21p21p31) in a newborn girl with low birth weight, growth retardation, and tetralogy of Fallot. The other is a 10-month-old girl with developmental delay, craniosynostosis, plagiocephaly, and an inv dup 1p34.1p31. Although, these patients have manifestations in common with previous cases, they do not establish a syndrome. Interestingly, all males with duplications spanning 1p31 had genital anomalies, whereas females with duplications of the same region had normal genitalia. Thus, genes within 1p31 appear to control the development of male genitalia and tentatively exclude effects of tda1, a sex-determining gene in a region of mouse chromosome 4 syntenic to 1p36 in man. However, it is necessary to identify the human tda1 homologue and candidate genes within 1p31 before drawing final conclusions.

Treatment of cutaneous leishmaniasis with localized current field (radio frequency) in Tabasco, Mexico

In Mexico cutaneous leishmaniasis (CL) occurs in 17 of 32 States, and is a serious public health problem. This is a report of treatment of CL patients in the State of Tabasco, Mexico with a localized current field-radio frequency (LCF-RF) device to generate precisely controlled heat as an alternative to prohibitively expensive drug treatment. It was not a controlled clinical trial, but rather an evaluation of the feasibility of this form of treatment for all CL patients encountered in the endemic area. A total of 201 previously diagnosed patients with CL caused by Leishmania mexicana were treated with a portable Thermosurgery LCF-RF generator powered by rechargeable batteries. The ages of the patients ranged from two to 75 years; the sex distribution was 63% males and 37% females. A single device was used in five different municipalities. Lesions were first anesthetized with 1% lidocaine HCl and moistened with normal saline solution. Treatment consisted of a single application that produced 50 degrees C for 30 sec. After four weeks, 122 patients were available for evaluation, of which 95% were totally cured; (even those involving ear cartilage, which respond poorly to antimonials). At eight weeks post-treatment, 191 patients were evaluated, with a total cure rate of 90%. This form of treatment proved to be effective and convenient for use in primary health care facilities in Mexico and has many advantages over traditional forms of therapy.

[Intestinal mucosa in rats with iron deficiency anemia]

Eighteen albino rats at the age of 15 days were separated in 2 groups of 9 and fed cow's milk exclusively. The milk supplied to the control rats (group I) was supplemented with iron and copper. The months later, the rats were scarificed. The animals of group II were severely anaemic. In each rat, a histological examination of gastric (in group II, only in 2 rats) and jejunal mucosa as well as measurements of total thickness, villous height, epithelial cell height and mitotic index were made. Histology was normal in all the rats. Measurements gave similar results in both groups except for the epithelial cell height which was significantly higher in anaemic rats than in controls. The authors take issue with the methodology followed in previous studies concerning iron-deficient children and suggest that the causal relation between iron deficiency and structural changes of intestinal mucosa in children has not yet been proven.