Distribution of amyloid deposits in the cerebral white matter of the Alzheimer's disease brain: relationship to blood vessels

The relationship between blood vessels and amyloid beta (A beta)-protein deposits in the cortex of the Alzheimer's disease (AD) brain is still controversial. It is difficult to distinguish whether the A beta deposits are associated with blood vessels or neurons because of their widespread and complicated distribution. In this study, we investigated the distribution of A beta deposits in the cerebral white matter of the AD brain as a means of removing the bias of neuronal distribution. An immunohistochemical study of 100 serial sections, after pretreatment with formic acid for 24 h, revealed the presence of A beta deposits in the cerebral white matter of the AD brain. There are various morphological types of plaques containing A beta deposits in the white matter, the same as in the gray matter. While the majority of A beta deposits was of a circumscribed type such as "classic" and "primitive" plaques, "compact" and "diffuse" plaques were also observed in the white matter. The location of the A beta deposits was, for the most part, immediately beneath the gray matter. The distribution of A beta deposits in the white matter was found to correspond to the orientation of the blood vessels. Serial sections also revealed that these A beta deposits were distributed along a single blood vessel. These findings suggest that the deposition of A beta in the cerebral white matter is primarily related to the blood vessels.

Distribution of apolipoprotein E in senile plaques in brains with Alzheimer's disease: investigation with the confocal laser scan microscope

In order to elucidate the mechanism of the occurrence of apolipoprotein E (ApoE) in senile plaques (SP) in the brain of Alzheimer's disease (AD) patients, we morphologically examined double immunofluorescent-stained sections by scanning with the confocal laser scan microscope (LSM) and reconstructed their three-dimensional structure by a computerized imaging technique. Brain samples were obtained from six pathologically diagnosed AD patients, including patients with the genotype ApoE epsilon 3/3 and epsilon 4/4 ApoE genotype. We found some clear differences in distribution and shape in the staining patterns of plaque-shaped deposits by ApoE antibody and amyloid beta-protein (A beta) antibody. ApoE deposits were generally larger than A beta deposits in the same region and were distributed widely at the periphery of A beta deposits. Several A beta deposits of typical, compact and primitive plaques were often included in one diffuse plaque-like deposit of ApoE. Some ApoE deposits did not exhibit any A beta-immunoreactivity. Each core represented by ApoE and A beta did not show complete overlap. Typical plaques tended to be composed mainly of A beta-immunoreactivity and had little ApoE-immunoreactivity. The discrepancy between ApoE and A beta deposition may reflect different stages of amyloidogenesis in SP. The presence of ApoE alone in plaques may represent the pathological stage before the beginning of massive A beta deposition.

A juvenile case of frontotemporal dementia: neurochemical and neuropathological investigations

1. An autopsy case of frontotemporal dementia with onset at the early age of 28 years is reported. 2. The neuropathological features consisted of limited, knife-like frontotemporal atrophy with severe neuronal loss, spongiform change and gliosis, which is compatible with the frontotemporal dementia. 3. Biochemical determinations disclosed that biogenic amines and their metabolites, predominant in the dopaminergic markers, were depleted in the damaged regions. 4. Since biochemical data in frontotemporal dementia are few in previous studies, it will be determined whether these biochemical changes are characteristic for the juvenile type of frontotemporal dementia or not.

Design of an antifungal methionine inhibitor not antagonized by methionine

Only a few biosynthetic pathways in fungal cells have been used as antifungal targets. Therefore, the number of antifungals has been limited, and a cross-drug resistance among them has emerged in the therapy of mycoses. Under such circumstances, the identification of an antifungal with a new mode of action is highly desirable. By infecting mice with a mutant of C. albicans deficient in the sulfate assimilation pathway, we have discovered a new target for the discovery of antifungal agents. We have proven that azoxybacilin inhibits the sulfate assimilation pathway by showing its inhibitory activity for [35S]SO4 incorporation into proteins. We have also demonstrated that azoxybacilin was taken up into fungal cells via an active transport system specific for methionine. This sharing of the uptake system with methionine may explain the mechanism by which the antifungal activity of azoxybacilin is antagonized by methionine, and led us to design azoxybacilin derivatives that lack the structural feature of amino acids and, at the same time, have increased hydrophobicity to give higher non-specific permeability through the cell membrane. As a result, we have found that ester derivatives of azoxybacilin were not antagonized by methionine in their uptake, and that they showed antifungal activity independent of methionine. The benzyl ester of azoxybacilin was the same as azoxybacilin in its mode of action, but was not markedly antagonized by methionine at concentrations up to 1 mg/ml. These results suggest that azoxybacilin may not merely interfere with the sulfate assimilation pathway.

Demonstration of CRP immunoreactivity in brains of Alzheimer's disease: immunohistochemical study using formic acid pretreatment of tissue sections

C-reactive protein (CRP) is a well-known serum protein which increases during inflammation and deposits in damaged tissues. To establish whether CRP appears in brain of Alzheimer's disease (AD), we immunohistochemically investigated tissue sections which were pretreated with formic acid. Positive immunostaining by anti-CRP antibodies was clearly recognized in senile plaques (SP) in the pretreated tissue sections, with very weak immunostaining in non-treated sections. These findings may suggest that the formation process of SP includes an acute-phase inflammatory state.

Synthesis and structure-activity relationships of a novel antifungal agent, azoxybacilin

A new antifungal substance, azoxybacilin (an unusual amino acid with an azoxy moiety) and its derivatives have been synthesized from Boc-L-Asp-OtBu utilizing the Moss procedure for the preparation of the azoxy moiety. The ester derivative, Ro 09-1824, showed more potent antifungal activity and a broader antifungal spectrum than azoxybacilin did.

Selective loss of calbindin D28K-immunoreactive neurons in the cortical layer II in brains of Alzheimer's disease: a morphometric study

To investigate the relationship between neuronal death and intracellular calcium homeostasis in brains from patients with Alzheimer's disease (AD), we quantitatively analyzed morphological changes of calbindin-immunoreactive neurons. Neuronal counts were made in the autopsy brains from 6 control and 6 AD patients. Calbindin-immunoreactive neurons were mainly distributed in cortical layer II and were selectively lost in the AD brains. Further, the number of calbindin-immunoreactive neurons showed a negative correlation with age in the control group. These findings strongly suggest that age-related reduction of calbindin-immunoreactive neurons may be exaggerated in AD brains and change in calcium homeostasis may be involved in the pathogenesis of AD.