Neuritogenic-neurotoxic effects of membrane-associated forms of amyloid precursor protein

The membrane-bound glycoprotein, amyloid precursor protein (APP), plays a central role in Alzheimer's disease (AD). The present paper investigates the neuritogenic-neurotoxic properties of this protein and relates them to possible aetiopathological mechanisms in AD. Marked differences in neuritic differentiation were detected when comparing untransfected tetraploid mouse neuroblastoma cells (or vector only cells) with transfected cells overexpressing APP(751). Transfected cells developed neurites quicker, and whereas all transfected cells differentiated, the degree of differentiation of untransfected cells was more variable. Fully differentiated transfected and untransfected cells had marked differences in neuritic morphology. Transfected cells had more neurites per cell, these being shorter and more branched than neurites on untransfected cells. The precocious differentiation of transfected cells was not maintained with neuritic process disintegration and cell death occurring from the seventh day onwards. Untransfected cells continued to extend their neuritic processes for up to five weeks. Membrane-associated forms of APP were responsible for these effects, rather than secreted APP or the beta/A4-peptide. Combined data from Western blot and immunocytochemical procedures showed a prominent accumulation of APP-C-terminal fragments in the perinuclear region, neuritic varicosities and growth cones of transfected cells, suggesting their involvement in the neuritogenic-neurotoxic process. Similar neuritogenic-neurotoxic mechanisms occurring in vivo, in association with compensatory synaptoplastic responses in the aged brain, may be part of the pathological process in AD.

HLA-DR antigens associated with major genetic risk for late-onset Alzheimer's disease

Hla-dr antigen types were determined from DNA isolated from post-mortem brain tissue of age-matched groups of 78 patients with pathologically confirmed late-onset Alzheimer's disease (AD) and 50 controls. The results suggest that for individuals with no apolipoprotein E epsilon 4 alleles the presence of either DR1, 2 or 3 antigens is associated with a significantly increased risk for development of late-onset AD. Conversely the DR4 or 6 antigens are associated with a decreased risk of similar magnitude. This DR effect, rather than prolonged use of non-steroidal anti-inflammatory drugs, could be responsible for the reported lower prevalence of AD in rheumatoid arthritis (a condition associated with an increased frequency of DR-4).

Clinically diagnosed presenile dementia of the Alzheimer type in the Northern Health Region: ascertainment, prevalence, incidence and survival

Potential cases of presenile dementia of the Alzheimer type (PDAT) in the Northern Health Region (estimated population aged 45-64, 655,800) were ascertained for the years 1979-86 from in-patient ICD-9 codes and other sources. An algorithm was applied to the casenote information to distinguish between Alzheimer-type and other forms of dementia. A search of the NHS central register was made to establish date and place of death. Estimates were made for patients with missing case records. The point prevalence rate for PDAT was estimated as 34.6 per 100,000 with an annual incidence of 7.2 per 100,000 in the 45-64 age range. These rates are compared with those reported in other studies. Five-year survival following diagnosis for incident cases of PDAT was 64% with a longevity quotient (LQ), the percentage of expected time actually survived, of 69%. There was no evidence of a more malignant course in PDAT when compared with survival in older patients with dementia of the Alzheimer type (DAT) in other studies. Sixty-six per cent of deaths occurred in hospital, 19% at home and 15% in residential homes.

Bone mass and dementia in hip fracture patients from areas with different aluminium concentrations in water supplies

The relationship between bone mass and dementia in elderly hip fracture patients from areas with different aluminium concentrations in water supplies has been investigated, to determine whether a high concentration of aluminium in the drinking water and the negative calcium balance of age-related osteoporosis together predispose to senile dementia. Mental test scores were recorded on admission to hospital, and Singh indices of radiographs taken at that time assessed blind by a single trained observer. No significant difference in either mental test score (chi 2 = 1.253, df = 2, P = 0.53) or Singh index (chi 2 = 1.039, df = 5, P = 0.96) was found between patients resident in high versus low water aluminum areas. No correlation was detectable between mental test score and Singh index (chi 2 = 0.95, df = 1, P = 0.33).

Cortical somatostatinergic system not affected in Alzheimer's and Parkinson's diseases

A reduction in the levels of somatostatin-like immunoreactivity (SLI) and somatostatin binding sites in the cerebral cortex has been previously reported to occur in Alzheimer's disease (AD) and Parkinson's disease with associated dementia. In the present study, the levels of both SLI and high affinity [3H]somatostatin binding sites have been measured in the frontal (Brodmann area 9) and temporal (Brodmann area 21) cortices in patients with presenile and senile Alzheimer's disease, and in mentally normal and cognitively impaired cases of Parkinson's disease. The results were compared with those obtained from a group of normal patients matched for age and postmortem delay. No significant changes in SLI or somatostatin binding in the frontal and temporal cortex were found between any of the disease groups. These results suggest that involvement of the somatostatinergic system in AD or Parkinson's disease is not a consistent or primary neurochemical feature of these diseases.

The hypothalamic arcuate nucleus-median eminence complex: immunohistochemistry of transmitters, peptides and DARPP-32 with special reference to coexistence in dopamine neurons

In this paper, we describe the results of a series of experiments which have examined the distribution within the arcuate nucleus of the hypothalamus of neurons containing the following immunoreactivities: TH-LI, GAD-LI, NT-LI, GAL-LI, GRF-LI, Met-ENK-LI, Leu-ENK-LI, Met-ENK-7-LI, Met-ENK-8-LI, metorphamide-LI, DYN-LI, NPY-LI, SOM-LI, FMRFamide-LI, and CLIP-LI and ependymal tanycytes containing DARPP-32-LI. Using elution-restaining and double antibody staining techniques we have established numerous patterns of coexistence of these various neurotransmitters and neuropeptides. Thus, neurons containing TH-LI were, in some instances, also found to contain GAD-LI, NT-LI, GAL-LI, GRF-LI, Met-ENK-8-LI, Leu-ENK-LI, or DYN-LI or combinations of these compounds. For example, some TH-IR neurons also contained GAL-LI and GRF-LI, while other TH-IR. neurons were also seen to contain GRF- and NT-LI. These neurons may, in fact, contain even more compounds. NPY-IR neurons and those containing SOM-LI and CLIP-LI were distinct and separate from those containing TH-LI. The distribution of these different neurochemical types of neurons and their patterns of coexistence are summarized in Fig. 34, while the relative distribution patterns of immunoreactive fibres in the median eminence are summarized in Fig. 35.

Treatment of ringworm in calves using griseofulvin

Ringworm infection of a farm manager is described. Treatment of 10 ringworm-infected calves (group A) on the farm was undertaken with the daily administration of griseofulvin powder for seven days at a rate of 7.5 mg per kg body-weight and compared with nine infected control calves (group B). Group A showed fewer new lesions (22) than group B (80) and fewer new lesions per infected animal (3.7 and 11.4 respectively). The appearance of the last new lesions was earlier in group A (21 days) than in group B (56 days) and the duration of infection in the former group was less (49 days and 98 days respectively). Two control calves were not infected until after infection in group A had resolved.

Investigation of cerebrospinal fluid neuropeptides in idiopathic senile dementia

Thyrotrophin-releasing hormone and gonadotrophin-releasing hormone were measured in lumbar CSF from patients with idiopathic senile dementia, cerebral tumours and spinal disc lesions. Somatostatin was also measured in lumbar CSF from patients with dementia and patients with other neurological disorders, but the numbers involved were much smaller. The levels of these neuropeptides were significantly reduced in the patients with senile dementia. These results suggest a possible involvement of hpothalamic neuropeptides in idiopathic senile dementia.

An outbreak of ringworm in a group of young cattle

In an outbreak of ringworm, 30 out of 32 bull calves being reared intensively for beef showed infection. Weekly observations were made from their arrival at the farm at about one week old until slaughter at approximately 10 1/2 to 12 months of age. The outbreak lasted for 33 weeks and appeared to originate from two animals brought into the unit. Lesions occurred first, and most commonly, in the head region. The disease in individual animals lasted eight weeks and each lesion had a mean duration of 3.6 weeks. New lesions occurred after those elsewhere on the same animal had healed. The mean incubation period was estimated at 4.6 weeks. Spread of ringworm was probably mainly due to the licking and grooming activities of the calves' tongues.