Group home care for adults with intellectual disabilities and Alzheimer’s disease

The growing numbers of individuals with intellectual disabilities affected by Alzheimer’s disease and related dementias has raised new challenges for community care providers. This article examines means of providing community group home-based care in a sample of care providers in five different countries. The aim is to identify trends that have emerged. Two samples of group homes for adults with intellectual disabilities affected by dementia were studied to determine: (1) what are the physical characteristics of the homes; (2) what physical environmental adaptations have been made in response to behavioral deterioration expressed by residents with dementia; and (3) what are the demands on staff resulting from dementia care. The first sample of group homes in five countries provided comparative international data on home designs, staffing, costs, and residents. The second sample, drawn from homes in the USA and the UK, provided data on the impact of dementia. Findings revealed staffing and design of homes varied but generally abided by general practices of dementia care; homes relied on existing resources to manage changes posed by dementia care; programmatic and environmental adaptations were implemented to address progression of dementia; and residents with dementia presented more demands on staff time with respect to hygiene maintenance and behavior management when compared to other residents not affected by dementia.

Vitamin E in aging persons with Down syndrome: A randomized, placebo-controlled clinical trial

OBJECTIVE

To determine whether vitamin E would slow the progression of cognitive deterioration and dementia in aging persons with Down syndrome (DS).

METHODS

A randomized, double-blind controlled clinical trial was conducted at 21 clinical sites, and researchers trained in research procedures recruited adults with DS older than 50 years to participate. Participants were randomly assigned to receive 1,000 IU of vitamin E orally twice daily for 3 years or identical placebo. The primary outcome was change on the Brief Praxis Test (BPT). Secondary outcomes included incident dementia and measures of clinical global change, cognition, function, and behavior.

RESULTS

A total of 337 individuals were randomized, 168 to vitamin E and 169 to placebo. Both groups demonstrated deterioration on the BPT with no difference between drug and placebo. At baseline, 26% were diagnosed with dementia and there was an overall rate of incident dementia of 11%/year with no difference between groups. There was no effect on the secondary outcome measures. Though numerically higher in the treatment group, there was no difference in the number of adverse events (p = 0.079) and deaths (p = 0.086) between groups.

CONCLUSIONS

Vitamin E did not slow the progression of cognitive deterioration in older individuals with DS.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that vitamin E does not significantly slow the progression of cognitive deterioration in aging persons with DS.

The mTORC1/4E-BP pathway coordinates hemoglobin production with L-leucine availability

In multicellular organisms, the mechanisms by which diverse cell types acquire distinct amino acids and how cellular function adapts to their availability are fundamental questions in biology. We found that increased neutral essential amino acid (NEAA) uptake was a critical component of erythropoiesis. As red blood cells matured, expression of the amino acid transporter gene Lat3 increased, which increased NEAA import. Inadequate NEAA uptake by pharmacologic inhibition or RNAi-mediated knockdown of LAT3 triggered a specific reduction in hemoglobin production in zebrafish embryos and murine erythroid cells through the mTORC1 (mammalian target of rapamycin complex 1)/4E-BP (eukaryotic translation initiation factor 4E-binding protein) pathway. CRISPR-mediated deletion of members of the 4E-BP family in murine erythroid cells rendered them resistant to mTORC1 and LAT3 inhibition and restored hemoglobin production. These results identify a developmental role for LAT3 in red blood cells and demonstrate that mTORC1 serves as a homeostatic sensor that couples hemoglobin production at the translational level to sufficient uptake of NEAAs, particularly L-leucine.

A systematic review of therapeutic interventions to reduce acute and chronic post-surgical pain after amputation, thoracotomy or mastectomy

Background

Perioperative neuropathic pain is under-recognized and often undertreated. Chronic pain may develop after any routine surgery, but it can have a far greater incidence after amputation, thoracotomy or mastectomy. The peak noxious barrage due to the neural trauma associated with these operations may be reduced in the perioperative period with the potential to reduce the risk of chronic pain.

Databases and data treatment

A systematic review of the evidence for perioperative interventions reducing acute and chronic pain associated with amputation, mastectomy or thoracotomy.

Results

Thirty-two randomized controlled trials met the inclusion criteria. Gabapentinoids reduced pain after mastectomy, but a single dose was ineffective for thoracotomy patients who had an epidural. Gabapentinoids were ineffective for vascular amputees with pre-existing chronic pain. Venlafaxine was associated with less chronic pain after mastectomy. Intravenous and topical lidocaine and perioperative EMLA (eutectic mixture of local anaesthetic) cream reduced the incidence of chronic pain after mastectomy, whereas local anaesthetic infiltration appeared ineffective. The majority of the trials investigating regional analgesia found it to be beneficial for chronic symptoms. Ketamine and intercostal cryoanalgesia offered no reduction in chronic pain. Total intravenous anaesthesia (TIVA) reduced the incidence of post-thoracotomy pain in one study, whereas high-dose remifentanil exacerbated chronic pain in another.

Conclusions

Appropriate dose regimes of gabapentinoids, antidepressants, local anaesthetics and regional anaesthesia may potentially reduce the severity of both acute and chronic pain for patients. Ketamine was not effective at reducing chronic pain. Intercostal cryoanalgesia was not effective and has the potential to increase the risk of chronic pain. TIVA may be beneficial but the effects of opioids are unclear.

Teleost growth factor independence (gfi) genes differentially regulate successive waves of hematopoiesis

Growth Factor Independence (Gfi) transcription factors play essential roles in hematopoiesis, differentially activating and repressing transcriptional programs required for hematopoietic stem/progenitor cell (HSPC) development and lineage specification. In mammals, Gfi1a regulates hematopoietic stem cells (HSC), myeloid and lymphoid populations, while its paralog, Gfi1b, regulates HSC, megakaryocyte and erythroid development. In zebrafish, gfi1aa is essential for primitive hematopoiesis; however, little is known about the role of gfi1aa in definitive hematopoiesis or about additional gfi factors in zebrafish. Here, we report the isolation and characterization of an additional hematopoietic gfi factor, gfi1b. We show that gfi1aa and gfi1b are expressed in the primitive and definitive sites of hematopoiesis in zebrafish. Our functional analyses demonstrate that gfi1aa and gfi1b have distinct roles in regulating primitive and definitive hematopoietic progenitors, respectively. Loss of gfi1aa silences markers of early primitive progenitors, scl and gata1. Conversely, loss of gfi1b silences runx-1, c-myb, ikaros and cd41, indicating that gfi1b is required for definitive hematopoiesis. We determine the epistatic relationships between the gfi factors and key hematopoietic transcription factors, demonstrating that gfi1aa and gfi1b join lmo2, scl, runx-1 and c-myb as critical regulators of teleost HSPC. Our studies establish a comparative paradigm for the regulation of hematopoietic lineages by gfi transcription factors.

Some effects of token rewards on school achievement of children with Down's syndrome

The effectiveness of a token economy system in producing improvement in the academic performance of children with Down's syndrome was tested. One group of seven children received token reinforcement for correct responses and showed significant improvement both in arithmetic and language. A second matched group of six children received only verbal praise for correct responses to the same instructional materials and failed to improve in arithmetic but showed significant gains in language. Re-test scores one year later revealed that the Token Group maintained its gains in both subjects whereas the language performance of the No-Token Group showed a significant decline.

Relationship between Amyloid β (Aβ) Protein and Inflammatory Markers in Down Syndrome (DS) (98.19)

Brain autopsy data from persons with DS showed that the neuropathology of Alzheimer disease (AD) is always present in DS 40 years of age and older. The core protein of the neuritic plaque is Aβ protein. Studies have suppoted the role of immune abnormalities and inflammation in the pathogenesis of DS. We hypothesized that the levels of TNFα and Cystatin C would be higher in DS than controls, and would correlate with Aβ levels. The study included 40 persons with DS (44±8 years old) and age-matched controls. Plasma levels of Aβ40 and Aβ42 , TNFα and Cystatin C were quantitated by using an ELISA. Aβ40 and Aβ42, TNFα and Cystatin C levels were higher in DS than controls (p<.001). Although there was significant relation between Aβ40 and Aβ42 levels (r=.6; p<.01)in DS, there was no relation between Aβ40 and Aβ42 levels with TNFα or Cystatin C. The higher TNFαand Cystatin C levels indicate a chronic state of immune activation in DS. Because there was no relation between Aβ and TNFα or Cyststin C the data suggests that increases in TNFα and Cystatin C reflect more infections in DS than AD neuropathology.

Aluminium and the pathogenesis of Alzheimer's disease: a summary of evidence

Known risk factors for Alzheimer's disease (AD) are few and insufficient knowledge is available to recommend steps to reduce AD in our ageing populations. Although not 'the cause', considerable evidence implicates human ingestion of aluminium as a possible risk factor for the expression of dementia of the Alzheimer type. A recent epidemiological study in Ontario relating the incidence of AD to aluminium in drinking water strongly supports this conclusion. To test further the hypothesis that aluminium may play a role in the pathogenesis of AD we conducted a clinical trial employing the trivalent metal ion binding compound, desferrioxamine. The design was a two-year randomized trial with behavioural assessments blinded to study assignment. Sixty-three patients with probable AD were selected who were living at home and were under 74 years. Forty-eight signed an informed consent and completed all initial testing. The main outcome measure was a video-recorded home-behavioural assessment of measures of skills of daily living. The principal outcome was that the mean slope for performance of the skills of daily living for the group without treatment was -1.72% maximum score/month, compared to -0.87% maximum score/month for the group treated with desferrioxamine (P = 0.038). Considerable evidence supports the hypothesis that aluminium has an active role in the pathogenesis of AD.

Increased serum neopterin levels in adults with Down syndrome

We quantitated serum neopterin levels in Down syndrome (DS), normal controls, Alzheimer's disease, multiple sclerosis and other neurological diseases. We then analyzed the relationships with age, sex, apolipoprotein E (Apo E) phenotype, and amyloid beta protein 1-40 (Abeta40) and 1-42 (Abeta42) levels. Neopterin levels were higher in DS than all other groups. Levels in young DS (< 40 years of age) and old DS (> 41 years) were similar. There was no significant correlation between neopterin levels and age, sex, Apo E phenotype, and Abeta40 or Abeta42 levels in DS. This lack of correlation between neopterin and Abeta levels suggests that the higher neopterin concentrations in DS group reflect inflammatory cell activation rather than AD neuropathology.

Relation between apolipoprotein E genotype, hepatitis B virus status, and thyroid status in a sample of older persons with Down syndrome

Dementia of the Alzheimer type (DAT) is common in older persons with Down syndrome (DS). There are three common alleles of the apolipoprotein E (ApoE) gene (Sigma 2, Sigma 3, and Sigma 4) resulting in three different isoforms (E2, E3, and E4) and six different genotypes (2,2; 2,3; 2,4; 3,3; 3,4; and 4,4). Sigma 4 is a risk factor for DAT whereas Sigma 2 appears prophylactic. As hepatitis B virus (HBV) infection and hypothyroidism also are common in DS, we evaluated associations between ApoE type, HBV status, and thyroid status in a sample of older persons with DS (n = 55; mean age, 44.3 +/- 10.8 years) using chi-squared analysis. Participants were classified as E2 (2,2 or 2,3), E3 (3,3), or E4 (3,4 or 4,4); positive for markers of HBV infection in the present or past (i.e., total HBcAb+ and/or HBsAg+ with or without infectivity, defined as HBV+) or negative for markers of HBV infection (defined as HBV-) and, currently receiving thyroid hormone supplement (defined as "hypothyroidism") or having normal thyroid function. The majority of the HBV+ were currently HBcAb+ and HBsAb+, but not HBsAg+. In females, there was an ApoE allele effect on thyroid status (P < or = 0.01), E2 being negatively (P < or = 0.01) and E4 being positively (P < or = 0.05) associated with "hypothyroidism". There was no evidence for an ApoE allele effect on thyroid status in males. There was no evidence for an ApoE allele effect on HBV status, or for an HBV status effect on thyroid status. As thyroid status can affect cognitive function, ApoE allele effects in DAT may, in part, be thyroid effects.

Plasma amyloid beta protein 1-42 levels are increased in old Down Syndrome but not in young Down Syndrome

Plasma amyloid beta protein 1-40 (Abeta40) and Abeta42 levels were quantitated from 28 young Down syndrome (DS) (20-40 years old), 28 age-matched controls, 32 old DS (41-65 years old) and 32 age-matched controls in a sandwich enzyme-linked immunosorbent assay. Abeta40 levels were higher in young DS and old DS than controls. Abeta42 levels in young DS and controls were similar, however Abeta42 levels were higher in old DS than controls or young DS. The higher Abeta42 levels in old DS suggests that Abeta42 is selectively increased in plasma concurrently with the development of Alzheimer disease neuropathology.

Are hereditary hemochromatosis mutations involved in Alzheimer disease?

Mutations in the class I-like major histocompatibility complex gene called HFE are associated with hereditary hemochromatosis (HHC), a disorder of excessive iron uptake. We screened DNA samples from patients with familial Alzheimer disease (FAD) (n = 26), adults with Down syndrome (DS) (n = 50), and older (n = 41) and younger (n = 52) healthy normal individuals, for two HHC point mutations-C282Y and H63D. Because the apolipoprotein E (ApoE) E4 allele is a risk factor for AD and possibly also for dementia of the AD type in DS, DNA samples were also ApoE genotyped. Chi-squared analyses were interpreted at the 0.05 level of significance without Bonferroni corrections. In the pooled healthy normal individuals, C282Y was negatively associated with ApoE E4, an effect also apparent in individuals with DS but not with FAD. Relative to older normals, ApoE E4 was overrepresented in both males and females with FAD, consistent with ApoE E4 being a risk factor for AD; HFE mutations were overrepresented in males and underrepresented in females with FAD. Strong gender effects on the distribution of HFE mutations were apparent in comparisons among ApoE E4 negative individuals in the FAD and healthy normal groups (P < 0.002). Our findings are consistent with the proposition that among ApoE E4 negative individuals HFE mutations are predisposing to FAD in males but are somewhat protective in females. Further, ApoE E4 effects in our FAD group are strongest in females lacking HFE mutations. Relative to younger normals there was a tendency for ApoE E4 and H63D to be overrepresented in males and underrepresented in females with DS. The possibility that HFE mutations are important new genetic risk factors for AD should be pursued further.

Prevalence of dementia and impact on intellectual disability services

In a statewide survey, dementia was found in 3% of adults age 40+; 6%, age 60+; and 12%, age 80+. Among adults with Down syndrome, the rates were 22% for adults age 40+ and 56% for adults age 60+. Observed onset occurred in the mid-60s (early 50s for those with Down syndrome). Alzheimer-type dementia was the most frequent diagnosis. With the occurrence of dementia expected to rise proportionately with the increase of longevity among adults with intellectual disabilities, care systems will have to raise the "index of suspicion" among staff and families, become "dementia capable," and improve their diagnostic and technical resources, as well as their care management supports designed to prolong the "aging in place" of adults affected by dementia.

Increased levels of tau-like protein in patients with Down syndrome

Tau-like protein levels from 40 Down syndrome (DS) persons (31-70 years old), 40 non-DS age-matched normal controls, 18 non-DS mentally retarded (MR) persons (26-91 years old), 25 probable Alzheimer disease (AD) patients (55-99 years old) and 24 non-demented elderly controls (54-79 years old) were measured using a sandwich enzyme linked immunosorbent assay. The levels were detected in 22 of 40 DS persons and were significantly higher in DS than any other group (P < 0.0001). There was no relationship between tau-like protein levels and age, gender or apolipoprotein E phenotypes in any of the five groups.

Mortality and morbidity among older adults with intellectual disability: health services considerations

PURPOSE

Described is a study of the mortality and morbidity characteristics of 2752 adults with intellectual disability, age 40 and older, who died over a 10 year period in one American state.

RESULTS

The main finding was that although individuals in the current generation of older adults with intellectual disability still generally die at an earlier age than do adults in the general population (average age at death: 66.1 years), many adults with intellectual disability live as long as their age peers in the general population. The results suggest that the longevity of adults with intellectual disability, whose aetiology is not attributable to organic causes, is progressively increasing. The results also confirm an increased longevity for adults with Down syndrome (average age at death: 55.8 years). Findings also showed that the causes of death for the study cohort were similar to those of the general older population, with cardiovascular, respiratory and neoplastic diseases among the most prominent causes of death.

CONCLUSIONS

It was proposed that clinical and prophylactic health practices could have significant social and health care consequences for delaying the onset or minimizing the occurrence of life threatening diseases (and thus prolonging life) in adults with intellectual disability. It was suggested that clinical practices could be implemented that deter the onset and lessen the impact and burden of older age-related diseases and secondary conditions and that greater attention needs to be given to training of health care professionals in the area of geriatric medicine and intellectual disability.

Increased plasma amyloid beta protein 1-42 levels in Down syndrome

Amyloid beta protein 1-40 (A beta40) and A beta42 levels were quantitated in plasma from 43 persons with Down syndrome (DS; 26-68 years of age), 43 age-matched normal controls, and 19 non-DS mentally retarded (MR) persons (26-91 years of age) by using a sandwich enzyme linked immunosorbent assay. A beta40 levels were higher in DS and MR than controls, but were similar between DS and MR groups. A beta42 levels were higher in DS than controls or MR persons. The ratios of A beta42/A beta40 were higher in DS than controls or MR persons. The findings are consistent with those seen in DS brains.

Immunoglobulin G subclasses in older persons with Down syndrome

IgG subclasses were measured in sera from 33 persons with Down syndrome (DS) (mean age 55 +/- 7 years) and 33 age- and sex-matched control individuals using a mouse monoclonal antibody based sandwich enzyme linked immunosorbent assay. Significantly higher levels of IgG1 and IgG3 and lower levels of IgG2 and IgG4 subclasses were found in the DS group compared to the control individuals. The higher levels of IgG1 and IgG3 subclasses found in DS persons were consistent with those seen in patients with autoimmune diseases and chronic viral infections; the lower levels of IgG2 and IgG4 subclasses were consistent with those seen in patients with recurrent infections. Our findings are similar to those reported in children with DS. We speculate that the subclass levels may have little or no relationship to the development of brain lesions typical of Alzheimer disease in older persons with DS. There were no significant differences between the levels of IgG subclasses of persons with DS showing signs of dementia of the Alzheimer type compared to those without such manifestations.

Age-associated chromosome 21 loss in Down syndrome: possible relevance to mosaicism and Alzheimer disease

We previously observed low level mosaicism (2-4% normal cells) in phytohemagglutinin-stimulated peripheral blood lymphocytes (PBL) in 29% of a small group of elderly persons with Down syndrome (DS). An analysis of cytogenetic data on 154 trisomy 21 cases (age 1 day to 68 years) showed that the proportion of diploid cells in such cultures significantly increased (P < 0.005) with advancing age. Thus, the "occult" mosaicism in PBL of the elderly persons with DS is likely due to the accumulation of cells that have lost a chromosome 21. A consequence of chromosome 21 loss could be uniparental disomy of the 2n cells, a factor that might have significant biological consequences if some chromosome 21 genes are imprinted. Loss of a chromosome 21 from trisomic cells might result in tissue-specific mosaicism and "classical" mosaicism in different age groups. Chromosome 21 loss might also be relevant to the development of Alzheimer-type dementia in DS and in the general population.

Lessons from the United Kingdom: fightback on workplace hazards, 1979-1992

For the past 13 years there has been an aggressive anti-union government in the United Kingdom. Yet despite this fact, very real advances have been made in the area of working-class activity over the issue of workplace hazards. Trade unions, because of membership concern and activity, have been forced to keep this topic on their agenda. The European Community has been a big factor in these advances. This article describes some of the issues and elements of the fightback. In the 1990s, with the rediscovery of environmental issues, the hazards movement of the United Kingdom, and elsewhere, is here to stay and set to expand.

Intramuscular desferrioxamine in patients with Alzheimer's disease

Although epidemiological and biochemical evidence suggests that aluminium may be associated with Alzheimer's disease (AD), there is no convincing proof of a causal link for aluminium in disease progression. We have completed a two year, single-blind study to investigate whether the progression of dementia could be slowed by the trivalent ion chelator, desferrioxamine. 48 patients with probable AD were randomly assigned to receive desferrioxamine (125 mg intramuscularly twice daily, 5 days per week, for 24 months), oral placebo (lecithin), or no treatment. No significant differences in baseline measures of intelligence, memory, or speech ability existed between groups. Activities of daily living were assessed and videorecorded at 6, 12, 18, and 24 month intervals. There were no differences in the rate of deterioration of patients receiving either placebo or no treatment. Desferrioxamine treatment led to significant reduction in the rate of decline of daily living skills as assessed by both group means (p = 0.03) and variances (p less than 0.04). The mean rate of decline was twice as rapid for the no-treatment group. Appetite (n = 4) and weight (n = 1) loss were the only reported side-effects. We conclude that sustained administration of desferrioxamine may slow the clinical progression of the dementia associated with AD.

Autoimmune thyroiditis associated with mild "subclinical" hypothyroidism in adults with Down syndrome: a comparison of patients with and without manifestations of Alzheimer disease

Serum tests of thyroid function were compared in Down syndrome (DS) patients with and without manifestations of Alzheimer disease (AD). Relative to control individuals, DS patients had, overall, lower mean total T4 (P = 0.070) and T3f (P = 0.015), higher T3U (P = 0.013) and TSH (P = 0.020), no difference in free T4, and higher thyroid antithyroglobulin (ATA) (P = 0.033) and antimicrosomal autoantibody (AMA) titres (P = 0.0097). Similar trends were apparent in DS males and females, and in DS patients off all drugs. In an analysis of case/control pairs with corrections for age and sex, DS patients with AD manifestations (n = 9) had significantly lower T3 (P = 0.029) and higher AMA (P = 0.043) than paired control individuals, whereas DS patients without AD manifestations (n = 20) had significantly lower T3 (P = 0.013) but higher ATA (P = 0.0065). T3 was significantly lower in the DS patients with AD manifestations than in the unaffected (P = 0.0013). These data suggest that autoimmune thyroiditis associated with a mild "subclinical" form of hypothyroidism is common in adult DS patients and more pronounced in patients with AD manifestations than in those without. This "subclinical" hypothyroidism may contribute to cognitive deficits in ageing DS patients.

Red cell superoxide dismutase, glutathione peroxidase and catalase in Down syndrome patients with and without manifestations of Alzheimer disease

The activities of red blood cell enzymes that scavenge the superoxide radical and hydrogen peroxide were measured in severely to profoundly retarded adult Down syndrome (DS) patients with and without manifestations of Alzheimer disease (AD), and control individuals matched for sex, age, and time of blood sampling. Cu,Zn superoxide dismutase (SOD-1) and glutathione peroxidase (GSHPx) activities were significantly elevated (1.39-fold and 1.24-fold, respectively) in DS individuals without AD. When an adjustment was made for the SOD gene dosage effect, DS patients with AD manifestations had significantly lower SOD levels than the matched control individuals. In contrast, DS patients with and without AD had a similar elevation in GSHPx (an adaptive phenomenon). The mean catalase (CAT) activity was no different in DS and control individuals; however, in a paired regression analysis, DS patients without AD had marginally lower CAT activity than control individuals, whereas DS patients with AD had slightly but not significantly higher CAT activity. Thus, AD manifestations in this DS population are associated with changes in the red cell oxygen scavenging processes.

Aluminium and calcium in soil and food from Guam, Palau and Jamaica: Implications for amyotrophic lateral sclerosis and parkinsonism-dementia syndromes of Guam

Low calcium and high aluminium concentrations in the soils, waters and native foods have been hypothesised as environmental factors contributing to the unusually high incidence of amyotrophic lateral sclerosis and parkinsonism with dementia (ALS-PD) found on the island of Guam. The amounts of elemental aluminium and calcium were measured in foods of the native diet of the Chamorro people of Guam. The amount of aluminium eluted from topsoil by water at pH 7 at 22 °C was also measured. For comparison, food, water and soil samples were collected from two islands which have not reported a high incidence of ALS-PD syndromes: Palau and Jamaica.Compared with agricultural soils of Jamaica or Palau, the agricultural soils of Guam averaged 42-fold higher yield of elutable aluminium. The food data, however, do not indicate a differentially high exposure to elemental aluminium or low calcium intake in the diet of any one population. While this study did not detect an unusually high dietary aluminium or low dietary calcium content, the soils and possibly the dusts of Guam may be a major source of aluminium entering the body of the native people, particularly through the respiratory epithelium. Since iipid soluble organic ligands of aluminium more readily penetrate epithelial membranes, further study of soil aluminium ligands is required.

Clinical expression of Alzheimer's disease in Down's syndrome

Reports of the clinical manifestations of dementia in persons with Down's syndrome have been conflicting. Neuropathologic studies have been inconsistent with the clinical picture in many cases. Clarification of these issues requires longitudinal studies of patients combined with postmortem studies of brain tissue.

Alzheimer's disease in Down's syndrome: clinicopathologic studies

Clinical and neuropathologic evidence points to the development of Alzheimer's disease (AD) in seven Down's syndrome patients above age 40. Dementia was observed in these patients over periods of 2.5 to 9.2 years. The first clinical sign of AD, visual memory loss, was succeeded by impaired learning capacity and decreased occupational and social functioning, and culminated in seizures and urinary incontinence. The morphometric observations of the brains of these seven patients with AD showed that the numbers of plaques and tangles exceeded 20 per 1.5 X 10(6) microns2 area, in both the prefrontal and hippocampal cortices. Plaques and tangles were also evident in the basal ganglia, thalamus, hypothalamus, and midbrain. In addition, we found that four of the seven brains showed small strokes, and five of the seven amyloid angiopathy. This study also indicates that by longitudinal neuropsychological evaluations and lab tests, which exclude other causes of dementia, the diagnosis of AD can be made even in severely and profoundly retarded patients.

Intranuclear aluminum content in Alzheimer's disease, dialysis encephalopathy, and experimental aluminum encephalopathy

Nuclear and chromatin fractions were prepared from cerebral cortex of 34 human and 37 animal brains. Chromatin was separated into a heavy heterochromatin fraction and two euchromatin fractions: intermediate euchromatin and light euchromatin. Compared to age-matched controls, aluminum content expressed per gram of DNA was significantly increased in nuclear and heterochromatin fractions in pre-senile Alzheimer's disease. In contrast nuclear preparations from brains of patients who had died with dialysis encephalopathy contained less aluminum than controls, although whole tissue concentrations were elevated ten to fifteen times above the control concentrations. Direct injection of aluminum into the cerebrospinal fluid of cats resulted in a progressive encephalopathy with neurofibrillary degeneration and increased intranuclear aluminum content. It is speculated that in Alzheimer's disease the normal blood-brain and cytoplasmic barriers for this neurotoxic metal are defective permitting aluminum to gain access to DNA-containing constitutents of the nuclei.

Morphologic evidence for retrovirus production by epithelial cells derived from a human testicular tumor metastasis

Ultrastructural examination of primary and subcultured epithelial cells established in vitro from an abdominal metastasis of a human testicular tumor revealed particles with the morphology of retroviruses. These structures, found only after extensive scanning of the cells, were observed budding from microvilli and from the outer cell membrane and as extracellular particles. Production of these virus particles was stimulated by the incubation of cells in culture medium containing 5-iodo-2'-deoxyuridine and dexamethasone.

Xenotropic properties of an isolate from murine Rauscher leukemia virus in primates

Murine Rauscher leukemia virus (MuRLV) from BALB/c plasma consisting of a mixture of an ecotropic and a xenotropic virus could be separated out by a selection process when propagated in human and simian cell cultures. This hypothesis is supported by obtaining consistently lower infectivity titers of human cell propagated RLV in human and simian cells as compared to MuRLV propagated in mouse cell cultures. Furthermore, RLV passaged in a simian cell culture failed to replicate in mouse cells, had a wide host range, was able to rescue Moloney sarcoma genome, possessed murine type C group-specific antigen, and was neutralized by anti-HRLV. Its reverse transcriptase was strongly inhibited by antiserum to MuRLV enzyme; however, antiserum to woolly monkey enzyme also inhibited (30%) its reverse transcriptase, suggesting some difference in antigenic properties. Inoculation of this virus in rhesus monkeys was inconclusive.

Oncorna-like viruses in baboon prostate tissue

Oncorna-like virus particles were observed in prostate tissue of 2 of 11 baboons inoculated 3 years previously with a chemical carcinogen. There were no indications, however, of any relationship between the carcinogen and the development of virus particles. Biopsy specimens from the animals showed no evidence of neoplasia, and electron microscopic examination suggested that this virus should be categorized as a B-type oncornavirus.

Alzheimer degeneration in Down syndrome. Electrophysiologic alterations and histopathologic findings

Progressive electroencephalographic disorganization and decreased voltage amplitude in the late components of the averaged visual evoked potentials were recorded in the last two years of life of a patient with Down disease and Alzheimer degeneration. Taken together with quantitative histopathologic findings, the electrophysiologic alterations are interpreted in terms of recent evidence from an experimental animal model of dementia. Neurons with neurofibrillary degeneration become electrically inactive and contribute to the loss of voltage generators associated with neuron death in Alzheimer disease. Loss of voltage generators may result in disfacillitation and disinhibition of surviving neurons, thus causing the loss of normal rhythms.

Microvesicles and vesicles of multivesicular bodies versus "virus-like" particles

Pellets obtained by the centrifugation of unfiltered or filtered fetal bovine serum (FBS) contained, among other things, numerous elongate and spherical microvesicles, ranging from 30 to 60 nm. They possessed a trilaminar (unit membrane) envelope and a moderately electron-dense core. Vesicles of multivesicular bodies and microvesicles associated with secretory epithelial cells and human lymphoblastoid cells in suspension culture possessed the same structure and were in the same size range as the serum microvesicles. These structures were either normal cell components or they represented the breakdown products of normal cell components and should not be confused with viruses. Though microvesicles of FBS may have been involved in the tissue culture material, at least some of the microvesicles associated with, and phagocytosed by, human lymphoblastoid cells in suspension and those in the lumen of acini of the baboon prostate were derived from the breakdown of the cristae of mitochondria in degenerating cells.