Models of environmentally induced neurological disease: epidemiology and etiology of amyotrophic lateral sclerosis and parkinsonism-dementia in the Western Pacific

Water assessment of the Itapemirim River/Espírito Santo (Brazil): abiotic and toxicogenetic aspects

The Itapemirim River is considered one of the most important water resources in the state of Espírito Santo, Brazil. However, environmental problems due to continuous anthropogenic contamination are threatening its potential use. This study assessed water quality by analyzing abiotic and toxicogenetic aspects of the water from four stations along the river. Samples were collected in both dry and rainy seasons. Most of the abiotic variables were below the threshold established by CONAMA Resolution No. 357/2005, and so were most of the metals. However, Al and Cu contents were above those allowed by legislation, ranging from 0.2 to 0.9 mg/L. Regarding toxicogenetic aspects, genotoxic effects were observed in meristematic cells of Allium cepa, in micronucleus test and comet assay of Oreochromis niloticus, and CHO-K1 cells. Mutagenic effects were significant at RI 02 (0.34), RI 03 (0.46), and RI 04 (0.12) stations on the first campaign in A. cepa F1 cells, compared to the negative control (0.0). The second campaign revealed the same results, but with the addition of samples from RI 01 (0.17) and RI 03 (0.18) showing mutagenicity in the micronucleus test with fish erythrocytes when compared to the negative control (0.3). Essentially, all the samples evaluated in both campaigns showed damage in A. cepa, O. niloticus, and CHO-K1 cells, thus demonstrating that the water quality of the Itapemirim River is compromised and requires action plans for its recovery.

Alzheimer's Disease and its Related Dementias among Asian Americans, Native Hawaiians, and Pacific Islanders: A Scoping Review

BACKGROUND

The Asian American, Native Hawaiian, and Pacific Islander (AANHPI) aging population is rapidly growing and the burden of Alzheimer's disease and its related dementias (ADRD) will likely mirror this demographic growth. AANHPIs face significant barriers in obtaining timely ADRD diagnosis and services; yet little is known about ADRD in this population.

OBJECTIVE

The study objective is to conduct a systematic review on the published literature on ADRD among AANHPIs to identify gaps and priorities to inform future research and action plans.

METHODS

The systematic review was conducted following the PRISMA Protocol for Systematic Reviews. Co-author (TR), an experienced Medical Librarian, searched PubMed, EMBASE, PsycINFO, Cochrane Central of Clinical Trials, Ageline, and Web of Science for peer-reviewed articles describing ADRD among AANHPIs. The search was not limited by language or publication date. Each citation was reviewed by two trained independent reviewers. Conflicts were resolved through consensus.

RESULTS

The title/abstract and full texts of 1,447 unique articles were screened for inclusion, yielding 168 articles for analysis. Major research topics included prevalence, risk factors, comorbidities, interventions and outreach, knowledge and attitudes, caregiving, and detection tools. A limited number of studies reported on national data, on NHPI communities generally, and on efficacy of interventions targeting AANHPI communities.

CONCLUSION

To our knowledge, this is the first systematic review on ADRD among AANHPI populations. Our review provides a first step in mapping the extant literature on ADRD among this underserved and under-researched population and will serve as a guide for future research, policy, and intervention.

50 years of research on α-amino-β-methylaminopropionic acid (β-methylaminoalanine)

The isolation of α-amino-β-methylaminopropionic acid from seeds of Cycas circinalis (now C. micronesica Hill) resulted from a purposeful attempt to establish the cause of the profound neurological disease, amyotrophic lateral sclerosis/parkinsonism/dementia, that existed in high frequency amongst the inhabitants of the western Pacific island of Guam (Guam ALS/PD). In the 50 years since its discovery the amino acid has been a stimulus, and sometimes a subject of mockery, for generations of scientists in a remarkably diverse range of subject areas. The number of citations of the original paper has risen in the five decades from a few to 120 within the decade 2007-2016 and continues at a high rate into the next decade. The reasons for this remarkable outcome are discussed and examples from the literature are used to illustrate the wide range of scientific interest that the original paper generated.

Cytotoxic and phytotoxic effects of the main chemical components of spent pot-liner: a comparative approach

Spent pot-liner (SPL) is a hazardous solid waste produced by the aluminum industry. Although its composition may vary, fluoride and cyanide salts as well as aluminum are predominant components. A seed-germination and root-elongation test was performed with Lactuca sativa seeds as a test system. SPL induced decrease of seed germination rate and root elongation. The concentration of 26.5g/L SPL was established from a regression curve as the IC50 (inhibition concentration 50%). Through chemical analyses, the concentrations of fluoride, cyanide and aluminum in SPL solutions of 26.5g/L (IC50), 39.75g/L (1.5IC50) and 13.25g/L (0.5IC50) were determined. Further, a cell-cycle test was conducted with root tips of L. sativa exposed to these same SPL solutions. All test chemicals presented toxic effects on meristematic cells of L. sativa. Aluminum was identified as the SPL component mainly responsible for reduction of the mitotic index. Chromosomal alterations resulted from the interactions among the three main chemical components of SPL, without a clear predominantly responsible agent. Induction of condensed nuclei was mainly due to effects of aluminum and fluoride, and may serve as an indicator of induced cell death.

Equilibrium, kinetic and thermodynamic studies on aluminum biosorption by a mycelial biomass (Streptomyces rimosus)

This work focused on kinetic, equilibrium and thermodynamic studies on aluminum biosorption by Streptomyces rimosus biomass. Infrared spectroscopy analysis shows that S. rimosus present some groups: hydroxyl, methyl, carboxyl, amine, thiol and phosphate. The maximum biosorption capacity of S. rimosus biomass was found to be 11.76 mg g(-1) for the following optimum conditions: particle size, [250-560] μm, pH 4-4.25, biomass content of 25 g L(-1), agitation of 250 rpm and temperature of 25 °C. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms at free pH (pH(i) 4) and fixed pH (pH(f) 4). Langmuir model is the most adequate. With fixed pH, the maximum biosorption capacity is enhanced from 6.62 mg g(-1) to 11.76 mg g(-1). The thermodynamic parameters (ΔG°, ΔH° and ΔS°) showed the feasibility, endothermic and spontaneous nature of the biosorption at 10-80 °C. The activation energy (Ea) was determined as 52.18 kJ mol(-1) using the Arrhenius equation and the rate constant of pseudo-second-order model (the most adequate kinetic model). The mean free energy was calculated as 12.91 kJ mol(-1) using the D-R isotherm model. The mechanism of Al(III) biosorption on S. rimosus could be a chemical ion exchange and carboxyl groups are mainly involved in this mechanism.

Therapeutic effect of the combined use of growth hormone releasing peptide-6 and epidermal growth factor in an axonopathy model

Amyotrophic lateral sclerosis (ALS) is a disease of the central nervous system characterized by loss of spinal motor neurons, for which no effective treatment exists. Epidermal growth factor (EGF) and growth hormone releasing peptide-6 (GHRP-6) have been considered as good candidates for the treatment of this disease, due to their well documented effects in eliciting pleiotrophic and cell survival mechanisms. The aim of the present work was to evaluate the separate and combined effects of both peptides in an experimental animal model of ALS, the proximal axonopathy induced by 1,2 diacetylbenzene (1,2 DAB) in mice. The evaluations were conducted by means of behavioral tests (trapeze, tail suspension, gait pattern, and open field) and by recording the complex muscle action potential (CMAP) in three different hind limb segments: proximal S1, medial S2, and distal S3. Intraperitoneal daily administration of 1,2 DAB produced significant reduction in body weight, muscle strength, extensor reflex, spontaneous activity, and changes in gait pattern parameters. In parallel 1,2 DAB produced significant prolongation of onset latency and decrease in amplitude of CMAP and in the integrated complex action potential index. Daily administration of the separate compounds did not accelerate the recovery of the affected parameters, except for the gait pattern. The combined treatment produced significant improvement in behavioral parameters, as well as in electrophysiological recovery, particularly in the proximal segment of CMAP. The latter results confirm the proximal character of 1,2 DAB neuropathy, and suggest that combined therapy with EGF and GHRP-6 might be a good therapeutic strategy for the treatment of ALS.

Aluminium and Alzheimer's disease

The hypothesis that aluminium (Al) is a cause of (or a risk factor in) the development of beta-amyloid plaques and neurofibrillary tangles (NFT) and dementia in Alzheimer's disease (AD) is based on studies by Wisniewski et al, Klatzo et al and Terry & Peña in 1965 that showed that injection of experimental animals with Al compounds induces the formation of NFT. Other publications revealed that Al affects cognitive functions in experimental animals and humans undergoing dialysis for renal failure. Electron probe and laser microprobe mass analysis (LAMMA) studies have demonstrated the presence of Al in NFT and cores of amyloid stars and nuclei of neurons in AD patients. Other studies have indicated the association between amyotrophic lateral sclerosis/Guam parkinsonism-dementia complex and Al in the environment. A recent report suggests that the chelating agent desferrioxamine slows the rate of cognitive decline in AD patients. Extensive studies of the pathology of AD and Al-induced encephalopathy by our group and others indicate that Al does not cause Alzheimer's disease neuropathology. However, under certain conditions, cognition can be affected when Al enters the brain. Therefore, for individuals with renal failure or undergoing dialysis or individuals with a damaged blood-brain barrier, the intake of Al should be controlled.

A case of amyotrophic lateral sclerosis in electronic parts manufacturing worker exposed to lead

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting the motor neurons of the spinal cord and brain. Although the definite etiology of ALS remains unclear, occupational or environmental exposures have been considered as one of the potential causes of ALS. Here, we report the case of a patient with ALS who used to work in a factory manufacturing electronic parts and has evidence of acute exposure to lead in excess. A 39-year-old man visited a neurology clinic with symptoms of progressive limb weakness and spasticity, which began 2 years ago. Upon neurological examination, symptoms of atrophy, spasticity and fasciculation of the lower extremities were evident. There were no signs of impairment of the cranial nerves, and cognitive and sensory functions were normal. Complete blood counts, blood chemistries and urinalysis were normal. Serial electromyography showed progressive denervative changes, which were consistent with motor neuron diseases. ALS was diagnosed according to the standard of the "Diagnostic criteria of the World Federation of Neurology". The patient was handling lead oxide (PbO) for development of positive temperature coefficient (PTC) thermist, without being provided with proper respiratory protective equipment. Blood lead level of the patient was measured at 30.86 microg/dL 6 months after he quit his job. Bone lead levels from X-ray fluorescence (XRF) were below the normal range (3 ppm). Blood lead level of his co-workers at the same workplace were above the ACGIH recommended biological exposure index (BEI: 30 microg/dL). We speculated that the ALS in this case was related to excessive exposure to lead.

Neurodegenerative diseases and risk factors: a literature review

Degenerative diseases of the central nervous system are significant causes of mortality among elderly people in industrialized countries. For the most part, the causes of these diseases are unknown. It is also very difficult to diagnose this type of disease quickly and accurately. This article reviews the epidemiological research on the principal neurodegenerative disorders, focusing on geographical, hereditary and viral and toxicological exposure correlates. We look in particular at the effect of exposure to toxins as well as the effect that deficiencies of elements such as calcium and selenium could have on the development of these neurological diseases. We also consider the possible protectionist effect of some variables on the development of certain neurological diseases.