Transcription, structure, and organoids translate time across the lifespan of humans and great apes.

How the neural structures supporting human cognition developed and arose in evolution is an enduring question of interest. Yet, we still lack appropriate procedures to align ages across primates, and this lacuna has hindered progress in understanding the evolution of biological programs. We generated a dataset of unprecedented size consisting of 573 time points from abrupt and gradual changes in behavior, anatomy, and transcription across human and 8 nonhuman primate species. We included time points from diverse human populations to capture within-species variation in the generation of cross-species age alignments. We also extracted corresponding ages from organoids. The identification of corresponding ages across the lifespan of 8 primate species, including apes (e.g., orangutans, gorillas) and monkeys (i.e., marmosets, macaques), reveals that some biological pathways are extended in humans compared with some nonhuman primates. Notably, the human lifespan is unusually extended relative to studied nonhuman primates demonstrating that very old age is a phase of life in humans that does not map to other studied primate species. More generally, our work prompts a reevaluation in the choice of a model system to understand aging given very old age in humans is a period of life without a clear counterpart in great apes.

Going beyond established model systems of Alzheimer's disease: companion animals provide novel insights into the neurobiology of aging.

Alzheimer's disease (AD) is characterized by brain plaques, tangles, and cognitive impairment. AD is one of the most common age-related dementias in humans. Progress in characterizing AD and other age-related disorders is hindered by a perceived dearth of animal models that naturally reproduce diseases observed in humans. Mice and nonhuman primates are model systems used to understand human diseases. Still, these model systems lack many of the biological characteristics of Alzheimer-like diseases (e.g., plaques, tangles) as they grow older. In contrast, companion animal models (cats and dogs) age in ways that resemble humans. Both companion animal models and humans show evidence of brain atrophy, plaques, and tangles, as well as cognitive decline with age. We embrace a One Health perspective, which recognizes that the health of humans is connected to those of animals, and we illustrate how such a perspective can work synergistically to enhance human and animal health. A comparative biology perspective is ideally suited to integrate insights across veterinary and human medical disciplines and solve long-standing problems in aging.

Evolutionary and genomic perspectives of brain aging and neurodegenerative diseases.

This chapter utilizes genomic concepts and evolutionary perspectives to further understand the possible links between typical brain aging and neurodegenerative diseases, focusing on the two most prevalent of these: Alzheimer's disease and Parkinson's disease. Aging is the major risk factor for these neurodegenerative diseases. Researching the evolutionary and molecular underpinnings of aging helps to reveal elements of the typical aging process that leave individuals more vulnerable to neurodegenerative pathologies. Very little is known about the prevalence and susceptibility of neurodegenerative diseases in nonhuman species, as only a few individuals have been observed with these neuropathologies. However, several studies have investigated the evolution of lifespan, which is closely connected with brain size in mammals, and insights can be drawn from these to enrich our understanding of neurodegeneration. This chapter explores the relationship between the typical aging process and the events in neurodegeneration. First, we examined how age-related processes can increase susceptibility to neurodegenerative diseases. Second, we assessed to what extent neurodegeneration is an accelerated form of aging. We found that while at the phenotypic level both neurodegenerative diseases and the typical aging process share some characteristics, at the molecular level they show some distinctions in their profiles, such as variation in genes and gene expression. Furthermore, neurodegeneration of the brain is associated with an earlier onset of cellular, molecular, and structural age-related changes. In conclusion, a more integrative view of the aging process, both from a molecular and an evolutionary perspective, may increase our understanding of neurodegenerative diseases.

The Legionella pneumophila prp locus; required during infection of macrophages and amoebae.

Transposon mutagenesis was performed using mTn 10phoA to identify Legionella pneumophila genes that are expressed under certain in vitro conditions, and are required for intracellular replication. Of the 1653 PhoA fusions examined, 19 PhoA(+)fusion mutants were isolated and screened for differential expression of fusion proteins after growth at 30 or 37 degrees C, in the presence of low iron, or increased magnesium concentrations. The mutants were examined for their cytopathogenicity and intracellular replication within U937 macrophage-like cells and the protozoan Hartmannella vermiformis. One of the mutants generated, BS10, was defective in its multiplication within U937 macrophage-like cells and H. vermiformis. The defect in BS10 was complemented with a cosmid clone containing the wild type locus. The open reading frame interrupted by the insertion was homologous to prpD of Salmonella typhimurium and mmgE of Bacillus subtilis.

Toxic shock syndrome presenting as postoperative diarrhea in a postmenopausal woman.

Three days after laminectomy, toxic shock syndrome (TSS) presented as acute diarrhea, rash, and fever in a 62-year-old postmenopausal woman. Forty-eight hours later, the full syndrome of TSS developed. Exploration of a benign-appearing wound revealed an occult Staphylococcus aureus infection. This report and literature review underscore the need to consider TSS in the differential diagnosis of acute diarrhea regardless of age, sex, race, and menstrual status, particularly when there has been recent soft tissue infection, injury, or surgery of any type.

Human antibody-dependent cellular cytotoxicity. Isolation and identification of a subpopulation of peripheral blood lymphocytes which kill antibody-coated autologous target cells.

Antibody-dependent cellular cytotoxicity (ADCC), has been shown to be independent in vitro of thymus-derived lymphocytes, but the precise nature of the effector lymphocyte has not been fully clarified. To further study the identity of the ADCC effector cell type(s), peripheral blood leukocytes were purified by Ficoll-Hypaque density centrifugation and fractionated into surface immunoglobulin-positive [Ig(+)] and surface immunoglobulin-negative [Ig(-)] populations by chromatographic separation on Sephadex G-200 anti-human immunoglobulin columns. After column fractionations, the ADCC effector activity against antibody-coated autologous lymphocytes was predominantly and consistently found in the Ig(-) fraction. This latter population was then further fractionated, by rosetting techniques, into two subpopulations, The first was depleted by lymphocytes with surface receptors for sheep red blood cells [E(+)]and the second was depleted of lymphocytes with receptors for sheep red blood cell-antibody-complement [EAC-(+)]. Analysis of these populations showed that ADCC effector activity was predominantly a property of the Ig(-) lmyphocytes which are E(-) but EAC(+). These lymphocytes have been referred to as "null lymphocytes" and probably represent a subset of bone marrow-derived (B) cells. In addition, variable and low levels of ADCC activity were observed in some Ig(+) populations (B cells). Further purification of the null cell population by filtration over nylon wool columns to reduce the number of contaminating latex ingesting monocytes did not reduce ADCC effector activity. Isolated null cell ADCC effector activity was inhibited by either rabbit anti-human F(ab)2 or normal pooled rabbit gamma globulin, but not by rabbit F(ab)2 anti-human F)ab)2 or media. This supports the contention previously suggested in studies using unfractionated lymphocyte populations that the ADCC effector cell recognizes the Fc portion of the antibody molecule. The variable and low level of activity noted in the Ig(+) populations is unexplained but possibly due to a variable population of null cell-derived Ig(+) lymphocytes within the whole Ig(+) population. In conclusion, these experiments demonstrate that, in vitro, the major ADCC effector activity of circulating human peripheral blood lymphocytes resides in the Ig(-), E(-), EAC-(+) subpopulation termed "null cells." Since it has been noted that in certain disease states, such as immunodeficiency syndromes, autoimmune disorders, and neoplasms, the percentage of this population of lymphocytes in the peripheral blood is elevated, it is speculated that these cells, perhaps through their ADCC function, may play an important pathophysiologic role in these diseases.

Inhibition or enhancement of immunological injury of virus-infected cells.

Within hours after infection of cells with herpes simplex, vaccinia, influenza, or Newcastle disease virus, new antigens appeared on the surface of infected cells. The interaction of specific antiviral antibody and complement with these antigens resulted in cell destruction, which was quantitated by the release of (51)Cr. A number of factors can influence the degree of cell destruction, including the density of viral antigens on the surface of infected cells, the nature of the antiviral antibody, and the presence of anti-immunoglobulins. The immunological destruction of virus-infected cells may on the one hand serve as a defense mechanism against certain viral infections, while on the other hand it may contribute to the pathology of the host.

Inflammation and herpes simplex virus: release of a chemotaxis-generating factor from infected cells.

Infection of primary rabbit kidney cells with herpes simplex virus leads to the release of a cell factor or factors that upon incubation with serum results in the cleavage of the fifth component, C5, of complement. The product of this cleavage, C5a, is chemotactic for polymorphonuclear leukocytes and could be responsible for the accumulation of these cells at the site of herpetic lesions.