Self-Acceptance and Purpose in Life Are Mechanisms Linking Adverse Childhood Experiences to Mortality Risk

OBJECTIVE

Adverse childhood experiences (ACEs) are associated with an increased risk of premature mortality, but it is not clear why. Individuals with ACEs tend to have lower self-acceptance and purpose in life, which may be pathways between ACEs and risk of premature mortality. As such, we tested whether purpose and self-acceptance are mechanisms that link ACEs to mortality risk.

METHODS

We used the Midlife in the United States Survey ( N = 6218; mean [standard deviation] = 46.89 [12.94] years) to test whether these factors were indirect pathways between ACEs and mortality hazards over 24 years of follow-up. We used a comprehensive ACE measure that included 20 possible childhood adversities including emotional and physical abuse, household instability, socioeconomic climate, and ill health.

RESULTS

ACEs significantly increased mortality risk (hazard ratio = 1.028, 95% confidence interval = 1.008-1.047, p = .006). Self-acceptance and purpose accounted for an estimated 15% and 4% of the ACEs-mortality relation, respectively. These effects withstood a range of adjustments and sensitivity analyses.

CONCLUSIONS

ACEs may affect mortality risk partially through lower self-acceptance and purpose during adulthood. Given that self-acceptance and purpose may change through intervention, these factors may be useful targets for individuals with ACEs that could lead to a longer life.

CHILDHOOD ADVERSITY IMPACTS PERSONALITY DEVELOPMENT ACROSS ADULTHOOD

Throughout adulthood, people’s personalities typically change favorably such that agreeableness and conscientiousness increase, and neuroticism decreases. However, the impact of early life adversity on these changes in personality has yet to be examined. We utilized data from 6,382 community dwelling adults (ages 25–75) that completed 3-waves of the Midlife Development in the U.S. Study (MIDUS) in 1995–96, 2005–06, and 2013–14. Early life adversity was computed using 16 retrospective items assessing emotional and physical abuse, socioeconomic disadvantage, familial instability, and early-life poor health. Personality was assessed with the Big 5 MIDI measure. Latent growth curves confirmed there was significant variability in change over the ~20 year follow-up (all RMSEAS < .06; and CFI/TLI > .96). More specifically, higher levels of early adversity predicted higher initial levels of neuroticism, and lower levels of conscientiousness and extraversion. Additionally, higher adversity predicted a steeper decrease in neuroticism across 20-years (all p’s < .05). Examination of specific adversity types revealed that emotional abuse and having poor health at a young age were especially detrimental to personality development. This research provides evidence that high levels of adverse experiences in childhood predict unfavorable personality development throughout adulthood. Moreover, this research demonstrates that early life adversity, especially certain types, can have lifelong detrimental effects on development. Interventions for those who have experienced adversity should be implemented as early in life as possible to prevent suboptimal psychological development trajectories. Such interventions could improve life outcomes if personality development is more normalized.

PERSONALITY TRAITS PREDICT DIABETES RISK IN ADULTHOOD: THE MEDIATING EFFECTS OF USING FOOD TO COPE WITH STRESS

Identifying the individual characteristics that predict which adults will develop obesity and diabetes is crucial. This study included national data from 902 participants (aged 25-75) in the Midlife Development in the U.S. (MIDUS) study. Participants completed the Big-5 personality trait measure in 1995-1996, and behavior/health variables between 2004-2009. We tested whether levels of certain personality traits would predict an elevated risk of diabetes via hemoglobin A1c (HbA1c) levels through eating behaviors. A structural equation modeling framework demonstrated good fit when testing indirect effects (CFI = 0.95; RMSEA = 0.05). Indirect effects revealed that higher levels of neuroticism predicted greater waist circumference and higher HbA1c levels due to an increased use of food to cope with problems (IE =0.10; p<0.05). Moreover, indirect effects were found for conscientiousness, albeit in a protective direction. Our findings suggest that personality traits may be an early predictor of behavior and thus long-term adverse health outcomes.

ADIPOSITY CHANGE IN ADULTS: THE IMPACT OF TRAIT NEUROTICISM

Increased body weight is a risk factor for poor health and shortened life expectancy. Thus, it is imperative to understand how body weight changes across adulthood and to identify factors that predict weight gain so effective prevention strategies can be implemented. It is well-known that eating habits and physical activity are two of the most important factors (along with genetic factors) contributing to weight gain. However, we seek to determine if personality levels predict weight gain because individual differences in personality are thought to be the root-cause of many behaviors related to weight gain. We utilized longitudinal data on over 6,000 adults (aged 20-75 at baseline) from the Midlife Development in the U.S. Study (MIDUS). The Big 5 personality traits, body weight, waist circumference, and body mass index were measured three times from 1995-2015. We estimated a growth curve model to determine whether each adiposity measure changed over 20 years, controlling for age, gender, and education. There was a significant increase in all adiposity measures over time. The rate of adiposity change over time varied among persons (random: weight b = 0.543; waist b = 0.008; BMI b = 0.009; p values &lt; .05). Higher levels of neuroticism predicted this variability (fixed: weight b = 0.211; waist b = 0.027; BMI b = 0.029; p values &lt; .05) such that those scoring higher in trait neuroticism had a steeper increase in all three adiposity measures. These findings suggest that personality traits are important in the progression of weight-gain in adults.

Dépression au travail

Les problèmes psychosociaux dans le monde de l’entreprise sont de plus en plus fréquents et de plus en plus graves. L’augmentation continue du nombre de suicides au travail, dont les médias se font régulièrement l’écho, en témoigne. La France est l’un des pays les plus touchés. Pourtant, les réponses proposées dans le monde de l’entreprise restent limitées à la gestion du stress, semblant ignorer l’existence de réels troubles de l’humeur d’origine professionnelle. Il est vrai que la plupart des intervenants au sein des entreprises n’ont pas de formation psychiatrique. Il existe d’authentiques dépressions professionnelles qui surviennent suite à des difficultés dans le monde du travail et s’expriment principalement au travail. Ces dépressions représentent la majeure partie des dépenses médicales occasionnées par les problèmes de santé mentale. La dépression des dirigeants d’entreprise, souvent méconnue, est un facteur causal de certaines faillites. La sémiologie est spécifique, les éléments de prise en charge et de prévention primaire, sont très différents de ceux du stress professionnel. De la même façon, le cadre législatif est surprenant. La dépression n’existe pas dans le tableau des maladies professionnelles, et sa reconnaissance hors tableau est difficile, avec en particulier, une absence de présomption d’origine. Au contraire, le suicide est désormais fréquemment reconnu comme accident du travail. Notre intervention, après avoir rappelé la sémiologie spécifique des troubles de l’humeur d’origine professionnelle, fera le point sur les aspects de prévention spécifique et sur les éléments de prise en charge. Nous présenterons, pour conclure, la prise en charge que nous avons mise en place dans un établissement bancaire français.

Design of a simplified histopathologic model for gastrointestinal inflammation in dogs

Significant interobserver variability in the diagnostic interpretation of endoscopic gastrointestinal (GI) specimens exists even with the use of World Small Animal Veterinary Association (WSAVA) standardization criteria. Chi-square analyses compared the extent of pathologists' agreement for microarchitectural features of inflammation in endoscopic specimens obtained from 253 animals of the original WSAVA study. Patterns of agreement between pathologists were classified as broad (3/4 pathologists agreed), dichotomous (2/4 pathologists agreed), or divergent (no agreement between pathologists). The simplified model for GI inflammation was based on those parameters for which the pathologists had either broad or minimally divergent opinions of histopathologic significance. In this model, the parameters chosen were as follows: gastric parameters (intraepithelial lymphocytes [IELs], lamina propria [LP] infiltrates, and mucosal fibrosis), duodenal parameters (villus atrophy, epithelial injury, IELs, crypt changes, and LP infiltrates), and colonic parameters (epithelial injury, crypt dilation, fibrosis, LP infiltrates, and goblet cell depletion). Preliminary data using this simplified model showed excellent correlation between pathologists in defining the presence and extent of GI inflammation in dogs.

Histopathological standards for the diagnosis of gastrointestinal inflammation in endoscopic biopsy samples from the dog and cat: a report from the World Small Animal Veterinary Association Gastrointestinal Standardization Group

The characterization of inflammatory change in endoscopic biopsy samples of the gastrointestinal mucosa is an increasingly important component in the diagnosis and management of canine and feline gastrointestinal disease. Interpretation has hitherto been limited by the lack of standard criteria that define morphological and inflammatory features, and the absence of such standardization has made it difficult, if not impossible, to compare results of retrospective or prospective studies. The World Small Animal Veterinary Association (WSAVA) Gastrointestinal Standardization Group was established, in part, to develop endoscopic and microscopical standards in small animal gastroenterology. This monograph presents a standardized pictorial and textual template of the major histopathological changes that occur in inflammatory disease of the canine and feline gastric body, gastric antrum, duodenum and colon. Additionally, a series of standard histopathological reporting forms is proposed, to encourage evaluation of biopsy samples in a systematic fashion. The Standardization Group believes that the international acceptance of these standard templates will advance the study of gastrointestinal disease in individual small companion animals as well as investigations that compare populations of animals.

Duodenal perforation in a cheetah (Acinonyx jubilatus)

An 11-yr-old female cheetah (Acinonyx jubilatus) from a privately owned breeding center for endangered species was referred for evaluation with a history of vomiting and depression of 10 days' duration. After anesthetic induction with tiletamine and zolazepam and anesthetic maintenance with isoflurane, a complete diagnostic workup was performed, including hematology, serum chemistry, and radiography. The clinical diagnosis was septic suppurative inflammation and hemorrhage in the abdomen, consistent with perforation or rupture of the gastrointestinal tract. An exploratory laparotomy showed a perforated duodenal ulcer, which was resected. Subsequent endoscopy revealed no further evidence of ulceration in the upper gastrointestinal tract. Biopsy of the ulcerated tissue collected from the duodenum revealed Gastrospirillum-like organisms. Histologic examination revealed widespread infiltration of lymphocytes and plasma cells into the lamina propria and submucosa. Intraepithelial leukocytes were present along with attenuation, erosion, and ulceration of the superficial epithelium. Fourteen days after surgery, this cheetah was returned to its breeding compound, and no subsequent vomiting has been observed for 4 yr.

Adenovirus-mediated transfer of a gene encoding human apolipoprotein A-I into normal mice increases circulating high-density lipoprotein cholesterol

BACKGROUND

In animal models of atherosclerosis, augmentation of circulating high-density lipoprotein (HDL) cholesterol exerts a protective effect against development of fatty streaks and promotes plaque regression.

METHODS AND RESULTS

To investigate the potential of gene transfer to increase HDL cholesterol, a fusion gene encoding human apolipoprotein A-I (apo A-I) under the control of the human cytomegalovirus (CMV) immediate-early promoter was packaged into a recombinant adenovirus (AdCMV apo A-I). BALB/c mice infected with AdCMV apo A-I by intravenous injection accumulate immunoreactive apo A-I in serum; levels 5 days after infection averaged 168 mg/dL. A 35% increase in HDL cholesterol and a 47% increase in total cholesterol were observed in mice infected with AdCMV apo A-I compared with control viruses. Analysis of size-fractionated lipoproteins revealed that human apo A-I is incorporated into murine HDL particles. Expression of human apo A-I declined to < 10% of maximum after 12 days and mRNA encoding apo A-I, prevalent 5 days after infection, was undetectable in the livers of infected mice after 12 days.

CONCLUSIONS

We conclude that adenovirus-mediated transfer of a gene encoding apo A-I produces transient elevations of circulating HDL cholesterol of a magnitude correlated with important physiological effects. These observations suggest the potential for gene-based therapeutic strategies to reduce cardiovascular risk.

The development of a patient satisfaction questionnaire in the ambulatory setting

Patient satisfaction is of critical interest to medical care providers. The main objective of this study was to evaluate the psychometric properties of a patient satisfaction questionnaire. A preliminary 80-item questionnaire was created, and a random sample of 268 family practice patients participated. Subjects rated items on a 4-point Likert scale (strongly disagree, disagree, agree, strongly agree). Items were subjected to a principal components varimax rotated factor analysis and five factors (60 items) were extracted, accounting for 47.5% of the variance. These factors were: satisfaction with physician, dissatisfaction with practice management, physician availability, receptionist behavior, and wait time. Alpha reliability coefficients for factors 1-5 were: .96, .93, .89, .84, and .78, respectively. All items correlated highly with total scores on the respective factors. Factor intercorrelations were all significant (P less than .001) and in the expected direction. Patients with a higher level of education were significantly less satisfied about physician availability than patients without a high school education (P less than .05). Implications of the findings are discussed.

Identification of serine 473 as a major phosphorylation site in the neurofilament polypeptide NF-L

Neurofilaments are composed of 3 polypeptides designated NF-H, NF-M, and NF-L, all of which are subject to posttranslational phosphorylation. It has been suggested that phosphorylation of the NF-L polypeptide can influence the assembly of NF-L into filaments, but the sites at which NF-L is phosphorylated are unknown. To locate these phosphorylation sites, we have identified phosphopeptides of NF-L by labeling them with 32P both in vitro and in cultured neurons and also by observing their change in chromatographic behavior after they have been treated with phosphatase. We report here that serine 473, in the carboxy-terminal tail domain of NF-L, is a major substrate in vitro for protein kinases endogenous to a crude cytoskeleton-containing fraction. Moreover, serine 473 is a major phosphorylation site in vivo; in neurofilaments isolated from rat spinal cord, approximately 73% of serine 473 was phosphorylated, and accounted for at least one-third of the total phosphate associated with NF-L. The identification of this phosphorylation site in NF-L provides a criterion for identifying the protein kinase that phosphorylates NF-L and raises the question of its function.

Purification of the growth-associated protein GAP-43 by reversed phase chromatography: amino acid sequence analysis and cDNA identification

GAP-43 is a neuronal phosphoprotein. Increased synthesis and axonal transport of GAP-43 has been associated with axon growth, and altered phosphorylation of GAP-43 has been associated with changes in synaptic efficacy. Here we report a rapid and effective procedure employing reverse-phase HPLC for the purification of GAP-43 from rat brain. To characterize the protein purified by this procedure, we generated proteolytic fragments and determined their amino acid sequences. These directly determined sequences, corresponding to 56% of the GAP-43 amino acids, confirm recently reported sequences deduced from the nucleotide sequences of cDNAs. Using oligonucleotide probes constructed according to these amino acid sequences, we identified GAP-43 cDNAs in a library prepared from neonatal rat superior cervical ganglion cells. One of these cDNAs was 1.1 kB in size; it hybridized specifically with a 1.5 kB RNA from brain, but not from liver, and contained the entire coding sequence for GAP-43. This cDNA differed from recently reported cDNAs in its 3' untranslated region.

Anxiolytic and sedative properties of BW A78U, a novel anticonvulsant adenine derivative

The anticonvulsant BW A78U, tested in a free mouse exploratory situation, reduced in a dose-dependent fashion the locomotion and the number of rearings, this sedative effect being significant up to a dose of 15 mg/kg (IP, 20 min before testing). In an unconditioned conflict test, the light/dark box choice situation, specific for anxiolytics, low doses of BW A78U increased the time spent by mice in the lit box as well as the number of transitions between the two boxes. Finally, we demonstrated that this drug was able to protect mice against pentylenetetrazole-induced convulsions. Our data show that BW A78U possesses some of the characteristic properties of the minor tranquilizers. However, since this compound binds to the benzodiazepine receptor with a very low affinity (IC50 = 13.6 microM), it can be assumed that this drug does not exert its behavioral effects through these receptors. It may interfere with other targets involving adenosine, another potent physiological regulator of neuronal excitability.

A GAP-43-like protein in cat visual cortex

We have purified a protein that changes in relative concentration during the development of the kitten visual cortex. It resembles GAP-43 (a neuronal protein that is expressed at elevated levels during periods of development and regenerative axon growth) in the following respects: (1) it is an acidic protein (pI = 4.7) whose electrophoretic mobility on SDS-PAGE is similar to, but lower than rat GAP-43, suggesting that the cat protein is larger; (2) its electrophoretic mobility varies with the acrylamide concentration in a manner that is characteristic of GAP-43; (3) its concentration in kitten forebrain is elevated during early postnatal development; (4) the sequence of ten consecutive amino acids from a chemically generated fragment matches the expected sequence from GAP-43; and (5) its amino-acid content also matches GAP-43. We conclude that our purified protein is cat GAP-43. Immunoblots with an antibody prepared against rat GAP-43 suggested that the concentration of GAP-43 in the visual cortex declines with age.

Distribution and phosphorylation of the growth-associated protein GAP-43 in regenerating sympathetic neurons in culture

Sympathetic neurons regenerating in culture were studied in order to gain further insight into the intracellular distribution and phosphorylation of GAP-43, a protein that has been suggested to have a role in axonal outgrowth and neuronal plasticity (Willard et al., 1987). Superior cervical ganglion neurons from embryonic rats were highly reactive with a polyclonal antibody against the growth-associated protein GAP-43 soon after they were placed in culture on a laminin substrate. As these neurons extended neurites, the distribution of GAP-43 reactivity changed. The cell body became progressively less reactive, whereas the growth cone at the tip of the growing neurite reacted strongly. The pattern of immunofluorescence was punctate both in the growth cone and the adjacent neurite, but appeared more diffusely distributed in the cell body. The antibody reacted only with cells that had been subjected to treatment that permeabilized the plasma membrane. When antibody was supplied in the medium of growing neurons, it neither bound to the cells nor altered normal neurite initiation or elongation. Of the different types of cells in these cultures, the antibody reacted only with neurons; it did not react with Schwann cells or fibroblasts. The stimulation of protein kinase C in these cultures resulted in a 7-fold stimulation of the phosphorylation of a protein of similar electrophoretic mobility to GAP-43. These observations demonstrate that GAP-43 is neuron-specific, is present throughout the neuron but at higher levels in the growth cone, and is a major substrate of protein kinase C. The high concentration of GAP-43 in the growth cones may necessitate its increased synthesis in neurons with elongating axons. Its location and phosphorylation by kinase C suggest that it could perform a function in the growth cone that is modulated by extracellular signals, such as those used in pathfinding or in the control of axonal elongation.

Axonal transport of synapsin I-like proteins in rabbit retinal ganglion cells

Synapsin I is a neuronal phosphoprotein that is associated with the cytoplasmic surface of small, clear synaptic vesicles in neuronal synaptic terminals; it may play an important role in synaptic transmission. In vitro, it can interact with fodrin, a relative of the erythrocyte protein spectrin. We have investigated the delivery of synapsin I from its site of synthesis in neuronal cell bodies to synaptic terminals by means of the process of axonal transport. We labeled the newly synthesized proteins of rabbit retinal ganglion cells by injecting 35S-methionine into the vitreous humour, and subsequently observed the appearance of radioactive synapsin I (identified by its 2-dimensional electrophoretic mobility) in tissues containing the axons and synaptic terminals of these neurons. A portion of the newly synthesized synapsin I was axonally transported at the velocity of the most rapidly transported (group I) proteins, which comprise membrane-associated proteins and may include elements of synaptic vesicles. However, the subsequent time course of labeling of synapsin I in the axons suggests that greater than 90% of the axonally transported synapsin I may comprise 2 additional populations--one transported rapidly, the other slowly--that are released from the cell bodies only after a delay of more than 1 d. The delayed, slowly transported population moves at the velocity (approximately 6 mm/d) of groups III and IV (which include fodrin and other proteins of the membrane cytoskeleton). We consider whether such distinct populations may correspond to functionally specialized variants of synapsin I-like proteins that may be transported in association with different organelles. The electrophoretic mobility of labeled synapsin I-like proteins in the axons changed subtly with time. Additional subtle differences between labeled synapsin I-like proteins in the axons and the terminal-containing tissues suggest that certain posttranslational modifications occur specifically in the terminals.

Translocations of fodrin and its binding proteins

Fodrin, a protein related to erythrocyte spectrin, redistributes within the cell in certain situations. We compare such movements of fodrin and several fodrin binding proteins during the processes of axonal transport in neurons, and capping of surface proteins in lymphocytes. In neurons, three different populations of newly synthesized fodrin appear to be transported down the axons at different velocities corresponding to those of groups of transported proteins designated II, IV, and V. Actin, which can interact with fodrin, is transported at the velocity of group IV. Synapsin, a component of synaptic vesicles, is also reported to bind to fodrin. One population of synapsin is transported more rapidly than fodrin, at the velocity of group I: two additional populations of transported synapsin may overlap fodrin in groups II and IV. We consider possible functional associations of these different populations of fodrin and fodrin binding proteins. We note that the transport of group IV proteins resembles in certain respects the process of capping in lymphocytes, suggesting the possibility of a common mechanism. We outline one of several possible mechanisms.

Localization of fodrin during fertilization and early development of sea urchins and mice

Fodrin, a spectrin-like protein, is localized in gametes, zygotes, and embryos from sea urchins and mice. Mammalian fodrin comprises two polypeptides with molecular weights of approximately 240 kDa (alpha) and 235 kDa (beta). An antibody specific for mammalian alpha-fodrin cross-reacted with a 240-kDa polypeptide from sea urchin egg extracts. This indicates that sea urchins contain a protein of similar electrophoretic mobility and immunological properties to mammalian alpha-fodrin. When this antibody was used to stain the sea urchin gametes with indirect immunofluorescence, fodrin-specific fluorescence was localized to the acrosome of the sperm and was distributed over the entire egg near the surface in a punctate pattern similar to the distribution of polymeric actin. During sperm incorporation, the fodrin-specific fluorescence is found at the site of sperm incorporation, in the fertilization cone. After fertilization, the intensity of fodrin fluorescence increases. During mitosis and cytokinesis in sea urchins, the entire surface of the egg remains stained; the cleavage furrow also was stained but no more intensely than was the rest of the egg surface. Antibody labeling with colloidal gold followed by electron microscopy showed that fodrin was loated in the cytoplasm immediately beneath the plasma membrane. In unfertilized mouse oocytes, both actin and fodrin were stained most intensely beneath the membrane adjacent to the meiotic spindle. After insemination, the cell surfaces of the pronucleate egg and the second polar body were stained; however, the actin matrix surrounding the apposed pronuclei did not bind the fodrin antibody. During cytokinesis in the mouse, the cleavage furrow stained more intensely than did the rest of the egg cortex, and in embryos the cell borders were delineated. These results indicate that organisms as unrelated to mammals as sea urchins have fodrin-like proteins; the rearrangements of such proteins suggest that they participate in the actin-mediated events at the cell surface during fertilization and early development in both mice and sea urchins.

Modulations of neurofilament axonal transport during the development of rabbit retinal ganglion cells

We have compared the polypeptides undergoing axonal transport in the retinal ganglion cells of neonatal and adult rabbits, and have observed the following: (1) Representative polypeptides of five different adult transport groups are axonally transported from the time of birth. (2) Polypeptides of group IV (a group that includes actin and myosin) are transported two-fold more rapidly in neonates than in adults. (3) Two polypeptides, M (145K) and L (73K) that are components of neurofilaments and move with the fifth, slowest group of transported proteins, are transported approximately eight-fold more rapidly in neonatal rabbits than in adults. (4) H, a third group V polypeptide, that serves to crosslink neurofilaments, was not detected in the rabbit optic nerve until 12 days after birth. We consider the possibility that the late induction of the crosslinker precipitates a cytoskeletal "phase transition" that may be responsible for the developmental alterations in apparent transport velocities, and may have additional consequences for neuronal development.

Location of a protein of the fodrin-spectrin-TW260/240 family in the mouse intestinal brush border

We have determined that a protein of the fodrin-spectrin-TW260/240 (FST) family is a component of the thin fibrils (approximately 5 nm wide, 100-200 nm long) that cross-link bundles of actin filaments to adjacent actin bundles and to the plasma membrane in the terminal web of the brush border of the intestinal epithelium. When isolated brush borders were incubated with anti-fodrin antibodies and prepared for electron microscopy by the quick-freeze, deep-etch technique, these approximately 5 nm fibrils were specifically decorated with the antibody. In addition, these cross-linking fibrils disappeared when the anti-fodrin-reactive proteins were extracted from the brush border. We conclude that FST is a component of a cross-linking system composed of approximately 5 nm fibrils that are morphologically distinct from the approximately 8 nm myosin-containing fibrils which were identified by anti-myosin decoration. In addition to linking actin bundles to adjacent actin bundles and to the plasma membrane, these FST fibrils may mediate actin-vesicle, actin-intermediate filament and vesicle-plasma membrane linkages.

Redistribution of fodrin (a component of the cortical cytoplasm) accompanying capping of cell surface molecules

Fodrin, a protein composed of two polypeptides with molecular weights of 250,000 and 240,000, is concentrated in the cortical cytoplasm of neurons, and moves down the axons by the process of axonal transport. We have used immunofluorescence techniques to determine whether fodrin antigens also move in non-neuronal cells when cell surface ligands are induced to redistribute by crosslinking them. A redistribution of fodrin antigens occurred in the following instances: (i) when 3T3 cells were incubated with concanavalin A and anti-concanavalin A, surface concanavalin A receptors formed aggregates and fodrin antigens formed corresponding intracellular aggregates; (ii) when B lymphocytes were incubated with anti-Ig, the surface Ig formed caps and fodrin antigens formed intracellular subcaps; (iii) when T lymphocytes were treated with anti-H-2 followed by a secondary antibody, the H-2 antigen formed caps and fodrin formed corresponding subcaps. These observations show that fodrin antigens can move within non-neuronal cells, as well as in axons, and that their organization can be regulated by interaction between surface proteins and environmental stimuli. They also raise the possibility that fodrin, together with other proteins that form subcaps in lymphocytes (e.g., actin, myosin, and alpha-actinin) is a component of the cellular machinery responsible for the capping process. We consider whether the similarities between the movements of fodrin in lymphocyte capping and axonal transport may indicate that certain aspects of these two processes are related.

Intracellular movement of fodrin

Fodrin is an actin/calmodulin-binding protein with similarities to spectrin (erythrocytes) and TW 260/240 (brush border). It is concentrated beneath the plasma membranes of neurons and other cells. We have observed translocations of fodrin in both neurons and lymphocytes. Newly synthesized, radiolabeled fodrin moves down axons at a maximum velocity (about 50 mm/day) that is slower than the most rapidly axonally transported proteins (group I). A portion of fodrin appears to move more slowly at velocities (1-10 mm/day) resembling those of actin and myosin (group IV) and tubulin and neurofilament proteins (group V). In lymphocytes, when certain surface antigens are induced by cross-linking agents to migrate to one pole of the cell and form a cap, fodrin redistributes beneath the membrane and forms a subcap. The movements of fodrin in lymphocyte capping and in the axonal transport of group IV polypeptides have certain similarities. In both cases, the redistribution of fodrin is accompanied by concomitant redistributions of actin, myosin, and calmodulin, and both processes proceed at similar velocities. We consider the possibilities that these two processes are related, both being driven by a submembrane force-generating system comprising in part actin, myosin, and fodrin, and that fodrin serves to link various organelles or proteins to this system.

Separation of neurofilaments from ATPase activity by precipitation with anti-neurofilament antibodies

The possibility that neurofilaments could be involved in the transduction of chemical and mechanical energy in axons led us to investigate whether neurofilament proteins can hydrolyze ATP. We fractionated neurofilaments from rabbit spinal cord and found that preparations highly enriched for neurofilament proteins hydrolyzed ATP at a substantial rate (as high as 0.4 mumol/min/mg protein). However, the ATPase activity was neither inhibited by anti-neurofilament antibody, nor was it precipitated by the antibody under circumstances that precipitated most of the neurofilament polypeptides. We conclude that neurofilament proteins do not hydrolyze ATP at a significant rate under the conditions of our assay; if hydrolysis of ATP is a physiological function of neurofilaments, additional factors are required.

Fodrin: axonally transported polypeptides associated with the internal periphery of many cells

Fodrin (formerly designated 26 and 27) comprises two polypeptides (250,000 and 240,000 mol wt) that are axonally transported at a maximum time-averaged velocity of 40 mm/d--slower than the most rapidly moving axonally transported proteins, but faster than at least three additional groups of proteins. In this communication, we report the intracellular distribution of fodrin. Fodrin was purified from guinea pig brain, and a specific antifodrin antibody was produced in rabbit and used to localize fodrin in tissue sections and cultured cells by means of indirect immunofluorescence. Fodrin antigens were highly concentrated in the cortical cytoplasm of neurons and also nonneuronal tissues (e.g., skeletal muscle, uterus, intestinal epithelium). Their disposition resembles a lining of the cell: hence, the designation fodrin (from Greek fodros, lining). In cultured fibroblasts, immunofluorescently labeled fodrin antigens were arranged in parallel arrays of bands in the plane of the plasma membrane, possibly reflecting an exclusion of labeled fodrin from some areas occupied by stress fibers. The distribution of fodrin antigens in mouse 3T3 cells transformed with simian virus 40 was more diffuse, indicating that the disposition of fodrin is responsive to altered physiological states of the cell. When mixtures of fodrin and F-actin were centrifuged, fodrin cosedimented with the actin, indicating that these proteins interact in vitro. We conclude that fodrin is a specific component of the cortical cytoplasm of many cells and consider the possibilities: (a) that fodrin may be indirectly attached to the plasma membrane via cortical actin filaments; (b) that fodrin may be mobile within the cortical cytoplasm and that, in axons, a cortical lining may be in constant motion relative to the internal cytoplasm; and (c) that fodrin could serve to link other proteins and organelles to a submembrane force-generating system.

Electrophoretic analysis of axonally transported proteins in toad retinal ganglion cells

As a preliminary step to studying changes in axonal transport in regenerating neurons, we have analyzed the composition and organization of polypeptides normally axonally transported in a neuronal system capable of regeneration, i.e., the retinal ganglion cells of the toad, Bufo marinus. We labeled proteins synthesized in the retina with 35S-methionine and subsequently used one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis to analyze labeled, transported proteins in tissues containing segments of the axons (the optic nerve, optic tract, and optic tecta) of the retinal ganglion cells. The transported polypeptides could be divided into five groups according to their apparent transport velocities. Many of the polypeptides of each group were electrophoretically similar to polypeptides of corresponding groups previously described in rabbit and guinea pig retinal ganglion cells, and in some cases, additional properties of the polypeptides indicated that the transported materials of the two vertebrate classes were homologous. These results serve two purposes. First they establish the retinal ganglion cells of the toad Bufo marinus as a model system in which changes in gene expression related to regeneration may be studied. Second they show that the organization and many aspects of the composition of axonal transport in retinal ganglion cells have been conserved in animals as unrelated as amphibians, and mammals.

Antibody decoration of neurofilaments

We have decorated neurofilaments with antibodies against three polypeptides (designated here as H [mol wt = 195,000], 45[mol wt = 145,000], and 46[mol wt = 73,000]) in an effort to understand the arrangement of these polypeptides within neurofilaments. The three polypeptides were purified and antibodies were raised against each. The cross-reactivity of the antibodies suggested that each polypeptide contains both shared and unique antigenic determinants. The differential reactivities of each antibody preparation were enhanced by adsorption with the two heterologous polypeptides, and the resulting preparations were used to decorate purified neurofilaments, which were then negatively stained and examined in an electron microscope. The appearance of the antibody-decorated structures led to the following conclusions: All three polypeptides are physically associated with the same neurofilament. However, the disposition of H and 46 within a filament is different; 46 antigens appear to be associated with a "central core" of the filament, whereas H antigens compose a structure more loosely and peripherally attached to the central core and periodically arranged along its axis. The antibody-decorated H-containing structure assumes variable configurations; in some cases it appears asa bridge connecting two filaments; in other cases it appears as a helix wrapping the central core with a period of approximately 1,000 A and an apparent unit length of approximately 1.5 periods. These configurations suggest several functional implications, including the possibility that H is a component of the cross-bridges observed between filaments in situ. We also note that the central core-helix relationship could be used in the design of an intracellular transport motor.

Axonally transported proteins associated with axon growth in rabbit central and peripheral nervous systems

In an effort to determine whether the "growth state" and the "mature state" of a neuron are differentiated by different programs of gene expression, we have compared the rapidly transported (group I) proteins in growing and nongrowing axons in rabbits. We observed two polypeptides (GAP-23 and GAP-43) which were of particular interest because of their apparent association with axon growth. GAP-43 was rapidly transported in the central nervous system (CNS) (retinal ganglion cell) axons of neonatal animals, but its relative amount declined precipitously with subsequent development. It could not be reinduced by axotomy of the adult optic nerves, which do not regenerate; however, it was induced after axotomy of an adult peripheral nervous system nerve (the hypoglossal nerve, which does regenerate) which transported only very low levels of GAP-43 before axotomy. The second polypeptide, GAP-23 followed the same pattern of growth-associated transport, except that it was transported at significant levels in uninjured adult hypoglossal nerves and not further induced by axotomy. These observations are consistent with the "GAP hypothesis" that the neuronal growth state can be defined as an altered program of gene expression exemplified in part by the expression of GAP genes whose products are involved in critical growth-specific functions. When interpreted in terms of GAP hypothesis, they lead to the following conclusions: (a) the growth state can be subdivided into a "synaptogenic state" characterized by the transport of GAP-23 but not GAP-43, and an "axon elongation state" requiring both GAPs; (b) with respect to the expression of GAP genes, regeneration involves a recapitulation of a neonatal state of the neuron; and (c) the failure of mammalian CNS neurons to express the GAP genes may underly the failure of CNS axons to regenerate after axon injury.

Characteristics of growth-associated polypeptides in regenerating toad retinal ganglion cell axons

We report here certain properties of three polypeptides that are rapidly transported in greatly increased amounts during the regeneration of toad optic nerves. All three of these growth-associated polypeptides (GAPs) are associated with a membrane(s) with a buoyant density similar to the plasma membrane. Since none of these GAPs are solubilized substantially by washing the membranes in either low or high ionic strength media, they may be "integral membrane proteins. All three GAPs contain a significant number of polar amino acids (judging from their isoelectric points and their rapid electrophoretic migration under their native charge), suggesting that portions of each molecule must extent away from the membrane surfaces. One of these proteins (GAP-50) is a fucosylated glycoprotein. GAP-50 and GAP-43 appear to be transported preferentially to axon tips; GAP-24 may be distributed more uniformly along the axons. GAP-24 has an extremely short half-life (4 to 6 hr), while the maximum half-lives of GAP-43 (2 to 3 days) and GAP-50 (approximately 1 day) are longer. We discuss the relevance of these properties to possible roles for these polypeptides in the control of nerve regeneration.

Changes in axonally transported proteins during axon regeneration in toad retinal ganglion cells

In an effort to understand the regulation of the transition of a mature neuron to the growth, or regenerating, state we have analyzed the composition of the axonally transported proteins in the retinal ganglion cells of the toad Bufo marinus after inducing axon regeneration by crushing the optic nerve. At increasing intervals after axotomy, we labeled the retinal ganglion cells with [35S]methionine and subsequently analyzed the labeled transported polypeptides in the crushed optic nerve by means of one- and two-dimensional electrophoretic techniques. The most significant conclusion from these experiments is that, while the transition from the mature to the regenerating state does not require a gross qualitative alteration in the composition of axonally transported proteins, the relative labeling of a small subset of rapidly transported proteins is altered dramatically (changes of more than 20-fold) and reproducibly (more than 30 animals) by axotomy. One of these growth-associated proteins (GAPs) was soluble in an aqueous buffer, while three were associated with a crude membrane fraction. The labeling of all three of the membrane-associated GAPs increased during the first 8 d after axotomy, and they continued to be labeled for at least 4 wk. The modulation of these proteins after axotomy is consistent with the possibility that they are involve in growth-specific functions and that the altered expression of a small number of genes is a crucial regulatory event in the transition of a mature neuron to a growth state. In addition to these selective changes in rapidly transported proteins, we observed the following more general metabolic correlates of the regeneration process: The total radioactive label associated with the most rapidly transported proteins (groups I and II) increased three to fourfold during the first 8 d after the nerve was crushed, while the total label associated with more slowly moving proteins (group IV) increased about 10-fold during this same period. Among these more slowly transported polypeptides, five were observed whose labeling increased much more than the average. Three of these five polypeptides resemble actin and alpha- and beta-tubulin in their electrophoretic properties.

The composition and organization of axonally transported proteins in the retinal ganglion cells of the guinea pig

We labeled the proteins of guinea pig retinal ganglion cells with [35S]methionine and analyzed the axonally transported polypeptides by means of sodium dodecyl sulfate gel electrophoresis. Five groups of transported polypeptides could be distinguished by their characteristic times of initial appearance in segments of the axons of the retinal ganglion cells. The times of initial appearance of the groups corresponded to maximum transport velocities ranging from greater than 200 mm/day to 0.5 mm/day. We directly compared these transported polypeptides to polypeptides undergoing axonal transport in the retinal ganglion cells of the rabbit. Electrophoretically similar polypeptides were transported at the same relative velocities in the two animals. Our results lead to the following conclusions. (1) The basic composition and organization of axonally transported proteins is probably a general constant feature of mammalian retinal ganglion cells, implying that the correct organization is important for the proper functioning of these neurons. Therefore, the results obtained by the analysis of individual model systems should have general significance. (2) Four discontinuities in the transport process (in addition to the 5 discontinuities represented by the major transport groups) were revealed by a consideration of subtle differences between the rabbit and guinea pig, as well as differences in the rate of disappearance of label from individual polypeptides within each transport group. (3) The guinea pig should provide a useful model system for studying axonal transport, especially for immunological studies, since antibodies against axonally transported proteins of the guinea pig can be conveniently prepared in the rabbit. (4) While the structure (as reflected by electrophoretic mobility) of most major axonally transported polypeptides appears to be conserved over the evolutionary period (about 30 million years) separating two orders of mammals, the electrophoretic mobility of one neurofilament-associated polypeptide, H, was abnormally variant between the two species.

Association of an axonally transported polypeptide (H) with 100-A filaments. Use of immunoaffinity electron microscope grids

Polypeptide H (mol wt 195,000) is axonally transported in rabbit retinal ganglion cells at a velocity of 0.7--1.1 mm/d, i.e., in the most slowly moving of the five transport groups described in these neurons. To identify the organelle with which H is associated, we purified H, prepared antibodies directed against it, and adsorbed the antibodies onto Formvar-coated electron microscope grids. When the resulting "immuno-affinity grids" were incubated with extracts of spinal cord and then examined in the electron microscope, they contained as many as 100 times more 100-A filaments than did grids coated similarly with nonimmune IgG. The ability of the anti-H IgG to specifically adsorb filaments to grids was completely blocked by incubating the IgG with polypeptide H. The 100-A filaments adsorbed to anti-H immunoaffinity grids could be specifically decorated by incubating them with anti-H IgG. These observations demonstrate that H antigens (and most likely H itself) are associated with 100-A neurofilaments. In addition, they suggest that the use of immunoaffinity grids may be a useful approach for determining the organelle associations of polypeptides.

Axonal transport of actin in rabbit retinal ganglion cells

We labeled proteins in the cell bodies of rabbit retinal ganglion cells with [35S]methionine and subsequently observed the appearance of radioactive actin in tissues containing the axons and synaptic terminals of these neurons, i.e., the optic nerve (ON), optic tract (OT), lateral geniculate nucleus (LGN) and the superior colliculus (SC). The temporal sequence of appearance of labeled actin (which was identified by its specific binding to DNase I, its electrophoretic mobility, and its peptide map) in these tissues indicated that actin is an axonally transported protein with a maximum transport velocity of 3.4--4.3 mm/d. The kinetics of labeling actin were similar to the kinetics of labeling two proteins (M1 and M2) which resemble myosin; these myosin-like proteins were previously found to be included in the groups of proteins (groups III and IV) transported with the third and fourth most rapid maximum velocities. The similarity in transport between actin and myosin-like proteins supports the idea that a number of proteins in the third and fourth transport groups may be functionally related by virtue of their involvement in a force-generating mechanism and suggests the possibility that these proteins may be axonally transported as a preformed force-generating unit.

Subcellular fractionation of intra-axonally transport polypeptides in the rabbit visual system

We analyzed the subcellular distributions of proteins that are transported down the axons of rabbit retinal ganglion cells and compared these distributions to those of enzyme markers for endoplasmic reticulum, plasma membrane, and mitochondria. The proteins of each of five previously identified transport groups were uniquely distributed through the subcellular fractions, suggesting that each transport group is associated with different subcellular organelles. In particular, all of the observed group I polypeptides (the most rapidly moving, group, maximum velocity greater than 240 mm/day) were associated with material of hydrodynamic properties similar to those of the plasma membrane. The proteins of group II (maximum velocity = 34--68 mm/day) were heterogenous in their subcellular distributions but included mitochondrial proteins. Groups III and IV (maximum velocity = 4--8 and 2--4 mm/day, respectively) included materials that may be involved in motile processes; group V (maximum velocity = 0.7--1.1 mm/day) contained material of very high density which may be associated with neurofilaments.

The identification of two intra-axonally transported polypeptides resembling myosin in some respects in the rabbit visual system

Two polypeptides (M1 and M2) which co-sediment with F-actin in an ATP-reversible way have been detected in extracts of tissue from the rabbit visual system. Both polypeptides resemble skeletal muscle myosin in their ATP-sensitive co-sedimentation with actin, while they resemble the heavy chain of myosin and the lighter polypeptide of erythrocyte spectrin in their electrophoretic mobilities. (The estimated molecular weights are: MI congruent to 195,000; myosin congruent 200,000; M2 and spectrin congruent to 220,000). M1 and M2 were labeled in the cell bodies of the retinal ganglion cells with a radioactive amino acid and subsequently recovered in tissues (optic nerve, optic tract, lateral geniculate nucleus, and superior colliculus) containing segments of the retinal ganglion cell axons. The temporal sequence of labeling M1 and M2 in these tissues indicated that both polypeptides were synthesized in the cell bodies of retinal ganglion cells and subsequently transported down their axons at different maximum velocities. The estimated velocities were: M1, 4-8 mm per day; and M2, 2-4 mm per day.

[A comparative follow up study about intellectual and motoric development of breech presentations (author's transl)]

75 breech- and 71 cephalic deliveries between the years 1965-1970 at the University Clinic, Mannheim, were later examined in their 3 rd. to 7 th. years of life with respect to intelligence and motor developments. Mean intelligence quotient (IQ) of breech deliveries was 109, cephalic deliveries 110. The IQ was correlated with following other criteria: lie, age and parity of the mother, EPH-Gestose, methods of delivery, course and duration of labor, first Apgar score, weight of infant, bilirubin concentration, suspect cerebral damage and morbidity between discharge and recall for examinations. No significant differences in intelligence or motor development were found between the two groups of children.

The polypeptide composition of intra-axonally transported proteins: evidence for four transport velocities

Using a method of gradient gel electrophoresis coupled with autoradiography, we have analyzed the polypeptide composition of the proteins being transported down the axons of the projecting neurons of the rabbit retina. This analysis reveals: (1) the molecular weight distribution of 43 transported polypeptides; (2) the existence of at least four components of intra-axonal protein transport, each characterized by an unique polypeptide composition as well as by an unique velocity of transport; (3) the disappearance of individual labeled intra-axonally transported proteins from the axons and synaptic terminals with half-times ranging from several hours to more than 8 days. The possibility that intra-axonal transport functions as a temporal mediator of alterations in axonal or synaptic events is discussed in relation to these findings.