AI-driven translations for kidney transplant equity in Hispanic populations

Health equity and accessing Spanish kidney transplant information continues being a substantial challenge facing the Hispanic community. This study evaluated ChatGPT's capabilities in translating 54 English kidney transplant frequently asked questions (FAQs) into Spanish using two versions of the AI model, GPT-3.5 and GPT-4.0. The FAQs included 19 from Organ Procurement and Transplantation Network (OPTN), 15 from National Health Service (NHS), and 20 from National Kidney Foundation (NKF). Two native Spanish-speaking nephrologists, both of whom are of Mexican heritage, scored the translations for linguistic accuracy and cultural sensitivity tailored to Hispanics using a 1-5 rubric. The inter-rater reliability of the evaluators, measured by Cohen's Kappa, was 0.85. Overall linguistic accuracy was 4.89 ± 0.31 for GPT-3.5 versus 4.94 ± 0.23 for GPT-4.0 (non-significant p = 0.23). Both versions scored 4.96 ± 0.19 in cultural sensitivity (p = 1.00). By source, GPT-3.5 linguistic accuracy was 4.84 ± 0.37 (OPTN), 4.93 ± 0.26 (NHS), 4.90 ± 0.31 (NKF). GPT-4.0 scored 4.95 ± 0.23 (OPTN), 4.93 ± 0.26 (NHS), 4.95 ± 0.22 (NKF). For cultural sensitivity, GPT-3.5 scored 4.95 ± 0.23 (OPTN), 4.93 ± 0.26 (NHS), 5.00 ± 0.00 (NKF), while GPT-4.0 scored 5.00 ± 0.00 (OPTN), 5.00 ± 0.00 (NHS), 4.90 ± 0.31 (NKF). These high linguistic and cultural sensitivity scores demonstrate Chat GPT effectively translated the English FAQs into Spanish across systems. The findings suggest Chat GPT's potential to promote health equity by improving Spanish access to essential kidney transplant information. Additional research should evaluate its medical translation capabilities across diverse contexts/languages. These English-to-Spanish translations may increase access to vital transplant information for underserved Spanish-speaking Hispanic patients.

Conversational technology and reactions to withheld information

People frequently face decisions that require making inferences about withheld information. The advent of large language models coupled with conversational technology, e.g., Alexa, Siri, Cortana, and the Google Assistant, is changing the mode in which people make these inferences. We demonstrate that conversational modes of information provision, relative to traditional digital media, result in more critical responses to withheld information, including: (1) a reduction in evaluations of a product or service for which information is withheld and (2) an increased likelihood of recalling that information was withheld. These effects are robust across multiple conversational modes: a recorded phone conversation, an unfolding chat conversation, and a conversation script. We provide further evidence that these effects hold for conversations with the Google Assistant, a prominent conversational technology. The experimental results point to participants' intuitions about why the information was withheld as the driver of the effect.

Genetic counselors' utilization of ChatGPT in professional practice: A cross-sectional study

PURPOSE

The precision medicine era has seen increased utilization of artificial intelligence (AI) in the field of genetics. We sought to explore the ways that genetic counselors (GCs) currently use the publicly accessible AI tool Chat Generative Pre-trained Transformer (ChatGPT) in their work.

METHODS

GCs in North America were surveyed about how ChatGPT is used in different aspects of their work. Descriptive statistics were reported through frequencies and means.

RESULTS

Of 118 GCs who completed the survey, 33.8% (40) reported using ChatGPT in their work; 47.5% (19) use it in clinical practice, 35% (14) use it in education, and 32.5% (13) use it in research. Most GCs (62.7%; 74) felt that it saves time on administrative tasks but the majority (82.2%; 97) felt that a paramount challenge was the risk of obtaining incorrect information. The majority of GCs not using ChatGPT (58.9%; 46) felt it was not necessary for their work.

CONCLUSION

A considerable number of GCs in the field are using ChatGPT in different ways, but it is primarily helpful with tasks that involve writing. It has potential to streamline workflow issues encountered in clinical genetics, but practitioners need to be informed and uniformly trained about its limitations.

Study protocol for factors influencing the adoption of ChatGPT technology by startups: Perceptions and attitudes of entrepreneurs

BACKGROUND

Generative Artificial Intelligence (AI) technology, for instance Chat Generative Pre-trained Transformer (ChatGPT), is continuously evolving, and its userbase is growing. These technologies are now being experimented by the businesses to leverage their potential and minimise their risks in business operations. The continuous adoption of the emerging Generative AI technologies will help startups gain more and more experience with adoptions, helping them to leverage continuously evolving technological innovation landscape. However, there is a dearth of prior research on ChatGPT adoption in the startup context, especially from Entrepreneur perspective, highlights the urgent need for a thorough investigation to identify the variables influencing this technological adoption. The primary objective of this study is to ascertain the factors that impact the uptake of ChatGPT technology by startups, anticipate their influence on the triumph of companies, and offer pragmatic suggestions for various stakeholders, including entrepreneurs, and policymakers.

METHOD AND ANALYSIS

This study attempts to explore the variables impacting startups' adoption of ChatGPT technology, with an emphasis on comprehending entrepreneurs' attitudes and perspectives. To identify and then empirically validate the Generative AI technology adoption framework, the study uses a two-stage methodology that includes experience-based research, and survey research. The research method design is descriptive and Correlational design. Stage one of the research study is descriptive and involves adding practical insights, and real-world context to the model by drawing from the professional consulting experiences of the researchers with the SMEs. The outcome of this stage is the adoption model (also called as research framework), building Upon Technology Adoption Model (TAM), that highlight the technology adoption factors (also called as latent variables) connected with subset of each other and finally to the technology adoption factor (or otherwise). Further, the latent variables and their relationships with other latent variables as graphically highlighted by the adoption model will be translated into the structured questionnaire. Stage two involves survey based research. In this stage, structured questionnaire is tested with small group of entrepreneurs (who has provided informed consent) and finally to be distributed among startup founders to further validate the relationships between these factors and the level of influence individual factors have on overall technology adoption. Partial Least Squares Structural Equation Modeling (PLS-SEM) will be used to analyze the gathered data. This multifaceted approach allows for a comprehensive analysis of the adoption process, with an emphasis on understanding, describing, and correlating the key elements at play.

DISCUSSION

This is the first study to investigate the factors that impact the adoption of Generative AI, for instance ChatGPT technology by startups from the Entrepreneurs perspectives. The study's findings will give Entrepreneurs, Policymakers, technology providers, researchers, and Institutions offering support for entrepreneurs like Academia, Incubators and Accelerators, University libraries, public libraries, chambers of commerce, and foreign embassies important new information that will help them better understand the factors that encourage and hinder ChatGPT adoption. This will allow them to make well-informed strategic decisions about how to apply and use this technology in startup settings thereby improving their services for businesses.

Lercanidipine ameliorated doxorubicin-induced neuroinflammation and maintained the expressions of choline acetyltransferase via enhancing the levels of PI3K/AKT/HIF1-α expressions

BACKGROUND

Doxorubicin (DOX) may cause various neurological side effects in the brain. Lercanidipine (LRD) has antioxidant, anti-inflammatory, and anti-apoptotic properties. The aim of this study was to investigate the potential benefits of.

METHODS AND RESULTS

Lercanidipine in reducing doxorubicin-induced neuroinflammation and maintaining the expressions of choline acetyltransferase. Thirty-two adult Wistar albino female rats were divided into four groups as Control, DOX (20 mg/kg intraperitoneally), DOX + LRD 0.5 (0.5 mg/kg orally), and DOX + LRD2(2 mg/kg orally). Twenty-four hours after the last drug administration (9th day), brain tissues were taken for histopathological, immunohistochemical (choline acetyltransferase [CHAT], interleukin-10 [IL-10], and caspase-3 [Cas-3] staining), biochemical (total antioxidant status [TAS], total oxidant status [TOS], and oxidative stress index [OSI]), and genetic analyzes (PI3K/AKT/HIF1-α and IL-6 gene expressions). Histopathological analyses revealed hyperemia, slight hemorrhage, degeneration, neuronal loss, gliosis in the cerebellum, and neuronal loss in the brain cortex and hippocampus in the DOX group. According to other analyzes, decreased CHAT, PI3K, AKT, HIF1-α and increased IL-6, IL-10, Cas-3 expression were observed in the DOX group.

CONCLUSIONS

Both LRD doses reversed all these findings, but LRD2 was observed to be more effective. In conclusion, we determined that LRD has potential therapeutic effect by reducing DOX-induced neuroinflammation, oxidative stress and apoptosis in brain tissues.

Is ChatGPT an Effective Tool for Providing Dietary Advice?

The chatbot Chat Generative Pretrained Transformer (ChatGPT) is becoming increasingly popular among patients for searching health-related information. Prior studies have raised concerns regarding accuracy in offering nutritional advice. We investigated in November 2023 ChatGPT's potential as a tool for providing nutritional guidance in relation to different non-communicable diseases (NCDs). First, the dietary advice given by ChatGPT (version 3.5) for various NCDs was compared with guidelines; then, the chatbot's capacity to manage a complex case with several diseases was investigated. A panel of nutrition experts assessed ChatGPT's responses. Overall, ChatGPT offered clear advice, with appropriateness of responses ranging from 55.5% (sarcopenia) to 73.3% (NAFLD). Only two recommendations (one for obesity, one for non-alcoholic-fatty-liver disease) contradicted guidelines. A single suggestion for T2DM was found to be "unsupported", while many recommendations for various NCDs were deemed to be "not fully matched" to the guidelines despite not directly contradicting them. However, when the chatbot handled overlapping conditions, limitations emerged, resulting in some contradictory or inappropriate advice. In conclusion, although ChatGPT exhibited a reasonable accuracy in providing general dietary advice for NCDs, its efficacy decreased in complex situations necessitating customized strategies; therefore, the chatbot is currently unable to replace a healthcare professional's consultation.

Artificial Intelligence in Medicine: Cross-Sectional Study Among Medical Students on Application, Education, and Ethical Aspects

BACKGROUND

The use of artificial intelligence (AI) in medicine not only directly impacts the medical profession but is also increasingly associated with various potential ethical aspects. In addition, the expanding use of AI and AI-based applications such as ChatGPT demands a corresponding shift in medical education to adequately prepare future practitioners for the effective use of these tools and address the associated ethical challenges they present.

OBJECTIVE

This study aims to explore how medical students from Germany, Austria, and Switzerland perceive the use of AI in medicine and the teaching of AI and AI ethics in medical education in accordance with their use of AI-based chat applications, such as ChatGPT.

METHODS

This cross-sectional study, conducted from June 15 to July 15, 2023, surveyed medical students across Germany, Austria, and Switzerland using a web-based survey. This study aimed to assess students' perceptions of AI in medicine and the integration of AI and AI ethics into medical education. The survey, which included 53 items across 6 sections, was developed and pretested. Data analysis used descriptive statistics (median, mode, IQR, total number, and percentages) and either the chi-square or Mann-Whitney U tests, as appropriate.

RESULTS

Surveying 487 medical students across Germany, Austria, and Switzerland revealed limited formal education on AI or AI ethics within medical curricula, although 38.8% (189/487) had prior experience with AI-based chat applications, such as ChatGPT. Despite varied prior exposures, 71.7% (349/487) anticipated a positive impact of AI on medicine. There was widespread consensus (385/487, 74.9%) on the need for AI and AI ethics instruction in medical education, although the current offerings were deemed inadequate. Regarding the AI ethics education content, all proposed topics were rated as highly relevant.

CONCLUSIONS

This study revealed a pronounced discrepancy between the use of AI-based (chat) applications, such as ChatGPT, among medical students in Germany, Austria, and Switzerland and the teaching of AI in medical education. To adequately prepare future medical professionals, there is an urgent need to integrate the teaching of AI and AI ethics into the medical curricula.

Evaluation of the reliability and readability of ChatGPT-4 responses regarding hypothyroidism during pregnancy

Hypothyroidism is characterized by thyroid hormone deficiency and has adverse effects on both pregnancy and fetal health. Chat Generative Pre-trained Transformer (ChatGPT) is a large language model trained with a very large database from many sources. Our study was aimed to evaluate the reliability and readability of ChatGPT-4 answers about hypothyroidism in pregnancy. A total of 19 questions were created in line with the recommendations in the latest guideline of the American Thyroid Association (ATA) on hypothyroidism in pregnancy and were asked to ChatGPT-4. The reliability and quality of the responses were scored by two independent researchers using the global quality scale (GQS) and modified DISCERN tools. The readability of ChatGPT was assessed used Flesch Reading Ease (FRE) Score, Flesch-Kincaid grade level (FKGL), Gunning Fog Index (GFI), Coleman-Liau Index (CLI), and Simple Measure of Gobbledygook (SMOG) tools. No misleading information was found in any of the answers. The mean mDISCERN score of the responses was 30.26 ± 3.14; the median GQS score was 4 (2-4). In terms of reliability, most of the answers showed moderate (78.9%) followed by good (21.1%) reliability. In the readability analysis, the median FRE was 32.20 (13.00-37.10). The years of education required to read the answers were mostly found at the university level [9 (47.3%)]. Although ChatGPT-4 has significant potential, it can be used as an auxiliary information source for counseling by creating a bridge between patients and clinicians about hypothyroidism in pregnancy. Efforts should be made to improve the reliability and readability of ChatGPT.

Distribution, quantification, and characterization of substance P enteric neurons in the submucosal and myenteric plexuses of the porcine colon

The pig is an important translational model for studying intestinal physiology and disorders for its many homologies with humans, including the organization of the enteric nervous system (ENS), the major regulator of gastrointestinal functions. This study focused on the quantification and neurochemical characterization of substance P (SP) neurons in the pig ascending (AC) and descending colon (DC) in wholemount preparations of the inner submucosal plexus (ISP), outer submucosal plexus (OSP), and myenteric plexus (MP). We used antibodies for the pan-neuronal marker HuCD, and choline acetyltransferase (ChAT) and neuronal nitric oxide synthase (nNOS), markers for excitatory and inhibitory transmitters, for multiple labeling immunofluorescence and high-resolution confocal microscopy. The highest density of SP immunoreactive (IR) neurons was in the ISP (222/mm2 in the AC, 166/mm2 in the DC), where they make up about a third of HuCD-IR neurons, compared to the OSP and MP (19-22% and 13-17%, respectively, P < 0.001-0.0001). HuCD/SP/ChAT-IR neurons (up to 23%) were overall more abundant than HuCD/SP/nNOS-IR neurons (< 10%). Most SP-IR neurons contained ChAT-IR (62-85%), whereas 18-38% contained nNOS-IR with the highest peak in the OSP. A subpopulation of SP-IR neurons contains both ChAT- and nNOS-IR with the highest peak in the OSP and ISP of DC (33-36%) and the lowest in the ISP of AC (< 10%, P < 0.001). SP-IR varicose fibers were abundant in the ganglia. This study shows that SP-IR neurons are functionally distinct with variable proportions in different plexuses in the AC and DC reflecting diverse functions of specific colonic regions.

[Clinical application of large language models : Does ChatGPT replace medical report formulation? An experience report]

Artificial intelligence (AI)-based language models, such as ChatGPT offer an enormous potential for research and medical care but also for clinical workflow optimization by making medical documentation easier and more efficient in taking over standardized routine tasks. With their ability to guess a text's content using word statistics and thus outputting contextually relevant results in chat dialogues, large language models (LLM) can provide appropriate summaries of medical documentation for different target groups. For instance, text generation in easy to understand language could potentially contribute to an increase in patients' health literacy and, consequently, to increased adherence to treatment. Subsequent, the function of AI-based chatbot models to improve user experiences and enhance competence in the use of AI-based language models will be adressed. Current limitations and chances in creating epicrises are presented as an experience report. In the future, the implementation of local LLMs in medical management systems (hospital information systems, HIS and practice administration systems, PAS) and in conjunction with the electronic patient records (ePA) can fundamentally change clinical and outpatient care.

Choline-acetyltransferase (ChAT) and acetylcholinesterase (AChE) in the human infant dorsal motor nucleus of the Vagus (DMNV), and alterations according to sudden infant death syndrome (SIDS) category

Amongst other molecules, the cholinergic system consists of choline-acetyltransferase (ChAT, - synthesis enzyme), acetylcholinesterase (AChE - primary hydrolysis enzyme), and butyrylcholinesterase (BuChE - secondary hydrolysis enzyme). In the brainstem, the Dorsal Motor Nucleus of The Vagus (DMNV) has high cholinergic expression and is a region of interest in the neuropathology of sudden infant death syndrome (SIDS). SIDS is the unexpected death of a seemingly healthy infant, but postmortem brainstem abnormalities suggesting altered cholinergic regulation have been found. This study aimed to determine the percentage of positive ChAT and AChE neurons within the infant DMNV through immunohistochemistry at the three levels of the brainstem medulla (caudal, intermediate, and rostral), to investigate whether the proportion of neurons positive for these enzymes differs amongst the diagnostic subgroups of SIDS compared to those with an explained cause of Sudden unexpected death in infancy (eSUDI), and whether there were any associations with SIDS risk factors (male gender, cigarette smoke exposure, co-sleeping/bed sharing, and prone sleeping). Results showed that ChAT-positive neurons were lower in the rostral DMNV in the SIDS II cohort, and within the caudal and intermediate DMNV of infants who were exposed to cigarette smoke. These findings suggest altered cholinergic regulation in the brainstem of SIDS infants, with potential contribution of cigarette smoke exposure, presumably via the nicotinic acetylcholinergic receptor system.

Maternal choline supplementation protects against age-associated cholinergic and GABAergic basal forebrain neuron degeneration in the Ts65Dn mouse model of Down syndrome and Alzheimer's disease

Down syndrome (DS) is a genetic disorder caused by triplication of human chromosome 21. In addition to intellectual disability, DS is defined by a premature aging phenotype and Alzheimer's disease (AD) neuropathology, including septohippocampal circuit vulnerability and degeneration of basal forebrain cholinergic neurons (BFCNs). The Ts65Dn mouse model recapitulates key aspects of DS/AD pathology, namely age-associated atrophy of BFCNs and cognitive decline in septohippocampal-dependent behavioral tasks. We investigated whether maternal choline supplementation (MCS), a well-tolerated treatment modality, protects vulnerable BFCNs from age- and genotype-associated degeneration in trisomic offspring. We also examined the effect of trisomy, and MCS, on GABAergic basal forebrain parvalbumin neurons (BFPNs), an unexplored neuronal population in this DS model. Unbiased stereological analyses of choline acetyltransferase (ChAT)-immunoreactive BFCNs and parvalbumin-immunoreactive BFPNs were conducted using confocal z-stacks of the medial septal nucleus and the vertical limb of the diagonal band (MSN/VDB) in Ts65Dn mice and disomic (2N) littermates at 3-4 and 10-12 months of age. MCS trisomic offspring displayed significant increases in ChAT-immunoreactive neuron number and density compared to unsupplemented counterparts, as well as increases in the area of the MSN/VDB occupied by ChAT-immunoreactive neuropil. MCS also rescued BFPN number and density in Ts65Dn offspring, a novel rescue of a non-cholinergic cell population. Furthermore, MCS prevented age-associated loss of BFCNs and MSN/VDB regional area in 2N offspring, indicating genotype-independent neuroprotective benefits. These findings demonstrate MCS provides neuroprotection of vulnerable BFCNs and non-cholinergic septohippocampal BFPNs, indicating this modality has translational value as an early life therapy for DS, as well as extending benefits to the aging population at large.

Identifying depression and its determinants upon initiating treatment: ChatGPT versus primary care physicians

OBJECTIVE

To compare evaluations of depressive episodes and suggested treatment protocols generated by Chat Generative Pretrained Transformer (ChatGPT)-3 and ChatGPT-4 with the recommendations of primary care physicians.

METHODS

Vignettes were input to the ChatGPT interface. These vignettes focused primarily on hypothetical patients with symptoms of depression during initial consultations. The creators of these vignettes meticulously designed eight distinct versions in which they systematically varied patient attributes (sex, socioeconomic status (blue collar worker or white collar worker) and depression severity (mild or severe)). Each variant was subsequently introduced into ChatGPT-3.5 and ChatGPT-4. Each vignette was repeated 10 times to ensure consistency and reliability of the ChatGPT responses.

RESULTS

For mild depression, ChatGPT-3.5 and ChatGPT-4 recommended psychotherapy in 95.0% and 97.5% of cases, respectively. Primary care physicians, however, recommended psychotherapy in only 4.3% of cases. For severe cases, ChatGPT favoured an approach that combined psychotherapy, while primary care physicians recommended a combined approach. The pharmacological recommendations of ChatGPT-3.5 and ChatGPT-4 showed a preference for exclusive use of antidepressants (74% and 68%, respectively), in contrast with primary care physicians, who typically recommended a mix of antidepressants and anxiolytics/hypnotics (67.4%). Unlike primary care physicians, ChatGPT showed no gender or socioeconomic biases in its recommendations.

CONCLUSION

ChatGPT-3.5 and ChatGPT-4 aligned well with accepted guidelines for managing mild and severe depression, without showing the gender or socioeconomic biases observed among primary care physicians. Despite the suggested potential benefit of using atificial intelligence (AI) chatbots like ChatGPT to enhance clinical decision making, further research is needed to refine AI recommendations for severe cases and to consider potential risks and ethical issues.

Sedentary Activities and Food Intake among Children and Adolescents in the Zhejiang Province of China: A Cross-Sectional Study

BACKGROUND

Sedentary behavior may affect the types of food consumed in children and adolescents' daily diets. Previous published studies are limited to local surveys. This study aimed to explore the relationship between sedentary behavior and food intake among children and adolescents.

METHODS

A stratified sampling technique was employed in the present cross-sectional study. Demographic characteristics, sedentary behavior, transportation modes, and food intake were investigated.

RESULTS

We found that children and adolescents who watched movies or TV programs online or on their smartphones on weekends and who chatted online on weekends, including on QQ (an instant messaging software service) and WeChat (an instant messaging software service), increased their intake of instant noodles and fried pasta (Spearman's rho = 0.468, 0.575, 0.465, and 0.323; p < 0.05). Children and adolescents who chatted online on weekends, including on QQ and WeChat, increased their intake of tofu skin (Spearman's rho = 0.461; p < 0.05), and those who browsed online on weekdays increased their intake of whole-fat liquid milk (Spearman's rho = 0.455; p < 0.05). Children and adolescents who browsed and chatted online on weekends, including on QQ and WeChat, and who played computer or smartphone games, increased their intake of fried potato chips (French fries or other fried snacks) (Spearman's rho = 0.568, 0.270, and 0.412; p < 0.05). With respect to modes of transportation used to travel to and from school, children and adolescents who took buses and subways increased their intake of rice, instant noodles, sweet potatoes, soybean milk, tofu skin, processed meat products (sausage, ham sausage, or lunch meat), fish, shrimp, vegetables, nuts, and sweet cookies (buns, cakes, Dim sum, and moon cakes) (Spearman's rho = 0.394, 0.536, 0.630, 0.408, 0.485, 0.441,0.410, 0.424, 0.444, 0.541, and 0.366; p < 0.05).

CONCLUSIONS

Sedentary behavior affects the types of food consumed in children and adolescents' daily diets. Children and adolescents who browsed online on weekdays increased their intake of whole-fat liquid milk, but also increased their intake of foods with high fat, high salt, and low nutrient density. Children and adolescents taking buses and subways increased their intake of low-nutrition quality products. Public awareness efforts should focus on reducing the consumption of low-nutrition quality products and nutritional education.

Large Language Models

Large Language ModelsIn the latest edition of Stats, STAT!, Fralick and colleagues explain the statistics behind large language models - used in chat bots like ChatGPT and Bard. While these new tools may seem remarkably intelligent, at their core they just assemble sentences based on statistics from large amounts of text.

Human heuristics for AI-generated language are flawed

Human communication is increasingly intermixed with language generated by AI. Across chat, email, and social media, AI systems suggest words, complete sentences, or produce entire conversations. AI-generated language is often not identified as such but presented as language written by humans, raising concerns about novel forms of deception and manipulation. Here, we study how humans discern whether verbal self-presentations, one of the most personal and consequential forms of language, were generated by AI. In six experiments, participants (N = 4,600) were unable to detect self-presentations generated by state-of-the-art AI language models in professional, hospitality, and dating contexts. A computational analysis of language features shows that human judgments of AI-generated language are hindered by intuitive but flawed heuristics such as associating first-person pronouns, use of contractions, or family topics with human-written language. We experimentally demonstrate that these heuristics make human judgment of AI-generated language predictable and manipulable, allowing AI systems to produce text perceived as "more human than human." We discuss solutions, such as AI accents, to reduce the deceptive potential of language generated by AI, limiting the subversion of human intuition.

Human Pulmonary Vein Myocardial Sleeve Autonomic Neural Density and Cardiovascular Mortality

Myocardial sleeves around pulmonary veins (PVs) are highly innervated structures with heterogeneous morphological and electrophysiological characteristics. Autonomic nerve dysfunction in the myocardium may be associated with an increased risk of cardiovascular morbidity and mortality. This article studied autonomic neural remodeling in myocardial sleeves around PVs and atrial-PV ostia with immunohistochemical and morphometric methods with clinicopathological correlations. PVs were collected from 37 and atrial-PV ostia from 17 human autopsy hearts. Immunohistochemical analysis was performed using antibodies against tyrosine hydroxylase (TH), choline acetyltransferase (CHAT), and growth-associated protein 43 (GAP43). In the PV cohort, subjects with immediate cardiovascular cause of death had significantly decreased sympathetic nerve density in fibro-fatty tissue vs those with non-cardiovascular cause of death (1624.53 vs 2522.05 µm2/mm2, p=0.038). In the atrial-PV ostia cohort, parasympathetic nerve density in myocardial sleeves was significantly increased in subjects with underlying cardiovascular cause of death (19.48 µm2/mm2) than subjects with underlying non-cardiovascular cause of death with no parasympathetic nerves detected (p=0.034). Neural growth regionally varied in sympathetic nerves and was present in most of the parasympathetic nerves. Heterogeneous autonomic nerve distribution and growth around PVs and atrial-PV ostia might play a role in cardiovascular morbidity and mortality. No association in nerve density was found with atrial fibrillation.

Spiking Neural P Systems with Enzymes

The neurotransmitter is a chemical substance that transmits information between neurons. Its metabolic process includes four links: synthesis, storage, release and inactivation. As one of the important chemical components of neurotransmitters, acetylcholine is synthesized under the catalysis of acetylcholine coenzyme A and choline acetylase. Inspired by the biological fact that enzymes exist in neurons and that enzymes are involved in neurotransmitter synthesis, we propose spiking neural P systems with enzymes (SNPE). Different from the previous spiking neural P systems and their variants, each neuron of SNPE contains two classes of objects, and each spiking rule has the participation of enzymes. In addition, the number of spikes and enzymes in a neuron can also serve as a consumption condition for controlling whether a reaction (rule execution) occurs. When the number of enzymes meets the requirements of a specific biochemical reaction, the number of occurrences of the reaction can also be controlled. As number generation and acceptance devices, the proposed SNPE systems are proved to be Turing universal. In addition, 61 neurons are used to construct an SNPE system that realizes function computation, which proves the Turing universality in this mode. Finally, we also explore using a uniform SNPE model to solve the subset sum problem and compare it with the standard SN P and its several variants.

Higher levels of α7 nicotinic receptors, but not choline acetyltransferase, in the dorsolateral prefrontal cortex from a sub-group of patients with schizophrenia

It has been suggested the study of sub-groups within the syndrome of schizophrenia will assist in elucidating the complex pathophysiology of the syndrome. Hence, we have studied a number of cholinergic markers in the cortex from a sub-group of subjects with schizophrenia that have a marked decrease in levels of muscarinic M1 receptors (MRDS). The displacement of [³H]NMS by cortical extracts was used to measure tissue anticholinergic load, [¹²⁵I]α bungarotoxin binding was used to measure levels of the α7 nicotinic receptor (CHRNA7) and western blotting was used to measure levels of choline acetyltransferase (ChAT) 68 and 82 as well as synaptosome nerve-associated protein 25 (SNAP25). In comparing schizophrenia, MRDS and non-MRDS to controls, there were no differences in levels of ChAT 68 or 82, SNAP 25 or cholinergic load in BA 9. However, levels of CHRNA7 were higher in BA 9, but not BA 6 or 44, from subjects with MRDS. These data argue that there is no change in cholinergic innovation (measured using ChAT), presynaptic neurons (measured using SNAP25) or cholinergic load in schizophrenia, MRDS or non-MRDS. However, increased levels of CHRNA7 may be contributing to a breakdown in cholinergic homeostasis in BA 9, but not BA 6 or 44, in subjects with MRDS.

Slowing blood flow to fight viral infection

T cells produce acetylcholine to dilate blood vessels and migrate into infected tissues

Effects of surgical lesions on choline acetyltransferase activity in the cat cochlea

Although it is well established that the choline acetyltransferase (ChAT, the enzyme for acetylcholine synthesis) in the mammalian cochlea is associated with its olivocochlear innervation, the distribution of this innervation in the cochlea varies somewhat among mammalian species. The quantitative distribution of ChAT activity in the cochlea has been reported for guinea pigs and rats. The present study reports the distribution of ChAT activity within the organ of Corti among the three turns of the cat cochlea and the effects of removing olivocochlear innervation either by a lateral cut aimed to totally transect the left olivocochlear bundle or a more medial cut additionally damaging the superior olivary complex on the same side. Similarly to results for guinea pig and rat, the distribution of ChAT activity in the cat outer hair cell region showed a decrease from base to apex, but, unlike in the guinea pig and rat, the cat inner hair cell region did not. As in the rat, little ChAT activity was measured in the outer supporting cell region. As previously reported for whole cat cochlea and for rat cochlear regions, transection of the olivocochlear bundle resulted in almost total loss of ChAT activity in the hair cell regions of the cat cochlea. Lesions of the superior olivary complex resulted in loss of ChAT activity in the inner hair cell region of all cochlear turns only on the lesion side but bilateral losses in the outer hair cell region of all turns. The results are consistent with previous evidence that virtually all cholinergic synapses in the mammalian cochlea are associated with its olivocochlear innervation, that the olivocochlear innervation to the inner hair cell region is predominantly ipsilateral, and that the olivocochlear innervation to the outer hair cells is bilateral.

[Neurons with Different Neurotransmitters in Embryonic Neocortical Allografts in the Rat Sciatic Nerve]

Different subsets of interneurons in the Wistar rat neocortex and in neocortical transplants developing in a damaged nerve were identified by the following immunohistochemical markers: glutamate decarboxylase (GAD 67) for GABAergic nerve cells, NO-synthase (NOS) for NO-ergic neurons, choline acetyltransferase (ChAT) for cholinergic cells, and tyrosine hydroxylase for catecholaminergic structures. Twenty-eight days after surgery, individual GAD 67-ir, NO-ir, ChAT-ir, and very rarely TH-ir cells were detected in the graft. It was shown that the number of GAD 67-ir neurons per unit area in the grafts was less than in the rat neocortex P20.

[Effects of Different Compatibilities of Ramulus Cinnamomi and Peony in Guizhi Decoction on Diabetic Cardiac Autonomic Neuropathy]

OBJECTIVE

To observe the preventive effect different compatibilities of Ramulus Cinnamomi (RC) and peony in Guizhi Decoction (GD) on diabetic cardiac autonomic neuropathy (DCAN).

METHODS

Totally 60 male rats were randomly divided into 5 groups, i.e., the blank control DM group, the model group, the methycobal group, the 1:1 (RC/peony) Guishao group, the 2:1 Guishao group, and the 1:2 Guishao group, 10 in each group. Rats were pretreated with corresponding drugs for 1 week, and then induced diabetes by intraperitoneal injection of STZ. Drugs were administrated by gastrogavage for 4 more weeks after STZ-injection. Enzyme-linked immunosorbent assay (ELISA) was employed to detect levels of tyrosine hydroxylase (TH), choline acetyltransferase (CHAT), nerve growth factor. (NGF), and ciliary neurotrophic factor (CNTF) in myocardial homogenates.

RESULTS

After 4-week modeling, body weight (BW) was obviously lower, but blood glucose (BG) was higher in STZ rats than in rats of the blank control DM group. There was no statistical difference in BW or BG among the 5 groups (P >0.05). Compared with the blank control group, TH, TH/CHAT, and NGF in left ventricle and ventricular septum increased, CHAT and CNTF increased in the model group (P < 0.05, P < 0.01). Compared with the model group, TH and TH/CHAT in left ventricle decreased (P < 0.05, P < 0.01), CNTF in left ventricle increased (P < 0.05), CHAT in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the methycobal group. TH and TH/CHAT in left ventricle and ventricular septum decreased, CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01), CHAT in left ventricle and ventricular septum increased (P < 0.01), NGF in ventricular septum decreased (P < 0.01) in the 1:1 Guishao group. TH/CHAT in left ventricle decreased (P < 0.01), CHAT and CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the 1:2 Guishao group. Compared with the methycobal group, CHAT in left ventricle decreased, TH and TH/CHAT in left ventricle increased in the 2:1 Guishao group (P < 0.05, P < 0.01). TH and TH/CHAT in ventricular septum decreased (P < 0.05), CHAT and CNTF in left ventricle and ventricular septum increased (P < 0.05, P < 0.01) in the 1:1 Guishao group. Compared with the 1:2 Guishao group and the 2:1 Guishao group, CHAT in left ventricle increased, TH/CHAT in left ventricle decreased, TH and TH/CHAT in ventricular septum decreased, CHAT in ventricular septum increased, CNTF in left ventricle and ventricular septum also increased in the 1:1 Guishao group (all P < 0.01).

CONCLUSIONS

STZ model rats had autonomic neural injury, manifested as lowered vagal nerve activity and hyperactive sympathetic nerves. GD could effectively suppress hyperactive cardiac sympathetic nerves and protect the vagus. Besides, GD (1:1) showed the optimal effect in regulating the balance of cardiac autonomic nerves and could be used in early prevention of DCAN.

An Anatomical Study of Ethiopian Khat (Leaf of Catha Edulis Forsk)

The morphology and anatomy of the leaves of Catha edulis Forsk. obtained from Ethiopia is described and illustrated. A list of the characters of powdered Khat is also given.

[Immunotherapy and Alzheimer's disease]

Recent progress in biological studies on Alzheimer's disease (AD) could lead to a new strategy for its treatment. One of the representative and leading therapies is passive and active immunotherapy. The first active immunotherapy using the full length of Abeta protein was stopped due to the serious side-effect of encephalitis. Currently, a new revised immunotherapy using humanized mouse monoclonal antiserum against a part of Abeta protein is under clinical trials. Here, future advance concerning AD treatment as well as the present situation will be reviewed.

Mechanisms of nitrosamine-mediated neurodegeneration: potential relevance to sporadic Alzheimer's disease

Streptozotocin (STZ) is a nitrosamine-related compound that causes Alzheimer's disease (AD)-type neurodegeneration with cognitive impairment, brain insulin resistance, and brain insulin deficiency. Nitrosamines and STZ mediate their adverse effects by causing DNA damage, oxidative stress, lipid peroxidation, pro-inflammatory cytokine activation, and cell death, all of which occur in AD. We tested the hypothesis that exposure to N-nitrosodiethylamine (NDEA), which is widely present in processed/preserved foods, causes AD-type molecular and biochemical abnormalities in central nervous system (CNS) neurons. NDEA treatment of cultured post-mitotic rat CNS neurons (48 h) produced dose-dependent impairments in ATP production and mitochondrial function, and increased levels of 8-hydroxy-2'-deoxyguanosine, 4-hydroxy-2-nonenal, phospho-tau, amyloid-beta protein precursor-amyloid-beta (A beta PP-A beta), and ubiquitin immunoreactivity. These effects were associated with decreased expression of insulin, insulin-like growth factor (IGF)-I, and IGF-II receptors, and choline acetyltransferase. Nitrosamine exposure causes neurodegeneration with a number of molecular and biochemical features of AD including impairments in energy metabolism, insulin/IGF signaling mechanisms, and acetylcholine homeostasis, together with increased levels of oxidative stress, DNA damage, and A beta PP-A beta immunoreactivity. These results suggest that environmental exposures and food contaminants may play critical roles in the pathogenesis of sporadic AD.

Identification of motoneurons supplying multiply- or singly-innervated extraocular muscle fibers in the rat

In mammals, the extraocular muscle fibers can be categorized in singly-innervated and multiply-innervated muscle fibers. In the monkey oculomotor, trochlear and abducens nucleus the motoneurons of multiply-innervated muscle fibers lie separated from those innervating singly-innervated muscle fibers and show different histochemical properties. In order to discover, if this organization is a general feature of the oculomotor system, we investigated the location of singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons in the rat using combined tract-tracing and immunohistochemical techniques. The singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons of the medial and lateral rectus muscle were identified by retrograde tracer injections into the muscle belly or the distal myotendinous junction. The belly injections labeled the medial rectus muscle subgroup of the oculomotor nucleus or the greatest part of abducens nucleus, including some cells outside the medial border of abducens nucleus. In contrast, the distal injections labeled only a subset of the medial rectus muscle motoneurons and exclusively cells outside the medial border of abducens nucleus. The tracer detection was combined with immunolabeling using antibodies for perineuronal nets (chondroitin sulfate proteoglycan) and non-phosphorylated neurofilaments. In monkeys both antibodies permit a distinction between singly-innervated muscle fiber and multiply-innervated muscle fiber motoneurons. The experiments revealed that neurons labeled from a distal injection lack both markers and are assumed to represent multiply-innervated muscle fiber motoneurons, whereas those labeled from a belly injection are chondroitin sulfate proteoglycan- and non-phosphorylated neurofilament-immunopositive and assumed to represent singly-innervated muscle fiber motoneurons. The overall identification of multiply-innervated muscle fiber and singly-innervated muscle fiber motoneurons within the rat oculomotor nucleus, trochlear nucleus, and abducens nucleus revealed that the smaller multiply-innervated muscle fiber motoneurons tend to lie separate from the larger diameter singly-innervated muscle fiber motoneurons. Our data provide evidence that rat extraocular muscles are innervated by two sets of motoneurons that differ in their molecular, morphological, and anatomical properties.

Expression of Hand2 is sufficient for neurogenesis and cell type–specific gene expression in the enteric nervous system

The basic helix-loop-helix DNA binding protein Hand2 is expressed in neural crest-derived precursors of enteric neurons and has been shown to affect both neurogenesis and neurotransmitter specification of noradrenergic sympathetic ganglion neurons. In the current study, our goal was to determine whether Hand2 affects neurogenesis and/or expression of vasoactive intestinal polypeptide and choline acetyltransferase in developing enteric neurons. Gain-of-function of Hand2 in HNK-1(+) immmunoselected precursor cells resulted in increased neurogenesis. The number of neurons expressing vasoactive intestinal polypeptide increased in response to Hand2 overexpression although choline acetyltransferase was not affected. Targeted deletion of Hand2 in neural crest cells resulted in loss of all neurons expressing vasoactive intestinal polypeptide along the length of the gastrointestinal tract, patterning defects in the myenteric plexus of the stomach, and altered number and morphology of neurons expressing TH. Our data demonstrate that expression of Hand2 is sufficient and necessary for neurogenesis and expression of a subset of cell type-specific markers in the developing enteric nervous system.

A humanin derivative, S14G-HN, prevents amyloid-?-induced memory impairment in mice

Humanin (HN) is a 24-amino acid peptide that protects neuronal cells from death caused by Alzheimer's disease (AD)-related genes and amyloid-beta (Abeta). Multiple studies have revealed its biochemical and neuroprotective characteristics in vitro; however, little has been known regarding whether HN is effective in vivo in AD model systems. We examined the effect of S14G-HN, a 1,000-fold more potent derivative of HN in vitro, on amnesia induced by Abeta25-35 in mice. The Y-maze test revealed that at least 50 pmol of S14G-HN by intracerebroventricular injection prevented Abeta-induced impairment of short-term/spatial working memory; however, 5 nmol of S14A-HN, a neuroprotection-defective mutant in vitro, did not prevent Abeta-induced amnesia. These results are in agreement with the structure-function correlation shown previously in vitro. In the water-finding task, S14G-HN prevented prolongation of finding latency (the time to find water) observed in Abeta-amnesic mice, indicating that S14G-HN also blocked Abeta-induced impairment of latent learning. In accordance with these observations, immunohistochemical analysis showed that S14G-HN sustained the number of cholinergic neurons in the basal forebrain and the striata nearly to the normal level. Furthermore, genistein, a specific inhibitor of tyrosine kinases, blocked recovery from scopolamine-induced amnesia by S14G-HN, suggesting that certain tyrosine kinase(s) are involved in the inhibitory function of S14G-HN in vivo. Taking these findings together, we conclude that S14G-HN has rescue activity against memory impairment caused by AD-related insults in vivo by activating the same intracellular neuroprotective machinery as elucidated previously in vitro.

Light and electron microscopic study of cholinergic and noradrenergic elements in the basolateral nucleus of the rat amygdala: evidence for interactions between the two systems

Pharmacological studies have suggested that the cholinergic (ACh) and noradrenergic (NA) systems in the amygdala (AM) play an important role in learning and memory storage and that the two systems interact to modulate memory storage. To obtain anatomical evidence for the interaction, the organization of the ACh and NA fibers in rat AM was investigated by immunocytochemistry for choline acetyltransferase (ChAT) and dopamine-beta-hydroxylase (DBH) in conjunction with light, confocal laser scanning, and electron microscopy (LM, CLSM, and TEM, respectively). LM showed that the ChAT immunoreactivity was densest in the basolateral nucleus (BL), whereas the DBH immunoreactivity was densest in the posterior BL. CLSM demonstrated that the ChAT-immunoreactive profiles in the BL were frequently located in juxtaposition to the DBH-immunoreactive axons. The TEM observations were as follows: The majority of the synapses formed by ChAT-immunoreactive terminals were symmetric, but DBH-immunoreactive axons formed both asymmetric and symmetric synapses. The ChAT-immunoreactive terminals usually established the symmetric synaptic contacts with the DBH-immunoreactive terminals and varicosities. The DBH-immunoreactive terminals formed the asymmetric synapses with the ChAT-immunoreactive dendrites of the intrinsic neurons within the AM. The results provide anatomical substrates for mnemonic functions of the ACh and NA systems and for the interactions between the two systems in the AM.

Choline acetylase in the gill plates of Mytilus edulis

Previous work has shown that ciliary movement in the gill plates ofMytilus edulisis controlled by acetylcholine. This substance was shown to be present in the gill plates together with the enzyme ‘ true ’ cholinesterase. The action of acetylcholine, eserine, atropine andd-tubocurarine was consistent with the view that naturally formed acetylcholine maintained the ciliary rhythm. The evidence of the presence of a choline-acetylase system was however weak, and a new investigation has therefore been made, in which tenfold higher values for choline acetylase have been obtained. The effect of temperature on this enzyme has been studied.

Comparison of cholinergic and histaminergic axons in the lateral geniculate complex of the macaque monkey

The cholinergic and histaminergic projections have important neuromodulatory functions in the ascending visual pathways, so we compared the pattern and mode of innervation of the two projections in the lateral geniculate complex (dorsal lateral geniculate nucleus and pregeniculate nucleus) of the macaque monkey. Brain tissue from macaques was immunoreacted by means of antibodies to choline acetyltransferase (ChAT) or to histamine and processed for light and electron microscopy. A dense plexus of thin, highly branched ChAT-immunoreactive axons laden with varicosities was found in all layers of the dLGN including the koniocellular laminae and in the pregeniculate nucleus. ChAT label was more dense in magnocellular layers 1 and 2 than in parvocellular layers 3-6 and relatively sparse in the interlaminar zones. Varicosities associated with the cholinergic axons had an average of three conventional asymmetric synapses per varicosity, and these appeared to contact dendrites of both thalamocortical cells and interneurons. Histamine-immunoreactive axons were distributed homogeneously throughout all laminar and interlaminar zones of the dLGN, but were denser in the pregeniculate nucleus than in the dLGN. Histaminergic axons branched infrequently and were typically larger in caliber than cholinergic axons. The overwhelming majority of varicosities were found en passant and rarely displayed conventional synapses, despite the abundance of synaptic vesicles, and were not associated preferentially with specific cellular structures. The innervation of the macaque dLGN complex by cholinergic and histaminergic systems is consistent with their proposed role in state dependent modulation of thalamic activity. The dense and highly synaptic innervation by cholinergic axons supports the proposal of additional involvement of these axons in functions related to eye movements.

Codistribution of nicotinic acetylcholine receptor subunit alpha3 and beta4 mRNAs during rat brain development

We have used in situ hybridization to characterize the ontogeny of alpha3 and beta4 nicotinic acetylcholine receptor (nAChR) subunit mRNA expression in rat brain. Transcripts for both subunits were detected in embryonic brain, although overlapping expression of alpha3 mRNA was only evident in areas of strong beta4 mRNA expression, including the medial habenula, locus coeruleus, the cerebellar primordium, and several motor and sensory brainstem nuclei. During the perinatal period, the independent expression of alpha3 mRNA declined, and greater correspondence in the temporal and spatial expression of alpha3 and beta4 subunit mRNAs emerged. In general, beta4 mRNA expression preceded that of alpha3 mRNA by 1 to 2 days. Overlapping expression patterns were transiently detected in the caudate putamen, basal forebrain, frontal and visual cortices, and in the CA3 field of hippocampus. Codistribution that lasted throughout development and into adulthood was noted in a number of brain areas, including the retrosplenial cortex, subiculum, medial habenula, interpeduncular nucleus, locus coeruleus, and brainstem motor nuclei. In many of these regions, alpha5 subunit mRNA was also expressed. Colocalization of alpha3 and beta4 mRNAs with choline acetyltransferase mRNA was detected in cholinergic neurons of the brainstem motor nuclei, nucleus ambiguus, dorsal motor nucleus of the vagus, motor trigeminal nucleus, and facial nucleus, but not in most forebrain cholinergic cells. The extensive correspondence in temporal and spatial distribution of alpha3 and beta4 mRNAs throughout postnatal brain development suggests that these subunits may be coordinately regulated and may form functional neuronal nAChRs with significant developmental roles.

Improvement of cognitive deficits and decreased cholinergic neuronal cell loss and apoptotic cell death following neurotrophin infusion after experimental traumatic brain injury

This study explores the effects of infusion of nerve growth factor (NGF) on behavioral outcome and cell death in the septal region using the clinically relevant model of fluid-percussion brain injury in the rat. Animals were subjected to fluid-percussion brain injury and 24 hours later a miniosmotic pump was implanted to infuse NGF (12 animals) or vehicle (12 animals) directly into the region of maximum injury for 2 weeks. Four weeks postinjury the animals were tested for cognitive function using a Morris Water Maze paradigm. Neurological motor function was evaluated over a 4-week postinjury period. The rats receiving NGF infusions had significantly higher memory scores than vehicle-treated animals. Examination of the cholinergic neurons in the medial septal region using choline acetyltransferase immunohistochemistry demonstrated significant cell loss after injury. Infusion of NGF significantly attenuated loss of these cholinergic neurons. A second group of animals was subjected to fluid-percussion brain injury alone (23 rats) or injury followed by NGF infusion (18 rats). These animals were killed between 24 hours and 2 weeks postinjury and the septal region was examined for the presence of apoptotic cells using the terminal deoxynucleotidyl transferase-mediated biotinylated-deoxyuridinetriphosphate nick-end labeling technique. Apoptotic cells were identified as early as 24 hours postinjury; their numbers peaked at 4 and 7 days, and then declined by 14 days. The NGF-treated animals had some apoptotic cells; however, even at 7 days there were significantly fewer of these cells. No significant motor differences were observed between the NGF- and vehicle-treated groups. These data indicate that NGF administration beginning 24 hours after fluid-percussion brain injury has a beneficial effect on cognition and results in sparing of cholinergic septal neurons. These improvements persist after cessation of NGF administration. The beneficial effects of NGF may be related to its ability to attenuate traumatically induced apoptotic cell death.

Transcriptional activation by the androgen receptor in X-linked spinal and bulbar muscular atrophy

Polyglutamine tracts encoded by trinucleotide CAG repeats have been found in some transcription factors. Expansion of the polyglutamine tracts in the androgen receptor (AR) has been recognized as a cause of X-linked spinal and bulbar muscular atrophy (SBMA). To study the role of AR as a transcription factor in SBMA, we constructed AR genes encoding expanded polyglutamine tracts (repeat numbers = 52, 92, 132, and 212), and analyzed AR-induced transcriptional activation in NG108-15 cells. We found that AR-induced transcriptional activation gradually decreased with increasing glutamine repeat numbers, and polyglutamine expansion caused a specific reduction in transcription activity in motor neurons. However, the degree of reduction was slight in comparison with the normal AR gene and that of SBMA. Thus, subtle disorders of transcriptional control may occur in SBMA.

Immunohistochemical study of neurons in the rat abducens nucleus that project to the flocculus

The neurons of the rat abducens nucleus that project to the flocculus of the cerebellum were studied by double labelling using the retrograde transport of horseradish peroxidase (HRP) and choline acetyltransferase (ChAT) immunohistochemistry. Double-labelled cells were present bilaterally in the dorsal and dorsomedial zones of the cranial pole of the nucleus. They represented about half of the total number of HRP-positive neurons. These findings show the existence of a bilateral projection from the abducens nucleus to the flocculus which uses acetylcholine as a neurotransmitter. This projection could be part of the system of the nerve circuits through which the cerebellum modulates visual activities.

Multiple origins of cerebellar cholinergic afferents from the lower brainstem in the gerbil

The possible origins of cerebellar cholinergic afferents from the lower brainstem of the gerbil were examined using immunohistochemistry combined with retrograde neuronal labelling techniques. Choline acetyltransferase (ChAT) monoclonal antibody was used in conjunction with a retrogradely transported tracer, horseradish peroxidase (HRP). The use of this technique allowed an unequivocal localisation of cholinergic neurons in different parts of the lower brainstem projecting to the cerebellum. In addition, single labelling of acetylcholinesterase (AChE), ChAT and HRP was carried out to elucidate the efferent projection from the lower brainstem to the cerebellum as well as the cholinergic distribution in these two areas. Our results showed the presence of HRP/ChAT double-labelled neurons in (1) the midline medulla: the periventricular gray beneath the 4th ventricle, C3 adrenergic area, raphe obscurus nucleus and medial longitudinal fasciculus, (2) the reticular formation: the medullary, lateral, intermediate, gigantocellular, lateral paragigantocellular and dorsal paragigantocellular reticular nuclei and gigantocellular reticular nucleus ventralis, and (3) sensory nuclei: the gracile nucleus, cuneate nucleus, external cuneate nucleus, spinal trigeminal nucleus interpolaris, prepositus hypoglossal nucleus and medial vestibular nucleus. In the cerebellum, AChE-positive mossy fibres were chiefly localised in the vermian lobules VIb,c, VII and X, paramedian lobule, crura I and II, paraflocculus and flocculus, and they were distributed in the white matter and granular layer of the cortex. The 3 above-mentioned cerebellar cholinergic afferent systems associated with the unique AChE distribution pattern in the cerebellum may be of important functional significance.

Apolipoprotein E in animal models of CNS injury and in Alzheimer's disease

Recent evidence indicates that apolipoprotein E (ApoE) plays a central role in the hippocampal response to injury. The co-ordinated expression of ApoE and its receptor, the ApoE/ApoB [low density lipoprotein (LDL)] receptor, appears to regulate the transport of cholesterol and phospholipids during the early and intermediate phases of the reinnervation process. During dendritic remodeling and synaptogenesis, neurons progressively repress the synthesis of cholesterol in favor of cholesterol internalization through the ApoE/LDL receptor pathway. The discovery that the epsilon 4 allele is strongly linked to both sporadic and familial late-onset Alzheimer's disease (AD) raises the possibility that a dysfunction of the lipid-transport system associated with compensatory sprouting and synaptic remodeling could be central to the AD process. The role of ApoE in the CNS is particularly important in relation to the function of the cholinergic system, which relies to a certain extent on the integrity of phospholipid homeostasis in neurons. Recent evidence suggests that the epsilon 4 allele has a direct impact on cholinergic function in AD.

Light microscopic distribution of some cholinergic markers in the rat and rabbit locus coeruleus and the nucleus angularis grisea periventricularis of the domestic pig (Sus scrofa): a correlative electron microscopic investigation of cholinergic receptor proteins in the rabbit

Cholinergic modulation of locus coeruleus (LC) neurons evokes a variety of neuronal and behavioural effects. In an attempt to understand the LC cholinergic circuit, several markers has been investigated and compared. (Immuno)-histochemical and autoradiographic methods have been used on rat, rabbit, and pig tissue. To identify the boundaries of the LC in each of these species, sections through the entire brainstem have been stained for tyrosine hydroxylase. The results indicate that the pig does not possess a LC proper that conforms to the accepted features of this cell group. However, in this location fusiform cells reminiscent of LC interneurons are still present. This group of fusiform neurons has been named the nucleus angularis grisea periventricularis (NAGP). LC cells of the rat and rabbit show strong acetylcholinesterase (AChE) activity. In the pig the NAGP is markedly free from AChE staining. Muscarinic binding sites are densely distributed over the rabbit LC and adjacent region. The rat and rabbit LC neurons synthesise both muscarinic (mAChR) and nicotinic receptor protein (nAChR). In the pig NAGP region mAChR and nAChR positive cell bodies are almost absent, while some nAChR immunoreactive dendrites are present. The light microscopic data in the rabbit have been confirmed by electron microscopic analysis. It is concluded that the general concept of a noradrenergic LC that is present throughout mammals is questionable. At present, choline acetyltransferase immunoreactive terminals that closely correspond to the other cholinergic components in the rat or rabbit LC have not been observed. However, in these species the cholinergic sensitivity of LC cells is mediated via both muscarinic and nicotinic receptors on somata and dendrites.

Formation of synapses between basal forebrain afferents and cerebral cortex neurons: an electron microscopic study in organotypic slice cultures

Co-cultures of rat basal forebrain and cerebral cortex were maintained from 1 to 5 weeks in vitro with serum-free defined medium. The formation of synaptic connections between basal forebrain afferent fibres and cortical neurons was studied by specific labelling with three staining techniques, including (i) neuronal tract tracing with the fluorescent dye 1,1'-dioctodecyl-3,3,3'3'- tetramethylindocarbocyanine perchlorate, (ii) acetylcholinesterase histochemistry, and (iii) choline acetyltransferase immunocytochemistry. Both basal forebrain and cerebral cortex tissue displayed organotypic characteristics in culture. Cerebral cortex revealed a dense innervation by axonal projections from the basal forebrain. All three labelling techniques produced similar results at the light microscopic level, with densest innervation located in the marginal zone. At the fine structural level, the 1,1'-dioctodecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate-, acetylcholinesterase- and choline acetyltransferase-stained basal forebrain afferents all revealed a number of synaptic contacts with cortical neurons. The contacts displayed consistent synaptic features, including presynaptic accumulation of small round vesicles, cleft widening, and postsynaptic densities forming symmetric synapses. These morphological characteristics of connections formed in vitro are similar to basal forebrain cholinergic projections to cerebral cortex in normal brain. Based on these results, this tissue culture model appears to be an useful tool for investigations of the development of cholinergic innervation of cerebral cortex.

Cholinergic and non-cholinergic neurons in the rat pedunculopontine tegmental nucleus

Choline acetyltransferase immunhistochemistry was employed at light and electron microscopic levels in order to determine the distribution of cholinergic neurons in two subdivisions of the rat pedunculopontine tegmental nucleus that were previously defined on cytoarchitectonic grounds, and to compare the synaptic inputs to cholinergic and non-cholinergic somata in the subnucleus dissipatus, which receives major input from the substantia nigra. Large cholinergic neurons were found in both the pars compacta and the pars dissipata of the pedunculopontine nucleus. However, they were intermingled with non-cholinergic neurons and did not respect the cytoarchitectural boundaries of the nucleus. Ultrastructural study showed that all cholinergic neurons in the subnucleus dissipatus exhibited similar features. The majority had large somata (largest diameter greater than or equal to 20 microns) containing abundant cytoplasmic organelles and nuclei displaying a few shallow invaginations. Synaptic terminals on the cholinergic cell bodies were scarce and unlabeled boutons containing spherical synaptic vesicles and establishing asymmetric synaptic junctions were the dominant type. In contrast, the non-cholinergic neurons presented prominent differences in the size of their somata as well as in the distribution of axosomatic synapses. Two almost equally represented classes of non-cholinergic neurons which are referred to as large (largest diameter greater than or equal to 20 microns) and small (largest diameter less than 20 microns) were recognized. Large non-cholinergic cell bodies were ultrastructurally similar to the cholinergic ones, but they received rich synaptic input by unlabeled nerve terminals which contained pleomorphic vesicles and were engaged in symmetric synaptic junctions. Small non-cholinergic cell bodies were characterized by deeply invaginated nuclei surrounded by a narrow rim of cytoplasm, and were often found near or in direct apposition to the cholinergic somata. Their major input consisted of axosomatic boutons containing round synaptic vesicles. These results demonstrate that cells in the pedunculopontine tegmental nucleus are differentiated with regard to their axosomatic synaptic inputs which may influence their firing properties. Furthermore, they support previous suggestions that nigral afferents may be preferentially distributed to a subpopulation of the pedunculopontine neurons.