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PubMed2025

Rehabilomics Strategies Enabled by Cloud-Based Rehabilitation: Scoping Review.

BACKGROUND: Rehabilomics, or the integration of rehabilitation with genomics, proteomics, metabolomics, and other "-omics" fields, aims to promote personalized approaches to rehabilitation care. Cloud-based rehabilitation offers streamlined patient data management and sharing and could potentially play a significant role in advancing rehabilomics research. This study explored the current status and potential benefits of implementing rehabilomics strategies through cloud-based rehabilitation. OBJECTIVE: This scoping review aimed to investigate the implementation of rehabilomics strategies through cloud-based rehabilitation and summarize the current state of knowledge within the research domain. This analysis aims to understand the impact of cloud platforms on the field of rehabilomics and provide insights into future research directions. METHODS: In this scoping review, we systematically searched major academic databases, including CINAHL, Embase, Google Scholar, PubMed, MEDLINE, ScienceDirect, Scopus, and Web of Science to identify relevant studies and apply predefined inclusion criteria to select appropriate studies. Subsequently, we analyzed 28 selected papers to identify trends and insights regarding cloud-based rehabilitation and rehabilomics within this study's landscape. RESULTS: This study reports the various applications and outcomes of implementing rehabilomics strategies through cloud-based rehabilitation. In particular, a comprehensive analysis was conducted on 28 studies, including 16 (57%) focused on personalized rehabilitation and 12 (43%) on data security and privacy. The distribution of articles among the 28 studies based on specific keywords included 3 (11%) on the cloud, 4 (14%) on platforms, 4 (14%) on hospitals and rehabilitation centers, 5 (18%) on telehealth, 5 (18%) on home and community, and 7 (25%) on disease and disability. Cloud platforms offer new possibilities for data sharing and collaboration in rehabilomics research, underpinning a patient-centered approach and enhancing the development of personalized therapeutic strategies. CONCLUSIONS: This scoping review highlights the potential significance of cloud-based rehabilomics strategies in the field of rehabilitation. The use of cloud platforms is expected to strengthen patient-centered data management and collaboration, contributing to the advancement of innovative strategies and therapeutic developments in rehabilomics.

Cloud Computing↗
PubMed2025

Large-scale analysis of MYB genes in Cucurbitaceae identifies a novel gene regulating plant height.

The MYB transcription factor (TF) family, which is involved in plant growth and development, is large and diverse. Previous studies on MYB family in Cucurbitaceae were mostly based on a single genome or focused on the R2R3 subfamily. Here, we analyzed 91 genomes of 11 Cucurbitaceae species and identified a total of 15 858 MYB genes. According to phylogenetic relationships, these genes were divided into 27 subgroups. The identified MYB genes were further classified into 121 MYB orthologous gene groups (OGGs), including 25 core, 57 softcore, 19 shell and 20 line-specific/cloud groups. Whole-genome duplication was the most common mechanism of MYB genes expansion. In core group, the higher proportions of MYB genes were found to be in the coexpression network constructed by the RNA-seq data. Through the comprehensive analysis including phylogeny and gene expression profile of cucumber MYB genes, as well as genetic variations in 103 cucumber germplasms, we identified a MYB gene CsRAX5, which may be related to cucumber plant height. We used gene editing technology to knockout and overexpress CsRAX5. In the knockout lines, Csrax5, the height was significantly increased compared with wild type (WT), whereas after overexpression the height of CsRAX5-OE plants was significantly decreased compared with WT. These results indicated that MYB gene CsRAX5 negatively regulated cucumber plant height. The large-scale analysis of MYB genes in Cucurbitaceae in this study provides insights for further investigating the evolution and function of MYB genes in Cucurbitaceae crops.

Journal Article↗
PubMed2024

Small noncoding RNAs and sperm nuclear basic proteins reflect the environmental impact on germ cells.

BACKGROUND: Molecular techniques can complement conventional spermiogram analyses to provide new information on the fertilizing potential of spermatozoa and to identify early alterations due to environmental pollution. METHODS: Here, we present a multilevel molecular profiling by small RNA sequencing and sperm nuclear basic protein analysis of male germ cells from 33 healthy young subjects residing in low and high-polluted areas. RESULTS: Although sperm motility and sperm concentration were comparable between samples from the two sites, those from the high-pollution area had a higher concentration of immature/immune cells, a lower protamine/histone ratio, a reduced ability of sperm nuclear basic proteins to protect DNA from oxidative damage, and an altered copper/zinc ratio in sperm. Sperm levels of 32 microRNAs involved in intraflagellar transport, oxidative stress response, and spermatogenesis were different between the two areas. In parallel, a decrease of Piwi-interacting RNA levels was observed in samples from the high-polluted area. CONCLUSIONS: This comprehensive analysis provides new insights into pollution-driven epigenetic alterations in sperm not detectable by spermiogram.

Male↗
PubMed2026

Genomic insights into Aeromonas infections in diarrheal patients: high diversity, emerging resistance, and potential outbreak in Beijing.

BACKGROUND: Aeromonas species are ubiquitous aquatic bacteria that have emerged as significant foodborne enteric pathogens worldwide, yet their genomic landscape in clinical settings remains poorly delineated, particularly in Beijing. METHODS: To address this gap, we performed active surveillance for Aeromonas among 691 consecutive diarrheal outpatients in a Beijing district from January to December 2024. Isolates were recovered using enrichment culture coupled with PCR screening and identified by MALDI-TOF MS. Antimicrobial susceptibility was tested against 17 agents. Whole-genome sequencing was conducted on all isolates, enabling average nucleotide identity (ANI) analysis, comprehensive annotation of antimicrobial resistance and virulence genes, multilocus sequence typing (MLST), and core-genome SNP (cgSNP)-based phylogenetics. RESULTS: Aeromonas was detected in 3.3% (23/691) of patients, with Aeromonas veronii (56.52%, 13/23) and Aeromonas caviae (26.09%, 6/23) predominating. Co-infections with other enteric pathogens occurred in 65.2% of positive cases. Resistance rates were notably high for ampicillin/ampicillin-sulbactam (78.26%), nalidixic acid (56.52%), and ertapenem (21.73%), and 65.21% of isolates were multidrug-resistant. Genotypic-phenotypic concordance was robust, with β-lactamase genes ampS (60.87%) and blaCEPH-A3 (47.83%) being most prevalent. Strikingly, mcr-3.25 and mcr-3.3, which belong to the mcr family (originally described as mobile colistin resistance genes), were identified in 8.70% of isolates, exhibiting perfect correlation with phenotypic resistance. Plasmer analysis suggested both mcr genes to be chromosomally encoded. Comparative genomic analysis of virulence-associated genes revealed striking species-specific specialization: A. veronii predominantly carried complete T3SS clusters (61.5%), A. caviae and Aeromonas enteropelogenes were enriched in T6SS genes, and a single A. dhakensis isolate possessed an extensive arsenal including T3SS, T6SS, and a full RTX toxin cluster. MLST resolved the 23 isolates into 22 sequence types, 18 of which were novel. Phylogenetic reconstruction identified a tight monophyletic cluster of three A. veronii isolates (9-27 SNP differences) recovered within a 96-h window, suggestive of a potential cluster that warrants further epidemiological investigation. Comparative genomic analysis of the rare species Aeromonas allosaccharophila demonstrated that the Beijing clinical isolate S14 differs from the U.S. clinical strain ATCC 35942 by 42,099 SNPs, confirming its distinct genetic lineage. CONCLUSION: Collectively, this study delineates high genetic diversity, emerging chromosomal colistin resistance, and species-specific virulence specialization among Aeromonas isolates from diarrheal patients in Beijing. The detection of a potential outbreak cluster and a rare clinical isolate underscores the power of genomics-based surveillance for detecting and mitigating foodborne pathogen threats.

Aeromonas↗
PubMed1991

Alleles at four HLA class II loci determined by oligonucleotide hybridization and their associations in five ethnic groups.

The use of polymerase chain reaction (PCR) and oligonucleotide hybridization offers a new approach for the definition of HLA class II alleles. It has been possible to determine 43 alleles of DRB1, four of DRB3, two of DRB4, four of DRB5, eight of DQA1, and 14 of DQB1. These alleles are inherited together in members of families and form closely associated groups which are found repeatedly and in characteristic patterns in different populations. We have determined the HLA class II alleles and analyzed their association in 431 healthy unrelated subjects including 161 North American Caucasians, 53 Latin Americans, 61 Blacks, 88 Chinese, and 68 Israeli Jews. For-locus haplotypes (DRB1; DRB3/4/5; DQA1; DQB1) were derived from 79 B cell lines and the analysis of segregation in 34 nuclear families. The B-cell lines yielded 37 and the families showed the same, and 20 other, haplotypic combinations. In addition to these 57 haplotypes, associated alleles were assigned in the unrelated panels following certain rules. The resulting haplotypes were assigned to groups known to share associated alleles. The groups were: 1) DR1, DR2, and DRw10 (13 haplotypes); 2) DR3 and DRw6 (26 haplotypes); 3) DR5 and DRw8 (24 haplotypes); 4) DR4, DR7, and DR9 (24 haplotypes). Their distribution in populations with different ethnic backgrounds was analyzed. The expressed DRB4 allele and its null mutant were determined by PCR and oligonucleotide hybridization. The different DR7 haplotypes resulting from these determinations were analyzed in a panel of 130 North American Caucasoids. This comprehensive analysis of class II HLA haplotypes in human populations should be useful in understanding the role of these genes and in various applications including anthropology, disease susceptibility, and transplantation of allogeneic organs and tissues.

Alleles↗
PubMed1990

Cloning and expression of a rat neuromedin K receptor cDNA.

Functional cDNA clones for rat neuromedin K receptor were isolated from a rat brain cDNA library by cross-hybridization with the bovine substance K receptor cDNA. Injection of the mRNA synthesized in vitro from the cloned cDNA into Xenopus oocytes elicited electrophysiological responses to tachykinins, with the most potent sensitivity being to neuromedin K. Ligand-binding displacement in membranes of mammalian COS cells transfected with the cDNA indicated the rank order of affinity of the receptor to tachykinins: neuromedin K greater than substance K greater than substance P. The hybridization analysis showed that the neuromedin K receptor mRNA is expressed in both the brain and the peripheral tissues at different levels. The rat neuromedin K receptor consists of 452 amino acid residues and belongs to the family of G protein-coupled receptors, which are though to have seven transmembrane domains. The sequence comparison of the rat neuromedin K, substance P, and substance K receptors revealed that these receptors are highly conserved in the seven transmembrane domains and the cytoplasmic sides of the receptors. They also show some structural characteristics, including the common presence of histidine residues in transmembrane segments V and VI and the difference in the numbers and distributions of serine and threonine residues as possible phosphorylation sites in the cytoplasmic regions. This paper thus presents the first comprehensive analysis of the molecular nature of the multiple peptide receptors that exhibit similar but pharmacologically distinguishable activities.

Amino Acid Sequence↗
PubMed2025

Amplicon-based analyses of single-nucleotide polymorphisms reveal the genetic structure of a forest insect baculovirus.

Amplicon-based next-generation sequencing (aNGS) is a powerful tool in diagnostics and genetic studies. We developed an aNGS approach to study the population structure of the Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV), a specific pathogen of the spongy moth Lymantria dispar, a devastating lepidopteran pest in European, Asian, and American deciduous forests. Naturally occurring pathogens, such as LdMNPV, are frequently reported to cause epizootics and a rapid decline of insect pest populations. DNA samples of pooled LdMNPV-infected larvae from forest regions in Northern Bavaria (Germany) were subjected to whole genome sequencing (WGS) and aNGS optimization. Then, five marker regions were identified in the genome of LdMNPV for PCR amplification, covering 21 highly specific single-nucleotide polymorphism (SNP) positions that enabled comprehensive analysis at the intra- and intersample levels. These markers were used in aNGS analyses of 70 single larvae collected in 12 forest sites, followed by SNP-based hierarchical clustering on principal components (HCPC). This approach identified three LdMNPV population clusters consisting of homogenous (pure) and heterogeneous (mixed) LdMNPV samples. To explain the genetic variability within each sample, a model based on linear optimization was developed and validated by comparing the predictions from aNGS and WGS data. The analyses showed that LdMNPV from Bavarian forests carried genetic variants highly similar to those present in the commercial product Gypchek®, developed for biocontrol. The distribution of genetic characteristics showed some trends of geographic and temporal prevalence, which are indicative of short-distance and long-distance transmission. The aNGS approach offers a fast, cost-effective, and comprehensive insight into the natural population structure of LdMNPV.

insects↗
PubMed1990

Analysis of sequence diversity in hypervariable regions of the external glycoprotein of human immunodeficiency virus type 1.

Nucleotide sequences in three hypervariable regions of the human immunodeficiency virus type 1 (HIV-1) env gene were obtained by sequencing provirus present in peripheral blood mononuclear cells of HIV-infected individuals. Single molecules of target sequences were isolated by limiting dilution and amplified in two stages by the polymerase chain reaction, using nested primers. The product was directly sequenced to avoid errors introduced by Taq polymerase during the amplification process. There was extensive variation between sequences from the same individual as well as between sequences from different individuals. Interpatient variability was markedly less in individuals infected from a common source. A high proportion of amino acid substitutions in the hypervariable regions altered the number and positions of potential N-linked glycosylation sites. Sequences in two hypervariable regions frequently contained short (3- to 15-bp) duplications or deletions, and by amplifying peripheral blood mononuclear cell DNA containing 10(2) or 10(3) proviral molecules and analyzing the product by high-resolution electrophoresis, the total number and abundance of distinct length variants within an individual could be estimated, providing a more comprehensive analysis of the variants present than would be obtained by sequencing alone. Sequences from many individuals showed frequent amino acid substitutions at certain key positions for neutralizing-antibody and cytotoxic T-cell recognition in the immunodominant loop. The rates of synonymous and nonsynonymous nucleotide substitution in the region of this and flanking regions indicate that strong positive selection for amino acid change is operating in the generation of antigenic diversity.

Amino Acid Sequence↗
PubMed1991

Expression dynamics of the tomato rbcS gene family during development.

The tomato rbcS gene family is composed of five genes (rbcS1, 2, 3A, 3B, and 3C) that are differentially expressed during tomato development. Nuclear run-on transcription assays and RNA analysis were used to determine the contribution of transcriptional and post-transcriptional regulation to the accumulation of mRNA from the five rbcS genes in tomato seedlings, leaves, and fruit. We found that the qualitative pattern of mRNA accumulation is regulated at the transcriptional level and that, in general, there is a correlation of rates of rbcS transcription with overall rbcS mRNA abundance in fruit and leaves. Although transcriptional control is a primary determinant for rbcS gene expression in tomato, examination of relative transcription rates and mRNA accumulation of each rbcS gene demonstrated that there is also significant post-transcriptional control of rbcS gene expression during organ development. Individual rbcS mRNAs, which have highly conserved coding sequences and differ only in their 5' and 3' untranslated sequences, have different stabilities. We showed that both transcription and stability of individual rbcS mRNAs are altered in different organs and by the developmental program within these organs as well as by exposure to light. Together, the results provide a comprehensive analysis of the extent of transcriptional and post-transcriptional control that operates within the rbcS gene family during plant development.

Base Sequence↗
PubMed2025

A century of research on the Planctomycetota bacterial phylum, previously known as Planctomycetes.

One hundred years after planctomycetes were discovered and 50 years since the first isolate was successfully cultured, this bacterial phylum remains enigmatic in many ways. In the last few decades, a significant effort to characterize new isolates has resulted in >150 described species, allowing a more comprehensive analysis of their features. However, metagenomic studies reveal that a diverse group of planctomycetes has yet to be cultured and characterized, and that many biological surprises are yet to be revealed. This is the case for the recently discovered phagotrophic Candidatus Uabimicrobium, which challenges our understanding of the distinction between prokaryotes and eukaryotes. The unique biology of planctomycete cells, such as their ability to divide without the FtsZ protein, their complex structure and characteristic morphology, their relatively large genomes containing many genes with unknown function, and their variable metabolic capabilities, imposes significant barriers for researchers. Although ubiquitous, the precise ecological roles of planctomycetes in various environments are still not fully understood. However, their distinctive metabolism opens the door to a large number of potential biotechnological applications, which are beginning to be unveiled. In this article, we first review the historical milestones in planctomycetes research and describe the pioneers of the field. We then describe the controversies and their resolutions, we highlight the past discoveries and current interrogations related to planctomycetes, and discuss the ongoing challenges that hinder a comprehensive understanding of their biology. We end up with directions for exploring the biology and ecological roles of these fascinating organisms.

Bacteria↗
PubMed1991

Clinical correlates of response to botulinum toxin injections.

We studied 242 patients with cervical dystonia who had adequate follow-up after botulinum toxin injections to determine which clinical variables had a predictive value in the treatment outcome. Twenty-one patients (16%) categorized as nonresponders were compared with 113 patients (47%) considered to be definite responders. On average, the nonresponders had symptoms for 14 years longer than responders. Seventy-eight of 100 patients with complications were female compared with 54% of 190 patients without complications. In addition, patients with complications weighed less than those without complications. Both findings suggest that the occurrence of complications is related to smaller mean neck muscle mass. Botulinum toxin antibodies were detected in 35.7% of the nonresponders tested and in none of the responders. This comprehensive analysis of outcome variables leads us to conclude that patients with a long duration of dystonia before their first botulinum toxin injection respond less well than those with a short duration of symptoms, that some patients lose their responsiveness because of the development of blocking antibodies, and that women are more likely to develop complications, such as dysphagia and neck weakness, than are men.

Adolescent↗
PubMed2025

Tonic signaling of the B-cell antigen-specific receptor is a common functional hallmark in chronic lymphocytic leukemia cell phosphoproteomes at early disease stages.

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by highly heterogeneous genomic alterations and altered signaling pathways, with limited studies on its proteome. Our study presents a comprehensive analysis of the proteome and phosphoproteome in B-CLL and CLL-like monoclonal B-cell lymphocytosis (MBL) primary cells. Using high-resolution mass spectrometry, we identified 2970 proteins and 316 phosphoproteins across five tumor samples, including 55 newly identified phosphopeptides (ProteomeXchange-PXD005997). Our multifaceted approach also integrated protein microarrays and western blotting for further data validation in a new patient cohort of 14 patients. Despite sharing 73% of their proteomes, the phosphoproteomes varied significantly among samples, independent of cytogenetic alterations and immunoglobulin heavy variable cluster (IGHV) mutational status. We identified common functional hallmarks in B-CLL and MBL phosphoproteomes, notably tonic signaling (low-level, constitutive signaling) of the B-cell antigen-specific receptor (BCR) and nuclear factor NF-kappa-B (NF-kβ)/signal transducer and activator of transcription 3 (STAT3) pathways. Nine phosphoproteins involved in BCR signaling were further validated, showing a high correlation with early disease stages. Our study advances the field by providing a detailed perspective on the proteome and phosphoproteome of B-CLL cells, revealing signaling pathways crucial for disease development and progression. Integrating diverse proteomics techniques and identifying novel phosphopeptides offers new insights into CLL biology, potentially informing future therapeutic strategies and biomarker development for early diagnosis and personalized treatment.

Humans↗
PubMed1978

Cerebral hemodynamics and metabolism in pseudotumor cerebri.

A comprehensive analysis of cerebral hemodynamics and metabolism was carried out in 14 patients with pseudotumor cerebri. Tracer techniques were employed to measure cerebral blood flow (CBF) and vascular reactivity to acute changes in arterial carbon dioxide tension and blood pressure, cerebral blood volume (CBV), and the cerebral metabolic rate for oxygen and glucose. There was a small reduction (p less than 0.01) in CBF (44 +/- 7 ml/100 gm/min; normal, 54 +/- 9) with normal vascular reactivity; an increase (p less than 0.005) in CBV (4.8 +/- 0.8 ml/100 gm; normal, 3.6 +/- 0.5), and normal cerebral metabolism. We conclude that an abnormality of the cerebral microvasculature is responsible for an elevation in CBV, but the intracranial hypertension can be explained only by tissue swelling due to an increase in water content. The relationship between the vascular abnormality and the tissue swelling remains to be defined.

Adolescent↗
PubMed1992

Memory T lymphocyte hyporesponsiveness to non-cognate stimuli: a key factor in age-related immunodeficiency.

Previous studies from our laboratory have suggested that aging leads to an accumulation of cells expressing high levels of CD44, thought to be a marker for memory lymphocytes, and that positively selected CD44hi T cells, from mice of any age, respond poorly to concanavalin A (Con A) in limiting dilution estimates of interleukin (IL)-2-producing cells. We now report the results of a more comprehensive analysis of memory T cell function, in old and young mice, to non-cognate activators (Con A and the staphylococcal enterotoxin SEB). We report that memory T cells, isolated by removing cells bearing the CD45RB determinant, contain very few cells able to respond to either Con A or SEB under limiting dilution culture conditions, whether the responses are measured by IL-2 or by IL-3 accumulation. As a control, we show that memory T cells do respond strongly, at limiting dilution, to recently encountered priming antigens, i.e. Schistosoma mansoni egg antigen; the limiting dilution culture protocol thus does not preclude activation of memory T cells when cognate stimuli are presented to antigen-specific cells. These data suggest that virgin and memory T cells may differ fundamentally in their activation requirements, and suggest further that the accumulation, with age, of memory T cells accounts for the low responsiveness of old mice to non-cognate mitogens.

Aging↗
PubMedDate not supplied

Neuroendocrine tumors of the larynx.

A review of the international literature has revealed 68 paragangliomas, 42 large cell, and 74 small cell tumors of the larynx. Paragangliomas are usually benign, although malignant cases have been reported. Large cell tumors are malignancies associated with a high incidence of early cervical metastasis. Small cell tumors are aggressive cancers characterized by early, diffuse metastatic disease. All three neoplasms demonstrate a propensity for the supraglottic larynx. While surgery remains the treatment of choice for paragangliomas and large cell cancers, small cell cancers are best treated by radiotherapy and chemotherapy. The determinate 5-year survival for patients with paragangliomas, large cell, and small cell cancers is 60%, 34%, and 14%, respectively. While representing distinct clinical entities, these neoplasms demonstrate similar ultrastructural and histochemical features and should be classified as neuroendocrine tumors of the larynx (NETL). A comprehensive analysis of these laryngeal tumors is presented herein. Their clinical behavior and management options are reviewed and a scheme for their nomenclature and classification is proposed.

Adolescent↗
PubMed2025

Identification of Novel Wraparound Transcripts in JC Polyomavirus.

JC polyomavirus (JCPyV) is a ubiquitous pathogen that causes progressive multifocal leukoencephalopathy (PML). Although a recent study using next-generation sequencing (NGS) provided detailed transcriptome atlases for polyomaviruses (PyVs) such as BK polyomavirus and simian virus 40, the transcriptome of JCPyV remains poorly characterized. Here, we conducted a comprehensive analysis using both short-read and long-read NGS technologies to construct a transcriptome atlas of JCPyV. RNA extracted from IMR-32 and HEK293 cells transfected with the circular JCPyV genome was analyzed, leading to the identification of 39 previously uncharacterized viral transcripts in addition to 12 known ones. Among the novel transcripts, we identified wraparound transcripts, conserved across PyVs, which are generated through continuous, multicyclic transcription of the circular viral genome. These included both late transcripts containing leader-to-leader repeated sequences and SuperT transcripts with multiple LxCxE motifs. Notably, wraparound transcripts, including SuperT transcripts, were also detected in brain tissues from PML patients. Collectively, this study significantly expands our understanding of the JCPyV transcriptome, revealing the expression of wraparound transcripts in PML lesions. These findings provide valuable insights into the molecular basis of JCPyV gene expression and PML pathogenesis, potentially facilitating the development of effective countermeasures against PML.

JC Virus↗
PubMed1990

Incidence of regional lymph node metastasis in operable osteogenic sarcoma.

Records of 182 consecutive patients with the diagnosis of operable osteogenic sarcoma, treated between 1954 through 1980 by the Breast, Bone and Mixed Tumors Department of the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru), were reviewed to study the incidence of regional lymph node metastases in this disease. All the patients included in this study had radical surgery, which means the complete resection of the bone where the tumor is located, including the proximal joint, which permitted excision of the regional lymph nodes. Nineteen patients (10.4%) had evidence of sarcoma metastatic to draining lymph nodes. A comprehensive analysis of the literature shows that the incidence of metastasis to the lymph nodes in this study, is higher than those cited in a review of the literature, probably due to the policy in the management of osteogenic sarcoma in our institution, during the period of study.

Adolescent↗
PubMed1992

The microanatomy of canine islets of Langerhans: implications for intra-islet regulation.

In recent years models for the internal ("intra-islet") regulation of hormone secretion have been proposed to explain how different islet cells might regulate each other by means of their respective secretory peptides. Models that emphasize the importance of a directed intra-islet blood flow and sequence of perfusion of islet cells rely on a certain type of islet microanatomy and vascular supply. The experimental studies underlying these models have partly been performed in dogs. To extend the incomplete morphological knowledge of the canine endocrine pancreas both canine islets of Langerhans and extrainsular cells have been analysed in immunostained serial semithin (0.5 microns) sections. In addition to their occurrence within islets of Langerhans, all endocrine cell types are also found at extrainsular sites (about 9% of all endocrine cells) where they are distributed in different quantities among the epithelial lining of exocrine acini or excretory ducts and the connective tissue. There are continuous transitions from single extrainsular cells to small mono- and polycellular cell groups to islets. In a comprehensive analysis of whole islets, including computer-assisted three-dimensional reconstructions, the size, shape and vascularization of the islets as well as their cellular composition and the microtopology of islet cells have been studied. We have found marked intra- and inter-islet heterogeneities of the parameters investigated that are not compatible with concepts of a uniform and directed vascular perfusion of the various islet cell populations. Instead, their paracrine regulation may occur primarily via hormonal secretion into the intercellular spaces or vascular hormonal delivery to adjacent cells.

Animals↗