Various Stages Of Digestion Research Articles

Metabolic changes and isoflavone biotransformation in natto for improved nutritional distribution and bioavailability

We used LC-MS to identify the metabolic changes in soybean fermented by Bacillus subtilis DC-15 to comprehend the biochemical alterations. Total 650 distinct metabolites were observed, with amino acids, dipeptides, fatty acids, small molecule sugars, and isoflavones having the largest abundances. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the primary metabolic pathways involved during the fermentation of soybeans were related to amino acid metabolism, including beta-alanine metabolism, phenylalanine metabolism, glycine, serine, and threonine metabolism. In the gastric phase, the maximum amount of soy isoflavones was successfully converted from its glycoside form (50.04 μg/mL) to the aglycone form (104.07 μg/mL). The distribution of protein and lipid particles in natto during various stages of digestion showed changes from aggregated particles to more scattered particles. For the future development and enhancement of fermented soybean products, our metabolomic data can shed light on activated biochemical pathways and changes in metabolic pattern.

Optimization of fecal sample homogenization for untargeted metabolomics.

Fecal samples are highly complex and heterogeneous, containing materials at various stages of digestion. The heterogeneity and complexity of feces make stool metabolomics inherently challenging. The level of homogenization influences the outcome of the study, affecting the metabolite profiles and reproducibility; however, there is no consensus on how fecal samples should be prepared to overcome the topographical discrepancy and obtain data representative of the stool as a whole. Various combinations of homogenization conditions were compared to investigate the effects of bead size, addition of solvents and the differences between wet-frozen and lyophilized feces. The homogenization parameters were systematically altered to evaluate the solvent usage, bead size, and whether lyophilization is required in homogenization. The metabolic coverage and reproducibility were compared among the different conditions. The current work revealed that a combination of mechanical and chemical lysis obtained by bead-beating with a mixture of big and small sizes of beads in an organic solvent is an effective way to homogenize fecal samples with adequate reproducibility and metabolic coverage. Lyophilization is required when bead-beating is not available. A comprehensive and systematical evaluation of various fecal matter homogenization conditions provides a profound understanding for the effects of different homogenization methods. Our findings would be beneficial to assist with standardization of fecal sample homogenization protocol.

Bioaccessibility of ferulic acid in hulless barley varieties at stages of simulated in vitro digestion

AbstractBackground and ObjectivesFerulic acid has antioxidant, anti‐inflammatory, and antimicrobial activity. Ferulic acid in barley is present in esterified form in the bran layer, however, only the free form is bioaccessible in the upper gastrointestinal tract. The objectives of this study were to investigate the bioaccessibility of ferulic acid at four stages of simulated gastrointestinal digestion of two barley varieties to determine when ferulic acid is released and investigate factors which may affect the release of ferulic acid including digestive enzymes and pH.FindingsThe release of ferulic acid was strongly influenced by digestive enzymes and minimally by pH. The presence of enzymes reduced free ferulic acid but increased the amount of esterified ferulic acid. The major release of esterified ferulic acid occurred during the final hour of small intestinal digestion. The amount of bioaccessible ferulic acid remained constant throughout digestion. The bran thickness, measured by microCT imaging, significantly differed between the varieties.ConclusionDuring digestion, ferulic acid changed structurally, as observed by the changes in the amount of free and esterified ferulic acid at four digestion timepoints. The release of ferulic acid was strongly influenced by exposure to digestive enzymes and minimally by pH, although the mechanism of the presence of enzymes on ferulic acid release is unclear. The bioaccessibility of ferulic acid may be determined by the bran layer thickness and further investigation is required.Significance and NoveltyThis is the first study to investigate the bioaccessibility of ferulic acid in barley at various stages of digestion and to measure the bran thickness of barley using microCT imaging with preliminary findings indicating enhanced ferulic acid bioaccessibility in grains with a thinner bran layer.

Biology, affinity and description of an unusual aquatic new genus and species of Isotomidae (Collembola) from high altitude lakes in Tasmania

A new species of Isotomidae (Collembola) was collected from submerged stones on the edge of nine lakes on Tasmania's Central Highland Plateau. Because it did not comply fully with the characters of any existing genus, a new genus, Chionobora gen. n. is erected for it here. An Antarctic species, Desoria klovstadi (Carpenter), has characters which conform with the new genus so is formally transferred to the new genus here. The Antarctic Continent and Tasmania were last in proximity 60 million years b.p. so it is suggested both species are relicts persisting in probable ice-free refugia during glacial cycles. Gut contents of specimens of the new species ex- clusively contained diatoms in various stages of digestion and the species appears to graze on aquatic macrophytes, a feeding habit not recorded before for Collembola. We note the high numbers of endemic invertebrate taxa of restricted distributions in cold habitats of southern regions compared to warmer regions and stress their conservation values and threats to their populations.

Cholelithiasis as a possible manifestation of systemic digestive diseases

To comprehensively study of the function of digestive organs in cholelithiasis (CL). Three hundred and seventeen patients with the early (prestone) stage of CL were examined. The latter was verified by ultrasonography (USG) and biochemical bile tests. The patients underwent pH metry and esophagogastroduodenoscopy, followed by histological examination of gastroduodenal mucosa (GDM) biopsy specimens. Manometry was used to evaluate duodenal function. The serum levels of pepsinogen-1 (PG-1), pepsinogen-2 (PG-2), cholecystokinin (CCK), gastrin, cyclic nucleotides (cAMP and cGMP), α1-antitrypsin, insulin, and C-peptide were analyzed by an enzyme immunoassay. Small intestinal function was examined using a set of diagnostic tests. Gallbladder USG revealed biliary sludge in 273 (86.1%) patients. Biochemical examination of bile established a lower cholatocholesterol coefficient in its cystic as well as hepatic portions, suggesting enhanced bile lithogenicity. Manometry of the duodenum showed its hypertension, hypotension, and normotension in 57.6, 24.8, and 17.6% of the CL patients, respectively. There were significant increases in basal gastric body pH and PG-1 and PG-2 levels as compared to the control group. Morphological examination of GDM biopsy specimens revealed chronic superficial gastritis in 61.8% of the patients, chronic atrophic gastritis in 17.4%, and moderate diffuse duodenitis in 18.3%. In 148 (46.7%) patients with CL, the latter was burdened by pancreatic comorbidity. Stress tests using water-soluble starch, sucrose, and glucose demonstrated impairments in various stages of digestion; substantially decreased levels of CCK, gastrin and cyclic nucleotides were observed in the patients with CL compared to the controls. Most patients with CL were detected to have digestive organ structural and functional disorders. Moreover, CL may be regarded as a possible manifestation of systemic digestive diseases.

Bioefficacy of Tea Catechins Associated with Milk Caseins Tested Using Different In Vitro Digestion Models

Milk proteins, and in particular caseins, are avid binders of polyphenols. The objective of this work was to understand how the presence of a polyphenol–casein complex may affect the bioefficacy of tea catechins [epigallocatechin-3-gallate (EGCG)]. In vitro digestion was carried out using two different models: a batch model and a dynamic digestion model, using a simulator of the human intestinal microbial ecosystem (SHIME). SDS-PAGE electrophoresis of the digestates showed that the presence of EGCG did not affect hydrolysis of the caseins, regardless of the digestion model used. However, there was a slower digestion of the caseins in the dynamic model (SHIME) compared to the in vitro batch model. The cytotoxic effect of free and complexed EGCG was tested using adenocarcinoma cells (HT-29) and the HT29-MTX subclone. The HT29-MTX closely mimics the presence of the mucus barrier in the intestine. HT-29 cells showed a decrease in cell viability proportional to the concentration of ECGC, free or complexed and after digestion. The proliferation rate of HT29 assessed on digested EGCG-casein complexes indicated that the binding of EGCG and milk proteins does not affect its bioactivity. Antiproliferative activities were comparable to those for free EGCG, in spite of the lower recovery of EGCG after the various stages of digestion. Exposure of EGCG (free or complexed) to mucus-producing cells HT29-MTX did not show a decrease in viability, and the cell response was typical of normal cells. The presence of mucus also protected coculture monolayers of HT29-MTX and Caco-2. All the models demonstrated that the presence of EGCG–casein micelle complex did not affect the bioefficacy of the polyphenol.

Improved method for the quantitative determination of ultra trace level of Pu-239+240 in siliceous base samples using microwave assisted dissolution

Mobilisation of alpha emitting radionuclides from silicious base sample is one the challenging task for environmental radiochemist. During this study, rapid and complete dissolution of the siliceous base samples were carried out by optimizing temperature, pressure and power of the microwaves. The Pu-239+240 in digested samples was pre-concentrated by scavenging Fe as Fe(OH)3. Pu-239+240 was isolated from the Fe(OH)3 by co-precipitating Pu with Bi(PO4) in HNO3 medium at pH 2. Pu-239+240 was separated from Bi(PO4) and other transuranics by passing through cation and anion exchange resin. Pu-239+240 was counted by alpha spectrometry after electroplating on stainless steel planchet. The detection limits achieved for Pu-239+240 was 60 μBq/g (2.6 × 10−14 g/g). Pu-242 was used as a tracer for the evaluation of recovery of Pu-239+240. Samples prepared after complete destruction of matrix in microwave, showed 10–20% higher concentration of Pu-239+240 compared to conventional acid leached. Consistent recovery in the range of 97–99% for Pu-242 were observed in microwave digested samples whereas inconsistent results were observed in acid leached samples where the recoveries were in the range of 75–86%. Siliceous matrix degradation was tracked by monitoring the surface morphology and composition of the residue left at various stages of digestion using Scanning Electron Microscope (SEM) coupled with Energy dispersive X-ray spectrometer (EDS).

Peristalsis in the junction region of the Drosophila larval midgut is modulated by DH31 expressing enteroendocrine cells

BackgroundThe underlying cellular and molecular mechanisms that coordinate the physiological processes in digestion are complex, cryptic, and involve the integration of multiple cellular and organ systems. In all intestines, peristaltic action of the gut moves food through the various stages of digestion from the anterior end towards the posterior, with the rate of flow dependent on signals, both intrinsic and extrinsic to the gut itself.ResultsWe have identified an enteroendocrine cell type that regulates gut motility in the Drosophila melanogaster larval midgut. These cells are located at the junction of the anterior and the acidic portions of the midgut and are a group of enteroendocrine cells that express the peptide hormone Diuretic Hormone 31 in this region of the gut. Using cell ablation and ectopic activation via expression of the Chlamydomonas reinhardtii blue light-activated channelopsin, we demonstrate that these enteroendocrine cells are both necessary and sufficient for the peristalsis in the junction region of the midgut and require the Diuretic Hormone 31 to affect normal peristalsis in this region. Within the same junction region of the midgut, we have also identified morphological features suggesting that this region acts as a valve that regulates the transit of food from the anterior midgut into the acidic portion of the gut.ConclusionsWe have characterized and described a set of enteroendocrine cells called the Midgut Junction DH31 expressing cells that are required for peristaltic movement in the junction region between the anterior portion and acidic region of the larval midgut of Drosophila melanogaster. We have shown that the Midgut Junction DH31 expressing cells are necessary and sufficient for motility and that the peptide hormone DH31 is required for peristalsis in the junction region of the midgut. The Drosophila model system will allow for a further dissection of the digestion process and provide a better understanding of the mechanisms that regulate digestion in all organisms.

Expression of macrophage CD14 receptor in the course of experimental inflammatory responses induced by lipopolysaccharide and muramyl dipeptide

The aim of this study was to determine whether expression of CD14 on macrophages is regulated differently during initiation and resolution of the inflammatory response caused by CD14-dependent (lipopolysaccharide) and CD14-independent (muramyldipeptide) bacterial signals. In cell suspensions from the site of inflammation we observed two types of macrophages: non-vacuolized (<sub>N</sub>MAC) and vacuolized (<sub>V</sub>MAC) cells. <sub>N</sub>MAC (monocyte-like cells) were dominant during the early stage of the inflammatory response, whilst <sub>V</sub>MAC contained phagocytosed apoptotic neutrophils in various stages of digestion. These latter cells were dominant during resolution (particularly at the last time point of 168 h). Intramammary instillation of muramyldipeptide (MDP) and lipopolysaccharide (LPS) resulted in a significant increase in the total count of CD14+ <sub>N</sub>MAC after 24 h (muramyldipeptide <I>P</I> < 0.01 and lipopolysaccharide <I>P</I> < 0.05) compared to phosphate buffered saline (PBS). During resolution of the inflammatory response, a gradual decrease in the total count of CD14+ <sub>N</sub>MAC was observed. The difference compared with PBS was significant at 48 h and 72 h after instillation of both bacterial agents (muramyldipeptide: <I>P</I> < 0.05; lipopolysaccharide: <I>P</I> < 0.05). A lower total count of CD14+ <sub>V</sub>MAC was observed as an effect of MDP and LPS at 24 h after induction (<I>P</I> < 0.05), when compared to PBS. During resolution, the total count of CD14+ <sub>V</sub>MAC increased. Differences (<I>P</I> < 0.01) were observed at 72 h and 168 h after LPS compared to PBS. We therefore assume that the expression of CD14 on macrophages is not regulated differently during the inflammatory responses caused by CD14-dependent and CD14-independent bacterial signals. On the other hand, the stage of the inflammatory response to MDP and LPS played an important role in the regulation of CD14 expression on macrophages.

A study on the feeding habits and gnathal appendages in oribatid mites (Acarina: Cryptostigmata)

Gut contents of eight species of oribatid mites collected from the field were analysed employing suitable staining techniques, which showed the presence of bacteria, fungal hyphae and spores, pollen grains, leaf and wood particles in various stages of digestion. Based on this, the species considered could be placed under different trophic niches. The pedipalp, chelicera and rutellum which formed the major grasping and masticating appendages of these mites were subjected to detailed structural analysis which established their functional role in food grasping, collection and mastication.

Methane‐based symbiosis in a mussel, Bathymodiolus platifrons, from cold seeps in Sagami Bay, Japan

Abstract. Bathymodiolus platifrons, a chemosynthetic mussel from cold seeps off Japan, relies for its nutrition on the productivity of methylotrophic or methanotrophic endosymbionts. High densities of bacterial symbionts appearing to be type I methanotrophs were observed in transmission electron micrographs of gill tissues. Methanol dehydrogenase activity in gill tissue from a single individual was positive compared to non‐methanotrophic control samples, indicating a high potential for methanotrophy. Stable isotopic ratios of carbon in symbiont‐containing gill tissue, as well as host tissues, were extremely depleted in 13C, and similar to values reported for other methanotrophic species. TEMs of gill tissue showing symbionts in various stages of digestion support the hypothesis that carbon transfer from symbionts to B. platifrons occurs through intracellular digestion of the symbionts. Discovery of methane‐ or methanolbased symbioses in B. platifrons from cold seeps in Sagami Bay extends the range of such symbioses to include cold seeps and hydrothermal vents, and supports the idea that environmental methane levels control the distribution of these symbioses.

Parasitism of Leptasterias spp. (Echinodermata: Asteroidea) by the ciliated protozoan Orchitophrya stellarum (Scuticociliata)

Abstract. The parasitic ciliate Orchitophrya stellarum was found in the testes of brooding, winter‐spawning Leptasterias spp. from San Juan Island, Washington, but not in the testes of Leptasterias spp. from the Lynn Canal, Alaska. Dense populations of the ciliate were localized within the fuller areas of testes, where sperm counts were significantly reduced. The ciliates were loaded with phagosomes, some of which contained sperms in various stages of digestion. Leptasterias spp. are not as severely impacted by this ciliated protozoan parasite as Pisaster ochraceus. Leptasterias spp. may serve as seasonal hosts for O. stellarum; this ciliate lives in seawater and in ripe males of winter‐brooding and spring‐summer broadcasting sea stars. The wet weight of parasitized and non‐parasitized males did not differ. The sex ratio did not deviate from the expected (1:1) in any population except at Point Louisa, Alaska, where males outnumbered females. Testis indexes of parasitized males from 2 of the 4 locations on San Juan Island, Washington were significantly reduced relative to non‐parasitized males, indicating a loss of sperm output during spawning.

Rates of RNA degradation in isolated rat hepatocytes

1. RNA degradation in isolated rat hepatocytes was measured as the release of radioactive cytidine from fed rats previously labeled in vivo for 60 h with [6-14C]orotic acid. Rates were determined from the linear accumulation of [14C]cytidine between 30 and 120 min of incubation in the presence of 0.5 mM unlabeled cytidine to suppress reutilization. 2. In the absence of amino acids, rates of RNA degradation in isolated hepatocytes averaged 3.97%/h. A complete mixture of amino acids added at 10-20 times normal plasma concentration inhibited RNA degradation by 65-70%. However, at physiological concentrations of amino acids, RNA degradation in isolated rat hepatocytes was less responsive as compared to perfused rat livers. 3. Numerous and large autophagic vacuoles at various stages of digestion were identified throughout the cytoplasm of isolated hepatocytes after 2 h of incubation in the absence of amino acids. The addition of amino acids at 20 times normal plasma concentration abolished almost completely the appearance of autophagic vacuoles. Furthermore, prophylamine, which accumulates in lysosomes, suppressed RNA degradation by 65% and the inhibitor of autophagic vacuole formation, 3-methyladenine, inhibited 70-80% of the degradation. Taken together, these results strongly suggest a contribution of the lysosomal system in the increase of RNA degradation rates in isolated rat hepatocytes.

Rates of RNA degradation in isolated rat hepatocytes. Effects of amino acids and inhibitors of lysosomal function

1. RNA degradation in isolated rat hepatocytes was measured as the release of radioactive cytidine from fed rats previously labeled in vivo for 60 h with [6-14C]orotic acid. Rates were determined from the linear accumulation of [14C]cytidine between 30 and 120 min of incubation in the presence of 0.5 mM unlabeled cytidine to suppress reutilization. 2. In the absence of amino acids, rates of RNA degradation in isolated hepatocytes averaged 3.97%/h. A complete mixture of amino acids added at 10-20 times normal plasma concentration inhibited RNA degradation by 65-70%. However, at physiological concentrations of amino acids, RNA degradation in isolated rat hepatocytes was less responsive as compared to perfused rat livers. 3. Numerous and large autophagic vacuoles at various stages of digestion were identified throughout the cytoplasm of isolated hepatocytes after 2 h of incubation in the absence of amino acids. The addition of amino acids at 20 times normal plasma concentration abolished almost completely the appearance of autophagic vacuoles. Furthermore, prophylamine, which accumulates in lysosomes, suppressed RNA degradation by 65% and the inhibitor of autophagic vacuole formation, 3-methyladenine, inhibited 70-80% of the degradation. Taken together, these results strongly suggest a contribution of the lysosomal system in the increase of RNA degradation rates in isolated rat hepatocytes.

The digestive process of the dinoflagellate, Oxyrrhis marina Dujardin, feeding on the chlorophyte, Dunaliella primolecta Butcher: a combined study of ultrastructure and free amino acids

SUMMARYThe digestive process of Oxyrrhis marina Dujardin feeding on Dunaliella primolecta Butcher commences with the capture of the phototroph, perhaps involving trichocysts which restrain the prey, followed by engulfing by a membrane that appears to originate from near the fiagella pit of the O. marina. The prey, still within the capture membrane, enters the O. marina and is digested over a period estimated to be of the order of 12‐24h. During digestion the prey first becomes more electron dense and the contents coagulate. Later the prey becomes less distinct and disintegrates; by this stage remains from several prey may be enclosed within one vacuole. Small O. marina, captured by large prey‐depleted O. marina, suffer the same fate. Absence of any correlation between changes in intracellular amino acids and digestion of prey probably resulted from each O. marina containing several prey at various stages of digestion. However, the value of the glutamine/glutamate (Gln/Glu) ratio remained at around 0‐3, whilst the population changed from one dominated by N‐replete D. primolecta to one dominated by prey‐replete O. marina, N‐deplete D. primolecta and prey‐deplete O. marina both have Gln/Glu of < 0.1. The Gln/Glu ratio may therefore be of use in assessing the nutrient status of heterotrophic microflagellates.

Macrophage function during Wallerian degeneration of rat optic nerve: clearance of degenerating myelin and Ia expression

This study examined Wallerian degeneration (WD) of rat optic nerve (ON) with 2 goals: to determine which cell types are involved in myelin degradation and clearance and to evaluate the extent to which Ia antigen, a product of the immune response genes, is expressed. We examined immunostained 1-micron and ultrathin cryosections of rat ON at 1, 8, and 16 weeks after nerve transection. Serial 1-micron cryosections were stained with monoclonal antibodies to rat Ia antigen (Ox6) and with antibodies that identify astrocytes (GFAP) and monocytes/macrophages (ED1). In normal ON, ED1-positive cells were not found. A few ED1-positive monocytes/macrophages were present in the transected ON at one week. Macrophages were prominent throughout the ON at 8 weeks; by 16 weeks their number was decreasing. These cells contained myelin debris in various stages of digestion. GFAP-positive astrocytes did not contain myelin debris in their cytoplasm. At all 3 times a subpopulation of the ED1-positive monocytes/macrophages expressed Ia antigen. Ia antigen was not detected in endothelial cells or GFAP-positive astrocytes. In ultrathin cryosections stained by immunogold procedures, Ia immunoreactivity was found exclusively in cells containing multiple vacuoles and myelin debris and lacking intermediate filaments. The same cell type was labeled by ED1 antibodies. Our results indicate that macrophages remove the vast majority of debris during Wallerian degeneration in the CNS; a proportion of these macrophages concomitantly express Ia antigen. These results suggest that the Ia expression by macrophages observed in other CNS disorders does not necessarily reflect specific local immune events, but in some instances can represent a nonspecific response to CNS damage.

Quantitative histological and histochemical studies on the occurrence and stages of controlled cell death (apoptosis) during regression of rat liver hyperplasia.

Hyperplasia of the rat liver can be induced by cyproterone acetate (CPA). The fate of this hyperplasia after cessation of CPA treatment has been studied and the following findings were obtained: Liver DNA content decreased by about 25% within a few days after CPA withdrawal. In histological sections some hepatocytes showed degenerative changes. Among these, small membrane bounded bodies ("apoptotic bodies"; ABs) with or without chromatin were most numerous. Their incidence coincided with the phase of DNA elimination. Inflammatory reactions were not observed. Their small size and occurrence in clusters suggests that many of these ABs are formed by fragmentation of dying hepatocytes. Liver DNA was prelabelled with 3H-thymidine. Autoradiographic evaluation showed that many hepatocytes contained labelled nuclei, but unlabelled ABs. This finding strongly suggests that ABs, after the fragmentation stage, can be phagocytized by intact hepatocytes. About 80% of all ABs were found within hepatocytes. Extracellular ABs (early stage) contained no or very few active lysosomes. Intracellular ABs were sometimes surrounded by lysosomes, while others were in various stages of digestion. These observations suggest that the lysosomes of the phagocytizing hepatocytes degrade intracellular ABs, whereas intraapoptotic lysosomes seem to be inactive until the late stages of this degradation. Hepatocytes that did not replicate during CPA-induced liver growth appear to die off preferentially after CPA withdrawal. Retreatment with CPA greatly reduced the number of ABs within 4 h. Phenobarbital, another stimulus of liver growth, had the same effect. These findings suggest that the present type of cell death can be inhibited by growth stimuli and is therefore a controlled event serving to eliminate an excess of cells, rather than a manifestation of toxic injury to hepatocytes. The findings also suggest that this type of cell death and elimination is a rapid process completed within a few hours. It is concluded that cell death under the present experimental conditions probably occurs through apoptosis.

Electrophoresis in the study of diets and digestive rates of seabirds

1. 1. Attempts were made to identify unknown gut contents of seabirds by protein analysis using electrophoresis. 2. 2. Standards of undigested fish and squid muscle tissue were compared with muscle tissue at various stages of digestion. 3. 3. Digested mixtures of squid ( Loligo reynaudi), Pelagic Goby ( Sufflogobius bibarbatus) and Cape Anchovy ( Engraulis capensis) did not resemble the undigested standards of each species respectively. 4. 4. Electrophoresis could prove useful in the study of differential digestion rates of seabird prey species.

Electron microscopic studies of macrophages in early human yolk sacs.

Distribution and fine structure of macrophages were studied in 10 human embryos in the 6th and 7th week of gestation, 5.5 to 12 mm in crown-rump length. The yolk sac macrophages were found in the extravascular mesenchymal tissues and intravascular spaces long before the first appearance of bone marrow and lymphatic tissues in the embryos. In addition to the macrophages, the fibroblastic cells and the cells of erythropoietic series were also present in the extravascular space. The macrophages showed a variety of cellular structures suggesting transition from immature cell type with no heterophagolysosomes to mature cell type in phagocytosis. The mature macrophages avidly phagocytized the primitive erythroblasts and occasionally platelets. They were positively stained for lysosomal enzymes and were characterized by numerous pleomorphic heterophagolysosomes which exhibited various stages of digestion of phagocytized blood cells. The origin of intravascular macrophages may be in either migrated extravascular macrophages or phagocytic endothelial cells. The phagocytosis and degradation of erythroblasts appear to be one of the main functions of yolk sac macrophages. The presence of the macrophages in mitosis indicates their proliferation in situ.

Interaction between polymorphonuclear leukocytes and varicella-zoster virus-infected cells.

The addition of polymorphonuclear leukocytes (PMNL) to human fibroblasts infected with varicella-zoster virus (VZV) resulted in a reduced virus yield. The reduction was greater when antibodies specific for VZV were added to the system. Addition of VZV-specific antibodies without PMNL also reduced virus yield, but a 10-fold greater concentration of antibodies was required to effect the same reduction. PMNL adhered to and formed rosettes around VZV-infected cells. By electron microscopy, it was possible to observe activation of PMNL incubated with VZV-infected fibroblasts. Activated PMNL extended cytoplasmic projections toward virions and had vacuoles containing virions in various stages of digestion.