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PubMed2003

Different effects of amino acid-based and glucose-based dialysate from peritoneal dialysis patients on mesothelial cell ultrastructure and function.

BACKGROUND: Peritoneal dialysis fluid (PDF) containing amino acids has been introduced recently aiming to improve the nutritional status of PD patients. Dextrose-based PDFs have been implicated in progressive functional and structural deterioration of the peritoneal membrane. Limited data are currently available regarding the effect of amino acid-based PDF on the function and ultrastructure of human peritoneal mesothelial cells (HPMCs), which play a critical role in peritoneal membrane pathophysiology. METHODS: We investigated the effects of two commercially available PDFs, which utilized dextrose (1.5% Dianeal) or amino acids (1.1% Nutrineal) as the osmotic agent, obtained from patients after a 4 h dwell, on HPMC proliferation (MTT assay and cell counting) and viability [lactate dehydrogenase (LDH)release], interleukin-6 (IL-6) secretion (commercial enzyme-linked immunosorbent assay) and ultrastructure (scanning and transmission electron microscopy). RESULTS: Exposure of HPMCs to 1.5% Dianeal reduced cell proliferation, total cellular protein synthesis, IL-6 secretion and cell attachment, but prolonged the cell doubling time on recovery, and increased LDH release (P<0.001, P<0.001, P<0.0001, P<0.0001, P<0.001 and P<0.001, respectively). The 1.1% Nutrineal reduced HPMC proliferation (P<0.001) and increased IL-6 secretion (P<0.0001), but did not affect cell attachment, LDH release, protein synthesis or cell doubling time. Ultrastructural studies of HPMCs exposed to Dianeal showed cell flattening, increased cell surface area, reduced microvilli, and intracellular organelles compatible with dysfunctional mitochondria. In contrast, the ultrastructural morphology of HPMCs was relatively preserved after incubation with Nutrineal. CONCLUSIONS: Our results showed that HPMC ultrastructure, viability and protein synthesis were better preserved with amino acid-based PDF, compared with conventional dextrose-based PDF. The significance of IL-6 induction by Nutrineal remains to be elucidated.

Adult↗
PubMed1990

Comparative effectiveness of a clinostat and a slow-turning lateral vessel at mimicking the ultrastructural effects of microgravity in plant cells.

The object of this research was to determine how effectively the actions of a clinostat and a fluid-filled, slow-turning lateral vessel (STLV) mimic the ultrastructural effects of microgravity in plant cells. We accomplished this by qualitatively and quantitatively comparing the ultrastructures of cells grown on clinostats and in an STLV with those of cells grown at 1 g and in microgravity aboard the Space Shuttle Columbia. Columella cells of Brassica perviridis seedlings grown in microgravity and in an STLV have similar structures. Both contain significantly more lipid bodies, less starch, and fewer dictyosomes than columella cells of seedlings grown at 1 g. Cells of seedlings grown on clinostats have significantly different ultrastructures from those grown in microgravity or in an STLV, indicating that clinostats do not mimic microgravity at the ultrastructural level. The similar structures of columella cells of seedlings grown in an STLV and in microgravity suggest that an STLV effectively mimics microgravity at the ultrastructural level.

Brassica↗
PubMed2000

Nucleolar proteins and nuclear ultrastructure in preimplantation bovine embryos produced in vitro.

The aim of the present investigation was to describe the basic cell biology of the postfertilization activation of rRNA genes using in vitro-produced bovine embryos as a model. We used immunofluorescence confocal laser scanning microscopy and transmission electron microscopy to study nucleolar development in the nuclei of embryos up to the fifth postfertilization cell cycle. During the first cell cycle (1-cell stage), fibrillarin, upstream binding factor (UBF), nucleolin (C23), and RNA polymerase I were localized to distinct foci in the pronuclei, and, ultrastructurally, compact spherical fibrillar masses were the most prominent pronuclear finding. During the second cell cycle (2-cell stage), the findings were similar except for a lack of nucleolin and RNA polymerase I labeling. During the third cell cycle (4-cell stage), fibrillarin, UBF, nucleophosmin, and nucleolin were localized to distinct foci. Ultrastructurally, spherical fibrillar masses that developed a central vacuole over the course of the cell cycle were observed. Early in the fourth cell cycle (8-cell stage), fibrillarin, nucleophosmin, and nucleolin were localized to small bodies that with time developed a central vacuole. UBF and topoisomerase I were localized to clusters of small foci. Ultrastructurally, spherical fibrillar masses with a large eccentric vacuole and later small peripheral vacuoles were seen. Late in the fourth cell cycle, nucleophosmin and nucleolin were localized to large shell-like bodies; and fibrillarin, UBF, topoisomerase I, and RNA polymerase I were localized to clusters of small foci. Ultrastructurally, a presumptive dense fibrillar component (DFC) and fibrillar centers (FCs) were observed peripherally in the vacuolated spherical fibrillar masses. Subsequently, the presumptive granular component (GC) gradually became embedded in the substance of this entity, resulting in the formation of a fibrillo-granular nucleolus. During the fifth cell cycle (16-cell stage), a spherical fibrillo-granular nucleolus developed from the start of the cell cycle. In conclusion, the nucleolar protein compartment in in vitro-produced preimplantation bovine embryos is assembled over several cell cycles. In particular, RNA polymerase I and topoisomerase I are detected for the first time late during the fourth embryonic cell cycle, which coincides with the first recognition of the DFC, FCs, and GC at the ultrastructural level.

Animals↗
PubMed1999

Hyalinizing spindle cell tumor with giant rosettes: a report of three cases with ultrastructural analysis.

We report the light microscopic, ultrastructural appearance and immunohistochemical staining profile of three distinctive soft-tissue tumors recently designated hyalinizing spindle cell tumor with giant rosettes. The tumors occurred in two men, 41 and 54 years old, and one woman, 62 years old. Two tumors arose in the lower extremities and one in the upper arm. Two tumors were resected and measured 3 and 13.2 cm in greatest diameter; a biopsy only was done of the third tumor. Grossly, the tumors had a tan, pink, or white cut surface. The largest tumor exhibited central cystic change. Microscopically, they all displayed similar features and were composed of fibromyxoid regions, with areas of hyalinization in two tumors and focal ossification in one tumor. Scattered throughout each of the tumors were rosette-like structures in which neoplastic cells were arranged around a central collagenous core. Ultrastructurally, the neoplastic cells demonstrated the features of fibroblasts. In all tumors, there was abundant extracellular collagen fibers and in one there were large aggregates of amorphous extracellular external lamina-like material. The center of the rosette-like structures was composed of banded collagen fibers and the cells at the periphery of the rosettes had ultrastructural features similar to the neoplastic spindle cells located elsewhere in the tumor. Immunohistochemically, the tumor cells stained for vimentin. There was focal staining of the widely distributed spindle cells and cells that formed the rosettes for Leu-7, S-100 protein, and CD34. In one tumor, there was faint diffuse staining of the spindle cells for neuron-specific enolase. One tumor (with the amorphous extracellular material) stained for type IV collagen. There was no staining for desmin, muscle actin, smooth muscle actin, keratin, or epithelial membrane antigen. These results demonstrate that hyalinizing spindle cell tumor with giant rosettes is composed of fibroblasts. We did not demonstrate any ultrastructural or immunohistochemical differences between the spindle cells that comprised the majority of the mass and those that surrounded the rosette-like structures. There was no ultrastructural evidence of neural differentiation to explain the focal S-100 protein and Leu-7 staining of the tumor cells.

Adult↗
PubMed2002

Ultrastructure of the human intervertebral disc during aging and degeneration: comparison of surgical and control specimens.

STUDY DESIGN: Human intervertebral disc tissue from the annulus was obtained in a prospective study investigating the ultrastructural features of disc cells and extracellular matrix. Experimental studies were approved by the authors' Human Subjects Institutional Review Board. Discs were obtained from surgical specimens and control donors. OBJECTIVE: To compare the cellular and extracellular matrix characteristics of the annulus from control and surgical disc specimens using electron microscopy and specialized fixation that visualizes proteoglycans. SUMMARY OF THE BACKGROUND DATA: The ultrastructural features of disc cells and the disc matrix have received little attention, as compared with the literature on age- and disease-related changes in bone and cartilage. METHODS: Ultrastructural studies investigated disc tissue obtained from control and surgical disc specimens using transmission electron microscopy. Specialized fixation with ruthenium red was used to highlight matrix proteoglycans. RESULTS: Cellular and extracellular matrix fine structure was assessed in disc specimens from 29 control donors (newborns to 79-year-olds) and surgical disc specimens from 49 patients (16- to 77-year-olds). Control and surgical tissue showed similar ultrastructural features. Unusual matrix surrounding and encircling single cells or clusters of cells was common (48% of control and 63% of surgical specimens) and often contained fibrous long-spacing collagen (41.3% of control and 36.7% of surgical specimens). Ruthenium red greatly aided visualization of proteoglycans pooled in lacunar spaces. Variable cross-sectional diameters of collagen fibrils was present in 34% of control and 59% of surgical specimens. Regions with sparse interterritorial matrix were common. Cell morphology showed both cells with apoptotic nuclei and synthetically active cells that appeared healthy. CONCLUSIONS: Control and surgical specimens of the annulus showed similar ultrastructural features. Heterogeneity of collagen fibril diameter is an important observation because it is believed that fibril size relates to biomechanical disc function. Fibrous long-spacing collagen may reflect extracellular matrix remodeling or the presence of previous fibril depolymerization followed by repolymerization and reassociation with proteoglycans. Synthetic activity of disc cells is reflected in active rough endoplasmic reticulum, Golgi, and pools of proteoglycans in lacunar spaces and unusual extracellular matrix components that encircle cells and cell clusters. Such components may influence biomechanical quality. Departures from normal extracellular matrix organization of the aging or degenerating disc undoubtedly contribute to decreased biomechanical function of the annulus because they disrupt the normal annulus architecture. This study underscores the need for a fuller understanding of the dynamic relation between disc cells and the surrounding extracellular matrix, which they continually produce and remodel.

Adolescent↗
PubMed2002

Antioxidant actions and early ultrastructural findings of thiopental and propofol in experimental spinal cord injury.

Thiopental and propofol are effective antioxidant agents. The current study was undertaken to examine the neuroprotective effects of a single intraperitoneal dose of thiopental and propofol. Effects of the drugs were evaluated by lipid peroxidation and ultrastructural findings. Fifty male Wistar rats were divided into five groups. Group 1 was the control group. Rats underwent laminectomy only, and nontraumatized spinal cord samples were obtained 1 hour after surgical intervention. All other rats sustained a 50-g/cm contusion injury by the weight drop technique. Group 2 rats underwent spinal cord injury alone, group 3 rats received 1 mL intralipid solution intraperitoneally immediately after trauma as the vehicle group, group 4 rats received a 15-mg/kg single dose of thiopental, and group 5 rats received a 40-mg/kg single dose of propofol intraperitoneally following the trauma. Samples from groups 2, 3, 4, and 5 were obtained 1 hour after injury. Lipid peroxidation was determined by measuring the concentration of malondialdehyde in the spinal cord tissue. The ultrastructure of the spinal cord was determined by electron microscopy. The contusion injury was associated with a rise in lipid peroxidation. Compared with the trauma group there was significant attenuation in lipid peroxidation of groups 4 and 5. Ultrastructural findings showed that the rats of group 4 sustained minor damage after spinal cord injury, but there was more evident damage in group 5 rats. These results indicate that thiopental decreases lipid peroxidation and improves ultrastructure, whereas propofol decreases lipid peroxidation without improving ultrastructure 1 hour after spinal cord injury in rats.

Anesthetics, Intravenous↗
PubMed2007

Ultrastructural changes of the cochlea after oral and maxillofacial firearm wounds.

BACKGROUND: There have been reports that maxillofacial firearm wounds could induce hearing loss. The effects on the ultrastructure of the cochlea and cochlear nerves after oral and maxillofacial firearm wounds are still unclear. This experiment investigates the ultrastructural changes of the cochlea and cochlear nerve after oral and maxillofacial firearm wounds. METHODS: Twenty dogs were wounded by steel spheres or detonators to establish animal models of oral and maxillofacial firearms wound. At different times after trauma, the wounds were examined and the specimens of the cochlea and cochlear nerve were taken to study the ultrastructural changes. RESULTS: The ultrastructural changes of the cochlea and cochlear nerve at 1 hour after trauma were cilia disorganization, edema of the nerve, and mitochondrial denaturalization. At 6 hours, there was extensive degeneration in the cochlea and cochlear nerve, cilia falling off of hair cells, and dissolution of the nerve sheath structure. CONCLUSIONS: The ultrastructure of the cochlea and cochlear nerve after injury is severe, but in the early period the injury is reversible.

Animals↗
PubMed1992

Quick-freezing of cultured cardiac cells in situ with special attention to the mitochondrial ultrastructure.

A new method has been developed which allows quick-freezing in situ of primary, cardiac cell cultures grown to confluence on gas-permeable membranes (Petriperm dishes). Small pieces of the growth substratum, with rhythmically beating myocardial cells, were slam-frozen, without cryoprotectants, against the surface of a helium-cooled copper block at approximately 16 K. The quality of the cellular cryopreservation, as judged by ultrastructural criteria, was studied in freeze-substituted specimens processed for transmission electron microscopy. The ultrastructure of cryofixed cardiac cells was compared with that of unfrozen, chemically fixed samples. The severity of cryodistortions increased progressively with increasing distance from the point of first impact. Of particular interest were the dramatic alterations of the mitochondrial ultrastructure. The concept that the reticular and the outer mitochondrial membranes are intimately and strongly associated was clearly demonstrated. Optimally frozen material revealed cryopreserved ultrastructure of high quality. The method described appears to offer an ideal model system for correlating the information gained by phase-contrast microscopy of living cell cultures with the ultrastructure of the same samples fixed in situ by chemical or physical techniques. Cryofixation would be particularly useful for studying dynamic cellular processes associated with physiological and pathophysiological conditions, e.g. metabolic inhibition, anoxia and substrate deprivation.

Animals↗
PubMed1996

Immunohistochemical, morphological and ultrastructural resemblance between dendritic cells and folliculo-stellate cells in normal human and rat anterior pituitaries.

Immunolabeling of cryo-sections of human anterior pituitaries obtained at autopsy, and of cryo-sections of freshly prepared rat anterior pituitaries, with a panel of monoclonal antibodies against markers of the monocyte/dendritic cell/macrophage lineage, reveals in both species a characteristic pattern of immunopositive cells, among which many cells with dendritic phenotype are found. Cells characterized by marker expression of MHC-class II determinants and a dendritic morphology are present in both human and rat anterior pituitary. Markers characteristic of dendritic cells such as the L25 antigen and the OX62 antigen were present in anterior pituitaries from human and rat respectively. The population of MHC-class II expressing dendritic cells of the rat anterior pituitary is compared at the ultrastructural level with the folliculo-stellate cell population, which cell type has been previously characterized by its distinctive ultrastructure and immunopositivity for the S100 protein. Using immuno-electron microscopy of rat anterior pituitaries fixed with periodate-lysine-paraformaldehyde, we were able to distinguish non-granulated cells expressing MHC-class II determinants, whereas no MHC-class II expression was found in the granulated endocrine cells. Using double immunolabeling of cryo-sections of these rat AP with 25 nm and 15 nm gold labels, we demonstrated an overlap between the populations of MHC-class II-expressing and S100 protein-expressing cells. Furthermore, MHC-class II-expressing and S100-positive cells showed ultrastructural characteristics that have been previously ascribed to folliculo-stellate cells. At the light microscopical level in the rat AP, a proportion of 10 to 20% of the S100-positive cells was found immunopositive for the MHC-class II marker OX6. In the human AP, S100-positive folliculo-stellate cells and cells expressing the leukocyte common antigen CD45 were found to occupy predominantly different tissue compartments in the human anterior pituitary, namely the epithelial parenchyme cords and perivascular compartments respectively. A proportion of CD45+ cells was found in the parenchyme compartment and, vice versa, indicating an overlap of the tissue compartments in which both cell types occur. However, at the light microscopical level we could not find cells expressing both the S100 and CD45 marker. The present finding of a proportion of S100-positive pituitary cells with ultrastructural and immunohistochemical characteristics of both dendritic cells and folliculo-stellate cells, confirms the suggested heterogeneity of the latter cell group with respect to their ultrastructural phenotype and putative function. The possibility of a myeloid origin of part of the folliculo-stellate cell group in the AP, is discussed and might elucidate some of the discrepancies in the literature concerning the embryological origin of this cell group.

Adult↗
PubMed2005

Ultrastructural pathology of prion diseases revisited: brain biopsy studies.

We report here a detailed ultrastructural comparison of brain biopsies from 13 cases of Creutzfeldt-Jakob disease (CJD) and from one case of fatal familial insomnia (FFI). The latter disease has not heretofore benefited from ultrastructural study. In particular, we searched for tubulovesicular structures (TVS), 35-nm particles regarded as the only disease-specific structures at the level of thin-section electron microscopy. Our material consisted of brain biopsies obtained by open surgery from one FFI case from a new French family, one case of variant CJD (vCJD), nine cases of sporadic CJD (sCJD), two cases of iatrogenic (human growth hormone) CJD and one case of hereditary CJD (Val203Iso). The ultrastructural picture of the cerebral cortex of the FFI patient was virtually indistinguishable from that of CJD. TVS were found, albeit only after prolonged search. Typical spongiform change was observed, consisting of intracellular membrane-bound vacuoles containing secondary chambers (vacuoles within vacuoles) and amorphous material. Neuronal degeneration was widespread: some processes contained degenerating mitochondria and lysosomal electron-dense bodies and these met the criteria for neuroaxonal dystrophy. Other processes contained branching cisterns; still others were filled with electron-dense masses and amorphous vesicles. The overall ultrastructural appearance of variant CJD was similar to that of FFI cerebral cortex, except for a much higher number of cellular processes containing TVS. We detected TVS in the majority of sCJD cases that, in addition to typical spongiform change and robust astrocytic reaction, showed widespread neuritic and synaptic degeneration and autophagic vacuoles. We conclude that TVS are readily found in FFI, vCJD and sCJD and that widespread neuritic degeneration is a part of ultrastructural pathology in prion diseases.

Adult↗
PubMed2006

Ultrastructural clues for the potent therapeutic effect of melatonin on aging skin in pinealectomized rats.

Recently we have reported a significant reduction in the thickness of epidermis and epidermis + dermis in the back, abdominal and thoracic skin of the long-term pinealectomized rats and the potent therapeutic effect of melatonin on the pinealectomy-induced morphometric changes. The present study was aimed to determine the fine structure of the abdominal and thoracic skin in pinealectomized rats and the effect of melatonin on skin ultrastructure. Rats were pinealectomized or sham operated (control) for 6 months. Half of the pinealectomized rats were treated with 4 mg/kg melatonin during the last month of the experiment. Pinealectomy resulted in prominent ultrastructural changes in the skin. Epidermal atrophy, disorganization and cytological atypia were obvious. Tonofilament distribution was not uniform, and intercellular space was narrow. Nuclear irregularity and heterochromatin condensation were detected. Many mitochondria were irregular and edematous with increased translucence of the matrix, either partial or total destruction of crests and frequently the presence of vacuoles, myelin figures and dense bodies. Microprojections of basal cells into the dermis were observed. The dermis was thin, and collagenous fibers were loosely arranged. The epidermis in melatonin administered pinealectomized rats was obviously thicker than that of pinealectomized rats. The cells of each layers had characteristic morphological and ultrastructural features. Nuclear irregularity and heterochromatin condensation were not seen. Mitochondria were generally normal in ultrastructural appearance but rarely vacuoles and myelin figures were observed. The dermis was thick, and collagenous fibers were closely packaged. This paper provides an additional ultrastructural evidence that the damage to mitochondria is the major contributory factor to skin aging and that melatonin has potent therapeutic effects in reducing age-related changes via protecting fine structure of the skin.

Animals↗
PubMed1987

Ultrastructural features in 100 cases of acute myeloid leukaemia.

Ultrastructural features thought to be significant in acute myeloid leukaemia (AML) have been examined in 100 cases entered into the Medical Research Council 9th AML Trial. It is concluded that, of the features examined, only rarely is there a striking correlation with diagnosis which could be usefully employed with confidence. This is a consequence of there being both a large overlap of similar ultrastructural features between the different sub-types of the disease and also wide variations in ultrastructure within the conventionally diagnosed sub-types of AML. Thus the similarities between cells from different cases which allow them to be classified by light microscopy do not necessarily extend to the ultrastructural level. However, it is suggested that a classification on ultrastructural grounds might have a prognostic significance which would only be revealed by a long-term study.

Chromatin↗
PubMed1987

Ultrastructural findings in oral Kaposi's sarcoma (AIDS).

Ten biopsies of oral Kaposi's sarcoma were examined histologically and ultrastructurally. Histologically, early and late tumor stages could be differentiated. On the ultrastructural level, endothelial-like and spindle-shaped tumor cells were revealed. Tumor cells associated with vessel-like spaces showed partly interrupted basal membranes, Weibel-Palade bodies, desmosomes and tight-junctions, while spindle-shaped cells lacked these ultrastructural features of endothelial cells. Within the cytoplasm of endothelial-like cells, aggregates of tubular structures were observed. Histological and ultrastructural findings in oral Kaposi sarcoma are comparable to those of such other organs as skin and intestines. The ultrastructural findings indicate an endothelial origin, at least of endothelial-like tumor cells.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Effects of dibutyryl cyclic adenosine monophosphate on the ultrastructure of endothelial cells in rat lungs cold preserved for 15 hours.

BACKGROUND: Dibutyryl cyclic adenosine monophosphate (db-cAMP) has been shown to protect vascular endothelial cells by increasing the level of intracellular cAMP, and we have previously reported its effectiveness in lung preservation. Here, the effects of db-cAMP in lung preservation were ultrastructurally investigated, and the ultrastructural changes before reperfusion were correlated with pulmonary function after reperfusion. METHODS: The lungs of 17 Lewis rats were flushed with perfusate and prostaglandin E(1), and were then divided into three groups. In the fresh group (n = 6), the lungs were flushed with extracellular-type trehalose-containing (ET-K) solution and were reperfused immediately. In the control group (n = 6) and db-cAMP group (n = 5), the lungs were flushed with ET-K solution and ET-K solution plus db-cAMP (2 mM), respectively, and were reperfused after cold preservation at 4 degrees C for 15 h. Before reperfusion, tissue was sampled and ultrastructurally analyzed by transmission electron microscopy. RESULTS: In the endothelial cells of pulmonary arterioles, the incidence of protrusion was significantly lower in the fresh and db-cAMP groups than in the control group (p < 0.05). The incidence of detachment and microvillus formation were significantly lower in the fresh and db-cAMP groups than in the control group (p < 0.01). The ultrastructure of the alveoli did not allow separation of the control and db-cAMP groups. The shunt fraction and wet to dry weight ratio of the lung tissue after reperfusion were significantly lower in the fresh and db-cAMP groups than in the control group (p < 0.01). Positive correlations were found between the incidence of these ultrastructural changes in the endothelial cells of the pulmonary arterioles and pulmonary function after reperfusion. CONCLUSION: These findings suggest that db-cAMP might attenuate the lung injury caused by cold preservation and ischemia-reperfusion, partly by suppressing the acceleration of the structural changes in the endothelial cells in the pulmonary arterioles.

Animals↗
PubMed1984

Effects of aminoglycosides on glomerular ultrastructure.

Effects of the aminoglycosides, gentamicin, netilmicin and tobramycin (30 mg/kg/day X 7, i.p.), on glomerular ultrastructure were determined in male Wistar rats. Glomerular ultrastructure was studied by scanning and transmission electron microscopy. The average number of capillary endothelial fenestrae per 5 microns of capillary wall decreased from a control value of 10.8 to 8.2 and 8.1 in gentamicin- and tobramycin-treated rats, respectively, as shown by transmission electron microscopy (TEM). Scanning electron microscopy (SEM) showed that the density of endothelial fenestrae decreased to about 80% of control in gentamicin- and tobramycin-treated rats. In addition, gentamicin and tobramycin produced a marked reduction in the number of granulated myoepithelioid++ cells of the juxtaglomerular apparatus. Netilmicin appeared to have no effect on glomerular ultrastructure. Both TEM and SEM, indicate that the nephrotoxic aminoglycosides gentamicin and tobramycin alter the ultrastructure of the fenestrated endothelia of the glomerular capillaries. These ultrastructural changes appear to be correlated to the impairment of the glomerular permeability for different compounds.

Aminoglycosides↗
PubMed1986

Intraepithelial migration of mucosal mast cells in hay fever: ultrastructural observations.

Evidence has been presented suggesting that a migration of nasal mast cells from the mucosal connective tissue stroma into the epithelium is part of the mucosal response in birch pollen allergy. In a previous study, the identification of these intraepithelial cells as tissue mast cells rather than blood basophils was based on light microscopical morphology and histochemistry. We have now studied the ultrastructure of these cells in mucosal biopsies taken before and during the birch pollen season. Intraepithelial cells with basophil or metachromatic granules were only observed in biopsies taken during the season. Some of these cells had the ultrastructural appearance of tissue mast cells, including cytoplasmic lipid droplets and a granular substructure composed of multilamellar arrays and scrolls, serving to distinguish human mast cells from blood basophils. The ultrastructural traits of the remaining cells were heterogeneous, some reminiscent of human blood basophils, others of globule leucocytes of other species, but entirely typical blood basophils could not be identified. The results thus support our previous suggestion that a migration of mucosal mast cells from the connective tissue stroma into the epithelium is part of the human allergic mucosal response. It cannot be determined whether the ultrastructural heterogeneity of these cells is the result of an adaptation to the intraepithelial environment of one single mast cell type or to the existence of an ultrastructurally distinct mucosal mast cell.

Basophils↗
PubMed1980

Ultrastructural evidence of microvascular damage and myocardial cell injury after coronary artery occlusion: which comes first?

Both microvascular damage and myocardial cell injury occur after coronary occlusion, but the relationship of these two events is unclear; specifically, it is unknown whether microvascular damage causes myocardial cell injury. Dogs were subjected to coronary occlusion for 20, 40, 60, 90 or 180 minutes, after which subendocardial and subepicardial biopsies were obtained for electron and light microscopy of 1-mu sections. Of 312 biopsies of ischemic myocadium, 181 showed myocardial cell injury with no microvascular damage; 131 showed myocardial cell injury and microvascular damage; but none showed microvascular damage without myocardial cell injury. Although ultrastructural evidence of myocardial cell damage was present in the subendocardium after 20-40 minutes of ischemia, ultrastructural evidence of microvascular damage was not prominent until 60-90 minutes after coronary artery occlusion. Morphologic ultrastructural evidence of microvascular damage lagged behind myocardial cell injury, suggesting that ultrastructural microvascular damage is not a primary cause of ultrastructural myocardial cell injury.

Animals↗
PubMed1983

The relationship of human atrial cellular electrophysiology to clinical function and ultrastructure.

Although previous studies have described the electrophysiological and ultrastructural characteristics of human cardiac fibers, no attempt has been made as yet to describe quantitatively the relationship between the ultrastructural and cellular electrophysiological derangements occurring with cardiac disease, and their clinical manifestations. In this study, we used standard microelectrode techniques to record the action potential characteristics of human atrial fibers obtained during cardiac surgery and correlated the electrophysiological parameters with clinical and ultrastructural data. Ultrastructure was studied by optical and electron microscopy. We found a multiple linear regression among maximum diastolic potential, atrial size and pressure, P wave duration and ultrastructure changes. Proliferations of Z band material, widening of intercalated discs, and degenerative changes were quantified and correlated with electrophysiological and clinical data. These studies emphasize the relationship between hemodynamic anomalies and resultant changes in both human atrial fiber structure and electrical function. Finally, the likelihood of occurrence of arrhythmias can be predicted using the analytic method described.

Adolescent↗