Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ultrastructure”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

Light microscopical and ultrastructural studies on the vas deferens of the lizard Mabuya carinata.

Adult male lizards (Mabuya carinata) were studied during breeding and non breeding seasons to determine the regional and seasonal differences if any in the vas deferens and to compare ultrastructural features of luminal epithelial cells with those of endotherms. The vas deferens of the lizard is a convoluted tube extending from the epididymis to the hemipenis passing over the kidney. Based on morphometric data of luminal diameter and epithelial cell height three distinct regions viz; proximal, middle and distal regions were identified in the vas deferens. The epithelium is surrounded by a thin layer of lamina propria, many layers of circular smooth muscle fibers and an outer layer of visceral pleuro peritoneum. Based on cell and nuclear morphology and ultrastructure, five different cell types viz; principal cell, basal cell, mitochondria rich cell, halo cell and narrow cell were identified in the epithelium during both breeding and non breeding season. Principal cells and basal cells were more abundant in both seasons. The types of luminal epithelial cells of vas deferens of M. carinata and their ultrastructural features are similar to those of mammals. Further, vas deferens of M. carinata differs from mammals in having only circular smooth muscles in contrast to circular and longitudinal muscles of mammalian vas deferens. To the best of our knowledge this is the first report describing cell types of vas deferens, their ultrastructure and ultrastructural seasonal variations in reptiles.

Animals↗
PubMed2005

[DNA damage, Bcl-2, Bax expression and ultrastructure change in spermatogenic cell of mice exposed to cadmium].

OBJECTIVE: To study DNA damage, Bcl-2 and Bax expression, and ultrastructure change in spermatogenic cell of mice by cadmium exposure. METHODS: Twenty-four male mice were divided into 4 groups: 3 groups treated with cadmium chloride of 1, 5, 10 micromol x kg(-1) x d(-1) i.p. respectively for 5 days, and one normal saline control group. The DNA damage of spermatogenic cell by single-cell gel electrophoresis technology was detected. The expression positive rate of Bcl-2, Bax protein in spermatogenic cell by the immunohistochemical method was assayed, and the ultrastructural change of spermatogenic cell by the transmission electron microscope was observed. RESULTS: DNA damage rates of of spermatogenic cell in 1, 5, 10 micromol/kg cadmium chloride groups were higher than that of normal group (P < 0.001). Bcl-2 protein expression positive rates were lower than that of normal group (P < 0.001). Bax protein positive expression rate in 5 micromol/kg group was higher than those in normal group, and 1, 10 micromol/kg groups. The ultrastructure of karyotis, karyotheca, mitochondria, endoplasmic reticulum in three treated groups had different degree of damage and the degree of ultrastructural change was increasing with rising concentration of cadmium. CONCLUSION: Cadmium exposure will cause the DNA break, Bcl-2 and Bax protein abnormal expression and ultrastructural change in spermatogenic cell.

Animals↗
PubMed1990

The effects of exposure of articular cartilage to air. A histochemical and ultrastructural investigation.

The effects of exposure of articular cartilage to air and the potential for reversibility of the histological and ultrastructural changes that were produced by this exposure were investigated in the knee joint of the rabbit. After a medial parapatellar arthrotomy and lateral dislocation of the patella, the surface of the articular cartilage was exposed to air for one, two, and three hours in forty-five rabbits. Reversibility of the changes was assessed in fifteen rabbits after exposure of the cartilage to air for three hours, closure of the joint, and six weeks of recovery. Histochemical and ultrastructural changes were evaluated, with use of the contralateral non-exposed knee joint as a control. Depletion of glycosaminoglycans in the matrix of articular cartilage, as indicated by a loss of surface staining with toluidine blue, occurred after one hour of exposure to air. Ultrastructural changes occurred in chondrocytes throughout the full thickness of articular cartilage after one hour of exposure. Increases in the time of exposure to air resulted in more pronounced ultrastructural abnormalities in chondrocytes throughout the entire thickness of the articular cartilage, but there was no apparent irreversible cellular injury. Six weeks after arthrotomy, the chondrocytes had fully recovered from the changes that had been noted immediately after exposure to air, and they were devoid of degenerative changes. The cells showed ultrastructural evidence of increased metabolic activity in the nucleus and cytoplasm. In addition, the chondrocytes had partially restored the depleted glycosaminoglycans.

Air↗
PubMed1990

[The ultrastructural characteristics of human lung adenocarcinomas as a factor in the prognosis in surgical treatment].

The material of 70 patients with lung adenocarcinomas radically operated at the All-Union Cancer Research Centre is analyzed. The spread of tumour expressed in terms of TNM system (I group--T1-3 N0M0--37 patients, II group--T1-3 N1M0--18 patients, III group--T1-3 N2M0--11 patients, IV group--T1-3 N1M1--4 patients) and its ultrastructure served as criteria. The correlation is found between the life-span, degree and type of the tumour cell ultrastructural differentiation. The most favourable prognosis at comparable tumour spread is found when the tumour cell ultrastructural differentiation corresponded to that of Clara type, pneumocytes of II order and ciliary type. Less favourable ultrastructural features were the domination of undifferentiated cells and the presence of goblet cells and those having the signs of differentiation into the various directions. The lack of correlation of the differentiation at the light microscopic and ultrastructural levels is found in some cases this being reflected in delayed results.

Adenocarcinoma↗
PubMed1988

Ultrastructural analysis of human T and TC mast cells identified by immunoelectron microscopy.

Tryptase and chymase were localized in human mast cells by immunoelectron microscopy, enabling the T (tryptase positive, chymase negative) and TC (tryptase positive, chymase positive) types of mast cells to be identified and ultrastructurally characterized. A double immunogold staining procedure was performed on samples of human skin, small intestine, and lung with rabbit polyclonal IgG anti-chymase and mouse monoclonal IgG anti-tryptase primary antibodies and gold-conjugated secondary antibodies. Approximately 225 mast cells were examined in this fashion; comparable sections from 170 of these mast cells along with approximately 200 additional mast cells also were examined using techniques optimized for ultrastructural detail. Each secretory granule of TC mast cells contained both tryptase and chymase; secretory granules of T mast cells stained strongly positive for tryptase alone. Extremely small amounts of chymase appeared to be present in an occasional T mast cell granule. Staining for the neutral proteases was more intense over electron-dense regions of the granules, particularly noticeable over the characteristic discrete scrolls of T mast cells. T and TC mast cells each had large numbers of cytoplasmic granules, nuclei with peripherally condensed chromatin and low nuclear/cytoplasmic ratios, indicating maturity of both cell types. TC mast cell granules generally were more uniformly electron dense, larger and more numerous than T mast cell granules, which were more variable in shape. Compact solid-core scrolls, peripheral parallel lamellae and amorphous electron-dense material were found in granules of both cell types. Only TC mast cells had granules with grating and lattice substructures; only T mast cells had granules containing discrete scrolls. Less commonly, T mast cells were detected containing granules with a characteristic beaded or particulate ultrastructure. The ultrastructural features noted above were observed in T and TC mast cells regardless of the tissue in which they were examined and thereby permit T and TC mast cells to be distinguished by ultrastructure alone.

Cell Nucleus↗
PubMed1989

Ultrastructural morphology of the lung in cystic fibrosis.

Cystic fibrosis (CF) is the most common lethal genetic disease among Caucasians, with much of the morbidity and most of the mortality related to pulmonary complications. The underlying defect in this disease has yet to be precisely defined, so it is somewhat surprising that a comprehensive study of the ultrastructural morphology of the lung in CF has not heretofore been reported. We used transmission electron microscopy to examine the small airways in 15 patients who had died of CF, and compared the findings with 15 disease controls with non-CF chronic airways disease and 15 patients with normal lung morphology. The lung parenchyma was also examined ultrastructurally in 7 patients with CF, 4 disease controls, and 4 normal lung cases. In addition, the literature regarding the ultrastructural morphology of the large airways in CF was reviewed. Patients with CF showed non-specific ciliary abnormalities, hyperplasia of mucous cells, increased numbers of pulmonary neuroendocrine and indeterminate cells, degeneration and sloughing of epithelial cells, and colonization of bacteria of the mucous layer of the small airways when compared with normal controls. Alveoli showed non-specific injury and regeneration of type II pneumocytes. However, these changes were all similar to those observed in the disease controls. Specifically, no cellular or subcellular ultrastructural abnormality unique to CF was observed. It is probable that the most useful ultrastructural approach to the lung in CF in future studies will involve X-ray microanalytical studies of ionic composition using cryotechniques.

Adolescent↗
PubMed1985

Ultrastructural characterization of pulmonary neoplasms. II. The role of electron microscopy in characterization of uncommon epithelial pulmonary neoplasms, metastatic neoplasms to and from lung, and other tumors, including mesenchymal neoplasms.

Ultrastructural analysis through better resolution adds significant information to the evaluation and classification of primary pulmonary neoplasms. Light microscopy is limited in the evaluation of lung neoplasms. In some cases the light microscopic appearance may be entirely misleading, whereas in others it is inconclusive. Immunocytochemistry provides information on cytoplasmic differentiation of various tumors and hence more data on their corresponding phenotypes. The data from immunocytochemistry without corresponding objective electron microscopic evaluation may be very difficult to interpret. Correlation of historical, gross, light, electron microscopic, and immunocytochemical data is essential for a final accurate diagnosis (fig. 20). Fine needle aspiration of pulmonary neoplasms is becoming very fashionable and a diagnosis, including type of neoplasm, is expected on the basis of examination of a limited number of cells which further emphasizes the importance of ultrastructural characterization in helping to establish an accurate diagnosis [63-69]. The current classification of pulmonary neoplasms may need to be modified in the near future to incorporate the newly created data [70-72]. At the present time, there appears to be, at least, a need for a 'double standard', as Sobin [73] has suggested, which would permit the evaluation of the biologic significance of the ultrastructural and immunocytochemical findings (as applied to classification of neoplasms) in an effort to derive meaningful clinicopathologic correlations. Figure 20 emphasizes the additive role which should be played by the various diagnostic modalities to enable a morphologic assessment which would be an accurate predictor of biologic behavior. With an accurate assessment of biologic behavior, a more appropriate and rational approach for therapy is possible. There is also an important role for ultrastructural analysis in metastatic pleural and pulmonary neoplasms, primarily adenocarcinomas, as well as in the differential diagnosis of pulmonary neoplasms versus other tumors that may be similar in histological appearance. The role of ultrastructure in mesenchymal neoplasms is also crucial in defining specific neoplastic cell populations and in some cases in the differentiation from other non-mesenchymal tumors. It seems that routine electron microscopic examination of pulmonary neoplasms provides additional information that may be of great value in the management of patients and in understanding the differentiation, and perhaps histogenesis, of pulmonary neoplasms.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1987

The ultrastructure of selected gynecologic neoplasms.

Several articles have been published recently that discuss the role of electron microscopy in the diagnosis and study of gynecologic neoplasms. It becomes apparent from those works and the review just presented that, although an ultrastructural study is not necessary for reaching a diagnosis of many of these tumors, it may be necessary or supportive in identifying the more poorly differentiated ones. Furthermore, electron microscopy is valuable in providing evidence for the histogenesis of some of these neoplasms. Unfortunately for the pathologist, a certain level of morphologic differentiation (and an absence of metaplasia) in a cell is usually necessary for these goals to be achieved. For example, an adenomatoid tumor (see the article by Dr. Srigley, Mr. Toth, and Mr. Edwards in this issue) of the fallopian tube can readily be accepted as being composed of mesothelial cells, because both the neoplastic cells and normal mesothelial cells have the same highly differentiated features of long, slender microvilli, prominent intercellular junctions, and many microfilaments. On the other hand, there is very little resemblance between the granulosa cells of a granulosa-cell tumor and mature mesothelial cells. Thus, if one of the theories of histogenesis of granulosa cells were correct--namely, that they are derived ultimately from mesothelial lining--the ultrastructural evidence would rest on recognizing a similarity between the two types of cells at an earlier stage of differentiation. The neoplastic granulosa cell has differentiated along a separate, specialized line in which the ultrastructural resemblance to the parent cell is partly, if not completely, lost. Another example of the type of information that electron microscopy can provide is in relation to the common epithelial tumors. There is good evidence that the serous tumors in this group arise from mesothelium, although ultrastructurally their differentiation has veered from a mesothelial direction to one in which the cells have a complement of organelles related to secretory activity. Paradoxically, the mucinous cystic tumors, which have been classified traditionally as tumors of surface epithelial origin, are now thought to be of germ-cell origin in some cases, as examples of monophyletic teratomas. The ultrastructural evidence for this conclusion rests on the presence of anchoring filaments in the microvilli of the neoplastic cells, similar to those of normal intestinal epithelium, and on an admixture of various types of gastrointestinal cells, including those that contain dense-core granules (argentaffin cells).(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1987

Ultrastructural analysis of human natural killer cell activation.

In this study we describe characteristic ultrastructural changes of CD3- large granular lymphocytes (LGL), ie, natural killer (NK) cells, following stimulation with recombinant (r) interleukin 2 (IL 2) or r-gamma interferon (r-gamma IFN) and after interaction with K562 target cells (TC) or Sepharose-bound anti-Fc gamma receptor (FcR) monoclonal antibody (MoAb). When compared to resting cells the cytolytic activity of r-IL 2- and r-gamma IFN-stimulated cells against K562 TC was enhanced. The r-IL 2-stimulated LGL were larger and consistently displayed the shape and cytoskeletal rearrangement characteristic of activated cells. The Golgi apparatus was expanded, and the number of electron-dense granules and vesicles was increased. The ultrastructural changes in r-gamma IFN-stimulated LGL were markedly different from those observed following r-IL 2 activation. Cells did not exhibit changes in size, shape, cytoskeletal organization, or in the structure of the Golgi apparatus. However, r-gamma IFN-stimulated cells exhibited distinctive changes in the structure and content of electron-dense granules with deaggregation of the matrix and parallel tubular arrays (PTAs). Within organelles apparently derived from the electron-dense granules, vesicular and tubular structures were noted that may be the morphological equivalent of cytotoxic factors produced by cytolytic effector cells. These ultrastructural observations indicate that r-IL 2 and r-gamma IFN enhance the lytic ability of NK cells by acting on distinct cell machineries. The cytolytic ability was decreased when LGL were pretreated with K562 TC or immobilized anti-FcR antibody. In both experimental conditions cells displayed ultrastructural features indicating activation as well as loss of cytoplasmic granules and other Golgi-derived organelles. Stimulation of r-gamma IFN- or r-IL 2-activated LGL with K562 TC or Sepharose-bound anti-FcR antibody decreased their cytolytic ability, with cells depleted of granules at the ultrastructural level. Intracytoplasmic fusion of granules and a massive release of the granule content were found in r-IL 2-stimulated cells, reminiscent of the mechanism of basophil degranulation. These observations suggest that multiple activation signals involving distinct surface membrane molecules induce release of cytolytic factors by both resting and activated NK cells.

Cell Line↗
PubMed1985

Ultrastructural analysis of a specific hamster alveolar macrophage antigen.

Alveolar macrophages of hamsters have a cell surface antigen not found on other pulmonary cells or macrophages from other sites. A specific mouse monoclonal antibody and protein A-colloidal gold were used to study the distribution of this antigen at the ultrastructural level. By quantitating the number of antigenic sites per unit linear distance of membrane of the total cell surface, it was established that this antigen is randomly distributed on the plasma membrane. Cell-to-cell heterogeneity in antigen density was correlated with other ultrastructural features of lung macrophages studied morphometrically. A strong correlation (r = 0.77) between antigen density and secondary lysosome content was found, supporting the thesis that expression of this antigen increases with macrophage age. No apparent topographic relationship of surface antigen to any cytoplasmic organelles could be inferred from the ultrastructural morphology. This study also used immuno-ultrastructural techniques to visualize stages of the internalization of labeled antigen in live cells. While some cells retained a random distribution of antigen at 0 degrees C, most showed movement of antigenic sites away from pseudopodia to clusters on more linear (less ruffled) portions of cell surface. At 37 degrees C, the antigen was internalized and could be visualized within coated pits and endocytic vacuoles. Definition of the anatomic distribution of this antigen under various conditions provides a baseline for further ultrastructural investigations of the function of this antigen.

Animals↗
PubMed1973

Ultrastructural autoradiographic studies of the early vasoproliferative response in tumor angiogenesis.

The early local vasoproliferative response induced by live tumor cells and an extract derived from such cells was studied in rat subcutaneous tissue by means of electron microscopy and ultrastructural autoradiography after local injections of tritium-labeled thymidine. DNA synthesis was localized in endothelial cells, pericytes, and perivascular cells 6 to 8 hours after exposure to 10(6) live Walker ascites tumor cells. At this time, DNA-synthesizing endothelial cells in parent vessels exhibited a continuous basement membrane and could not be readily differentiated, ultrastructurally, from control endothelium. At 48 to 50 hours, the number of labeled cells increased and there was ultrastructural evidence of regenerating endothelium: marked increase in ribosomes and endoplasmic reticulum, scarce or absent pinocytotic vesicles, attenuated or discontinuous basement membrane and marked irregularities in cytoplasmic surfaces. Labeled endothelial cells were present in parent vessels, as well as along newly formed sprouts. Autoradiographic and ultrastructural findings after tumor extract or live tumor cells at 48 hours were similar. Evidence was also presented that cells which were recognizable as pericytes, by ultrastructural criteria and by their localization within the basement membrane, were capable of DNA synthesis and mitosis.

Animals↗
PubMed1974

Ultrastructural comparison of human platelets separated from blood by various means.

Ultrastructural features of human platelets separated from blood by a number of different procedures were compared. Platelet isolation procedures included differential centrifugation, gel filtration and albumin density gradient centrifugation. Platelets separated from blood by the differential centrifugation procedure of Mustard showed the least ultrastructural change compared to platelets in plasma. Isolation of platelets from blood by gel filtration produced minor ultrastructural changes including irregularity of cytoplasmic outline, formation of a few short pseudopods and slight dilatation of the surface-connected canalicular system. Platelets separated by albumin density gradient centrifugation showed the most marked alterations of ultrastructure. Ultrastructural features of platelets isolated by the various procedures are compared to functional changes previously reported.

Blood Platelets↗
PubMed1981

Diagnostic electron microscopy. I. Hematology: differential diagnosis of acute lymphoblastic and acute myeloblastic leukemia. Use of ultrastructural peroxidase cytochemistry and routine electron microscopic technology.

We have described in detail a number of ultrastructural methods which we have found to be useful for the evaluation of hematologic cases submitted to our diagnostic electron microscopic unit. The techniques include the preparation of peripheral blood for study as both buffy coat and cell suspension specimens and the preparation of bone marrow spicules. Ultrastructural methods for the demonstration of glycogen and peroxidase are detailed. The study of such material includes light microscopic study of plastic-embedded, alkaline-Giemsa-stained one micron sections as well as ultrastructural studies. All hematological cases submitted for ultrastructural analysis in a two-year period were reviewed and are presented here. The identification of individual mature cells was relatively simple using light microscopy. Populations of blasts could also easily be recognized. Further differentiation of blasts, primarily lymphoblasts or myeloblasts, was done using ultrastructural cytochemistry where needed. These techniques can easily be done in electron microscopy units concerned with diagnostic work. We submit that pathologists and hematologists should have access to the diagnostic tools described here in order to manage patients with acute leukemia.

Cytological Techniques↗
PubMed1982

The formation and effect of stored platelet concentrate microemboli on pulmonary ultrastructure.

The formation of microaggregates of platelets and leukocytes and the infusion of these aggregated blood elements in pulmonary ultrastructure and function have been extensively studied. This study was undertaken to document the formation of platelet microaggregates during storage of platelet concentrate and to determine what effect the infusion of stored platelets has on pulmonary ultrastructure. The screen filtration pressure of platelet concentrate stored at 4 degrees C. for a period of 48 hours was measured after six, 24 and 48 hours of storage. Screen filtration pressure progressively rose from a mean of 47.20 millimeters of mercury to a mean of 237.40 millimeters of mercury at 48 hours, p less than 0.02 between six and 48 hours of storage. Specimens of the lung taken for biopsy from ten patients undergoing open heart operations were examined for ultrastructural alterations. Those specimens obtained following cardiopulmonary bypass, but prior to the infusion of platelet concentrate, showed only mild ultrastructural abnormalities. Those specimens obtained for pathologic study following the infusion of platelet concentrate exhibited extensive accumulations of platelet aggregates in the pulmonary microcirculation and widespread degenerative changes in the capillary endothelial cells, intra-alveolar septae and alveolar epithelial cells. In areas in which cellular discontinuities occurred, protein exudates, fibrin clumps and red blood cells were observed in the interstitium and in the alveolar air spaces. The storage of platelet concentrate results in the formation of aggregate material. The infusion of platelet concentrate results in the formation of aggregate material. The infusion of platelet concentrate results in the formation of ultrastructural lesions, similar to those observed in situations known to lead to pulmonary dysfunction, such as following massive transfusion, hypovolemia, sepsis and hypoxia.

Biopsy↗
PubMed1978

Effects of enteric microbial overgrowth on small intestinal ultrastructure in the rat.

The ultrastructural effects of bacterial proliferation in the upper gastrointestinal tract induced by intraperitoneal injections of mecamylamine HCl were investigated in rats. We found increased populations of nonspecific enteric bacteria in the lumen of the upper small intestine and ultrastructural abnormalities in the absorptive epithelial cells, including increased numbers of lysosomal vacular structures, fused microvilli and dilated endoplasmic reticulum. The bacteria did not penetrate into the damaged mucosal cells and so actual cytoplasmic infiltration is apparently not required in order to cause these ultrastructural changes. The alterations were not merely due to the pharmacologic agent we used, mecamylamine, since rats with subnormal numbers of enteric bacteria in the upper small intestine, whether subjected to the course of the drug or not, did not display the ultrastructural changes noted above. Concomitant with increased numbers of enteric bacteria in the small intestine, there were increased concentrations of deconjugated bile salts and decreased absorption of glucose. These findings are compatible with the following hypothetical sequence of pathogenesis: mecamylamine leads to intestinal stasis leads to bacterial overgrowth leads to deconjugation of the bile salts leads to ultrastructural alterations.

Animals↗
PubMed1980

[Protective effect of endogenous catecholamine depletion against hypoxic and reoxygenation damage in isolated rat heart: an ultrastructural study (author's transl)].

Using isolated, Langendorff-perfused rat hearts, we studied in the left ventricular wall myocardial ultrastructural modifications appearing under conditions of severe hypoxia and subsequent reoxygenation. Hypoxia was produced by gassing perfusate with nitrogen (aortic oxygen partial pressure less than 8 mmHg). The purpose of the present work was to evaluate whether or not endogenous catecholamines might be involved in the development of hypoxia-induced tissue damage isolated heart. Therefore, severe hypoxia and subsequent reoxygenation was studied using hearts isolated from (a) normal untreated rats, and (b) from rats in which endogenous catecholamine levels have been reduced to about 15% of control values by reserpine (2 I.P. injections: 1.5 mg/kg 48 hours, and 5 mg/kg 24 hours prior to the excision of the heart). Hearts were fixed by glutaraldehyde perfusion either after 10 min of control equilibration perfusion (with oxygen and glucose), or after 100 min hypoxia (nitrogen, glucose-free, high potassium), or after hypoxia plus reoxygenation (oxygen, substrate-free, high potassium). After fixation, dehydration, embedding in araldite, 6-8 blocks per heart were sectioned; the sections were doubly stained and examined under the electron microscope. 1. Control hearts perfused for a 10 min equilibration period exhibited well preserved and normal ultrastructure (Fig. 1). This observation indicated that our experimental conditions of perfusion were able to maintain the ultrastructural integrity of the myocardium satisfactorily, and that the fixation procedure used was correct. After severe hypoxia without substrate, untreated hearts exhibited ultrastructural alterations, the degree of which was consistently and severely increased by reoxygenation (Figs. 2 and 3). 2. In reserpine pretreated hearts, in which we observed a marked increase in the number of glycogen granules (Fig. 4), hypoxia did not induce morphological alterations. Even after 100 min hypoxia, some glycogen granules were still visible (Fig. 5). Furthermore, myocardial ultrastructure was not altered by reoxygenation (Fig. 6). It is proposed that in reserpine pretreated hearts, anaerobic metabolism of glycogen may be sufficient to sustain enough glycolytic ATP production during 100 min of oxygen deprivation. Such a preservation of myocardial high-energy phosphates could help myocardial cells to maintain their structural integrity. These results are discussed in connection with those of a previous biochemical study of reserpine's protective action in hypoxic isolated rat hearts.

Animals↗
PubMedDate not supplied

Diagnostic ultrastructural pathology--sub-speciality or special stain?

The high resolving power of the electron microscopy gives ultrastructural pathology many of the features of a 'sensitive, multipurpose stain'. But the high resolution gives rise to problems of evaluation since most pathological features of disease are specific in a quantitative rather than in a qualitative way. Thus, pathological changes may be of diagnostic importance when they are severe enough to be seen by light microscopy, but less so when only revealed by electron microscopy. Problems of evaluation and interpretation should not lead to paralysing nihilism but should make us realize that electron microscopy does not represent the ignorant pathologist's key to a diagnostic heaven, no more than do special stains, histochemistry and immunocytochemistry. At present it may be necessary to organize ultrastructural pathology as a kind of sub-speciality of pathology. In the long run, we feel that sub-specialities should be related to the object studied rather than to the instrument used. Thus, the neuropathologist should do ultrastructural neuropathology, the cytologist ultrastructural cytopathology, etc. in the same way as most kidney pathologists already do their own ultrastructural work.

Diagnosis, Differential↗
PubMedDate not supplied

When does the lung die? II. Ultrastructural evidence of pulmonary viability after "death".

Lung transplantation as a therapy for end-stage lung disease is limited by the paucity of suitable donors. If lungs could be retrieved from circulation-arrested cadavers (that is, after death), then more donors for lung transplantation might be available. This study was undertaken to determine the time course of ultrastructural deterioration of cellular organelles in pulmonary tissue after circulatory arrest and death and to determine the effect, if any, of postmortem ventilation on the development of these ultrastructural changes. Sprague-Dawley rats were sacrificed and then separated into three groups: (1) controls, from which the right lung was immediately harvested (n = 4); (2) ventilated group, in which mechanical ventilation with 100% oxygen was started after death (n = 15); and (3) nonventilated group (n = 15). In the ventilated and nonventilated groups, the right lung was harvested at 2, 4, or 8 hours after death. Portions of the lung from each rat were examined by electron microscopy, and each specimen was assigned a semiquantitative injury score that was based on nuclear chromatin clumping, mitochondrial degeneration, intracellular edema, and cellular membrane integrity. The lung in all four controls was normal. At 4 and 8 hours postmortem, ultrastructural damage was significantly attenuated in rats with oxygen ventilation compared with those in the nonventilated group. The degree of ultrastructural damage observed in the oxygen ventilation group at 2 and 4 hours postmortem was not significantly different from that of normal controls. Thus, mechanical ventilation with oxygen after death appears to preserve lung ultrastructure and may delay cell death. This study supports the hypothesis that lung transplantation from cadaver donors may be feasible.

Animals↗