The mast cells of the mammalian central nervous system. III. Ultrastructural characteristics in the adult rat brain.

The brains of young adult male and female Sprague-Dawley rats were studied with the electron microscope to determine the full ultrastructural picture of two types of perivascular granular cell. One of these, referred to here as the type I cell and described by both light and electron microscopy by several authors, including ourselves, has been reported to be a mast cell (MC) almost identical to MCs outside the CNS. The other, referred to here as the type II cell and described by many authors under almost as many names, was dealt with fully by Ibrahim in several reports and regarded by him as a type of MC. It is felt that the results warrant the conclusions that the type I cells are indeed MCs, while the type II cells are closely allied to the type I cells and probably better adapted to the function they subserve in the CNS of mammals. The similarities between the two cell types probably outnumber the dissimilarities and even these have their counterparts in MCs outside the CNS. The problem of the possible confusion between the type II cells and macrophages, whether reportedly within vessel walls or in the form of modified or special 'pericytic' microglia, is discussed. It is concluded that there is no justification for regarding these cells as macrophages. Because of the similarity between the type II cells and MCs, and because of the high lipid content of the type II cells, it is suggested that these elements be called neurolipomastocytes or neurolipomastocytoid cells.     

Small-cell-type poorly differentiated squamous cell carcinoma of the lung. Cytologic, immunohistochemical and nuclear DNA content analysis.

The relationship between the nuclear DNA content, the immunohistochemical findings, the clinical characteristics (tumor volume doubling time and survival) and the cytomorphologic features of small cell poorly differentiated squamous cell carcinoma of the lung was studied in ten cases. There were no significant correlations between the immunohistochemical stainings for neuron-specific enolase and keratin and the clinical characteristics in these cases. The DNA histogram patterns were classified as type I or type II, depending on the degree of dispersion of values. There was no relationship between the immunohistochemical findings and the DNA histogram patterns. Only the DNA histogram patterns were related to some of the clinical characteristics: patients with type II histograms had significantly shorter tumor volume doubling times than did patients with type I histograms. Such information may aid in distinguishing the small cell type of poorly differentiated squamous carcinoma from classic small cell carcinoma of the lung, with which it may be confused.     

Seasonal Changes in the Cambium of Trees. I. Sucrose Content in Thuja occidentalis

Cambium samples of Thuja occidentalis L. were collected at five different times, covering spring reactivation and early and late resting period, and used for sucrose determinations. Fragments of the different cell types - xylem ray, cambial initials, sieve-elements including phloem parenchyma cells, phloem ray - were dissected from freeze-dried radial sections and analyzed individually. Results show large differences in sucrose concentrations in the different cell types of the cambial layer. In addition, each cell type also shows seasonal fluctuations in sucrose content, whose amplitudes and patterns of variation appear specific for the particular cell type.     

Functional maturation of murine B lymphocyte precursors. II. Analysis of cells required from the bone marrow microenvironment

The development of mature B cells in cultures of early B cell precursors depends on the presence of a confluent adherent bone marrow (aBM) cell layer. Adherent and sIgM+ cell-depleted bone marrow (BM) from untreated or 5-fluorouracil-pretreated donors or day 12 fetal liver cells were used as precursor cell populations. When adherent cells from thymus or highly enriched BM-derived macrophages were co-cultured with precursor cells, mature B cells were not developed. Similarly, aBM cell layers generated in the presence of hydrocortisone and horse serum were unable to support aBM cell-dependent precursor differentiation, even though cortisone was removed before the addition of precursor cells. In contrast, this type of microenvironment promoted the differentiation of precursor of myeloid cell lineages. Repeated treatment of established aBM cell populations with a monoclonal anti-macrophage antibody (31.3, known to recognize a surface marker on a subset of BM macrophages) and complement abolished the capacity of otherwise functional aBM cells to sustain the development of B cell precursors. Macrophage-depleted aBM cells regained their function after supplementation with highly enriched BM-derived macrophages grown in vitro. Limiting dilution analysis of aBM cells in microcultures containing saturating numbers of early B cell progenitors also suggests the participation of more than one cell type in the BM cell population. In conclusion, differentiation of early B cell progenitors requires macrophages in addition to at least one additional cell type contained in the aBM cell population.     

Chronorhythms of the circulating erythrocytes and leukocytes--correlation with the E.S.R. cycles

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared. The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes. The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one. The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones. Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).     

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 3. Opiocorticomelanotropic cells

Staining and histochemical methods, immunofluorescence and electron microscopy were used to individualize the opiocorticomelanotropic cells in the adenohypophysis of the non-hibernating hedgehog. One cell type was differentiated; its characteristics at the electron-microscopic level were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'opiocorticomelanotropic cells'.     

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 2. Prolactin cells

Staining and histochemical methods, immunofluorescence, and electron microscopy were used to individualize the prolactin cells in the adenohypophyseal pars distalis of the nonhibernating hedgehog. One cell type was differentiated; their characteristics at the light and electron microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'prolactin cells'.     

Chronorhythms of the Circulating Erythrocytes and Leukocytes—Correlation with the E.S.R. Cycles

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared.

The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes.

The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one.

The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones.

Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).     

Species-specific aggregation factor in sponges. IV. Inactivation of the aggregation factor by mucoid cells from another species.

The role of protein synthesis in the cell union was investigated in conjugation of Blepharisma intermedium. In order to avoid possible complications due to the occurrence of other processes in conjugation, the homotypic cell union, in which conjugation is arrested at the stage of cell union without further changes, was used. Such unions were induced by treating cells of one mating type with the gamone of the other mating type for about 2 h. The induction of cell union was regularly accompanied by increased protein synthesis, which started 5 min after the beginning of the gamone treatment and continued for about 2 h. When protein synthesis was inhibited by cycloheximide, cell union was also inhibited. The extent of the two inhibitions were closely correlated. We concluded that gamone induces proteins and that protein synthesis is essential for cell union. Proteins synthesized in gamone-treated and non-treated cells were also separated and compared. Consideration of these results leads to a hypothesis that most of the gamone-induced proteins are membrane proteins normally synthesized, though in lesser amount, in non-conjugating cells and that cells gain the capacity to unite when these proteins are accumulated at a restricted area on the cell surface by another gamone-controlled mechanism.     

Morphology and histochemistry of the myotendineal junction of the rat calf muscles. Histochemical, immunohistochemical and electron-microscopic study.

The macromolecular composition and morphometry of the myotendineal junction (MTJ) of slow-twitch (type 1) and fast-twitch (type 2) muscle fibers were studied in gastrocnemius-soleus-Achilles unit of the rat. Proteoglycans and glycosaminoglycans, type III collagen, fibronectin and laminin could be detected at the myotendineal junction. Due to the membrane folding finger-like processes were seen at the MTJ. The processes of type 1 fibers were greater in size. However, due to the subdivisions the processes of type 2 muscle fibers had a significantly greater surface length per muscle cell diameter than type 1 fibers. The myotendineal endings of both fiber types had a characteristic basal lamina, which was about three times thicker than in the longitudinal site of the same muscle cells. The basal lamina of type 1 fibers at the MTJ was significantly thicker than that of type 2 fibers.     

Endocrine cells in the gastric mucosa of elasmobranch fishes. An ultrastructural study

The endocrine cells of gastric mucosa of two elasmobranch species were studied by light and electron microscopy. Five cell types were identified in the fundic mucosa, four of which are of "open type". All of them show pleomorphic granules of variable size, except those of the type V cell which are round in shape and of comparatively small diameter. Six different cell types are found in the pyloric mucosa, all of "open type" except for type XI cells which appear to be "closed". Pyloric types VIII, IX, X and XI cells show similar structural characteristics as fundus types I, V, II and IV respectively. Silver impregnation was also used at both light and electron microscopical levels. No functional classification or analogies with other vertebrate gastric endocrine cells were attempted as these would be too speculative on the basis of ultrastructural characteristics only.     

Postnatal maturation of the parenchymal cell types in the rabbit pineal gland.

An ultrastructural study on the maturation of the parenchymal rabbit pineal cell types from the first postnatal day up to 120 days is presented. Two main cell types are distinguished from the first 24h of postnatal life. Pinealocytes of the types I and II display different developmental degrees. Both immature cell types are arranged in groups. In addition, type II pinealocytes form rosette-like structures. Both cell types progressively become isolated and display cell processes. The nucleus and the cytoplasm of type I pinealocytes are barely electrondense. During the postnatal period, the number of cytoplasmic organelles, cell processes and terminal clubs increase progressively. Terminal clubs are frequently seen near blood vessels. After 30 days, type I pinealocytes show characteristics of adult pinealocytes. However, the maturation of most type I pinealocytes does not complete until the 90th postnatal day. Type II pinealocytes present a fairly electrondense nucleus and cytoplasm. Mature forms can be seen after the 5th postnatal day. During the postnatal period, a close relationship is determined among type II pinealocytes and cell processes and terminal clubs of type I pinealocytes.     

Association of the parainfluenza virus fusion and hemagglutinin-neuraminidase glycoproteins on cell surfaces.

We previously observed that cell fusion caused by human parainfluenza virus type 2 or type 3 requires the expression of both the fusion (F) and hemagglutinin-neuraminidase (HN) glycoproteins from the same virus type, indicating that a type-specific interaction between F and HN is needed for the induction of cell fusion. In the present study we have further investigated the fusion properties of F and HN proteins of parainfluenza virus type 1 (PI1), type 2 (PI2), and type 3 (PI3), Sendai virus (SN), and simian virus 5 (SV5) by expression of their glycoprotein genes in HeLa T4 cells using the vaccinia virus-T7 transient expression system. Consistent with previous results, cell fusion was observed in cells transfected with homotypic F/HN proteins; with one exception, coexpression of any combination of F and HN proteins from different viruses did not result in cell fusion. The only exception was found with the closely related PI1 HN and SN HN glycoproteins, either of which could interact with SN F to induce cell fusion upon coexpression as previously reported. By specific labeling and coprecipitation of proteins expressed on the cell surface, we observed that anti-PI2 HN antiserum coprecipitated PI2 F when the homotypic PI2 F and PI2 HN were coexpressed, but not the F proteins of other paramyxoviruses when heterotypic F genes were coexpressed with PI2 HN, suggesting that the homotypic F and HN proteins are physically associated with each other on cell surfaces. Furthermore, we observed that PI3 F was found to cocap with PI3 HN but not with PI2 HN, also indicating a specific association between the homotypic proteins. These results indicate that the homotypic F and HN glycoproteins are physically associated with each other on the cell surface and suggest that such association is crucial to cell fusion induced by paramyxoviruses.     

Ultrastructal morphology of some prokaryotic microorganisms associated with the hindgut of cockroaches.

Scanning electron microscopy and transmission electron microscopy have been used to visualize the morphology and ultrastructure of two types of microorganisms in the hindgut of the cockroach Blaberus posticus. Both organisms, designated as either short or long rods, are attached to chitinous projections from the gut wall. Micrographs suggest that the organisms are prokaryotic with a cell wall complex characteristic of gram-negative bacteria. However, certain differences were noted between the cell wall complex of the two types. Two forms of the long-rod type were noted, with one form appearing to be a "degenerate" or "transitional" cell. In the degenerate cells, vesicles are observed that often are contiguous with the cytoplasmic membrane. There are indications that the long-rod type may divide by longitudinal fission. Neither the short- nor long-rod type has been cultivated in its respective recognizable form.     

Ultrastructural studies of regenerating spines of the sea urchin Strongylocentrotus purpuratus. II. Cell types with spherules.

The fine structure of spherulecytes, cell types with large, intracellular membrane-bound vacuoles termed spherules, was investigated in regenerating tips of spines of the sea urchin Strongylocentrotus purpuratus. Two categories of cell types were observed: red spherulecytes and colorless spherulecytes. Red spherulecytes were represented by a single cell type, the eleocyte, while colorless spherulecytes consisted of three morphologically distinct cell types termed morula cells, granulocytes, and vacuolecytes. Eleocytes and morula cells were distributed in both the epidermis and dermis, while granulocytes and vacuolecytes were present only in the dermis. After processing for light and electron microscopy, the spherules of eleocytes typically appeared empty, having lost their content of the red pigment, echinochrome. In contrast, the spherules of morula cell, granulocytes, and vacuolecytes enclosed a variety of granular and other material. The cell types reported in this paper resembled, to various degrees, spherulecytes in the coelomic fluid of echinoids described by other investigators.     

Cell line A549 as a model of the type II pneumocyte. Phospholipid biosynthesis from native and organometallic precursors.

1. A549 is a continuous cell line derived from a human pulmonary adenocarcinoma. To evaluate the suitability of this cell line as a model of the type II pneumocyte, the morphology and the composition and biosynthesis of phosphatidylcholine was examined under control culture conditions and during fatty acid supplementation with palmitate. A number of the ultrastructural characteristics of A549 cells were similar to the in situ type II pneumocyte and were unchanged by fatty acid supplementation. The phospholipid composition of the cell line was similar to that of primary isolates of type II cells in total phosphatidylcholine, disaturated phosphatidylcholine, and palmitate and saturated fatty acid. Phospholipid biosynthetic results were also consistent with those reported for isolated type II cell models. These included: (i) the pattern of incorporation of choline, palmitate and acetate into phosphatidylcholines; (ii) the effect of palmitate supplementation, which resulted in stimulation of the rate of phosphatidylcholine biosynthesis and in increased percentage of labeled precursor in disaturated phosphatidylcholine; and (iii) the preferential synthesis from labeled choline and palmitate of a highly disaturated phosphatidylcholine in short-term incubations. 2. The incorporation of an organometallic palmitate analog, 12,12-dimethyl-12-stannahexadecanoate, into A549 cell lipids was examined and compared to that of palmitate. These date demonstrate for the first time the incorporation of an organometallic substrate into the phospholipids of a mammalian cell line. This analog substitutes selectively for the native fatty acid at a rate similar to that of the native fatty acid with no cytotoxic effects. The organotin probe, coupled with spectroscopic detection and electron microscopy, may be useful for examining ultrastructural aspects of phospholipid synthesis, translocation and assembly.     

Populations of granulosa cells in small follicles of the sheep ovary.

The aim of this study in sheep ovaries was to determine the total number of granulosa cells in primordial follicles and at subsequent stages of growth to early antrum formation. The second aim was to examine the interrelationships among the total number of granulosa cells in the follicles, the number of granulosa cells in the section through the oocyte nucleolus, and the diameter of the oocyte. A third aim was to examine whether proliferating cell nuclear antigen labelling occurred in flattened granulosa cells in primordial follicles or was confined to follicles containing cuboidal granulosa cells. The follicles were classified using the section through the oocyte nucleolus by the configuration of granulosa cells around the oocyte as type 1 (primordial), type 1a (transitory), type 2 (primary), type 3 (small preantral), type 4 (large preantral), and type 5 (small antral). In type 1 follicles, the number of granulosa cells and oocyte diameter were highly variable in both fetal and adult ovaries. Each type of follicle was significantly different from the others (all P < 0.05) with respect to oocyte diameter, number of granulosa cells in the section through the oocyte nucleolus and total number of granulosa cells. Follicles classified as type 2, 3, 4 or 5 each corresponded to two doublings of the total granulosa cell population. The relationships between oocyte diameter and the number of granulosa cells (that is, in the section through the oocyte nucleous or total population per follicle) could all be described by the regression equation loge chi = a + b loge gamma with the correlation coefficients R always > 0.93. For each pair of variables the slopes (b) for each type of follicle were not different from the overall slope for all types of follicle pooled. Immunostaining for proliferating cell nuclear antigen was observed in granulosa cells in type 1 follicles, as well as in the other types of follicle. These findings indicate that 'flattened' granulosa cells in type 1 follicles express an essential nuclear protein involved in cell proliferation before assuming the cuboidal shape. Thus, when considering factors that regulate specific phases of early follicular growth, it is important to consider: (i) the follicle classification system used; (ii) the animal model studied; (iii) whether type 1 follicles are all quiescent; and (iv) the likelihood that each follicle type represents more than one doubling of the population of granulosa cells.     

Digital cell image analysis of Ewing's sarcoma.

We analyzed the lesional tissue in Ewing's sarcoma by means of a cell image processor computing 15 nuclear parameters in order to quantify the morphologic variability of the tumor cell nuclei. To this end we combined 32 cases (350-400 Feulgen-stained nuclei analyzed per case) in a data file, which was then subjected to principal component and canonical analyses. We found considerable heterogeneity within the cell nucleus population of Ewing's sarcomas. Indeed, after the arbitrary subdivision of the file into two cell classifiers (CC1 and CC2 cell types) on the basis of the first canonical function, the 32 Ewing's sarcomas showed a great deal of variability in the proportion of CC1 and CC2 cell nucleus types. The nuclei of the CC1 type had a more finely textured chromatin when compared to the CC2 type, the nuclei of which exhibited a more granular chromatin pattern. Additionally, these 32 Ewing's sarcomas were characterized by three distinct DNA histogram types. Eight tumors displayed a diploid nonproliferating DNA histogram pattern (type A), 11 a diploid proliferating (type B) and 13 an aneuploid (type C) DNA histogram profile. We found a highly significant relationship between these DNA histogram types and the CC1:CC2 cell type percentage ratio. The eight Ewing's sarcomas with a type A DNA histogram contained a significantly higher proportion of CC1 cell type nuclei as compared to the 13 tumors with a type C DNA histogram, which contained a great proportion of CC2 cell type nuclei.     

Phospholipids of the differentiating bacterium Caulobacter crescentus.

The phospholipid composition of the stalked and swarmer cell types of the differentiating, Gram-negative bacterium Caulobacter crescentus was determined. The phospholipid composition of the stalked cell type was 86.5% phosphatidylglycerol, 10.4% lysylphosphatidylglycerol, and 3.0% cardiolipin; that of the swarmer cell type was 84.1, 11.4, and 4.4% respectively. Phosphatidylethanolamine, which is a major phospholipid component of most Gram-negative bacteria, was totally absent.     

An immunohistochemical study on the cytogenesis of adenohypophysial cells in fetal rats.

An immunohistochemical study was undertaken in fetal rats to determine the time of differentiation of various types of adenohypophysial cells and the site where they first appear and proliferate during development. A cell count was carried out on the first and second days of cytodifferentiation in each type of cell. Both the time and the site of cytodifferentiation were peculiar to respective cell types. ACTH cells appeared on Day 15 of gestation in the ventral region of the pars distalis where it faces mesenchymal tissue. While TSH cells first appeared exclusively in the posterior half on Day 16, further proliferation of this cell type also occurred predominantly in the posterocentral portion of the gland. LH and FSH cells appeared on Days 17 and 19, respectively; both cell types showed a similar localization, i.e., they were almost concentrated in the ventral region in the anterior half and posteriorly they were distributed sparsely and homogeneously. GH cells appeared on Day 18 in the central region of the pars distalis. Prolactin cells failed to be seen in the fetal adenohypophysis, and even in newborns 0–1 days of age, this type of cell was not consistently seen, although sometimes a few cells were encountered in the central region of the gland. Of these cell types, TSH, LH, and FSH cells persisted to be concentrated even after birth in the area where they first appeared. These observations are discussed in relation to data previously reported by other investigators.