Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MICROSCOPY, PHASE”

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 1,657 records · Page 92Linked to original sources
PubMed2004

Acanthocytes in the urine: useful tool to differentiate diabetic nephropathy from glomerulonephritis?

OBJECTIVE: The presence of hematuria has been suggested to indicate nondiabetic nephropathy in diabetic patients with proteinuria. However, hematuria is frequently found in patients with biopsy-proven diabetic glomerulosclerosis without nondiabetic nephropathy. Urine microscopy allows discrimination of glomerular hematuria, which is defined as acanthocyturia (urinary excretion of acanthocytes, which are dysmorphic erythrocytes with vesicle-like protrusions), from nonglomerular hematuria. We hypothesized that acanthocyturia is an uncommon finding in diabetic nephropathy, which suggests the presence of a nondiabetic nephropathy in diabetic patients with proteinuria. RESEARCH DESIGN AND METHODS: Urine samples of patients with the clinical diagnosis of diabetic nephropathy (n = 68), of patients with biopsy-proven glomerulonephritis (n = 43), and of age-matched healthy control subjects (n = 20) were examined by phase-contrast microscopy for the presence of hematuria (>/=8 erythrocytes/ micro l) and acanthocyturia. Acanthocyturia of >/=5% (5 acanthocytes among 100 excreted erythrocytes) was classified as glomerular hematuria; acanthocyturia of 2-4% was classified as suspected glomerular hematuria. RESULTS: Hematuria was found in 62% of patients with the clinical diagnosis of diabetic nephropathy, in 84% of patients with glomerulonephritis, and in 20% of the healthy control subjects upon a single urine examination. In contrast, glomerular hematuria occurred in 4% of patients with diabetic nephropathy and in 40% of patients with glomerulonephritis (P < 0.001). CONCLUSIONS: In contrast to hematuria, acanthocyturia is uncommon in patients with the clinical diagnosis of diabetic nephropathy. In diabetic patients with proteinuria, the finding of acanthocyturia points to nondiabetic glomerulopathies, and renal biopsy should be considered.

Acanthocytes↗
PubMed2001

Primary ciliary dyskinesia: diagnosis in children with inconclusive ultrastructural evaluation.

The purpose of this study was to distinguish between acquired and genetically determined ciliary abnormalities in children with severe chronic respiratory diseases. Samples of nasal ciliated epithelium from 50 subjects (25 male, 25 female; age-range 2-19 years) with severe chronic respiratory diseases were examined using transmission electron microscopy (TEM). Based on TEM findings, patients were divided into two groups: A and B. Group A comprised 39 children with ciliary alterations compatible with a condition probably occurring secondary to chronic inflammation (alterations of peripheral pairs, swollen cilia, and compound cilia). The other 11 patients, Group B, exhibited a greater number of alterations of the central pair and dynein arms (p< 0.001), which were qualitatively similar to, but less numerous than, those observed in primary ciliary dyskinesia (PCD). In both groups, analysis of ciliary beat frequency and waveform was performed by phase contrast microscopy (PCM). All the children with a ciliary beat frequency of < 7 Hz were treated with daily physiotherapy and with antibiotics, as recommended for PCD, for a 6-month period. After this treatment, the children were reexamined by PCM. Almost 50% of the children from Group B (i.e. those with a small proportion of specific ultrastructural defects) showed permanence of low ciliary beat frequency. This was also observed in two children of Group A. These children were considered to be affected by PCD. Our study describes a method for the diagnosis of PCD in the absence of specific ultrastructural defects or when these defects are present in only a small proportion of the cilia.

Adolescent↗
PubMed1988

The control of DNA replication in a cell-free extract that recapitulates a basic cell cycle in vitro.

Cell-free extracts prepared from Xenopus eggs support chromosome decondensation and pronuclear formation on demembranated sperm heads. 32P-dCTP pulse-labelling studies demonstrate that DNA synthesis occurs in multiple bursts of 30-40 min in extracts containing pronuclei, each burst being followed by a period of 20-50 min during which no synthesis occurs. Density substitution with bromodeoxyuridine indicates that the synthesis in each burst is semiconservative and results from new initiations, and that, following multiple bursts of synthesis, reinitiation events can occur. Changes in nuclear morphology have been characterized in the extract by phase-contrast microscopy and by fluorescence microscopy following pulse labelling with biotin-11-dUTP and staining with anti-lamin antibodies. Lamin accumulation occurs as DNA decondenses and parallels the acquisition of membrane structures. Biotin-11-dUTP incorporation is first observed in small nuclei having decondensed DNA and an extensive lamina. While DNA synthesis is occurring nuclei remain relatively small, but rapid swelling accompanied by chromosome condensation occurs when biotin incorporation ceases. Nuclear swelling and chromatin condensation is followed by nuclear membrane breakdown, lamin dispersal and chromosome formation. Mitosis lasts for approximately 20 min. Nuclear reassembly is recognized by the appearance of membrane vesicles around small pieces of decondensed DNA, which parallels the appearance of lamin islands within a chromatin mass. These 'islands' incorporate biotin, indicating that DNA synthesis is occurring, and apparently fuse as larger S-phase nuclei are formed. Extensive protein synthesis occurs for at least 4 h in most extracts. This synthesis is required for the initiation of mitotic events and the reinitiation of DNA synthesis.

Animals↗
PubMed1990

Morphology and neurophysiology of focal axonal injury experimentally induced in the guinea pig optic nerve.

A new model of focal axonal injury was reproduced by rapid and controlled elongation (uniaxial stretch) of the guinea pig optic nerve. Light microscopy study of optic nerve specimens after horseradish peroxidase injection into the vitreous of the animal's eye showed that axonal lesions were identical to those seen in human and primate post-traumatic diffuse axonal injury (DAI). The lesions were characterized by the formation of terminal clubs in severed axons and focal axonal enlargements in those axons that were lesioned-in-continuity. Visual-evoked potentials upon flash stimulation were recorded before and after injury. Mean amplitude and mean latency of occipital peaks were significantly elongated in the acute post-traumatic phase. Electron microscopy examination showed that the main axonal changes observed in this model were cytoskeleton disorganization, accumulation of axoplasm membrane-bound bodies at the site of terminal balls and dilatations-in-continuity and detachment of the axolemma from the myelin sheath. Such axonal alterations were similar to those found in many other biological models of central and peripheral axonal injuries in which the lesion was produced by invasive methods. This model is unique since it reproduces the same mechanism of injury and the identical lesions that have been demonstrated in humans and primates with post-traumatic (DAI).

Animals↗
PubMed1967

Differential expression of bacteriophage genomes in vegetative and sporulating cells of Bacillus subtilis.

Two antigenically distinct bacteriophages, beta3 and beta22, have been isolated and characterized with Bacillus subtilis strain W23 as a host. They differ in plaque morphology, single-step growth characteristics, host range, and thermal stability. The deoxyribonucleic acids isolated from beta3 and beta22 differ in base composition, density in CsCl and Cs(2)SO(4), sedimentation coefficient, molecular weight, and thermal denaturation temperature. These phages have been used to analyze the ability of B. subtilis to sporulate despite infection by virulent phages. When development of phages beta3 and beta22 in sporulating cultures was compared with that in log cultures, an increase in the latent periods of infection and a decrease in the burst sizes for the two phages were observed. Sporulating cultures infected with beta3 yielded the usual percentage (85%) of mature spores; 80% of these contained phage determinants and 20% were uninfected. However, cultures infected with beta22 lysed. Of the small fraction (0.01%) which sporulated, 83% were uninfected and 17% were infected. Phage beta3-infected and uninfected spores were examined to distinguish any chemical or physical differences. Preparations of both types of spore contained 81.4 mug of dipicolinic acid per mg (dry weight), and examination by phase-contrast microscopy gave no evidence of any difference in outward appearance. A 20% decrease in infected spore count was observed upon heating at 80 C for 10 min. Differences in the infection processes of the two phages prompted an analysis of the transcription process after infection. Deoxyribonucleic acid-ribonucleic acid hybrid analysis of relative amounts of phage-specific and host-specific messenger ribonucleic acid (mRNA) present in infected cells suggested that beta3 was unable to repress the synthesis of host mRNA and that beta3-specific mRNA synthesis was repressed in sporulation-phase cultures. Phage beta22, in contrast, was able to repress host-specific mRNA synthesis in both log-infected and sporulation-infected cells. The results suggest that the differential expression of the phage genomes is due to the relative ability of the phages to repress the host genome.

Bacillus subtilis↗
PubMed2002

Preservation of urine for flow cytometric and visual microscopic testing.

BACKGROUND: Preservatives that could prevent destruction of cells, casts, and bacteria in urine are of great practical importance because they allow centralization and improvement of accuracy of urine particle counting. We compared two in-house mixtures and one commercial solution, as well as refrigeration, for their ability to preserve urine for both automated analysis (flow cytometry) and visual microscopy. METHODS: Urine specimens were preserved by refrigeration at 4 degrees C without preservatives (procedure 1); in a lyophilized solution intended to preserve specimens for bacterial culture (Urine C&S tubes; BD Preanalytical Solutions; procedure 2); in 10 mL/L formalin-0.15 mol/L NaCl (procedure 3); in 80 mL/L ethanol-20 g/L polyethylene glycol (procedure 4); and by storage at 20 degrees C without preservatives (procedure 5). Test strip measurements were used to select specimens positive for leukocyte esterase, hemoglobin, albumin, or nitrite. For 106 consecutive strip-positive specimens, urinalysis was performed by UF-100 (Sysmex) and by phase-contrast microscopy after Sternheimer supravital staining. Automated analysis was performed at arrival in the morning, on the same day in the afternoon, and after 1 and 3 days. Visual microscopy was performed at arrival and 3 days later. RESULTS: Urine bacterial counts were well preserved with procedures 1-3, with a false-positive rate of 0.0-3.4% at day 3 vs 28% without preservation (procedure 5). Erythrocytes were poorly preserved for 3 days (kappa coefficients, 0.24-0.61); after 1 day, fair preservation was seen with procedure 2 (kappa = 0.78), compared with less favorable preservation with procedure 1 (kappa = 0.61) or procedure 5 (kappa = 0.66). Leukocytes were well preserved by all five procedures in the acidic adult urines investigated. Counts of casts and large epithelial cells were artifactually increased by procedure 3. Procedure 2 performed at least as well as refrigeration for specimens analyzed with visual microscopy. CONCLUSIONS: Urine specimens from adults can be stabilized at room temperature for both automated particle analysis and visual microscopy.

Adult↗
PubMed1994

Tumor cell-derived 12(S)-hydroxyeicosatetraenoic acid induces microvascular endothelial cell retraction.

Our previous work demonstrated that the 12-lipoxygenase metabolite of arachidonic acid, 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] induced a nondestructive and reversible retraction of cultured endothelial cells. In the current study we tested the hypothesis that tumor cells produce 12(S)-HETE during their interactions with endothelial cells which in turn induces endothelial cell retraction. Coincubation of Lewis lung carcinoma cells or elutriated B16 amelanotic melanoma (B16a) cells but not 3T3 fibroblasts with microvascular endothelial cells (CD3) resulted in a time- and concentration-dependent retraction of the CD3 monolayers as revealed by quantitative binding assays and phase contrast microscopy. Lewis lung carcinoma cell-induced endothelial cell retraction was blocked by specific lipoxygenase inhibitors but not by cyclooxygenase inhibitors, suggesting the involvement of a lipoxygenase metabolite(s). Radioimmunoassay and high-performance liquid chromatography analysis of tumor cell extracts identified 12(S)-HETE as the major lipoxygenase metabolite of arachidonic acid and tumor cell generation of 12(S)-HETE was specifically blocked by a select 12-lipoxygenase inhibitor N-benzyl-N-hydroxy-5-phenyl-pentamide. The identity and stereochemistry of tumor cell-derived 12-HETE was substantiated by gas chromatography-mass spectrometry analysis and chiral phase high-performance liquid chromatography, respectively. Lewis lung carcinoma cell adhesion to CD3 monolayers was accompanied by an enhanced 12(S)-HETE biosynthesis by tumor cells, which paralleled the tumor cell-induced endothelial cell retraction in a cell number-dependent manner. Pretreatment of tumor cells with N-benzyl-N-hydroxy-5-phenylpentamide inhibited both increased 12(S)-HETE biosynthesis and tumor cell-induced endothelial cell retraction. Highly metastatic variants of elutriated B16a cells which had been shown to produce large quantities of 12(S)-HETE induced significant CD3 cell retraction, while low metastatic subpopulations of B16a cells which synthesized no or little 12(S)-HETE did not induce endothelial cell retraction. These results suggest that 12(S)-HETE synthesis during tumor cell-endothelial cell interactions may represent a key contributory factor in cancer metastasis.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1995

Semiquantitative analysis by scanning electron microscopy of cochlear hair cell damage by ototoxic drugs.

The ototoxicity of cisplatin and carboplatin in the organ of Corti of the guinea pig was evaluated semiquantitatively. Damage of the stereocilia of outer hair cells (OHCs) observed by scanning electron microscopy (SEM) was classified into normal, grade 1 (10-50% loss of stereocilia), grade 2 (less than 50% remaining stereocilia), or grade 3 (missing stereocilia). The OHCs observed by light microscopy (LM) were classified as remaining or missing cells. Fifty OHCs of each row in the middle part of each turn of the cochlea were counted (a total of 150 cells per turn). Guinea pigs were administered 5 mg/kg of cisplatin or 50 mg/kg of carboplatin intraperitoneally for three consecutive days. In groups 1 and 2, in which both cochlea were fixed in 2.5% glutaraldehyde and 1% osmium tetroxide (OsO4) and observed by SEM, the percentages of damage of the OHC stereocilia were similar in each cochlear turn bilaterally. In group 3, the right cochleae were fixed in OsO4 and observed by phase contrast microscopy as surface preparations. Left cochleae were submitted for SEM observation. Missing and grade 3 cells were observed at similar percentages in each row of each turn. In group 4, succinate dehydrogenase staining was performed in the right cochleae and observed by LM. The degree of damage in the right cochleae was compared with that of the left cochleae which was observed by SEM. On average, the mean numbers of missing cells and cells showing grade 3 damage were similar in each row of each turn. From these similarities of evaluation of ototoxicity at LM and SEM levels, it was concluded that semiquantitative analysis by SEM only is appropriate for the assessment of ototoxicity.

Animals↗
PubMed2002

Telomere and telomerase in the initial stage of immortalization of esophageal epithelial cell.

AIM: To search for the biomarker of cellular immortalization, the telomere length, telomerase activity and its subunits in cultured epithelial cells of human fetal esophagus in the process of immortalization. METHODS: The transgenic cell line of human fetal esophageal epithelium (SHEE) was established with E(6)E(7) genes of human papillomavirus (HPV) type 18 in our laboratory. Morphological phenotype of cultured SHEE cells from the 6th to 30th passages, was examined by phase contrast microscopy, the telomere length was assayed by Southern blot method, and the activity of telomerase was analyzed by telomeric repeat amplification protocol (TRAP). Expressions of subunits of telomerase, hTR and hTERT, were assessed by RT-PCR. DNA content in cell cycle was detected by flow cytometry. The cell apoptosis was examined by electron microscopy (EM) and TUNEL label. RESULTS: SHEE cells from the 6th to 10th passages showed cellular proliferation with a good differentiation. From the 12th to the 16th passages, many senescent and apoptotic cells appeared, and the telomere length sharply shortened from 23kb to 17kb without expression of hTERT and telomerase activity. At the 20th passage, SHEE cells overcame the senescence and apoptosis and restored their proliferative activity with expression of telomerase and hTERT at low levels, but the telomere length shortened continuously to the lowest of 3kb. After the 30th passage cells proliferation was restored by increment of cells at S and G2M phase in the cell cycle and telomerase activity expressed at high levels and with maintenance of telomere length. CONCLUSION: At the early stage of SHEE cells, telomeres are shortened without expression of telomerase and hTERT causing cellular senescence and cell death. From the 20th to the 30th passages, the activation of telomerase and maintenance of telomere length show a progressive process for immortalization of esophageal epithelial cells. The expression of telomerase may constitute a biomarker for detection of immortalization of cells.

Apoptosis↗
PubMed1992

Preparation and examination of flea larvae (Siphonaptera) by light and electron microscopy.

Techniques are described for making permanent slide-mounted specimens. Larvae were thoroughly macerated in KOH to remove soft internal tissue, yielding specimens with enhanced transparency and allowing examination of most of the exoskeleton in a single larva. Fatty material was removed in acetone to eliminate confusion of fat globules with sensilla in the cuticle. The more sclerotized exoskeletal elements, such as integumentary scales and the body sclerites together with their setae and sensilla, were highlighted by staining with carbol fuchsin. Resolution of numbers and arrangement of setae, especially those on the dorsum of the head capsule, in the anal comb, and on the anal mounds, was greatly facilitated by mounting larvae in dorsal orientation. Clearer views of the antennae and mouthparts were obtained, in orientations seldom achieved in whole mounts, by dissecting the head capsule. Discrimination of many taxonomically valuable features was enhanced by the use of phase-contrast microscopy. Interpretation of structures noted in light microscopy was complemented using scanning electron microscopy. The latter allowed differentiation between surface and internal cuticular structures.

Animals↗
PubMed2004

The effect of periodontal treatment on the salivary bacterial load and early plaque formation.

AIM: The purpose of the present study was to investigate in periodontitis patients the relationship between the number of bacteria in the saliva and the amount of de novo plaque formation before and after treatment. METHODS: At baseline, before any treatment was provided, patients rinsed with 10 ml sterile saline. After professional tooth cleaning the patients were instructed to abolish all tooth cleaning procedures for the subsequent 24 h. After this period, the rinsing procedure was repeated and the amount of de novo plaque was assessed. Three months after the initial periodontal therapy was completed the experiment was repeated. The microbiological evaluation of the rinsing samples was carried out by means of phase contrast microscopy and anaerobic culturing. RESULTS: After treatment the amount of de novo plaque was less compared to before treatment, 0.40 and 0.65 respectively. Both before and after treatment more de novo plaque was present at sites with inflammation than at healthy sites. In order to evaluate the contribution of the numbers of salivary bacteria to the amount of de novo plaque formation an analysis was carried out for healthy sites. This analysis included only healthy sites as determined before treatment and the same sites after treatment. The results showed a significant reduction in the de novo plaque formation after treatment (0.49 before and 0.22 after treatment). Phase contrast microscopic evaluation showed that the number of bacteria in the rinsing samples after treatment was less than before treatment. After treatment also a reduction was found in the prevalence of Prevotella intermedia, Tannerella forsythensis and Peptostreptococcus micros in the rinsing samples. CONCLUSION: The present study confirms the observation in the literature that the periodontal condition is of major importance in the rate of de novo plaque formation. In addition, the results suggest that the number of bacteria in the saliva may play a role.

Adult↗
PubMed2005

[Expression of SLP-2 mRNA in endometrial cancer and its significance].

OBJECTIVE: To characterize the differential expression of SLP-2 in endometrial cancer, and to study the effect of human SLP-2 gene on human endometrial cancer cell line. METHODS: The expression of SLP-2 gene in 32 cases of endometrial cancer and 28 cases of normal endometrial tissues was examined by semi-quantitative RT-PCR. Eukaryotic expression vectors of sense and antisense SLP-2 were constructed and transfected into HEC-1B cell line using lipofectamine 2000 respectively. The morphological changes of the cell were observed by phase contrast microscopy. The cell growth was detected by methyl thiazolyl tetrazolium (MTT) assay, and the cell cycles were analyzed by flow cytometry. RESULTS: The expression of SLP-2 mRNA in endometrial cancer tissues was higher than that in normal endometrial tissues (1.6 +/- 0.7 vs 0.7 +/- 0.3, P < 0.05). Sense and antisense human SLP-2 constructs were transfected into HEC-1B cell line respectively. After being transfected with sense SLP-2, the expression of SLP-2 mRNA in HEC-1B cell line was increased by about 2.4 times that of the control group, the cell growth was accelerated, and the number of cells in G(1) phase was decreased by 12.5%, S phase was increased by 8.0%. After being transfected with antisense SLP-2, the expression of SLP-2 mRNA was declined 50%. The transfected cells showed slower growth, and the number of cells in G(1) phase was significantly increased by 10.5%, and S phase was declined by 9.8%. CONCLUSION: SLP-2 mRNA shows up-regulation in endometrial cancer tissues, and it may have some relationship with carcinogenesis of endometrial cancer.

Blood Proteins↗
PubMed1986

Flicker spectroscopy of erythrocytes. A sensitive method to study subtle changes of membrane bending stiffness.

Frequency analysis of thermally excited surface undulations of erythrocytes leading to the flicker phenomenon is applied to determine biochemically and physically induced modulations of the membrane curvature elasticity. Flicker spectra of individual cells fixed to the window of a flow chamber by polylysine are taken by phase contrast microscopy, enabling investigations of the reversibility of the structural modifications. The spectra may be approximated by Lorentzian lines in most cases. By measuring the amplitude (at zero frequency) and the line width, effects of the structural changes on the curvature elastic constant, Kc, and the wavelength distribution of the undulations may be studied separately. Effect of physically induced modifications: The temperature dependence of the flicker spectra are taken from 10 degrees C to 37 degrees C. Above 20 degrees C, Kc decreases with increasing temperature whereas the reverse holds below this limit. The latter anomalous behaviour is explained in terms of a conformational change associated with protein and lipid lateral phase separation. The bending stiffness increases when the cells swell osmotically, owing to surface tension effects. The dependence of the flicker spectra on the viscosity of the suspension medium agrees with the theoretical prediction. Biochemically and drug induced modifications: 5 vol% of ethanol leads to a pronounced and reversible suppression of the long wavelength undulations without altering the discoid cell shape and without affecting the bending stiffness appreciably. Adsorption of dextran to the glycocalix increases Kc by a factor of 1.6 at saturation. The bending stiffness is increased by a factor of 1.3 after cross-linking the proteins with the SH-oxidizing agent diamid. Injection of Ca++ into the cell via ionophores evokes (within 10 min) the formation of fine--probably spectrin free--spicules. This leads to an increase in Kc by a factor of 1.3 which is explained in terms of a lateral condensation of the spectrin/actin network. The spicule formation and Kc change is completely reversible (within 2 min) after perfusion with Ca++-free buffer. Cholesterol depletion leads first to a continuous increase in Kc without change of the cell shape whereas a sudden discocyte- to echinocyte transformation sets in below a critical steroid content. The latter transition is also observed in cell suspensions and is reminiscent of a phase transition. The anti-tumor drug actinomycin D evokes an increase in the bending stiffness Kc by a factor of two, suggesting that its effect is at least partially due to a modulation of the membrane structure.(ABSTRACT TRUNCATED AT 400 WORDS)

Calcium↗
PubMed1996

Nuclear (DNA, RNA, histone and non-histone protein) and nucleolar changes during growth and senescence of may apple leaves.

Quantitative interference microscopy was used to determine changes in nuclear and nucleolar indices (dry mass and cross-sectional area) in upper and lower epidermal cells and adjacent leaf-margin hair cells of the May apple (Podophyllum peltatum L.) leaves over a 42-day period (after leaves emerged above the ground litter). These indices decreased in a highly correlated manner. A ploidy variation may exist between epidermal cells and leaf-margin hair cells. Using the leaf-margin hair cells model, six nuclear macromolecule indices (total nucleic acid, DNA, RNA, total nuclear protein, histone and non-histone protein), nuclear volume, nucleolar volume and perinucleolar volume (measured using quantitative epifluorescence-phase contrast microscopy) all declined with age (42-day study) in a highly correlated manner. The degeneration of the nucleus and nucleolus in the three leaf locations studied followed the patterns observed for programmed cellular senescence and death (necrosis) in epidermal cells of onion leaf bases (stored tissue; leaf bases did not contain chlorophyll) and human epithelial cells (buccal; cervical). We conclude that the epidermal cells and leaf-margin hair cells from green leaves of the May Apple are ideal for the study of programmed cell senescence and death in plants, especially for the partitioning of this process into the study of: the point-of-no-return (solubilization of the karyoskeleton and loss of non-histone proteins and RNA associated with the karyoskeleton from the nucleus); nuclear pycnosis (loss of nuclear dry mass and volume and loss of nuclear internal support structure); chromatin condensation, margination along the inner nuclear envelope; and DNA-histone degeneration; degeneration of the nucleolus and loss of the perinucleolar zone of exclusion. The characterization of chlorenchyma cells during the 42-day period should now be undertaken (leaf senescence as indicated by the beginning of yellowing about 35 days after emergence) to determine whether these cells with functional chloroplasts undergo nuclear changes like those lacking functional chloroplasts.

Allium↗
PubMed1990

[Effect of retinoic acid activated mouse macrophage on human alveolar cell carcinoma of lung(A549) in vitro].

The tumoricidal activity of mouse macrophage (M phi) activated with retinoic acid (RA) and the effect of RA in combination with CP on mouse M phi were studied with phase contrast microscopy, light microscopy, and 3HTdR labelling technique. The results of our studies suggest that: (1) RA can activate mouse peritoneal M phi both in vivo and in vitro, and the RA-activated M phi are cytostatic and cytolytic to A549 cells. The degree of activation is related to the concentration or dosage of RA given, and (2) RA can enhance the function of CP-activated M phi. A summation effect was obtained by giving RA in combination with CP. This effect was related to the dosage of RA. When optimal dosage was given in combination with CP, a synergistic action in activating M phi could be obtained. Morphological changes could be seen under phase contrast microscope and light microscope in killed tumor cells.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2006

Rapid phase change of lipid microdomains in giant vesicles induced by conversion of sphingomyelin to ceramide.

To understand the role of sphingomyelinase (SMase) in the function of biological membranes, we have investigated the effect of conversion of sphingomyelin (SM) to ceramide (Cer) on the assembly of domains in giant unilamellar vesicles (GUVs). The GUVs were prepared from mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), N-palmitoly-D-erythro-sphingosine (C16Cer), N-palmitoyl-D-erythro-sphingosylphosphorylcholine (C16SM) and cholesterol. The amounts of DOPC, sum of C16Cer and C16SM, and cholesterol were kept constant (the ratio of these four lipids is shown as 1:X:1-X:1 (molar ratio), i.e., X is C16Cer/(C16Cer+C16SM)). Shape and distribution of domains formed in the GUVs were monitored by a fluorescent lipid, Texas Red 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (0.1 mol%). In GUVs containing low C16Cer (X=0 and 0.25), round-shaped domains labeled by the fluorescent lipid were present, suggesting coexistence of liquid-ordered and disordered domains. In GUVs containing intermediate Cer concentration (X=0.5), the fluorescent domain covered most of GUV surface, which was surrounded by gel-like domains. Differential scanning calorimetry of multilamellar vesicles prepared in the presence of higher Cer concentration (X>or=0.5) suggested existence of a Cer-enriched gel phase. Video microscopy showed that the enzymatic conversion of SM to Cer caused rapid change in the domain structure: several minutes after the SMase addition, the fluorescent region spread over the GUV surface, within which regions with darker contrast existed. Image-based measurement of generalized polarization (GP) of 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan), which is related to the acyl chain ordering of the lipids, was performed. Before the SMase treatment domains with high (0.65) and low (below 0.4) GP values coexisted, presumably reflecting the liquid-ordered and disordered domains; after the SMase treatment regions with intermediate GP values (0.5) and smaller regions with higher GP values (0.65) were present. Generation of Cer thus caused a phase transition from liquid-ordered and disordered phases to a gel and liquid phase.

Ceramides↗