Analysis of chromosomal alterations induced by asbestos and ceramic fibers

Asbestos and other mineral fibers have long been known as carcinogenic agents. However, the primary mechanisms of fiber-induced carcinogenesis still remain unclear. We have investigated mitotic disturbances caused by amosite, crocidolite, and chrysotile in Syrian hamster embryo (SHE) fibroblasts. We also analyzed micronucleus formation as a result of mitotic disturbances, and carried out a characterization of the induced micronucleus population by kinetochore staining. In addition, the spindle fiber morphology was examined. Supravital UV-microscopy was used to analyze changes in chromatin structure, impaired chromatid separation and blocked cytokinesis. All three fiber types induced micronuclei in SHE cells with a high frequency (up to 200 MN/2000 cells; dose range: 0.1-5.0 microg/cm2) in a dose-dependent manner with a maximum between 48 and 66 h. Kinetochore staining revealed that 48% of fiber-induced micronuclei reacted positively. Furthermore, spindle deformation was observed in cells with disturbed meta- and anaphases while the spindle fiber morphology appeared unchanged. Our results show that asbestos fibers may cause both loss as well as breakage of chromosomes in the absence of direct interaction with spindle fibers. In addition, we analyzed the induction of micronuclei, hyperdiploidy and chromosome breakage in human amniotic fluid cells (AFC) in vitro by amosite, chrysotile and crocidolite asbestos and ceramic fibers. The response of human (AFC) and rodent (SHE) cells to fiber treatment was compared using the micronucleus assay. AFC were much less susceptible than SHE cells to the induction of micronuclei by mineral fibers. The application of fluorescence in situ hybridization (FISH) with tandem DNA probes yielded more detailed informations about specific structural chromosome aberrations in the 1(cen-q12) and 9(cen-q12) regions and about abnormal numbers of chromosomes in interphase AFC. Using this FISH approach we found a statistically significant increase of chromosomal breakage in the pericentric heterochromatin regions of chromosomes 1 and 9 in AFC after exposure to asbestos and ceramic fibers. The number of hyperdiploid cells was also significantly increased. These results show that asbestos as well as ceramic fibers are inducers of structural and numerical chromosomal alterations.

Light and electron microscopical immunohistochemical localization of large proteoglycans in human tooth germs at the bell stage

The immunohistochemical localization of large hyaluronate-binding proteoglycans has been studied in human tooth germs at the bell stage using a monoclonal antibody, 5D5, which is derived from bovine sclera and specifically recognizes the core protein of large proteoglycans, such as versican, neurocan and brevican, but not that of aggrecan. In the early bell stage before predentine secretion, when the enamel organs consisted of the inner and outer enamel epithelia, stratum intermedium and stellate reticulum, the enamel organs were not stained by 5D5, but the dental papillae and follicles stained strongly. Concomitant with the secretion of predentine, dentine and subsequent enamel matrix, strong 5D5 immunostaining distributed over the entire cell surfaces of secretory ameloblasts was observed. The forming enamel matrix showed strong staining. While most of the inner and outer enamel epithelia and stratum intermedium lacked staining, the cervical loop region and stellate reticulum showed weak staining. Although the forming dentine and odontoblasts appeared to lack 5D5 affinity, the predentine, dental papilla and dental follicle demonstrated moderate to strong reactivity. At the ultrastructural level, specific immunoreaction by immunogold particle deposition was clearly detected over the basal lamina of presecretory ameloblasts, secretion granules of secretory ameloblasts and the forming enamel matrix. These results indicate that a marked increase in the large proteoglycan associated with secretory ameloblasts may correlate with cell differentiation and enamel matrix biosynthesis.

ULTRAVIOLET MICROSCOPY OF THE VACUOLE OF SACCHAROMYCES CEREVISIAE DURING SPORULATION

Svihla, G. (Argonne National Laboratory, Argonne, Ill.), J. L. Dainko, and F. Schlenk. Ultraviolet microscopy of the vacuole of Saccharomyces cerevisiae during sporulation. J. Bacteriol. 88:449-456. 1964.-Normal cells of Saccharomyces cerevisiae and cells containing, in their vacuoles, large quantities of S-adenosylmethionine were induced to sporulate. In the latter case, the strong ultraviolet absorption of the compound permitted photomicrographic observation of cytological detail. Chromatographic and spectrophotometric analyses of cell extracts supplemented the cytological studies. The vacuole is abolished at the onset of sporulation, and its contents may be observed temporarily in the intersporular space. As sporulation progresses, the material is discharged into the culture medium. Sporulation of both types of cells also leads to a release of nucleic acid fragments into the culture medium.

The use of the lipophilic fluorochrome CM-DiI for tracking the migration of lymphocytes

In this study we examined the new cell dye CM-DiI for tracking the migration of lymphocytes from blood to lymph. This lipophilic marker intercalates in the plasma membrane like the PKH dyes and older DiI derivatives. The stability and intensity of staining achieved with these dyes is better than most other fluorochromes or radioisotopes, yet they are poorly soluble in aqueous solutions, which can make staining difficult, and they are not fixable in tissue sections. CM-DiI is reported to have increased water solubility and it can be fixed using traditional aldehyde fixatives, making it feasible to detect labeled cells in histological sections. To determine the suitability of CM-DiI as a lymphocyte marker, a labeling protocol was developed. We tested the ability of stained cells to recirculate in vivo. Following the intravenous injection of CM-DiI positive cells, their recovery in lymph over 40 h was comparable to that of cells labeled with other fluorochromes or radioisotopes. The kinetics of recirculation were also very similar, as labeled cells were detectable in lymph within 4 h of injection, and the peak percentage of labeled cells in lymph was generally observed between 20-30 h. We also confirmed that CM-DiI is retained in the lymphocyte membrane following routine paraffin processing. Thus CM-DiI does not appear to alter the process of lymphocyte recirculation, and it should be a useful marker for tracking these cells.

Retinal pigment epithelial cell proliferation: potentiation by monocytes and serum

BACKGROUND

The development of proliferative vitreoretinopathy (PVR) results often from a breakdown of the blood-retina barrier and the intraocular accumulation of serum proteins and leukocytes, particularly monocytes, that then come into contact with retinal pigment epithelial (RPE) cells. To examine the effect of these two factors on RPE proliferation, which is characteristic of PVR, we used a coculture system of blood monocytes and human RPE cells.

METHODS

RPE cells were incubated with a variable number of monocytes at different serum concentrations and assayed for proliferation by [3H]-thymidine incorporation and cell counting. To assess cell-cell communication. RPE cells were labeled with 2', 7' -bis(carboxyethyl)-5(and 6) carboxyfluorescein acetoxy-methyl ester, and the dye transfer to monocytes was analyzed using an UV microscope.

RESULTS

Monocytes (P < 0.0004) and serum (P < 0.0001), each on its own, significantly stimulated RPE cell growth, and these two variables were interrelated (P < 0.0001), showing a potentiating synergism. In serum-free medium, monocytes increased proliferation to just above control levels, whereas the same number of monocytes in 5% serum increased the [3H]-thymidine incorporation 3.8 times. This effect was greatly reduced by prevention of direct cell contact by means of placement of a well insert, which also lessened the monocyte-induced proliferation in both serum-free and serum-containing medium. Furthermore, the transfer of the intracellular dye from RPE cells to cocultured monocytes indicates that RPE cells transferred parts of their cytoplasm to monocytes.

CONCLUSION

These observations underline the importance of protein leakage through a damaged blood-ocular barrier and of direct contact of monocytes/macrophages with RPE cells, as well as their reciprocal potentiating effect on RPE cell proliferation. Thus, early stabilization of the blood-ocular barrier, which would preclude or reduce protein leakage and invasion of inflammatory cells into the eye, could be a target for pharmacologic prevention of PVR.

Induction of apoptosis by diethylstilbestrol in hormone-insensitive prostate cancer cells

BACKGROUND

Diethylstillbestrol (DES) and diethylstilbestrol diphosphate (DESdP) are effective agents for the treatment of advanced prostate cancers. Tumor-inhibiting effects of DES and DESdP are presumed secondary to suppression of androgen production in vivo. Little is known, however, about the direct cellular mechanisms of the tumor inhibition. Estrogens have been reported not only to stimulate growth but also to disrupt microtubule formation in prostate cancer cells.

PURPOSE

The study was designed to examine and compare mechanisms of in vitro growth inhibition of DES and DESdP in human androgen-insensitive prostate cancer cells (DU145, 1-LN, and PC-3) and human androgen-sensitive prostate cancer cells (LNCaP) and to examine estrogen receptor modulation of such effects.

METHODS

The cytotoxic effects of DES and DESdP were examined in vitro by use of a standard microculture tetrazolium assay to quantitate numbers of viable cells. Immunofluorescence microscopy, DNA fragmentation analysis, and fluorescence flow cytometry were used to investigate microtubules, the induction of apoptosis, and changes in cell cycle distribution. The degree of estrogen receptor positivity of untreated and treated cells was determined by immunohistochemistry and quantitative image analysis.

RESULTS

LD50 levels (the dose at which 50% of cells are no longer viable) in the concentration range of 19-25 microM were observed for both DES and DESdP in all cell lines examined. DESdP-induced growth inhibition was found to be dependent on heat-labile phosphatases present in fetal calf serum. DES-induced cytotoxicity was not affected by the presence of 17 beta-estradiol, and it was not dependent on the presence of estrogen receptor. Estrogen receptor-positive cells and estrogen receptor-negative cells were equally responsive to DES. PC-3 cells stained with fluorescent anti-tubulin, phalloidin (actin stain), and 4',6-diamidino-2-phenylindole (DNA stain) showed no inhibition of microtubules or actin filaments but revealed the presence of apoptotic bodies in the nuclei. Fluorescence flow cytometry of nuclear DNA content of propidium iodide-stained nuclei from androgen-insensitive prostate cancer cells treated with 15 or 30 microM DES or DESdP revealed an increase in relative numbers of hypodiploid (apoptotic) nuclei, a depletion of G1- and S-phase cells, and an accumulation of cells in G2/M phase. Conversely, androgen-sensitive cells contained a lower percentage of hypodiploid nuclei but no accumulation of cells in G2/M phase.

CONCLUSIONS

Direct cytotoxic effects of DES in prostate cancer cells are estrogen receptor independent and do not involve disruption of microtubule architecture but do involve the promotion of cell cycle arrest and apoptosis. These are the first data confirming direct cytotoxic effects of DES and DESdP in prostate cancer cells via an apoptotic mechanism. IMPLICATIONS. These results suggest that DES and DESdP have potential value as agents against androgen-insensitive prostate neoplasms through induction of an apoptotic cascade.

Hepatocyte death following transforming growth factor-beta 1 addition

Apoptosis is a morphological term which describes a sequence of events finally leading to cell death. In epithelial organs, induction of cell death is closely linked to an inhibitor of epithelial growth, transforming growth factor-beta 1 (TGF-beta 1). In this paper, we describe the morphology of TGF-beta 1-induced apoptosis in hepatocytes of the hyperplastic liver and primary cultures. Chromatin condensation, a hallmark of apoptosis, was observed in primary hepatocytes by confocal and vital UV microscopy. In addition, we have applied the morphological detection of DNA strand breaks both by in situ tailing (ISTAIL) and in situ nick translation (ISNT).

Ultrastructural analysis of mineralized matrix from human osteoblastic cells: effect of tumor necrosis factor-alpha

Recent work by a number of investigators has demonstrated that the process of bone matrix formation and mineralization is under the influence of growth factors and cytokines present in the local environment. Utilizing primary and established osteoblast cell culture systems, these studies have examined the regulation of bone matrix protein synthesis and deposition into the extracellular matrix (ECM) and subsequent mineralization. In previous studies, we have utilized the human osteoblastic cell line, HOS TE85, to study the effects of Tumor Necrosis Factor-alpha (TNF-alpha) on the regulation of matrix proteins and proteolytic function in monolayer cultures as well as during the development and calcification of ECM formed by HOS TE85 cells during extended culture. Our studies demonstrate that TNF-alpha inhibited formation and mineralization of nodules. In the study reported here, we evaluated the ultrastructural morphology of the cell-matrix complex formed by HOS TE85 cells in the presence and absence of TNF-alpha at selected time points during the matrix development process utilizing both transmission electron microscopy and light microscopy. In the presence of TNF-alpha, the cell-matrix complex does not develop normally, with a lack of organization and mineralization, when compared to untreated cells. The lack of mineralization appears to result from the lack of normal collagen fibril deposition and formation of an appropriate ECM essential for the mineralization process. These results support our previous observations that TNF-alpha inhibits HOS TE85 cells from forming a mineralizing ECM by inhibiting incorporation of collagen into the ECM and inducing the synthesis of proteolytic enzymes capable of degrading collagen in the ECM.

An immunofluorescence assay in microwell plate (IFA) for detecting serum antibodies to Chlamydia pneumoniae

An indirect immunofluorescence assay using a 96 microwell cell culture plate (IFA) was developed for the detection of antibodies to C. pneumoniae. The results obtained by IFA on 230 sera of healthy subjects were compared with those obtained with the microimmunofluorescence test. The correlation coefficient for IgG detection with the two methods was 0.96 showing good agreement.

Bisbenzimide: a fluorescent counterstain for tissue autoradiography

Interpretation of the data from experiments using autoradiography (e.g. using in situ hybridization histochemistry, receptor binding, neuronal tract-tracing etc.) is aided when the autoradiographic grains can be seen in the context of cellular boundaries. Studies making use of autoradiography in the central nervous system have sometimes used tinctorial stains, such as cresyl violet, as counterstains to visualize the labeling. Tinctorial stains are excellent Nissl stains however, under bright-field illumination such dyes tend to obscure autoradiographic grains. In addition, dark-field illumination provides a common means of visualizing autoradiographic grains but tictorial stains are not optimally visible under these conditions. In an effort to find a counterstain that would be compatible with dark-field illumination, we have investigated the use of fluorescent dyes. Of the fluorescent dyes tested, bisbenzimide (Hoechst 33258) in pH 2.0 buffer was found to be optimal. Bisbenzimide counterstaining gave good resolution of cellular boundaries and appeared not to interfere with the ability to visualize autoradiographic grains. Furthermore, the illumination of bisbenzimide and of the autoradiographic grains could be controlled independently, making it easy to visualize or photograph the bisbenzimide Nissl staining and the autoradiographic grains simultaneously. Thus, bisbenzimide is well suited for use as a fluorescent counterstain in autoradiographic studies.

Naturally occurring tetracycline-like fluorescence in sections of femur from jackals in Zimbabwe

In assessing the potential of the tetracycline compounds as biomarkers in oral rabies vaccination campaigns in jackals in Zimbabwe, the natural prevalence of fluorescent compounds in bone tissue from jackals was investigated. Femur samples were taken from unbaited jackals received for routine rabies diagnosis, and thin undecalcified sections were cut and viewed under an ultraviolet microscope. Of 131 femur samples examined, 49 (37 per cent) had fluorescent markings indistinguishable from those of tetracycline. The result implies that the tetracycline compounds, which are commonly used in rabies baiting campaigns in Europe and North America, cannot be used as biomarkers in jackals in Zimbabwe.

Cell-cycle dependent micronucleus formation and mitotic disturbances induced by 5-azacytidine in mammalian cells

5-Azacytidine was originally developed to treat human myelogenous leukemia. However, interest in this compound has expanded because of reports of its ability to affect cell differentiation and to alter eukaryotic gene expression. In an ongoing attempt to understand the biochemical effects of this compound, we examined the effects of 5-azacytidine on mitosis and on micronucleus formation in mammalian cells. In L5178Y mouse cells, 5-azacytidine induced micronuclei at concentrations at which we and others have already reported its mutagenicity at the tk locus. Using CREST staining and C-banding studies, we showed that the induced micronuclei contained mostly chromosomal fragments although some may have contained whole chromosomes. By incorporating BrdU into the DNA of SHE cells, we determined that micronuclei were induced only when the compound was added while the cells were in S phase. Microscopically visible effects due to 5-azacytidine treatment were not observed until anaphase of the mitosis following treatment or thereafter. 5-Azacytidine did not induce micronuclei via interference with formation of the metaphase chromosome arrangement in mitosis, a common mechanism leading to aneuploidy. Supravital UV microscopy revealed that chromatid bridges were observed in anaphase and, in some cases, were sustained into interphase. In the first mitosis after 5-azacytidine treatment we observed that many cells were unable to perform anaphase separation. All of these observations indicate that 5-azacytidine is predominantly a clastogen through its incorporation into DNA.

Remodelling of subchondral bone in osteoarthritis: a histomorphometric study

AIMS

To determine whether remodelling of subchondral bone in osteoarthritis is related to anatomical and mechanical factors operating on the joint surface.

METHODS

Ten femoral heads were examined. Patients due to have the femoral head removed because of osteoarthritis were given a double tetracycline label before surgery. The specimens were divided in three roughly equal parts, corresponding to the medial, central (weight bearing), and lateral aspects of the femoral heads. Undecalcified methylmethacrylate embedded sections were prepared. The subchondral bone was assessed for appositional bone formation by ultraviolet light microscopy, for resorptive activity by osteoclast count, and for trabecular bone volume by semiautomatic computerised image analysis. Appositional bone rate was also correlated with the presence or absence of overlying cartilage.

RESULTS

Bone density was reduced in the medial aspect of the femoral heads but there was no significant difference between the appositional bone rate or the resorptive activity in the three areas. Nor was there any correlation between appositional bone rate in the subchondral bone and the presence or absence of overlying cartilage.

CONCLUSION

Remodelling of subchondral bone in osteoarthritis, at least in the short term, is fairly constant and is not related to weight bearing.

Evaluation of an enzyme immunoassay kit for detecting cryptosporidium in faeces and environmental samples

AIMS

To evaluate a commercially available enzyme immunoassay based on a monoclonal antibody to a genus specific Cryptosporidium (IDEIA Cryptosporidium; Dako) antigen for detecting Cryptosporidium oocysts in faecal and environmental samples.

METHODS

435 human faecal samples and post-filtration deposits from 10 reservoir samples, and from six tap water samples seeded with Cryptosporidium oocysts, were examined by EIA according to the manufacturer's instructions, and by microscopic examination of phenolauramine stained smears. Samples giving discrepant results were examined by specific immunofluorescence, before and after concentration of oocysts.

RESULTS

Sixteen (3.6%) faecal samples were positive by both microscopy and EIA; five (1.1%) were positive by microscopy of auramine-phenol stained smears (but were not confirmed by specific immunofluorescence) and negative by EIA; one (0.2%) was positive by EIA alone, but confirmed by specific immunofluorescence; and 362 (83.2%) were negative by both microscopy and EIA. Compared with immunofluorescence positive faecal samples, the sensitivity of conventional microscopy and EIA were 94% and 100%, and specificity 76.4% and 100%, respectively. Fifty one (11.7%) were not examined by microscopy due to detection of other pathogens in a previous sample from that patient, but were found to be negative by EIA. Ten reservoir water samples (not suspected of being linked to cases of cryptosporidiosis) were negative by both microscopy and EIA. Of six samples of tap water seeded with varying concentrations of Cryptosporidium oocysts, two (10(2) and 10(3) oocysts/l) were positive by both microscopy and EIA, two (10 and 1/l) by EIA alone, and two (0.1/l and unseeded water) were negative by both microscopy and EIA.

CONCLUSIONS

The kit is simple and rapid to use and offers a less subjective method than microscopy for detecting Cryptosporidium in faecal samples submitted to a busy diagnostic laboratory.

Imaging of fluorescent neurons labelled with fluoro-gold and fluorescent axon terminals labelled with AMCA (7-amino-4-methylcoumarine-3-acetic acid) conjugated antiserum using a UV-laser confocal scanning microscope

This paper describes the implementation of an ultraviolet (UV) laser (Spectra Physics 171-18 with 3 lines: 334, 351 and 364 nm in UV) as light source for fluorescence confocal scanning microscopy. With this instrument it is possible to use fluorophores not previously available for confocal laser microscopical imaging of fluorophores such as fluoro-gold and AMCA. In the study we show confocal laser microscopical imaging of fluorescent motoneurons labelled by retrograde transport of fluoro-gold and AMCA-fluorescent axon terminals labelled with antisera against immunogenes as thyrotropin-releasing hormone (TRH) and calcitonin gene-related peptide (CGRP). These two fluorophores may be recorded simultaneously or separately by using a filter that suppresses the emission of one of the fluorophores. The described instrument should also be useful in applications involving detection of monoamines by the Falck-Hillarp technique, as well as measurements of cytosolic free calcium by indicators such as Fura-2 and Indo-1. Measurements performed in reflected and fluorescence light indicated that the resolution along the optical axis improved by about 25% when UV (351 nm) is used instead of visible light (514 nm). This figure is close to that expected on theoretical basis. There are, however, also serious problems related to the use of UV excitation. Firstly, objectives must be selected based on their UV transmission properties. Secondly, chromatic aberration may cause a substantial focal shift between illuminating and emitted light, calling for a flexible instrumental design in order to allow for compensation. As shown here, this problem can be circumvented by using reflecting objectives but at a price of lower resolution compared with high-aperture refracting objectives.

Class I and class II major histocompatibility complex antigens on hepatocytes: importance of the method of detection and expression in histologically normal and diseased livers

Methodological differences in major histocompatibility complex (MHC) antigen detection were investigated on isolated, viable hepatocytes and cryostat hepatic sections from 27 children with liver disorders, six of whom had normal histology. Class I antigens were constantly found on sections using a three step immunoperoxidase technique after acetone/chloroform fixation, other techniques being less sensitive, or on isolated hepatocytes by indirect immunofluorescence alone. With mechanical isolation the percentage of positivity ranged from 85 to 100%, while with collagenase isolation it ranged from 22 to 49% on immediate testing, and from 53 to 80% after 24 hour incubation. Class II antigens were only detected in one patient with autoimmune chronic active hepatitis and two with primary sclerosing cholangitis. Flow cytofluorimetric analysis in 11 cases confirmed class II or class I positivity, or both, on isolated hepatocytes, allowing MHC antigen expression on hepatocytes to be measured. Class I and II antigen detection on hepatocytes is influenced by the technique used. Although class I antigens are invariably expressed on hepatocytes, class II antigens are only found on hepatocytes from patients with immune mediated liver disorders.

Class I and class II major histocompatibility complex antigen expression on hepatocytes: a study in children with liver disease

Controversy exists regarding major histocompatibility complex antigen expression on hepatocytes. In this study, hepatocyte expression of class I and II major histocompatibility complex antigens was investigated in diseased and normal livers, using indirect immunofluorescent staining of mechanically isolated, viable hepatocytes. Hepatocytes were obtained from 76 children: 10 with autoimmune chronic active hepatitis, nine with primary sclerosing cholangitis, nine with chronic hepatitis B virus infection, five after liver transplantation, 19 with extrahepatic biliary atresia, 11 with alpha 1-antitrypsin deficiency, four with idiopathic neonatal hepatitis and nine with histologically normal liver. Immunohistochemistry was performed in all cases; flow cytofluorimetry was performed for class I antigens in 38 cases and performed for class II antigens in 18 cases. From three children with autoimmune chronic active hepatitis and two with chronic hepatitis B virus infection, isolated hepatocytes were also incubated with gamma-interferon before staining and analysis. By fluorescence microscopy, class I antigens were detected on hepatocytes from all children, the highest percentage (100%) of positive cells and the most intense staining were observed in untreated patients with autoimmune chronic active hepatitis or primary sclerosing cholangitis and in those with acute rejection of a liver transplant. Reduced class I antigen expression occurred in chronic hepatitis B virus infection. Class II antigens were only detected on hepatocytes from eight patients: three with autoimmune chronic active hepatitis and five with primary sclerosing cholangitis, all untreated. Flow cytofluorimetric analysis confirmed the results obtained by fluorescence microscopy, but it also demonstrated a weak class II antigen expression during liver allograft rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

[The traces of smokeless gunpowder]

The experimental investigation resulted in detection of new specific and characteristic signs of smokeless powder. Additional tests for determination and differential diagnosis of smokeless powder variants were suggested.

Interferon treatment reduces endocytosis of virus and facultatively intracellular bacteria in various cell lines

Previous studies have shown that interferons (IFNs) specifically interact with a number of cells cultured in vitro and reduce the invasiveness of facultatively intracellular bacteria. IFN treatment also reduced the internalization of vesicular stomatitis virus (VSV) in cell cultures. Here we show that the anti-invasive effect of IFN on bacteria is eliminated in an L-cell variant where its effect on the uptake of vesicular stomatitis virus is lost. The data strongly suggest that the anti-invasive effect of IFN is mediated through inhibition of endocytosis.

A light and scanning electron microscopic study of osteocyte activity in calcium-deficient rats

The material herein is an extension of an earlier study of osteocyte lacunae in calcium-deficient rats, utilizing morphometric measurements in undecalcified bone sections and scanning electron microscopy. The results confirm our earlier finding that bone resorption resulting from a low-calcium diet is not accompanied by osteocytic resorption.

[An analysis of the mechanisms of interpopulation interaction of Yersinia with Tetrahymena pyriformis infusorians at the cellular and subcellular levels]

The mechanisms of interaction between the populations of Yersinia and T. pyriformis have been analyzed on the cellular and subcellular levels. As shown in this investigation, Yersinia, when phagocytized by T. pyriformis, may undergo morphological changes, remain unchanged and also multiply, destroying the host cell in the process.

Effect of intravenous administration of corticosteroids on dentin formation in the adult rat molar

This study describes the effects of intravenously given corticosteroids on dentin formation in adult rat molars. Six rats twice a day received corticosteroids 20 mg/kg for 8 days, 10 mg/kg for 13 days, and 5 mg/kg for 19 days. Six rats given a heterotopic heart transplant received 10 mg/kg of corticosteroids twice a day for 40-64 days. Six rats were used as controls. Tetracycline was given at the start of the experiment and after 3 wk of treatment. After 40-46 days the rats were killed. Light microscopic examination of the molars showed no differences in the dentin formation or in the predentin zone between the experimental and control rats. In the ultraviolet light microscope two lines of tetracycline were visible along the root canal walls in both experimental groups. There was an obvious distance between the two lines, which indicated formation of new dentin. In the control group no formation of dentin was visible.

Light and electron microscopic changes in sural nerves in Ethiopian diabetics

The light and electron microscopic morphological changes in sural nerve biopsies from 32 Ethiopian diabetics and 4 malnourished non-diabetic subjects were studied in order to determine the role of malnutrition in the development of diabetic neuropathy. The most prominent finding in diabetics with clinical neuropathy was reduction in the density of myelinated axons of all diameters especially the large ones. Affected nerves showed abundant intraneural collagen, and evidence of nerve regeneration in some cases. Demyelination, though present, was less marked. Changes in the vasa nervorum were seen in only one case. The morphological changes correlated with the duration and severity of the diabetes and with nerve conduction velocity. No changes were seen in malnourished non-diabetics and diabetics without clinical neuropathy, thus suggesting that malnutrition by itself does not contribute significantly to the development of diabetic neuropathy. Axonal degeneration appears to be the predominant feature in diabetic neuropathy.

Enumeration of IFN-gamma-producing cells by flow cytometry. Comparison with fluorescence microscopy

A new intracytoplasmic immunofluorescence staining to detect and quantify human interferon-gamma (IFN-gamma)-producing cells by means of flow cytometry is described. Mononuclear leukocytes, stimulated in vitro to produce IFN-gamma, were fixed and made permeable to antibodies by sequential exposure to paraformaldehyde and the detergent n-octyl-glucoside. Cytoplasmic IFN-gamma was demonstrated by indirect immunofluorescence using IFN-gamma-specific mouse monoclonal antibodies. The staining exhibited a very characteristic morphology and was localized in the Golgi apparatus. An excellent agreement between the enumeration of cytoplasmic IFN-gamma-positive cells by immunofluorescence microscopy and flow cytometry was noted. However, the latter has the advantage of a standardized control, is less labor consuming and is observer independent.

Rigidity of the nucleus during nuclear rotation in 3T3 cells

Using near infrared microscopy and ultraviolet fluorescence microscopy of living 3T3 cells stained with the fluorochrome Hoechst 33342, we have demonstrated that the nucleoli and Hoechst 33342-stained chromocenters in the nucleus maintain a fixed pattern during nuclear rotation. We conclude that the term "nuclear rotation" refers to rotation of the entire nucleus in the cytoplasm of interphase cells, and that nuclear rotation is not an expression of karyoplasmic streaming. In conjunction with earlier results on nuclear rotation the data imply that the interface of nuclear rotation is located either between the two nuclear membranes or in the adjacent cytoplasm.

The role of vasoactive intestinal polypeptide as a neurotransmitter in canine penile erection: a combined in vivo and immunohistochemical study

Vasoactive intestinal polypeptide (VIP), a 28-amino-acid polypeptide found in the human gut and genitourinary tract, primarily affects vasodilation and smooth-muscle relaxation. These effects have led to speculation that this neuropeptide may be a neurotransmitter in certain bodily functions, such as penile erection. We therefore designed an in vivo animal model to elucidate the influence of VIP and VIP antibody on the different stages of penile erection. We also performed immunohistochemical studies of the penile tissue to obtain further information about the distribution of VIP in the corpora cavernosa. Intracavernous injection of VIP induced penile erection. Its effect on arterial inflow was minor, but it caused active venous outflow restriction and was important in maintaining erection. VIP antibody blocked venous outflow restriction during neurostimulation-induced erection. VIP was found in the cavernous tissue (in the area between the smooth-muscle cells and the sinusoidal spaces) in close proximity to the arteries. We conclude that VIP is a neurotransmitter in the erectile tissue of the penis, and that its effects are similar to those from electrostimulation of the cavernous nerve. VIP increases arterial flow, decreases venous flow, and induces sinusoidal relaxation.

[Structural changes in the contractile proteins of muscle fiber studied by polarization ultraviolet fluorescence microscopy. IX. The effect of the pH and ionic strength of the solution on the conformational restructurings of F-actin induced by the binding of heavy meromyosin]

The dependence of F-actin conformational changes induced by the F-actin-HMM complex on pH and ionic strength was found by polarized ultraviolet fluorescence microscopy. It is discovered that pH affects sufficiently the cooperativity of F-actin structural changes, while the ionic strength affects their depth. The actomyosin complex was supposed to be at least in two structural states, differing in their orientation as well as in flexibility of F-actin monomers.

Fluorescence of damaged myocardium in endomyocardial biopsy specimens for the evaluation of cardiac transplantation

Sections stained with hematoxylin-eosin from 138 endomyocardial biopsy specimens were examined in a Zeiss epifluorescent ultraviolet microscope for fluorescence indicative of myocardial injury. The biopsy specimens had been obtained from cardiac transplant recipients for routine follow-up evaluation or due to clinically suspected episodes of rejection. Yellow fluorescence and/or granularity of necrotic myofibers (with normal myocardium appearing olive green to yellow-brown), as reported in autopsy series, was observed in 22 of our specimens, for which the results of staining with hematoxylin-eosin and/or trichrome were found to contain areas of fiber fluorescence that were not recognized by staining with hematoxylin-eosin or trichrome. In some areas in an additional 13 specimens, the fiber damage seen on ultraviolet examination was greater than that suspected on the basis of the light microscopic morphologic changes. In seven cases routine light microscopy revealed fiber necrosis that could not be confirmed by ultraviolet illumination study. Fluorescence of damaged myofibers under ultraviolet illumination may contribute to the detection of early or mild myocardial injury in endomyocardial biopsy specimens from cardiac transplant recipients.

Identification and purification of NK cells with lysosomotropic vital stains: correlation of lysosome content with NK activity

The lysosome content of lymphocytes has been analyzed with lysosomotropic vital stains and the fluorescence-activated cell sorter (FACS). Large granular lymphocytes (LGL), which account for virtually all natural killing activity in peripheral blood, are quantitatively different from small lymphocytes (SL) in this respect. LGL obtained by Percoll gradient density centrifugation accumulate more of the lysosomotropic vital dyes than SL do, staining with either neutral red or mepacrine (quinacrine). Furthermore among the LGL-rich, low density lymphocyte population highly, granulated cells can be separated from less granulated ones by mepacrine staining and FACS. Thus, separated highly granulated LGL express very high natural killing, whereas the less granulated low density large lymphocytes do not kill.

Differential termination times of enamel formation on human deciduous anterior-tooth surfaces revealed by tetracycline labelling

The positional relationships between the cervical-enamel margin and the intersecting point of a fluorescent (tetracycline) line in dentine, with the outer dentine surface or the dentine-enamel junction, were investigated by ultraviolet microscopy of the human deciduous anterior teeth. The results suggest that enamel formation (1) ended earlier on the mesial than on the distal surface in 18 instances and, nearly simultaneously on both of these surfaces in four, (2) ended earlier on the distal than on the labial surface in all 28 specimens and (3) ended earlier on the labial than on the lingual surface in 14 instances and nearly simultaneously on both of these surfaces in eight instances.

Familial disorder of the central and peripheral nervous systems with particular cytoplasmic lamellated inclusions in peripheral nerves, muscle satellite cells, and blood capillaries

Four siblings of a family of 11 were afflicted with a predominant parkinsonian syndrome, pyramidal signs, intellectual deterioration, and peripheral neuropathy. Symptoms were noticed first when they were aged 8 years; the condition was slowly progressive. All presented similar clinical features of varying severity. Nerve and muscle biopsies of two patients exhibited inclusions of concentric lamellae 2 nm thick with a periodicity of 3.6 nm, in the cytoplasm of perineurial and Schwann cells, endothelial cells and pericytes of blood capillaries, and muscle satellite cells. These inclusions differ in their location and morphological features from other inclusions that have been described in nerve and muscle biopsies of many disorders. The features of these inclusions suggest that they may represent a storage deposit whose nature could not be determined. They may be a distinguishing morphological feature of a multisystem disorder which to our knowledge has not been identified previously.

[Structural changes in muscle fiber contractile proteins studied by polarization ultraviolet fluorescence microscopy. VIII. The effect of glutaraldehyde and phalloidine on F-actin conformation]

Conformational changes in F-actin, induced by glutaraldehyde or phalloidin, were found in glycerinated m. psoas rabbit fibres (ghost and reconstructed fibres). It is shown that the conformational changes of F-actin decreased the thin filament flexibility as well as weakened fibre's contractility. It is assumed that the stabilization in F-actin structure may be an important factor involved in the mechanism of muscle contraction regulation.

[Structural changes in the contractile proteins of muscle fiber studied by polarization ultraviolet fluorescence microscopy. VII. The effect of Ca2+ on the nature of the conformational changes in F-actin induced by the binding of heavy meromyosin]

Changes in anisotropy of tryptophan fluorescence and in birefringence of actin filaments induced by the binding to actin of heavy meromyosin (HMM), both containing DTNB light chains and devoid of them, were found in rabbit muscle fibres free of myosin, troponin, and tropomyosin. Ca2+ was shown to affect the pattern of changes in tryptophan fluorescence anisotropy and birefringence of actin filament at the moment of HMM interaction with actin, providing HMM contains DTNB light chains. Anisotropy of tryptophan fluorescence and birefringence of actin filaments rises in the absence of Ca2+ (pCa greater than or equal to 7), while in its presence (pCa less than or equal to 6) these values drop down. Furthermore, these changes become cooperative when Ca2+ concentration increases from pCa = 7 to pCa = 6. It was shown that the binding of HMM devoid of DTNB light chains to F-actin decreases tryptophan fluorescence anisotropy and birefrigence of actin filaments, regardless of Ca2+ concentration. Ca2+-dependent structural changes of F-actin induced by interaction of heads of myosin molecules with actin are assumed to be of great importance in regulation of muscle contraction of vertebrate skeletal muscles.

Morphological anomalies induced by Congo red in Aspergillus niger

Aspergillus niger germ tubes were exposed for 6 h to 0.15 mg/ml of Congo red, a stain which prevents chitin microfibril assembly. The most evident alterations, detected under ultraviolet light and by transmission and scanning electron microscopy, concerned the hyphal tips which burst or, most frequently, expanded into bulges. In the latter structures, new hyphal tips appeared which, after giving rise to more or less developed hyphae, were themselves converted into new bulges. Therefore, segments derived from isotropic and polarized growth alternated in the organisms exposed to the dye. An interpretation of these abnormalities is advanced based upon the assumption that the maintainance of a regular gradient of wall viscosity in the hyphal extension zone depends primarily on the capability of glycan chains to form crystalline aggregates of increasing complexity.

The development of the human interradicular dentine as revealed by tetracycline-labelling

The pattern of labelling of the interradicular dentine that forms the floor of the pulp chamber was studied in human deciduous second mandibular molars from patients who had undergone treatment with tetracycline during the period of formation of those teeth. Six teeth exhibited isolated mineralization centres for the interradicular dentine, indicating that this region in man, unlike in rodents, does not develop as a direct continuation of coronal dentine.

Calcofluor staining of cellulose during microcyst differentiation in wild-type and mutant strains of Polysphondylium pallidum

Calcofluor White ST was used to monitor the morphological events in the biogenesis of cellulose in the microcyst wall of the wild-type strain (WS-320) and two developmental mutants (mic-1 and mic-2) of Polysphondylium pallidum. During encystment, the cell surface acquires a Calcofluor-specific material which appears to be cellulose because of its sensitivity to purified cellulase. Cellulose-containing vesicles appear distributed throughout the cytoplasm of encysting cells of the three strains. Later, the cellulose-rich vesicles appear near the cell surface. Subsequently, the cell surface stains with Calcofluor, and the vesicles are no longer detectable. Intracellular vesicles resembling the cellulose-rich vesicles in size, in the timing of appearance, and in cellular location are also seen in thin sections. These vesicles are surrounded by a single unit membrane, and their amorphous matrix, which contains a dense irregular core, further implicates them as the basis for the bilayered microcyst wall.

[Determination of aerosol deposition in the maxillary sinus]

The penetration of aerosol into the maxillary sinus depends on the function of the maxillary ostium. Exact findings regarding the velocity of the air flow in the maxillary sinus can be gained by anemometry under optical control of the position of the thermistor. The penetration of aerosol (Patent Blue) can be observed even with a partially closed ostium, and deposit can be documented by photographs. The resorptive process on the mucosa - using fluorescent aerosols - can be visualized by direct excision under UV microscopy. Finally, it is pointed out that the aerosol has a therapeutic value in chronic sinusitis maxillaris even with only partial patency of the ostium.

A simple micromethod for leukocyte rosetting without cell purification

Conventional methods for leukocyte rosetting suffer from 2 major drawbacks: the length of time required for leukocyte purification prior to rosetting, and the necessity for large volumes of blood from which to purify the leukocytes. A simple method for leukocyte rosetting is described which uses small quantities (less than 100 microliter) of heparinized whole blood, does not require prior leukocyte purification and can be completed within 1 h of blood drawing. Percentages of rosetting polymorphonuclear leukocytes in cell preparations obtained by standard purification methods showed a close correlation (P less than 0.001) with percentages obtained by the method described. Additionally, the method described can potentially be applied to other non-neutrophil rosetting leukocytes in blood or body fluids.

Osteoinductivity of partially decalcified alloimplants in healing of large osteoperiosteal defects

About 3.5 cm osteoperiosteal circumferential gaps in rabbit ulnae were bridged by partially decalcified (by 0.6 M HCl) allogenic implants, 8-12 weeks after implantation complete bridging of the gap by new bone formation and union at host-graft junctions was observed in 97.2 per cent of the experiments. Instant permeability and the powerful osteo-inductive potential of the implant coupled with some degree of mechanical stability provided by partial decalcification ensured successful bone formation in almost all the experiments. It is suggested that partially decalcified allogenic bone matrix preserved in 70 per cent ethanol may be a reasonably good substitute for autologous bone graft.

[State of the contractile apparatus during the development of a pathological process in the muscles. V. The effect of Zenker's necrosis and of denervation atrophy on F-actin structure]

By means of polarized UV fluorescent microscopy, the state of F-actin was studied in single glycerinized muscle fibers from intact, locally damaged and denervated m. semi-tendinosus of the frog. It was shown that F-actin of denervated muscle fiber lost the ability to reply by increasing tryptophan fluorescence anisotropy during the fiber relaxation and its stretching in the rigor solution by 1--4 per cent compared to the original length. Zenker's necrosis retains this ability only slightly. It is supposed that both the denervation atrophy and Zenker's necrosis change the structure of F-actin.

[Structural changes in muscle fiber contractile proteins studied by polarization ultraviolet fluorescence microscopy. VI. Conformational restructurings of F-actin induced by the binding of heavy meromyosin]

Decrease in tryptophan fluorescence anisotropy of a single ghost muscle fibre was found at the binding of heavy meromyosin (HMM) to actin. Polarized fluorescence revealed its peak changes at a molar ratio of HMM/actin equal to 0.1. The changes observed in polarized fluorescence at F-actin-HMM interaction were found to depend on the state of HMM. The changes in anisotropy fluorescence under the same conditions were assumed to be independent of tryptophane residues in HMM, reflecting cooperative changes in F-actin conformation. Changes in the conformation of F-actin are of great importance in muscular contraction.

[State of the contractile apparatus in the development of a pathological process in muscle. IV. Effect of Ca2+ on the process of contraction nodule formation and on the ATPase activity of muscle actomyosin in Zenker's necrosis]

Using phase-contrast and polarized ultraviolet (UV) fluorescent microscopy, the structure of single muscle fibres was studied in the course of the contraction module formation during Zenker's necrosis. The degree of manifestation of destructive changes in the contractile system was shown to depend upon the concentration of extracellular Ca-ions. With decreasing Ca2+ concentration, the fibre loses the ability to form contraction nodules peculiar to the Zenker necrosis, and the development of this process is interrupted at the stage of sarcomere supercontraction. The UV fluorescent anisotropy pattern of fibre regions, conforming with the contraction nodules, suggests the occurrence of a more pronounced disorganization of contractile system in the presence of Ca2+. The ATPase activity of actomyosin isolated from altered muscle was studied to appreciate the functional state of the contractile system. This actomyosin was found to be inactivated 1.5 times as much as that isolated from muscles treated during Zenker's necrosis in calcium-free media.

Yellow hyaline membrane disease. Identification of the pigment and bilirubin binding

The distinguishing feature of yellow hyaline membrane disease (YHM) in the newborn is the presence of nonfading, bright yellow membrane lining the luminal aspects of conventional pink hyaline membranes (HM). Examination of yellow membranes, stained and unstained, under fluorescent microscopy reveals on orange-red fluorescent material heterogeneously dispersed within the membranes. Homogenates of lungs with YHM and HM were extracted with chloroform and tested spectrophotometrically, by thin layer chromatography, and for diazotized sulfanilic acid reactivity. Spectrophotometric profiles of YHM differed from those of HM by a unique absorption shoulder at 454 nm. in the former. This shoulder corresponded to the absorbance of unconjugated bilirubin. This profile could be reproduced by adding purified unconjugated bilirubin to non-YHM lung homogenate prior to extraction. Thin layer chromatography of the extracted YHM material produced two unique spots not found in extracts prepared from normal or HM-diseased lungs. These spots could be duplicated by thin layer chromatography using pure unconjugated bilirubin. The spots also fluoresced orange-red, the same color initially observed in the membranous preparations under fluorescent microscopy. Additional in vitro binding studies suggest that polymyxin, a decapeptide antibiotic used in endotracheal irrigation of newborn infants, binds bilirubin in pH-dependent, small molecular ratios. Although subsequent clinical studies disproved the etiologic significance of this particular drug, the unique properties of the bilirubin present in the YHMD lungs strongly suggest that the bilirubin there is bound by some yet unelucidated mechanism.

Cytophotometric analysis of lytically and persistently infected tissue culture cells with measles virus

Lytically and persistently infected VERO and LUB cells were cytophotometrically characterized with the aid of computer analysis. Images scanned at 260 and 280 nm were processed by computer algorithms. With this approach, infected cells could be segmented and differentiated from uninfected cells. Lytically and persistently infected cells could be distinguished by distinct differences in nuclear and cytoplasmic optical densities. These findings are supported by biologic data based on the analysis of virus-specific proteins and nucleic acids. The applied computer aided cytophotometry provides a new approach in the study of virus cell interaction.