Cytotoxicity of cholestane 3 beta,5 alpha,6 beta-triol on cultured intestinal epithelial crypt cells (IEC-6)

The effects of cholestane 3 beta,5 alpha,6 beta-triol on intestinal epithelial crypt cells were investigated using the IEC-6 cell line. Cholestane 3 beta,5 alpha,6 beta-triol decreased SH groups (glutathione and protein SH) in the cell, and showed cytotoxicity in a time-dependent manner. Although the concentration of cholestane 3 beta,5 alpha,6 beta-triol used in this study (100 microM) was very high compared with that in plasma of experimental animals, cholestane 3 beta,5 alpha,6 beta-triol did not show any cytotoxicity on IEC-6 cells without fetal calf serum (FCS). The level of cytotoxicity was dependent upon the concentration of FCS in the culture medium. Unknown components in FSC (not VLDL or LDL) were suggested to be associated with the cytotoxicity of cholestane 3 beta,5 alpha,6 beta-triol. Moreover, the fact that even heat-treated FCS (100 degrees C for 30 min) still mediated the cytotoxicity suggested the participation of non-protein components.

[Smoking behavior, knowledge and attitudes of freshmen students]

A questionnaire on smoking behavior, knowledge of smoking-related diseases and attitudes toward the passive exposure to smoking was administered and results analyzed for differences in (1) region, (2) major area of study in the university, (3) grade and (4) date of survey on smoking behavior, knowledge and attitude of the freshmen students. (1) 294 urban and 217 provincial university students, (2) 138 freshmen at the Department of Pharmacology and 156 freshmen at the Department of Technology, (3) 136 freshmen of Y. University and 158 freshmen in senior high school of Yamaguchi prefecture, and (4) 217 freshmen surveyed in 1990 and 136 freshmen surveyed in 1995 were the subjects. The results were as follows; 1) The percentage who had smoked once ranged from 0 to 3% among the senior high school girls and female students at minor universities. However, the percentage for male students ranged from 26% to 44% in each survey. There were clear gender differences in smoking behavior. 2) The proportion of students who admitted that they had smoked cigarettes was 30.9% for urban students and 38.6% for provincial university students, but was not a significant difference. There were no significant differences between urban and provincial students regarding knowledge of smoking-related diseases or attitudes toward passive smoke. 3) The proportion of students who admitted that they had smoked cigarettes was 44.0% for the Department of Pharmacology and 26.2% for the Department of Technology, a significant difference. There were no significant differences between pharmaceutical and engineering students in knowledge of smoking-related diseases or attitudes toward passive smoke. 4) The proportion of students who admitted that they had smoked cigarettes was 27.4% for university freshmen and 1.6% for senior high school freshmen. There was a significant difference between the two. The percentage who replied that the smoker must be considerate to non-smokers tended to be higher in the senior high school students than the university students. However, there was no significant differences between the two groups of students in knowledge of smoking-related diseases or attitudes toward passive smoke. 5) Although the proportion of students who admitted that they had smoked cigarettes was 38.6% in the 1990 survey and 27.4% in the 1995 survey, this was not a significant difference. The percentage of students in the 1990 survey who indicated an awareness of the relationship between smoking and coronary heart diseases was significantly greater than the percentage of students who indicated a similar awareness in the 1995 survey. These results suggest that the differences in the grade and the department of the university (or the nature of school) must be considered when surveying smoking behavior. It does not appear to be necessary, however, to consider regional differences or the date of survey, if students were surveyed relatively recently, concerning smoking behavior, knowledge of smoking-related diseases and attitudes toward the effect of passive exposure to smoking.

Estimation of CO exposure of road construction workers in tunnel

Carbon monoxide (CO) level in three different tunnels in Boston area have been measured during rush hour periods, and expected CO exposure of construction workers who possibly work there was also estimated. CO levels in these tunnels have been measured at outside of a car running through the tunnels. The data collected in this study include vehicle speed, length of tunnels and traffic volume. In addition, structure of each tunnel was investigated. These data were used to estimate relationship between CO level and the distance of sampling points from entrance/exit of each tunnel. CO concentration in each tunnel was distributed in the range of 5 ppm-42 ppm, and linear relationship between CO concentration and distance from entrance/exit has been observed. This study had been held from April 1989 to May 1989 in Boston, MA, USA.

A vector distribution model and an effective nearest neighbor search method for image vector quantization

In this correspondence, a modified version of Hunt's (1980) image model is used to interpret the distribution of image data vectors. The model suggests that the diagonal line of the coordinates system is a good approximation of the principal axis of the image data vector set. The validity of the model is supported by experiments. Following this suggestion, an effective nearest neighbor search method for vector quantization of image data is developed. The method is based on partitioning the vector space using hyperplanes which are perpendicular to the diagonal direction of the coordinate system. The validity of the method is assessed by analyzing its complexity and comparing its performance to those of existing algorithms on a number of images.

Cytotoxicity of 7-ketocholesterol toward cultured rat hepatocytes and the effect of vitamin E

The effects of 7-ketocholesterol on rat hepatocytes prepared by collagenase perfusion were examined. The viability of cells incubated with 100 microM 7-ketocholesterol was significantly lower than those with cholesterol, although the LDH activity in the cultured medium remained unchanged during the incubation. Hepatocytes treated with 7-ketocholesterol produced large amounts of .NO and O2- in the early stage of incubation. Treatment of the hepatocytes with Carboxy-PTIO, which selectively scavenged .NO, or with L-NMMA, an inhibitor of .NO synthase, increased the cell viability. The addition of 7-ketocholesterol to the culture medium tended to increase the ratio of total sterol to phospholipid of the hepatocytes in a time-dependent manner without changing the content of phospholipid. No lipid peroxidation or oxidation of the cellular SH groups, protein SH and glutathione, was apparent. Vitamin E added 1 h before the addition of 7-ketocholesterol prevented the hepatocytes from cell death by suppressing the incorporation of 7-ketocholesterol into the hepatocytes and by scavenging O2-.

Multiple alleles encoding a virus-like particle protein in the ichneumonid endoparasitoid Venturia canescens

Hymenopteran endoparasitoids produce nuclear secretions from ovarian glands, which are deposited into the host insect together with the egg, protecting the developing parasitoid against the host's defence reactions. In the ichneumonid Venturia canescens, virus-like particles (VLPs), are attached to the egg surface and provide passive protection against encapsulation by the host. One of the four major particle proteins (p40) is expressed not only in the calyx gland but also in tissues that are not involved in particle production. The p40 coding DNA from V. canescens was cloned and sequenced. Within the coding DNA a tandem repeat sequence, coding for a putative proteolytic cleavage site of the PEST type, is rearranged in a significant portion of the wasp population. A corresponding polymorphism was also detected in the protein. The amino-terminal region of the deduced protein contains a putative type II transmembrane domain. The carboxy-terminal region shows similarity to the phospholipid hydroxyperoxide glutathione peroxidase (PHGPX) of vertebrates. A peroxidase function of the p40, although not ruled out, is unlikely due to the absence of a reactive centre which is typical for many vertebrate peroxidases. The overall conservation of the hydropathic region is discussed in the context of the formation of the viral envelope and its possible function in the immune protection.

Highly hydrogenated dietary soybean oil modifies the responses to polychlorinated biphenyls in rats

The effects of dietary highly hydrogenated soybean oil (HSO) upon the changes caused by dietary polychlorinated biphenyls (PCBs) were examined in rats. Six groups of rats were fed the following diets for 30 d: a 20% soybean oil-containing diet (control diet), a diet in which a half of soybean oil was substituted with HSO (HSO-A diet), a diet in which cellulose powder was replaced with HSO (HSO-B diet) and these diets supplemented with 100 ppm PCBs (control + PCBs, HSO-A + PCBs and HSO-B + PCBs diets). Hepatic concentration of PCBs and relative liver weight were markedly decreased in rats fed with the HSO-A + PCBs diet compared with those fed with the other diets containing PCBs. Liver lipids and liver cholesterol were considerably decreased with a reciprocal increase in fecal sterol excretion by rats fed the HSO-A + PCBs and the HSO-B + PCBs diets compared with those fed with the control + PCBs diet. The fatty acid composition in hepatic phospholipids showed an independent increase of the saturated fatty acid content induced by dietary HSO and PCBs. Dietary PCBs also caused decreases in the amounts of monounsaturated and n-3 polyunsaturated fatty acids. These results suggest that dietary HSO prevents accumulation of PCBs in the liver and promotes the excretion of lipids stimulated by PCBs, accompanied by a change in fatty acid metabolism.

A new wound healing model of retinal pigment epithelial cells in sheet culture

PURPOSE

To evaluate some RPE cell functions, such as wound healing, in a preparation more similar to in situ conditions, we developed a method to obtain and culture retinal pigment epithelial (RPE) cells as a sheet. And we assessed the effects of fetal bovine serum (FBS) on the rate of RPE wound healing.

METHODS

We prepared RPE sheet cultures by incubating rat eyes in 0.1% proteinase K for 13 min, peeling away the neural retina-RPE complex, and then incubating the tissue for 1 h to promote spontaneous separation of the RPE sheet from the retina. After several days of incubation, the cultured sheets of RPE cells were examined by phase-contrast microscopy, scanning and transmission electron microscopy and immunocytochemistry. We made round defects 1 mm in diameter in cultured RPE sheets and estimated the rate of wound closure in media with different concentrations of FBS (0 to 10%).

RESULTS

The RPE cells cultured in sheets retained their in situ features, including microvilli, tight junctions and gap junctions, and the distribution of actin and cytokeratin filaments. A wound was noted to close with restoration of a polygonal configuration. The rate of wound closure depended on serum concentration in the culture medium; when supplemented with 10% fetal bovine serum, wound closure was complete in approximately 40 h.

CONCLUSIONS

The RPE sheet-culture technique we developed thus provides a suitable model for studying such RPE cell functions as wound healing or phagocytosis.

POU transcription factors differentially regulate the D1A dopamine receptor gene in cultured cells

Transcription is regulated by complex interactions between cis-elements and transcription factors. In this study, we found that members of the POU transcription factor family differentially regulate a cis-element of the human D1A dopamine receptor gene. The differences in transactivating abilities among POU factors are derived neither from their different binding affinities to the responsive element nor from their interaction with other types of transcription factors, suggesting the participation of coactivators. We also observed that POU family members, when expressed simultaneously, act competitively on this regulatory element. Our findings demonstrate that members of the same transcription factor family result in different outcomes in cultured cells. These observations suggest a novel model for in vivo gene regulation by different members of a transcription factor family through a single cis-element.

Production of recombinant human monoclonal antibody using ras-amplified BHK-21 cells in a protein-free medium

A ras oncogene-amplified recombinant BHK-21 cell line (ras-rBHK-IgG) has been established, and was shown to hyperproduce the recombinant IgG chimeric human monoclonal antibody (hMAb) AE6F4, which recognizes lung cancer cells. We found that the ras-rBHK-IgG cell could be easily cultured in a protein-free ERDF medium supplemented with iron(III) nitrate, hydroxyethyliminodiacetic acid, and non-protein synthetic attachment factor as well as in a serum-free ERDF medium supplemented with insulin, transferrin, ethanolamine, and sodium selenite. The productivity of recombinant hMAb from the cells cultured in dishes at high cell densities was higher in protein-free medium than in serum-containing medium. True high density culture of the ras-rBHK-IgG cells was done in protein-free medium using the Tecnomouse, which is a novel hollow fiber bioreactor system. After culture for 30 days in protein-free culture, a total amount of about 14 mg of the recombinant hMAb AE6F4 was obtained, and was shown to be reactive against lung cancer cells in tissues.

Surgical removal of submacular hemorrhage using tissue plasminogen activator and perfluorocarbon liquid

PURPOSE

To assess the result of surgical removal of submacular hemorrhage by using tissue plasminogen activator and perfluorocarbon liquid.

METHODS

In 22 consecutive patients (22 eyes), subretinal hemorrhage associated with age-related macular degeneration, which involved the fovea and completely obscured the choroidal vascular pattern, was treated by pars plana vitrectomy. The hemorrhages were liquefied with tissue plasminogen activator, squeezed into the vitreous cavity with perfluorocarbon liquid, and then evacuated.

RESULTS

Efficacy of the procedure was judged by the best postoperative corrected visual acuity, which was 20/100 or better in 16 eyes (73%). Submacular hemorrhage recurred in four (18%) eyes, epiretinal membrane formed in three (14%) eyes, and retinal detachment occurred in three (14%) eyes. Best-corrected final visual acuity was improved postoperatively in 18 (82%) of the 22 eyes, unchanged in three (14%) eyes, and decreased in one (5%) eye, final visual acuity was 20/200 or better in 15 eyes (68%) and limited in other eyes by subretinal hemorrhage of greater than 30 days' duration or subfoveal neovascularizations.

CONCLUSIONS

Use of tissue plasminogen activator and perfluorocarbon liquid in surgical removal of submacular hemorrhage may improve the outcome of surgery by reducing surgically induced retinal damage.

Some unusual responses of astrocytes to ghost tangles in a long duration case of juvenile Alzheimer's disease: an electron microscopic study

The ghost tangles (GTs) in usual Alzheimer's disease are separated into small bundles of abnormal straight filaments by many invading astrocytic processes lacking a basal lamina (BL). An electron microscopic study of GTs in the Ammon's horn of a case of juvenile Alzheimer's disease of 25 years' duration, however, revealed that only a small number of astrocytic processes had infiltrated the GTs, resulting in the GTs being composed of large bundles. Moreover, the majority of glial processes that had invaded or apposed GTs possessed an interrupted but still fairly well-developed BL with hemidesmosome-like profiles. Although pia-arachnoid cells are required for astrocytes to form a continuous BL, astrocytes can have a segmental BL on their surface facing even empty intercellular spaces within the brain parenchyma. The much greater frequency and better development of the GT-associated BL in our case indicate that the GT filaments somehow increased the ability of astrocytes to form a BL. On the other hand, the scarcity of GT-invading astrocytic processes implies that many of the glial processes that had once penetrated GTs had been withdrawn, with the result that GTs escaped expectable endocyto-phagocytosis by astrocytes.

Bcl-2 inhibits retinoic acid-induced apoptosis during the neural differentiation of embryonal stem cells

We report here that all trans-retinoic acid (RA), a classical morphogen, induces apoptosis during the neural differentiation of the embryonic stem cell line P19. The apoptotic cells showed, in addition to DNA cleavage, typical morphological changes including chromatin condensation, nuclear fragmentation, and cytoplasmic vacuolation. These apoptotic changes became obvious by 12 h after the addition of RA. The endogenous expression of bcl-2 in surviving cells was down-regulated during this process, and the compelled expression of bcl-2 by retroviral vectors reduced the number of apoptotic cells. Apoptosis was partially inhibited by adding antisense oligonucleotides against RA receptors (RARs) simultaneously or by transfecting a plasmid vector flanked with a RA-responsive element. Antisense oligonucleotides against retinoid X receptors (RXRs), the receptors for 9 cis-RA, did not inhibit apoptosis induced by all trans-RA. Cycloheximide and actinomycin D, inhibitors of protein and RNA syntheses, respectively, suppressed apoptosis. No changes were seen in the expression of tumor necrosis factors, their receptors, Fas, FasL, p53, or c-myc, molecules which have been suggested to participate in the apoptotic process. Addition of neurotrophins to the culture medium did not affect apoptosis. These findings suggest that the signals themselves, promote expression of molecules essential for apoptosis. Furthermore, we observed that RA induced apoptosis of cerebral neurons from murine embryos in primary culture, which suggests that RA might participate in cell death which occurs during neural development.

The rck/p54 candidate proto-oncogene product is a 54-kilodalton D-E-A-D box protein differentially expressed in human and mouse tissues

Expression of the RCK gene, which is a target gene on 11q23 of the t(11;14) (q23;q32) translocation in the B-cell lymphoma cell line RC-K8, was studied by Northern and Western blot analyses. The RCK gene product is a member of the D-E-A-D box protein/RNA helicase family. With the use of Northern blot analysis, a 7.5-kb transcript of the RCK gene was shown to be expressed ubiquitously in human and mouse tissues. Polyclonal antibodies against the RCK gene product were raised, and the RCK gene expression pattern was examined in human and mouse tissues. Two different polyclonal anti-rck antibodies detected a specific 54-kilodalton product named rck/p54 in the majority of human and mouse tissues tested by Western blot analysis. However, rck/p54 was shown to be very low in the human brain and was not detectable in lumbar muscle and lung tissues, although RCK mRNA is abundantly present in these tissues. It is of interest that malignant transformed human cells arising from tissues with low or no expression of rck/p54, such as neuroblastoma, glioblastoma, rhabdomyosarcoma, and lung cancer cell lines, produced a moderate amount of rck/p54 protein, suggesting that rck/p54 plays a role in tumorigenesis. In addition, the rck/p54 protein was localized to cytoplasm by immunostaining with the use of laser microscopy and by subcellular fractionation.

Effects of highly hydrogenated soybean oil and cholesterol on plasma, liver cholesterol, and fecal steroids in rats

We investigated the relationship between dietary highly hydrogenated soybean oil (HSO) and cholesterol transport in rats. In the first study, to examine the effects on cholesterol transport of different concentrations of HSO in dietary oil, rats were given one of the three diets containing 0, 25, or 50% HSO in dietary oil with cholesterol (5 g/kg diet) or a diet without HSO and cholesterol for 22 d. Feeding the high concentration of HSO prevented the increase in plasma total cholesterol, hepatic total lipids, and cholesterol and the decrease in high-density lipoprotein-cholesterol, which were caused by dietary cholesterol. Moreover, HSO increased the fecal excretion, fecal lipids, and steroids in a dose-dependent manner. In the second study, to examine the effects on cholesterol transport of redistribution of steric acid in the triacylglycerol species contained in HSO, rats were given one of the six diets containing HSO (distearoylmonoacylglycerol and tristearoylglycerol)-rich, monostearoylglycerol-rich, or palmitic acid-rich oil with/without cholesterol (5 g/kg diet), for 30 d. Whereas the accumulation of cholesterol in the body was reduced, cholesterol excretion was enhanced effectively in rats given the HSO-rich diet compared with rats given the monostearoylglycerol-rich diet. These results suggested that not only the high concentration of stearic acid but also its uneven distribution in HSO-triacylglycerol contributed to the reduction in intestinal cholesterol absorption in rats.

Rupture of congenital peripheral pulmonary aneurysm

A 58-year-old man presenting with solitary aneurysm of a peripheral pulmonary artery was treated by left lower lobectomy. Histologically, the aneurysmal wall showed medial hypertrophy with the loss of smooth muscle fibers, without evidence of a mycotic process or inflammatory exudate. The aneurysm appeared to be congenital in origin.

Congenital renal glomerular fibrosis in a case of swine chondrodysplasia

A dwarf male Large White neonate showing various external abnormalities was diagnosed to be chondrodysplasia. Microscopy revealed massive accumulation of eosinophilic homogeneous substance in the renal glomeruli, mainly along the capillary walls. The homogeneous substance, mainly consisted of type-III collagen, was not found in the primitive glomeruli in the superficial cortex, and was most frequently and intensely deposited in the mature glomeruli in the deep cortex. Electron microscopically, the deposits consisted of the collagen fibrils with various structural abnormalities. Glomerular fibrosis might be attributed to in situ production of type-III collagen by glomerular cells with differentiation and maturation, most likely by the mesangial cells.

A rapid method for isolation of retinal pigment epithelial cells from rat eyeballs

A new, simple method for isolating retinal pigment epithelial (RPE) cells from rat eyeballs was developed: incubation of the eyeballs in 0.1% proteinase K solution. This method yielded an average of 4 x 10(4) viable RPE cells from each Sprague-Dawley rat eyeball in 1 h. These RPE cells were hexagonal and had cytokeratin in their cytoplasm and numerous microvilli on their surface, similar to RPE cells evaluated in vivo. The results of this study thus show that our method for incubating eyeballs in proteinase K can provide good-quality RPE cells in sufficient quantities for study in a short time.

Gene regulation of trkB and trkC in the chick retina by light/darkness exposure

The trk gene family members; the neurotrophic receptors for neurotrophins, are implicated in the survival and the differentiation of neurons. The roles of these protooncogenes have been argued in the pathological conditions and in the specific developmental stage when the programmed cell death occurs to neurons. Here we studied a physiological role of the trk family members in the retina through observations of their gene regulation by light/darkness exposure. Northern blot analysis and immunohistochemistry demonstrate that trkB and trkC are up-regulated by light exposure and down-regulated by darkness in the rod/cone layer, the outer nuclear layer, and the ganglion cell layer. This physiological regulation suggests that these trk family members play a protective role from the damaging effect of light exposure in the retinal neurons.

Cancer-specific binding of a mouse MAb vs. Candida krusei cytochrome c: an antigen recognized by a cancer-associated human MAb HB4C5

More than 60 mouse monoclonal antibodies directed to cytochrome c from Candida krusei with different specificities were raised. Most of these monoclonal antibodies, except for three of them, did not cross-react with bovine cytochrome c. By the immunoblotting method, the monoclonal antibodies of clones HCC 5-13, 9-2, and 10-5 reacted with the Candida cytochrome c, which had been transferred onto nitrocellulose membrane, but those of clones HCC 1-22, 6-3, and 17-3 did not, although all these monoclonal antibodies strongly reacted with coated Candida cytochrome c on plastic immunoplates when examined by ELISA. On the contrary, monoclonal antibody activities of clones HCC 1-22, 6-3, and 17-3 in binding to the coated cytochrome c in ELISA were inhibited competitively by the addition of extra Candida cytochrome c, whereas those of clones HCC 5-13, 9-2, and 10-5 were not inhibited. Among these monoclonal antibodies, the antibody of clone HCC 6-3, which showed a good reactivity to added cytochrome c in inhibiting ELISA reaction but was not reactive with the transblotted cytochrome c on nitrocellulose, was found to be reactive with human lung cancer tissues specifically with no reactivity to normal tissues. The immunostaining of lung cancer tissue showed that this mouse monoclonal antibody to Candida cytochrome c reacted to the cytoplasmic fraction of the cancer cells specifically.

Molecular cloning and expression of a novel truncated form of chicken trkC

The trk family of tyrosine protein kinase genes serves crucial roles for the development of the nervous system and the survival of neurons. The members of this gene family, trk, trkB and trkC, bind a distinct neurotrophin of the nerve growth factor (NGF) gene family, and trigger the intracellular signals which elicit trophic and differentiating effects on neurons. Adding to these neurotrophic receptor kinases, the truncated forms without the tyrosine kinase domain have been cloned and characterized. It has been thought that the existence of truncated forms is limited to trkB; however, very recently the truncated trkC has been cloned in rat [(1993) Neuron 10, 963-974; (1993) Neuron 10, 975-990]. We independently approached and molecularly cloned a truncated form which belongs to the chicken trkC. The truncated trkC possesses the binding and the transmembrane domains but not the tyrosine kinase domain. Northern blot analysis shows that the truncated form is preferentially expressed in the adult central nervous system. The truncated form is scarcely expressed during the embryonic stages. The conservation of the truncated trkC beyond species suggests they have specific functions.

trk immunoreactivity at neuronal dendrite and cell body

Neurotrophins homologous to the nerve growth factor (NGF) bind the neurotrophic receptors of the trk gene family. Since the target tissues release these neurotrophic factors to the neuron, it has been believed that their trophic effects are mediated by the retrograde axonal transport. However it remains an open question whether the neurotrophins act through the autocrine or the paracrine mechanisms, since the protein-level expression of trk has not been studied so far. We have made polyclonal antibodies against the recombinant proteins of chicken trkC and rat trkB. These antibodies showed immunoreactivity at the dendrite and the cell body of neuron. This subcellular localization strongly suggests the autocrine or the paracrine mechanism of the neurotrophic factors. At the same time, our data provide basic knowledge to decide where to deliver these neurotrophic factors in the therapy of neurodegenerative diseases.