Search

Native and heat-treated RNAs from the purified Schmidt-Ruppin strain of Rous sarcoma virus (RSV) were fractionated by sucrose density gradients in the presence of ribonuclease inhibitor diethyl-pyrocarbonate and observed by electron microscopy. The structure of native 60-70S RNA was classified into two forms: tanglefolded type and linear type. In the tangle-folded type double stranded portions were observed in several sites. A high frequency of 60-70S RNA were 1.0 mum and 3-3.5 mum in length. Molecules with length about 9mum were of the tangle-folded type while molecules shorter than 6 mum were of the linear form. The structure of heat-treated RNA(30-40S) was linear with the most frequent length being 1-1.5 mum. These results indicate that native 60-70S RNA is folded with the total molecular length being in the order of 6 to 9 mum. Molecules about 3mum long are likely to be the main subunits of 60-70S RNA, and they are fragmented further into smaller subunits of about 1 mum length.

DNA-dependent RNA polymerases (EC 2.7.7.6) were extracted and partially purified form the nuclei of rat ascites hepatoma cells (AH-130) induced by 4-dimethylaminoazobenzene. The patterns of RNA synthesis and the properties of these enzymes were compared with enzymes from the nuclei of rat liver. The specific activity of RNA polymerase in the homogenate from the nuclei of AH-130 cells was the same as normal rat liver nuclei. RNA polymerase was solubilized from the homogenate at high ionic strength and separated into two forms by DEAE-Sephadex column chromatography. Enzymatic characterization showed that these enzymes corresponded to RNA polymerase I and II. RNA polymerase I more effectively transcribed native DNA than denatured DNA at low salt concentration, but at high salt concentration RNA polymerase I effectively transcribed denatured DNA. RNA polymerase II more effectively transcribed denatured DNA. In AH-130 cells the activity of RNA polymerase I was 4 to 5 times higher than RNA polymerase II, and in rat liver the activity of RNA polymerase I was 1.5 to 2 times higher than RNA polymerase II. The activity of RNA polymerase I in AH-130 cells may have increased by induction.

The content of beta-hydroxyaspartic acid was measured in the urine of man and several species of animals. The configuration of urinary beta-hydroxyaspartic acid was deduced to be L-erythro in form by chromatographic comparisons with authentic samples. An increased excretion of urinary beta-hydroxyaspartic acid was observed in cats when serine or thiamine was administered with glycine. Glycine-1-14C administered to rats was incorporated into the urinary beta-hydroxyaspartic acid. The formation of beta-hydroxyaspartic acid in pig-liver homogenate increased in the presence of glutamate and thiamine pyrophosphate. These results were discussed in relation to the author's working hypothesis on the biosynthesis of beta-hydroxyaspartic acid.

Renal tissues from 208 human necropsies were observed histologically for disseminated intravascular coagulation (DIC). The tissues were stained with hematoxylin-eosin, Mallory's phosphotungstic acid hematoxylin (PTAH) and cationic ferric hydroxide colloid stabilized with cacodylate (Fe-Cac), and tested by immunoenzyme histochemical (IEH) reaction for fibrin-related materials (FRMs). The use of the IEH method increased FRM recognition, and FRMs were detected in a total of 80 cases (38.5%). In 26 cases diagnosed clinically as DIC, FRMs were shown in 23 of the cases (88.5%). Thus, 57 patients with FRMs were clinically asymptomatic. In rats with DIC induced by endotoxin injection, glomerulus FRM was effluxed into the tubulus through the Bowman's capsule and was excreted into urine. The electric charge was reduced on the endothelial surface of the glomerular capillaries in both human and rat DIC. Under the scanning electron microscopy, the endothelial surface appeared coarse in the glomerular capillary and fibrin degradation was present. Our conclusions are: (a) PTAH is non-specific for FRMs, (b) IEH aids the pathohistological diagnosis of DIC, especially in asymptomatic forms including the compensated DIC state, (c) FRMs in tubuli suggest DIC, and (d) DIC is possibly initiated by a reduction in the capillary electric surface charge.

A new volatile derivative of taurine, N-isobutoxycarbonyltaurine methyl ester (methyl 2-(N-isobutoxycarbonylamino)ethanesulfonate), was prepared by a three-step procedure for the gas chromatographic determination of taurine in urine. First, taurine was converted to its silver salt by reaction with silver oxide; next the silver salt was reacted with isobutyl chloroformate to form the N-isobutoxycarbonyl derivative, and finally the derivative was reacted with methyl iodide to form N-isobutoxycarbonyltaurine methyl ester. The volatile derivative was analyzed by gas chromatography using a column of 3% OV-101 on Chromosorb W. When methyl 3-(N-isobutoxycarbonylamino) propanesulfonate was used as an internal standard, the calibration curve was linear between 0.5 and 5.0 mumol of taurine/ml and showed a good reproducibility. This method was applied to the determination of taurine in human urine. Recovery was 98.6 +/- 5.2%, when 1.25 to 5.0 mumol/ml of taurine was added to human urine.

Excretion of sulfate and taurine, two major metabolites of sulfur, was examined in rats to study the nutritional status of sulfur metabolism in the mammals. Rats maintained on a conventional laboratory diet excreted 1.83 +/- 0.14 mmol of free sulfate and 229.0 +/- 75.3 mumol of taurine/kg of body weight per day. When the diet was changed to a synthetic 25% casein diet, the taurine excretion decreased to 15% of the previous daily excretion, but sulfate excretion decreased only slightly. These decreased levels returned to the original levels when 5 mmol of L-cysteine/kg of body weight was administered into the stomach through a catheter. One week after the first L-cysteine administration, when sulfate and taurine excretion had returned to the original levels, 5 mmol of L-cysteine/kg of body weight was administered likewise. The rats excreted sulfur corresponding to about 95% of L-cysteine administered in the form of free sulfate and taurine within a few days following L-cysteine administration, and sulfate excretion was 3.5 times more than taurine excretion. These results seem to suggest that, in rats, sulfur metabolism is in a state of equilibrium and that sulfate is formed preferentially to taurine.

We performed a cytogenetic study on 140 nonpolymalformed patients with mental retardation of clinically undefined origin, using a high resolution banding technique, to determine how much chromosome abnormalities contribute to the etiology of this condition. A total of 15 patients (10.7%) were found to have autosomal or sex chromosomal abnormalities. Autosomal abnormalities included partial monosomy (5 cases), reciprocal translocation (one case), 13/14 robertsonian translocation (3 cases), unbalanced translocation (one case), inverted duplication of 15q (one case) and mosaic trisomy 21 (one case). Sex chromosomal abnormalities comprised structural rearrangement of the short arm of the X chromosome (one case) and 47, XXY in a pure or mosaic form (two cases). It should be noted that four out of the 5 cases of partial monosomy had subtle interstitial deletions, which might have been unidentified by the conventional G-banding method alone. In one case of the robertsonian translocation 46,XY,t(13;14)/45,XY,t(13;14), a small deletion was thought to have occurred in the cells with a chromosome number of 45. Comparison of clinical features of the 15 chromosomally abnormal patients with those of patients with normal karyotypes did not show any clinical parameter indicative of chromosome imbalance. These results suggest that a subtle chromosomal deletion is specific to mental retardation associated with few malformations. We believe that diagnostic evaluation of mentally retarded patients, even if nonmalformed, should include chromosome analysis using a high resolution banding technique.

A simple cell-free system for studying a priming factor involved in the repair of bleomycin-damaged DNA was established. The template-primer used for the repair DNA synthesis was prepared by treating the closed circular, superhelical form of pUC19 plasmid DNA with 2.2 microM bleomycin and 20 microM ferrous ions. Single-strand breaks were introduced into pUC19 DNA by the bleomycin treatment, and the DNA was consequently converted largely into the open circular form. A system for repair of this bleomycin-damaged DNA was constructed with a priming factor, DNA polymerase (DNA polymerase beta or Klenow fragment of DNA polymerase I), ATP, T4 DNA ligase and four deoxynucleoside triphosphates. After incubation, the conformation of the DNA was analyzed by agarose gel electrophoresis and electron microscopy. The open circular DNA was largely converted to the closed circular DNA, indicating that the single-strand breaks of DNA were repaired. When the priming factor was omitted, DNA repair did not occur. The present system seemed to be applicable to the study of priming factors involved in the repair of DNA with single-strand breaks caused not only by bleomycin but also by ionizing radiation or active oxygen.

To clarify the initiation, development and recovery processes of disseminated intravascular coagulation (DIC), rat glomerular capillaries and fibrin thrombi were examined under transmission and scanning electron microscopes. DIC was induced in rats by a single intraperitoneal injection of endotoxin (Et., 7.5 mg/kg lipopolysaccharide:B, E. coli 026:B6). At 2 h after Et. injection, the endothelial surface of the glomerular capillary became irregular with projections like a sea anemone. At 4 h after Et. injection, agglomerated fibrin thrombi composed of fibrin fiber bundles with fine cross-striated fibriform structures were observed in the capillary lumen. The fibrin thrombi gradually changed into fine reticular systems suggesting a degradation process by 6 h after Et. injection, and formed a coarse granular agglomerate by 8 h after Et. injection. These fibrin thrombi disappeared within 12 h of Et. injection, but the endothelial surface remained edematous. At 24 h after Et. injection, the microstructure of the glomerular capillaries returned normal. Based on these observations, we concluded that DIC was primarily initiated by injury to the capillary endothelium, and that changes on the endothelial surface contributed to the development of DIC.

In vivo inactivation of cystathionine gamma-lyase by D,L-propargylglycine, a suicide inhibitor, was found to be less profound in rat kidney than in the liver. We investigated the cause of this difference using rat tissues. We fractionated kidney extract to characterize the substance which protected enzyme, and found that cysteine exhibits protecting action. Addition of 0.3 mM L-cysteine to the incubation mixture containing dialyzed kidney supernatant and 0.5 mM D,L-propargylglycine resulted in the protection of cystathionine gamma-lyase from the inactivation by the inhibitor. The content of cysteine in the kidney was six-fold higher than that in the liver. Thus, we have concluded that one of the reasons why the in vivo inactivation of cystathionine gamma-lyase in rat kidney was less than that in the liver is the presence of a higher concentration of cysteine in the kidney. S-Carboxymethylcysteine, a cysteine derivative, exhibited a similar, but weaker, protective effect.

The effects of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the organization of cytoskeleton and growth of normal and established chick embryo cells (CEC) were studied. The cytoskeleton of normal CEC formed stress fibers, while that of the CEC lines established in our laboratory formed no stress fibers. TPA treatment of normal CEC resulted in disorganization of the stress fibers into amorphous structure, while that of the established CEC lines induced no reorganization of the cytoskeleton. TPA had no promotional effect in vitro or in vivo on tumor growth in normal or the established CEC.

In the human lymphoreticular system, the alpha and beta subunits of S-100 protein are found in ordinary monocyte-macrophages and non-phagocytic histiocytes such as Langerhans cells and interdigitating reticulum cells, respectively. The beta subunit is also present in some CD8+ T cells. In the present study, we investigated the ontogeny of these histiocytes and lymphocytes in humans. Yolk sacs and 4 to 21-week fetuses were examined immunohistochemically for the presence of S-100 protein subunits using antisera monospecific to each subunit. S-100 alpha + macrophages were present in the yolk sacs and the hepatic sinusoids of the 4th week embryos prior to bone marrow hematopoiesis. These macrophages later appeared in other lymphoid organs when anlagen of these organs were formed. No S-100 beta + cells were found in the yolk sacs. S-100 beta+ histiocytes were first detected in the hepatic sinusoids of the 5th week embryo, and after the 8th week of gestation, they were distributed in other lymphoid organs. S-100 beta+ lymphocytes were not found in the liver. They were first detected in the thymus at the 12th week of gestation, and were subsequently distributed in other lymphoid organs. These results suggest that S-100 beta+ lymphocytes and histiocytes may belong to different cell lineages, and the former may not be the precursor of the latter.

The effect of an intravenous injection of squid-ink (sepia-melanin) solution on adult mouse spheroid alveolar epithelial cells was observed by the electron microscope. Sepia-melanin particles were seen in all alveolar wall cells examined that seems to suggest the entrance of sepia-melanin particles into the spheroid alveolar epithlial cells from the alveolar blood capillary. In cases of large penetrations of sepia-melanin particles into spheroid alveolar epithelial cells, a greater increase was found in the intramitochondrial granules. In addition, the so-called inclusion body believed to be formed by the degeneration of mitochondria had very high electron density and its quantity was abundant. On the contrary, in cases where the quantity of sepia-melanin entrance into the spheroid alveolar epithelial cell was small, neither an increase of intramitochondrial granules, an increase of the electron density nor an increase in the quantity of specific inclusion body was found.

Electron microscope observations were conducted on the relationship between mitochondria and inclusion body in mice spheroid alveolar epithelial cells after injection of trypan blue, an acidic dye and Alcian blue 8GS, a basic dye, by vital staining procedures. When both dyes were injected, the mitochondria of the spheroid alveolar epithelial cell became degenerated; however, in injection of only trypan blue, the cristae showed an increase in electron density. In injection on only Alcian blue 8GS, the cristae showed negative contrast. In most cases the trypan blue particles did not enter into mitochondria, whereas particles of Alcian blue 8GS sometimes entered into the mitochondria. When trypan blue particles entered mitochondria, deposits were not evident in the inclusion body, whereas when Alcian blue particles entered mitochondria deposits were seen in the inclusion body. In both of these cases only a few inclusion bodies were formed so that only traces or no inclusion bodies with vacuolar appearance were observed. From these findings it is suggested that mitochondria maybe convert to inclusion bodies.

The relationship between alveolar macrophages and spheroid alveolar epithelial cells was studied with the electron microscope after injection of squid-ink solution into the trachea of the mouse. At 20 hours after injection of squid-ink solution slight degeneration was evident in alveolar macrophages with sepia-melanin particles being phagocytized with partial digestion by lysosmes. Furthermore, hardly any changes were seen in mitochondria and inclusion bodies of the spheroid alveolar epithelial cells. In contrast, at one week after injection of squid-ink solution, almost all alveolar macrophages were degenerated with destruction of the ectoplasm in which the ingested sepia-melanin particles were digested by lysosomes into fine particles, and the mitochondria of spheroid alveolar epithelial cells were degenerated and the inclusion bodies were hardly formed. At three weeks after injection of squid-ink solution, alveolar macrophages as well as speroid alveolar epithelial cells showed almost complete recovery of functional structure. As the phagocyte in the alveolar space, neutrophile leucocytes were also observed in addition to the so-called alveolar macrophage.

Today Vitallium is used for surgical implants. It is a casting alloy which, with advances in casting technology, is also used commercially for making instruments of fairly complex shape. Because of its expense, however, it is not widely used in Japan. Instead, a series of 18-8 Mo alloys are used in Japan even though of insufficient strength. Used over a long period of time in the body, especially for the purpose of preserving structual functions as part of the human skeleton, it often corrodes, resulting in either abnormalities in tissue cells or, because of its insufficient strength, danger of bending and breaking with aging. In spite of a marked advance in fracture treatment, we have hardly any suitable materials for making instruments appropriate to the internal fixation of fractures in Japan. We, therefore, conducted various experiments to develop an alloy with sufficient corrosive resistance and strength that could be formed into a complex shape to take the place of Vitallium alloy, finally succeeding in developing an alloy we call "COP". The characteristic properties of COP may be summarized as follows: 1. The main components are 20% Cr, 20% Ni, 20% Co and 4% Mo aside from 0.2% P. 2. As it contains "P", it shows a marked age-hardening. In its molten state its machinability is excellent, and later it can readily be hardened by heat-treatment. 3. It has not only a marked yield point and tensile strength but also has toughness in elongation and reduction of area, showing a strength which surpasses Vitallium. 4. Its corrosive resistance is great. 5. Its cost is far cheaper than Vitallium.

We compared the transfection efficiency of four types of positively charged liposomes composed of (i) N-(α-trimethylammonioacetyl)-didodecyl-D-glutamate chloride (TMAG), dilauroylphosphatidylcholine (DLPC), and dioleoylphosphatidylethanolamine (DOPE) (1:2:2 molar ratio); (ii) 3β [N-(N′, N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and DOPE (3:2 molar ratio); (iii) dimethyldioctadecylammonium bromide (DDAB) and DOPE (1:2.2 molar ratio); (iv) N-[1-(2,3-dioleyloxy) propyl] -N,N,N-trimethylammonium chloride (DOTMA) and DOPE (1:1, w/w; lipofectin). Luciferase gene was used as a reporter gene. Among the cationic liposomes used, the liposomes composed of TMAG, DOPE and DLPC showed a much higher efficiency of plasmid DNA entrapment than the other cationic liposomes tested. In the absence of serum, the cationic multilamellar vesicles (MLV) and small unilamellar vesicles (SUV) composed of TMAG, DOPE and DLPC gave highly efficient transfection. On the other hand, MLV, dehydration-rehydration vesicles (DRV), and SUV liposomes prepared with the mixtures of DC-Chol and DOPE showed similar levels of transfection efficiency. However, the cationic liposomes composed of DDAB and DOPE showed inferior efficiency, whether in the form of DRV, SUV or MLV. The transfection efficiency of lipofectin was also low. In the presence of serum, on the other hand, a considerable (about 30-50%) amount of transfection activity was still observed at 10% fetal calf serum in the cationic MLV and SUV composed of TMAG, DOPE and DLPC. Cationic MLV, composed of TMAG, DOPE and DLPC, can transfect plasmid DNA, not only in the adherent cell lines but also in the suspension cell lines. These findings indicate that the transfection efficiency of cationic liposomes is affected by the lipid composition, the type of liposome, or the presence or absence of serum. They also indicate that the cationic liposomes containing TMAG, DOPE and DLPC are efficient vectors for gene transfer into cells.

Retinal cells from chick embryos aged 7.5 days of gestation were cultured for two months in a non-adherent suspension culture dish to study the effects of growth factors and co-culture with retinal pigment epithelial cells on their differentiation. Dissociated retinal cells became cellular aggregates (multicellular spheroids) within a day, and rosettes were formed in the spheroids after 2 days. Ultrastructurally, neurons of the rosettes developed connecting cilia, ellipsoids (accumulation of mitochondria), and external limiting membrane, indicative of their differentiation into photoreceptor cells. Epidermal growth factor enhanced the expression of rhodopsin by rosette-forming neurons, while basic fibroblast growth factor induced the growth of Mueller cells at 4 weeks, and their transdifferentiation into lens-epithelial-like cells at 8 weeks. Co-culture of retinal cells with retinal pigment epithelial cells enhanced the formation of rosettes in spheroids. Multicellular spheroids formed in a dish for suspension culture would provide a convenient in vitro system to examine differentiation and transdifferentiation of the retina.

The serum levels of the carbohydrate antigen sialyl Lewis X (SLEX) increase in liver diseases (Sunayama T, Okada Y, Tsuji T., J Hepatol 1994; 19: 451-458). However, it is not known whether the increased serum SLEX levels are associated with the increased levels of its carrier molecules and/or the increased density of SLEX per carrier molecule. By using of rabbit antibody against an SLEX-positive fraction from HepG2 culture supernatant, we developed an enzyme-linked immunosorbent assay to determine the serum levels of the carrier molecules of SLEX (CM_SLEX). The CM_SLEX-levels in patients with hepatocellular carcinoma were significantly higher than those of normal controls (P < 0.001) and benign chronic liver diseases, i.e., chronic active hepatitis, mild and severe form, and liver cirrhosis (P < 0.05). Patients with chronic persistent hepatitis and chronic active hepatitis, mild form, had higher CM_SLEX-levels than normal controls (P < 0.05). The serum CM_SLEX-levels did not differ significantly among benign liver diseases. We concluded that serum CM_SLEX-levels increase nonspecifically in liver diseases. This is a possible molecular mechanism for the increased serum SLEX levels in liver diseases.