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Biomedical subjects

N Okada

Publications and source records attributed to N Okada.

At least 487 records · Page 27Linked to original sources
PubMed1984

[Pancreatic cancer in father and daughter].

A 77-year-old male patient was admitted because of jaundice and general malaise. Exploratory laparotomy disclosed pancreatic head cancer with invasion to the intrapancreatic bile duct. Three months later, his daughter, aged 51, was admitted for evaluation because of body weight loss and back pain. CT scan disclosed 3 low-density areas in the pancreas with irregular margins and multiple low-density areas in the liver. Pancreatic cancer with liver metastasis was confirmed by autopsy. In familial pancreatic cancer, it is essential that genetic in addition to environmental factors be examined in pancreatic carcinogenesis.

Adenocarcinoma↗
PubMed1984

Metastasizing eccrine sweat gland carcinoma. Report of a case.

We report a case of eccrine sweat gland carcinoma arising from the occipital region, which later metastasized to the regional lymph nodes and spread widely to the viscera. After wide local excision of the primary tumor, it recurred locally, and then metastasized presumably via regional lymph nodes. Widespread metastasis to visceral organs occurred after a ten-year latent period from the appearance of the original tumor. Histochemical and enzymatic histochemical examinations of the specimens from the original tumor and metastasized lesions obtained at autopsy disclosed the characteristics of eccrine sweat gland tumor.

Abdominal Neoplasms↗
PubMed1983

Estradiol suppresses electrically-induced arterial thrombosis by increasing prostaglandin biosynthesizing activity of the aorta in rats.

The anti-thrombotic effect of estradiol was studied using an electrically induced thrombus model in rats. Estradiol treatment significantly inhibited the thrombus formation induced by electric shock. In the meantime, a stimulation of prostacyclin biosynthesis by estradiol in aortas was found. This is the first report showing the correlation between the effects of the estradiol on the thrombus formation in an experimental model and on the prostacyclin production by aortas in the same animal system.

Animals↗
PubMed1983

Decreased Na+-gradient-dependent D-glucose transport in brush-border membrane vesicles from rabbits with experimental Fanconi syndrome.

The effect of anhydro-4-epitetracycline on sodium gradient-dependent D-glucose transport of rabbit renal brush-border membrane vesicles was studied. The purity of isolated brush-border membrane vesicles as judged by enzyme activities was not different between normal control and anhydro-4-epitetracycline-administered rabbits. There was no difference in estimate of intravesicular volume, either. When NaCl was used for sodium gradient, the overshoot of D-glucose uptake into brush-border membrane vesicles isolated from anhydro-4-epitetracycline-treated rabbits was significantly smaller than that of normal control rabbits. In the cases of NaSCN or Na2SO4, the former was also smaller than the latter, but not significantly so. To avoid the possible effect of membrane potential on D-glucose uptake, the voltage-clamp method was applied. Even in the voltage-clamped condition, the overshoot of D-glucose uptake into vesicles from anhydro-4-epitetracycline-treated rabbits was decreased compared to that of normal rabbits. In vitro incubation of brush-border membrane vesicles with 20 mM anhydro-4-epitetracycline caused no alteration in sodium gradient-dependent D-glucose uptake. Our results demonstrate that there exists a disorder in sodium gradient-dependent D-glucose uptake of renal brush-border membrane in anhydro-4-epitetracycline-treated rabbits, and suggest that this disorder is one of the underlying mechanisms of experimental Fanconi syndrome.

Animals↗
PubMed1983

Molecular cloning and characterization of a gene for rat U2 small nuclear RNA.

Six phage clones that contain sequences hybridizable with the small nuclear RNA U2 were isolated from a rat gene library. Of these clones, one which includes a candidate for a functional U2 RNA gene was selected and characterized. The sequence within the clone which hybridizes with rat U2 RNA was completely co-linear with that of the RNA. A T-A-T-A box was not found in the region of more than 400 base-pairs which lies upstream of the gene. However, several block homologies were found with the upstream sequences of a rat U1 RNA gene candidate cloned in our laboratory. An "identifier sequence", which was reported to be an element of gene regulation related to differentiation, was found downstream of the coding region at the same distance and with the same orientation as the identifier sequence located downstream of the U1 RNA gene candidate. We detected a presumed U2 RNA precursor elongated by about 11 nucleotides at the 3' end by S1 nuclease mapping using a fragment from the clone. A potential termination signal for transcription was found within the elongated region of the presumed precursor. Southern blot analysis suggests that families of U2 RNA genes that have conserved flanking sequences are present in the genomes of rat, mouse, man, calf and chicken.

Animals↗
PubMed1983

Structural analysis of gene loci for rat U1 small nuclear RNA.

Four phage clones which hybridize with U1 small nuclear RNA were obtained from a rat gene library. Two clones contain a presumed pseudogene. A third clone includes two gene candidates that are co-linear with the rat U1-RNA, 3.6kb apart and in the opposite orientation. The two genes are surrounded by identical sequences of 491bp upstream and 178bp downstream. The upstream sequences do not contain a TATA box, but share many block homologies with those for the human U1-RNA gene(1-3). A 101bp "identifier (ID) sequence", which was reported to be specifically expressed in rat brain (4), is inserted immediately after the shared sequence downstream of one of the genes. In the fourth clone, there are two putative pseudogenes, which have one or three nucleotide changes, 3kb apart and in the same orientation. Southern blot analysis of total rat DNA reveals about 50 U1-RNA genes/pseudogenes in the genome.

Animals↗
PubMed1983

Prevention of complement activation on the homologous cell membrane of nucleated cells as well as erythrocytes.

A C3b receptor, a glycoprotein with a molecular weight of 205 kDa (gp205) on human erythrocytes (Ehu), has been claimed to restrict the activation of human complement via the alternative complement pathway (ACP), thereby inhibiting the activation of the ACP even on neuraminidase (Nase)-treated Ehu. However, the Nase-treated Ehu were sensitive to hemolysis by guinea pig complement via ACP activation, although the C3b receptors on Ehu can react with guinea pig C3b. Furthermore, HeLa cells which had no detectable C3b receptor did not became reactive with guinea pig ACP. On the contrary, Nase treatment of guinea pig erythrocytes (Egp) as well as guinea pig line 10 tumor cells, which have no detectable C3b receptor, could not make those cells reactive with the homologous guinea pig ACP although they became reactive with human and rabbit ACP. Similarly, rabbit E did not become reactive with the homologous rabbit ACP following Nase treatment. Nase-treated Egp preincubated with human serum in the presence of EDTA were also not lysed by guinea pig serum. Therefore the unreactiveness of Nase-treated cell membrane with homologous ACP was not merely due to the absence of antibody to cell membrane in the homologous serum. There may be a membrane inhibitor which preferentially interacts with homologous complement to circumvent undesirable complement activation on the homologous cell membrane.

Animals↗
PubMed1983

Isolation of a viable eccrine sweat gland by dispase.

Dispase was used to obtain viable eccrine sweat glands from human skin in an intact shape. The full thickness of human skin was soaked in a solution of dispase in Eagle's minimum essential medium at a concentration of 500 units/ml and kept in a refrigerator at 4 degrees C for 24 h. The epidermal sheet with its appendages could then be easily separated from the dermis by lifting the epidermis with fine forceps. Electron-microscopic observation revealed that the eccrine sweat gland was completely separated froM the dermis at the basement membrane zone. The isolated epidermal sheet was scarcely dissociated by mechanical agitation in the presence of Ca2+ and Mg2+ ions. The eccrine sweat gland was cut away from the epidermis by using microscissors under a stereomicroscope. A cell suspension of the isolated eccrine sweat glands was obtained after trypsinization. The cells remained more than 90% viable up to 48 h in the culture medium. The obtained viable eccrine sweat glands will be useful for the study of the biology of sweating.

Eccrine Glands↗
PubMed1983

Activation of the alternative complement pathway by IgM antibody reacted on paragloboside incorporated into liposome membrane.

Liposomes containing paragloboside (PG) on their membrane were readily lysed by C4 deficient guinea pig serum (C4D-GPS). On the other hand, guinea pig serum from specific pathogen free Hartley guinea pigs (SPF-GPS) did not lyse PG-liposomes in Mg-EGTA-GVB (gelatin veronal buffered saline containing MgCl2 and ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetate) which permits complement activation via the alternative pathway but not via the classical pathway. However, the SPF-GPS could lyse the liposomes in Mg-EGTA-GVB when heated (56 degrees C, 30 min) C4D-GPS or other guinea pig serum (GPS) was added. Gel filtration of Hartley (Htl)-GPS through a Sephadex G-200 column revealed that IgM antibody to PG in Htl-GPS was responsible for sensitization of the liposomes to lysis by complement of SPF-GPS via the alternative pathway. This result indicated that guinea pig IgM antibody can initiate the activation of the alternative pathway of homologous complement on liposome membrane.

Animals↗
PubMed1983

Differing reactivities of human and guinea-pig complement on haptenized liposomes via the alternative pathway.

Several haptens coupled to dipalmitoylphosphatidylethanolamine (DPPE) were inserted into the liposome membrane with a base composition of an equimolecular mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol (Chol). Haptens used were trinitrophenyl (TNP)-DPPE, TNP-aminocaproyl (TNP-Cap)-DPPE, dinitrophenyl (DNP)-DPPE, DNP-aminocaproyl (DNP-Cap)-DPPE, fluoresceinthiocarbamyl (Fl)-DPPE, azobenzenarsonate-tyrosyl (ABA-Tyr)-DPPE, dansyl (DNS)-DPPE, dabsyl (DABS)-DPPE, dithiopyridyl (DTP)-DPPE and maleimidobenzoyl (MB)-DPPE. Reactivity of those haptenized liposomes with complement via the alternative pathway was assessed by release of trapped fluorescent marker from the liposomes following incubation with dilutions of guinea-pig and human sera in a diluent containing MgCl2 and ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetate (EGTA). In the diluent (Mg-EGTA-GVB), complement activation via the alternative pathway proceeds while that via the classical pathway is inhibited. Fl-liposomes were found to be extremely sensitive to guinea-pig complement, being lysed by guinea pig serum dilutions of up to 1:76 in Mg-EGTA-GVB. Guinea-pig serum could lyse TNP-Cap-liposomes, DNP-Cap-liposomes, TNP-liposomes, DTP-liposomes, MB-liposomes, DNP-liposomes and ABA-Tyr-liposomes, with the reactivity of the liposomes decreasing in this order. However, the only haptenized liposomes sensitive to human serum in Mg-EGTA-GVB were DTP- and MB-liposomes; the other liposomes including Fl-liposomes being unreactive via the alternative pathway in reaction with human complement.

Animals↗
PubMed1983

Total DNA transcription reveals the existence of highly repetitive transcribable sequences in higher animals.

Using HeLa S-100 extracts, we have transcribed total DNA isolated from several species of higher animals. Transcription of the total DNA from rat, mouse, or hamster gives a discrete product of 6S RNA (about 180 nucleotides) in addition to a smeared background, whereas transcription from chick, calf, or human DNA gives a discrete band of 5S RNA (about 120 nucleotides). In view of the sensitivity to a-amanitin, these transcripts are produced by RNA polymerase III. Fingerprint analysis demonstrated that the 6S RNA species transcribed from rodent DNA have conserved sequences. The composition of dinucleotides in these bands having a guanosine residue on the 3' side was analyzed by RNase T2 digestion. The results show that the CG ratios of the transcripts of rodent, calf and chick are quite low in comparison with AG, UG, or GG except in the case of the human transcript, suggesting that these highly repetitive transcribable sequences are derived from a common prototype sequence, except in human cells. We have isolated two phage clones and one phage clone from a rat and mouse genomic library, respectively, which give a transcript of 180 nucleotides in size, and whose pattern of RNase T2 digests is the same as that of the conserved transcriptional products of total DNA. These highly repetitive transcribable sequences appear to be reiterated at several to ten thousand copies per haploid genome. The relationship of these sequences with the highly repetitive interspersed sequence B1 or Alu family is discussed.

Animals↗
PubMed1983

Separation of the epidermal sheet by dispase.

Dispase is a bacterial neutral protease which is obtained from the culture filtrate of Bacillus polymyxa. After 24-h treatment of the human skin with 500 and 1000 U/ml dispase, the epidermal sheet was easily peeled from the dermis, and its undersurface retained rete ridges. Electron microscopic observation showed that the basal surface was composed of cells with numerous slender villi and cytoplasmic projections. Although the intercellular spaces of the spinous as well as the basal layers were wide, all desmosomes were intact with their accompanying tonofilaments. An epidermal cell suspension was obtained by incubating the dispase-separated epidermal sheet in trypsin solution for 15 min and the viability of the cells was more than 95% as measured by the trypan blue dye exclusion test. A culture of keratinocytes was established by seeding the dissociated cells in the usual way.

Cell Separation↗
PubMed1983

Cinemicrographic study of cell proliferation pattern and interdivision times of human keratinocytes in primary culture.

The stratified squamous epithelium of the skin, the epidermis, is a renewing cell population. In order for epidermis to remain the same size, each dividing basal cell must produce on an average, one daughter cell that will remain as a germinative cell and another that will perform terminal differentiation (differential mitosis). In order to investigate cell kinetics in the epidermis, the information obtained from in vivo study is limited, and offers only indirect evidence for the determination of cell cycle time and cell proliferation pattern. Keratinocytes in cell culture are unique in formation of a multilayered cellular sheet in which the keratinocytes form a structure resembling the epidermis in vivo, and keratinize at the top. In the early days of the primary culture of human keratinocytes, when the cells proliferate to form a monolayer sheet, direct access to cell proliferation pattern and measurement of interdivision time can be done using techniques of time-lapse cinemicrography. The primary cultures at 8-20 days of incubation were employed for cinemicrographic observation when small polygonal cells appeared in groups, when numerous mitotic figures were observed, and when stratification of the cells had not yet occurred. The appropriate field was marked and followed for up to 6 days. Photographic prints were made from the 16 mm cine film, and dendrograms were made and analyzed for pattern of cell proliferation and interdivision time. Most cells in the field divided two or three times during the period of observation. Sister-sister pairs of the second and third generations divided after approximately the same interdivision times. However, some cells have never divided. Some of the sister-sister pairs differed considerably in their interdivision times. In some cultures synchronous division was quite evident. The average interdivision time was about 26 hr in the majority of cultures, and it is suggested that the estimated long cell cycle time in vivo might be overestimated due to the existence of non-cycling cells in the germinative population.

Cell Division↗
PubMed1983

Myocardial protection during cardiac ischemia by coronary perfusion with cold lactated Ringer's solution plus mannitol.

This experimental and clinical study evaluates the degree of myocardial protection afforded by coronary perfusion with cold lactated Ringer's solution plus mannitol. In the experimental study, diluted blood at 30 degrees C (Control G.), lactated Ringer's solution at 4 degrees C (G. A), 1,000 ml lactated Ringer's solution plus 200 ml of 20% mannitol at 4 degrees C (G. B), and 1,000 ml lactated Ringer's solution plus 500 ml of 20% mannitol at 4 degrees C (G. C) were used for coronary perfusion. The myocardial-protecting effect of each perfusate was evaluated by examining serum isoenzymes (CPK-MB, LDH1+2), left ventricular function (Vmax, LVEDP, CO), and the ultrastructure of myocardium. there were no significant differences in myocardial changes between the control group, G. A and G. B. Left ventricular enddiastolic pressure increased significantly in G. A and a significant increase in CPK-MB was seen in G. C. Mitochondrial scores for each group were 98 (Control G.), 86 (G. A), 93 (G. B), and 51 (G. C). Minimal myocardial change was seen in G. B. In the clinical study aortic root perfusion with cold lactated Ringer' s solution (400 m Osm) under aortic cross clamping (27-144 min) was employed in 25 patients. They all survived and CPK-MB returned to preoperative values within 49 hours after operation. In 6 cases, the ultrastructure of left ventricular papillary muscle was examined. It was confirmed that no significant mitochondrial changes developed during aortic cross-clamping.

Animals↗
PubMed1983

Effects of hypertonic mannitol on renal function in open heart surgery.

An extracorporeal bypass was performed in mongrel dogs for 2 hours with or without hypertonic mannitol infusions. In animals given mannitol, the plasma osmolality was elevated maximally to 344 +/- 7.1 mOsm/L and the urine volume was maintained well during bypass. A hypertonic mannitol solution was effective in maintaining the CPAH during and after bypass, but was not effective in minimizing the reduction in Ccr. When the mean arterial pressure during bypass was kept at 60 mmHg, the carbon filling rates in glomeruli showed the favorable effects of mannitol upon renal function, but no effects were observed at a mean arterial pressure of 80 mmHg. In 11 patients who had undergone a bypass lasting more than 2 hrs with mannitol infusions, the plasma osmolality reflected the serum mannitol level and reached 320 +/- 11.0 mOsm/L at 150 min of bypass. The mean urine volume was 5.0 +/- 3.3 ml/min/M2 during the bypass, which was about 7 times as great as before the bypass. The Ccr increased during the first 30 min of the bypass, but it fell to about one half of the initial value after 90 min of the bypass. It was concluded that a hypertonic mannitol solution is effective in maintaining the RPF and urine volume during and after the bypass and that it also preserved the glomerular perfusion even at a low arterial pressure.

Acute Kidney Injury↗
PubMed1983

Activation of the alternative complement pathway by natural antibody to glycolipids in guinea-pig serum.

Liposomes containing paragloboside (PG) on their membrane were readily lysed by C4-deficient guinea-pig serum (C4D-GPS) through activation of the alternative complement pathway (ACP). Therefore we examined the reactivity of several types of guinea-pig serum (GPS) on PG-liposomes and determined that all GPS except that from specific pathogen-free (SPF) Hartley guinea-pigs had lytic capacity in Mg-EGTA-GVB (gelatin veronal-buffered saline containing Mg++ and ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetate). This lytic capacity of GPS corresponded with the amount of natural antibody to PG in those sera. Although GPS of SPF guinea-pigs (SPF-GPS) could not lyse PG-liposomes in Mg-EGTA-GVB, it could lyse the liposomes when heated C4D-GPS or Hartley GPS was added. Natural antibody to PG in the heated sera was regarded to have sensitized PG-liposomes to lysis by SPF-GPS via ACP activation. Since the antibody to PG-liposomes was removed by lacto-N-nor-hexaosylceramide which has the same chemical structure in the terminal oligosaccharide, the antibody to PG in GPS was suggested to have a specificity to the terminal structure of oligosaccharide shared by lacto-N-nor-hexaosylceramide. Furthermore, the IgM fraction, which had been prepared by gel filtration of heated C4D-GPS on a Sephadex G200 column, could also sensitize PG-liposomes to lytic reaction of SPF-GPS in Mg-EGTA-GVB. This sensitizing capacity of heated C4D-GPS was suppressed by absorption of the serum or its IgM fraction with anti-guinea-pig mu-chain antibody coupled to Sepharose. Therefore, it was concluded that the lysis of PG-liposomes by GPS in Mg-EGTA-GVB was a result of ACP activation mediated by natural antibodies to PG of the IgM type which are present in usual GPS. This conclusion indicated that natural antibodies of the IgM type might play a role with ACP in host defence, especially in C4-deficient guinea-pigs where the classical complement pathway is impaired.

Animals↗