Neurological picture. Spinal endoscopic biopsy in the diagnosis of central nervous system neurosarcoidosis.
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Biopsy↗
Biomedical subjects
M Tanno
Publications and source records attributed to M Tanno.
Mirthful laughter differentially affects serum pro- and anti-inflammatory cytokine levels depending on the level of disease activity in patients with rheumatoid arthritis.
OBJECTIVES: To examine the effect of mirthful laughter in rheumatoid arthritis (RA), we evaluated the levels of serum cytokines before and after patients experienced mirthful laughter. METHODS: Forty-one patients with RA and 23 healthy subjects were enrolled. They listened to 'Rakugo', a traditional Japanese comic story, to induce mirthful laughter. We measured serum IL-6, IL-1beta, TNF-alpha, IL-4 and IL-1 receptor antagonist (IL-1Ra) concentrations before and after patients listened to the story. The RA subjects were divided into two groups. One was designated the 'difficult-to-control RA' group (CRP > or =1.0 mg/dl); The other group was regarded as the 'easily controlled RA' group (CRP <1.0 mg/dl). RESULTS: The basal levels of serum IL-6 and TNF-alpha in the RA patients were significantly higher than those in the healthy group. After experiencing mirthful laughter, the levels of serum IL-6 decreased significantly in the RA group but not in the healthy subjects. Interestingly, the level of serum TNF-alpha decreased only in the easily controlled RA group. Serum IL-4 concentration in the RA group was significantly higher than that in healthy subjects before the story. After the story, the level of serum IL-4 significantly decreased in the RA group, especially in the difficult-to-control RA group. In contrast, serum IL-1Ra concentration was statistically higher in the RA group than that in healthy subjects before the story, and a further increase was observed after the story, especially in the easily controlled RA group. CONCLUSIONS: Our findings suggest that mirthful laughter affects the levels of serum pro- and anti-inflammatory cytokines differentially, depending on the RA disease activity.
Adult↗
Uni-axial cyclic stretch induces Cbfa1 expression in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament.
Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To clarify this mechanism, we investigated the effects of in vitro cyclic stretch (120% peak to peak, at 0.5 Hz) on cultured spinal ligament cells derived from OPLL (OPLL cells) and non-OPLL (non-OPLL cells) patients. The mRNA expressions of Cbfa1 (an osteoblast-specific transcription factor), type I collagen, alkaline phosphatase (ALP), osteocalcin and integrin beta1 (a mechanotransducer) were increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. The effects of cyclic stretch on the spinal ligament tissues derived from OPLL and non-OPLL patients were also analyzed by immunohistochemistry using an antibody against Cbfa1. The expression of Cbfa1 was increased by cyclic stretch at the center of the spinal ligament tissues of OPLL patients, whereas no change was observed in the tissues of non-OPLL patients. Furthermore, U0126, a specific inhibitor of MAPK kinase (MEK), suppressed the stretch-induced mRNA expressions of Cbfa1, ALP and type I collagen in OPLL cells. These results suggest that in OPLL cells, mechanical stress is converted by integrin beta1 into intracellular signaling and that Cbfa1 is activated through the MAP kinase pathway. Therefore, we propose that mechanical stress plays a key role in the progression of OPLL through an increase in Cbfa1 expression.
Aged↗
Uniaxial cyclic stretch induces osteogenic differentiation and synthesis of bone morphogenetic proteins of spinal ligament cells derived from patients with ossification of the posterior longitudinal ligaments.
Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To elucidate this mechanism, we investigated the effects of in vitro sinusoidal cyclic stretch (120% peak to peak, at 1 Hz) on cultured spinal ligament cells derived from OPLL and non-OPLL patients. The mRNA expressions of alkaline phosphatase (ALP), osteopontin, bone morphogenetic protein (BMP)-2, BMP-4, and BMP receptors as well as ALP activity in cell layers and production of BMPs into the conditioned medium were significantly increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. A stretch-activated Ca(2+) channel blocker, Gd(3+), the voltage-dependent L-type Ca(2+) channel blockers diltiazem and nifedipine, and Ca(2+)-free medium suppressed stretch-induced ALP activity, which suggests a role of Ca(2+) influx in the signal transduction of mechanical stress to the osteogenic response of OPLL cells. Our study provides first evidences that mechanical stress plays a key role in the progression of OPLL through the induction of osteogenic differentiation in spinal ligament cells and the promotion of the autocrine/paracrine mechanism of BMPs in this lesion.
Alkaline Phosphatase↗
Contribution of both the sarcolemmal K(ATP) and mitochondrial K(ATP) channels to infarct size limitation by K(ATP) channel openers: differences from preconditioning in the role of sarcolemmal K(ATP) channels.
The roles of sarcolemmal ATP-sensitive K+ (sarcK(ATP)) and mitochondrial ATP-sensitive K+ (mitoK(ATP)) channels in the cardioprotection induced by K(ATP) channel openers remain unclear, though the mitoK(ATP) channel has been proposed to be involved as a subcellular mediator in cardioprotection afforded by ischemic preconditioning (PC). In the present study, selective inhibitors of the sarcK(ATP) and mitoK(ATP) channels were used to examine the role of each channel subtype in infarct size limitation by KATP channel openers. Isolated rabbit hearts were perfused in the Langendorff mode with monitoring of the activation recovery interval (ARI) and subjected to 30-min global ischemia/2-h reperfusion to induce infarction. Before ischemia, hearts received 10 microM pinacidil, 100 microM diazoxide, or PC with or without preceding infusion of a sarcK(ATP) channel-selective blocker (5 microM HMR1098) or a mitoK(ATP) channel-selective blocker (100 microM 5-hydroxydecanoate, 5-HD). ARI, an index of action potential duration, was shortened from 118+/-3 ms to 77+/-5 ms after 10 min of ischemia in untreated control hearts. Pinacidil shortened ARI before ischemia from 113+/-2 ms to 78+/-5 ms and enhanced the ARI shortening during ischemia. Diazoxide did not affect ARI before ischemia but accelerated ischemia-induced shortening of ARI. Infarct size as a percentage of the left ventricle (%IS/LV) was reduced by pinacidil and diazoxide from the control value of 47.2+/-4.0% to 4.5+/-1.5% and 5.2+/-1.2%, respectively. HMR1098 significantly inhibited the shortening of ARI by ischemia, pinacidil and diazoxide and partially blocked infarct size limitation by these K(ATP) channel openers (%IS/LV=32.6+/-4.2% and 23.4+/-5.3%, respectively). Infusion of 5-HD did not modify the change in ARI caused by the K(ATP) channel openers but completely abolished cardioprotection (%IS/LV=46.0+/-6.2% with pinacidil and 57.2+/-7.0% with diazoxide). PC with two episodes of 5-min ischemia limited %IS/LV to 21.6+/-4.0%, and this protection was not inhibited by HMR1098. Neither HMR1098 nor 5-HD alone modified infarct size. In conclusion, both sarcK(ATP) and mitoK(ATP) channels may contribute to the anti-infarct tolerance afforded by pinacidil and diazoxide.
Analysis of Variance↗
Critical timing of mitochondrial K(ATP) channel opening for enhancement of myocardial tolerance against infarction.
OBJECTIVE: The present study was designed to assess the relationship between the timing of a mitoK(ATP) channel opener, diazoxide, and its infarct size-limiting effect. METHODS: In isolated rabbit hearts, infarction was induced by 30 min of global ischemia and 2 h of reperfusion, and infarct size was determined by tetrazolium staining and expressed as a percentage of the left ventricle (%IS/LV). Diazoxide, a mitoK(ATP) channel selective opener, and/or 5-hydroxydecanoate (5-HD), a mitoK(ATP) channel blocker, were infused before or after the onset of ischemia. When these agents were infused during the ischemic period, they were dissolved in a hypoxic buffer at concentrations 10-fold higher than those in the pre-ischemic period, and the infusion rate was set at 2% of the pre-ischemic coronary flow. RESULTS: In untreated controls, %IS/LV was 53.2+/-4.1 (SE). Pretreatment with diazoxide (100 microM) with a 10-min washout period reduced %IS/LV to 7.8+/-2.4 and this protection was abolished by co-infusion of 5-HD (50 microM). Pre-ischemic infusion of diazoxide without a washout period reduced %IS/LV to 7.3+/-1.4, and infusion of diazoxide from 10 min after the onset of ischemia also limited %IS/LV to 14.9+/-4.6. However, diazoxide infusion from 25 min after the onset of ischemia failed to reduce infarct size (%IS/LV = 54.5+/-7.2). Furthermore, pretreatment with 5-HD (50 microM) also completely abolished the protection afforded by early post-ischemic diazoxide infusion (%IS/LV = 48.3+/-6.5). Neither infusion of 5-HD nor the anoxic vehicle alone during ischemia modified %IS/LV. CONCLUSION: These findings suggest that opening of mitoK(ATP) channels before ischemia and during early ischemia, but not that upon reperfusion, is important for enhancement of myocardial tolerance against infarction.
Animals↗
Age-related changes in cortical and trabecular bone mineral status. A quantitative CT study in lumbar vertebrae.
PURPOSE: To investigate the age and sex dependence of the bone mineral status of human lumbar vertebrae with special regard to differences between cortical and trabecular bone. MATERIAL AND METHODS: The study group comprised 125 normal Japanese healthy volunteers (54 males and 71 females), and was subdivided into adult male and female groups (subjects younger than 40 years), intermediate male and female groups (ages ranging between 41 and 64 years) and old male and female groups (subjects older than 65 years). The cortical bone mineral status was estimated using a single-energy quantitative CT (SE-QCT) technique, whereas trabecular bone mineral density (BMD) was estimated using a dual-energy (DE-QCT) technique. RESULTS: A considerable gender difference in the age-related cortical bone status was found. There was a significant reduction of the mean values of the cortical volume and BMD in the old female group compared with those obtained in the old male group. CONCLUSION: The results suggest that in men, cortical and trabecular bone volume decrease very little with age. In women, cortical volume and BMD and trabecular BMD decrease with age while trabecular bone volume does not. The study showed that all variables had higher values in men than in women and that the difference increased with age.
Adult↗
Changes in liver fatty acid unsaturation after partial hepatectomy in the rat.
The purpose of this study was to assess changes in the degree of fatty acid unsaturation in rat liver after partial hepatectomy. This is the first study in which liver fatty acid unsaturation has been analyzed over a long period of regeneration until day 28 after operation. The relationship between changes in unsaturation and fatty acid composition in the regenerating liver were also investigated in this study. Proton nuclear magnetic resonance spectroscopy revealed significantly elevated levels of unsaturation with a maximum on day 5 after partial hepatectomy, compared with untreated controls (11.72+/-0.55 vs. 11.05+/-0.26%, P < 0.05). No significant changes in unsaturation were found in day 1 regenerating liver, which is rich in absolute amounts of fatty acids. Based on gas-liquid chromatography, the relative amounts of oleic acid (18:1n-9) and linoleic acid (LA; 18:2n-6) were increased, while polyunsaturated fatty acids such as arachidonic acid (20:4n-6) and docosahexaenoic acid (DHA; 22:6n-3) were decreased on day 1. On the other hand, on day 5 of regeneration, while most fatty acids were returning to their preoperative control levels, only DHA was higher than the control value (7.69+/-0.58 vs. 5.57+/-0.37%, P < 0.001). The high levels of unsaturation on day 5 were found to be partly due to the increase in DHA. The findings suggest that some significant signals are transmitted during the regeneration process owing to alterations in the membrane structure by the high levels of fatty acid unsaturation and the increase in DHA levels on day 5 after partial hepatectomy.
Animals↗
Infarct size limitation by bradykinin receptor activation is mediated by the mitochondrial but not by the sarcolemmal K(ATP) channel.
Earlier studies have shown that activation of bradykinin B2 receptor triggers protein kinase C (PKC)-mediated cardioprotective mechanism in ischemic preconditioning (PC). In the present study, we examined whether the effector in this B2-receptor triggered pathway of PC is the ATP sensitive potassium (K(ATP)) channel in the mitochondria (mito-K(ATP) channel) or K(ATP) channel in the sarcolemma (sarc-K(ATP) channel). Isolated rabbit hearts were perfused with modified Krebs-Henseleit buffer in a Langendorff mode, and regional myocardial ischemia was induced by occluding a left coronary artery for 30 min and then reperfusing for 2 hours. Infarct size was determined by triphenyltetrazolium chloride staining and expressed as a percentage of area at risk (% IS/AR). Infusion of bradykinin (500 nmol/L) for 15 min prior to ischemia significantly reduced % IS/AR from 37.4 +/- 2.9 (SE) of the untreated controls to 12.0 +/- 3.3%. This protective effect of bradykinin was completely abolished by coinfusion of 5-hydroxydecanoate (5-HD, 50 micromol/L), a selective mito-K(ATP) channel blocker (% IS/AR = 44.2 +/- 6.4). In contrast, a high dose of HMR1098 (20 micromol/L), which is a newly developed sarc-K(ATP) channel selective blocker with IC50 of 0.6 micromol/L, failed to modify the infarct size limitation by preischemic infusion of bradykinin (% IS/AR = 11.7 +/- 3.4). Neither 5-HD nor HMR1098 alone modified infarct size (% IS/AR = 37.8 +/- 3.8 and 35.1 +/- 6.2, respectively). These results suggest that opening of the mito-K(ATP) channel but not the sarc-K(ATP) channel is involved in infarct size limitation by a mechanism triggered by bradykinin B2 receptor activation.
Analysis of Variance↗
Roles of tyrosine kinase and protein kinase C in infarct size limitation by repetitive ischemic preconditioning in the rat.
In this study, we examined the possibility that infarct-size limitation by repetitive preconditioning (PC) is achieved by activation of both protein kinase C (PKC) and tyrosine kinase. In addition, we assessed whether such kinase activation is triggered by angiotensin II type 1 (AT1) and alpha1-adrenergic receptors and whether sarcolemmal and mitochondrial adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channels play roles as effectors of cardioprotection in the rat. Under pentobarbital anesthesia, myocardial infarction was induced by 20-min coronary occlusion and 3-h reperfusion in the rat. Infarct size was determined by tetrazolium and expressed as a percentage of area at risk (%IS/AR). PC with one cycle of 5-min ischemia/5-min reperfusion before 20-min ischemia significantly reduced %IS/AR from the control value of 49.4 +/- 2.0 to 35.4 +/- 2.8, and repetitive PC with two cycles of 5-min ischemia/5-min reperfusion further limited %IS/AR to 3.2 +/-0.9. Infarct-size limitation by single-cycle PC was completely abolished by a PKC inhibitor, staurosporine (100 microg/kg; %IS/ AR, 45.7 +/- 5.0). In contrast, the cardioprotection by repetitive PC was only partially blocked by staurosporine (%IS/AR, 19.8 +/- 2.4), another PKC inhibitor, polymyxin B (5 mg/kg; %IS/AR, 16.2 +/- 3.1), or a tyrosine kinase inhibitor, genistein (5 mg/kg; %IS/AR, 21.8 +/- 1.4). However, a combined injection of genistein and staurosporine additively inhibited protection of repetitive PC (%IS/AR, 36.4 +/- 1.7). Staurosporine, polymyxin B, or genistein alone did not modify %IS/AR in nonpreconditioned rat hearts. Infarct-size limitation by repetitive PC was not attenuated by pretreatment with a selective AT1-receptor blocker (CV11974, 10 mg/kg), prazosin (0.6 mg/kg; %IS/AR, 6.4 +/- 3.2 and 1.6 +/- 0.5, respectively). A selective blocker of mitochondrial K(ATP) channels, 5-hydroxydecanoate (3 mg/kg), completely abolished the cardioprotective effect (%IS/AR, 50.8 +/-3.5), but HMR1883 (3 mg/kg), a selective blocker of sarcolemmal K(ATP) channels, failed to inhibit the preconditioning effect (%IS/AR, 4.4 +/- 0.7). These findings suggest that repetition of PC provokes activation of both PKC and tyrosine kinase, leading to enhanced antiinfarct tolerance by opening of mitochondrial but not sarcolemmal K(ATP) channels. It is unlikely that activation of either AT1 or alpha1-adrenergic receptor alone is crucial to trigger preconditioning. Key Words: Tyrosine kinase-Genistein-Angiotensin II-alpha1-Adrenergic receptor-Sarcolemmal K(ATP) channel-Mitochondrial K(ATP) channel.
Analysis of Variance↗
[Nitric oxide (NO) donor].
Nitric oxide (NO), which is synthesized from L-arginine by nitric oxide synthase (NOS) in mammals, acts as a signal molecule for vasorelaxation, cytotoxicity and neurotransmission. The difficulty in handling of a gaseous and labile NO causes problems with the effective and precise studies using NO. The increasing interest in the biological roles of NO requires the use of NO donors which releases NO under the various desirable conditions. We systematized the most commonly used NO donors in this article to support the biological investigation. NO donors were classified according to the functional groups based on NO-donating characteristics. The preparation, chemical properties and NO-donating ability of these NO donors are summarized. It is particularly described in some detail on the stability both as a solid and in solution and the handling of the compounds.
Animals↗
Role of the monocarboxylic acid transport system in the intestinal absorption of an orally active beta-lactam prodrug: carindacillin as a model.
Transport of carbenicillin (CBPC) and its orally active prodrug (carindacillin, CIPC) was studied with rat intestinal brush border membrane vesicles (BBMV). CIPC was transported uphill into BBMV in the presence of a H(+) gradient, indicating that CIPC absorption is carrier-mediated. Indeed, CIPC was predominantly transported by the monocarboxylic acid transport system, although it might be possible that CIPC possesses some affinity to the oligopeptide transporter. In contrast, CBPC exhibited no affinity to either the oligopeptide or the monocarboxylic acid transport system. Apparent uptake clearance of CIPC was approximately 70-fold greater than that of CBPC. It was clarified that the modification of the chemical structure of CBPC (a dicarboxylic acid) to CIPC (a monocarboxylic acid) by ester formation may have resulted in the increased affinity to the monocarboxylic acid transport system, which, in turn, led to improved absorption of the prodrug.
Algorithms↗
Proliferating cell nuclear antigen in normal and regenerating rat livers.
Immunohistochemical analysis using proliferating cell nuclear antigen (PCNA) antibody shows a negligible number of cells stained in normal liver, but much higher numbers in regenerating liver 24 and 48 h after surgery. We also verified different results by biochemical analysis. Two forms of PCNA, L type (eluted at low concentrations of KCl from a phosphocellulose column) and H type (eluted at high KCl concentrations), were observed in the nucleoplasm of regenerating livers 24 and 48 h after surgery. Treatment of the H type fraction with nuclease caused the H type to disappear and the amount of L type to increase. PCNAs in the cytoplasm are P type (eluted in the pass through fraction) and L type. Surprisingly, the total amounts of P type and L type in cytoplasmic extracts are comparable to those of L type and H type in the nucleoplasm. These results suggest that newly synthesized PCNA is immediately converted into the P and L complex forms. The P type and some of the L type that lacks a nuclear localization signal remain in the cytoplasm; the rest of the L type with a nuclear localization signal is transferred into the nuclei. Then, some of the L type in the nucleoplasm forms the H type, which binds to DNA. These three types of PCNA are also found in significant amounts in the nucleoplasm and cytoplasm of normal rat liver despite its nonproliferating state.
Animals↗
Time window for the contribution of the delta-opioid receptor to cardioprotection by ischemic preconditioning in the rat heart.
The present study aimed to examine (1) whether the role of the opioid receptor in ischemic preconditioning (PC) is consistent regardless of the duration of ischemic insult and (2) which opioid receptor subtype contributes to PC. In the first series of experiments, the effects of PC, a nonselective opioid receptor antagonist (naloxone), and their combination on the infarct size after various durations of ischemia were assessed. In anesthetized, open-chest rats, the coronary artery was occluded for 20, 30, or 40 minutes to induce infarction and was reperfused for 3 hours, PC was performed with two cycles of 5-minute ischemia followed by 5-minute reperfusion before the sustained ischemia. At 25 minutes before the ischemia, naloxone was injected alone or in combination with subsequent PC. Infarct size was determined by tetrazolium staining and was expressed as a percentage of the risk area size (%IS/RA). In the second series of experiments, the effects of a delta-receptor-selective antagonist, naltrindole (NTI), and a kappa-receptor selective antagonist, nor-binaltrophimine (nor-BNI), on PC before 30-minute coronary occlusion were assessed. In untreated controls, %IS/RA was 53.1 +/- 3.2 after 20 minutes, 67.9 +/- 3.9 after 30 minutes, and 87.8 +/- 2.0 after 40 minutes of ischemia, respectively. PC significantly reduced %IS/RA after 20, 30, and 40 minutes of ischemia to 3.1 +/- 0.8, 12.8 +/- 1.1, and 42.1 +/- 4.3, respectively (P < 0.05 vs. each control). Naloxone (6 mg/kg) partially attenuated the protection afforded by PC when the sustained ischemia was 30 minutes (%IS/RA = 27.4 +/- 4.5; P < 0.05 vs. PC), but this inhibitory effect of naloxone was not detected when the duration of the ischemia was 20 or 40 minutes. NTI (10 mg/kg) also attenuated infarct size limitation by PC after 30 minutes of ischemia (%IS/RA = 25.6 +/- 3.7), but nor-BNI (10 mg/kg) failed to modify infarct size limitation by PC (%IS/RA = 13.3 +/- 3.2). The present results suggest that activation of the opioid delta-receptor partly contributes to preconditioning against infarction in the rat and that there may be a time window (at around 30 minutes after the onset of ischemia) for this opioid receptor-mediated protective mechanism.
Animals↗
[Evaluation of epidural blood patch in the treatment of two cases of spontaneous intracranial hypotension].
We evaluated the effect of epidural blood patch (EBP) in the treatment of two cases of spontaneous intracranial hypotension (SIH). Both case 1 (53-year old female) and case 2 (44-year old female) had severe postural headache and showed meningeal thickening by cranial MRI, and were diagnosed as SIH. Case 1: Although her intracranial pressure remained within normal ranges, an extradural leakage was shown in the middle thoracic region on isotope cisternography using indium-111 labeled DTPA. She underwent epidural blood patch with autologous blood at Th 6-7 level twice (10 ml and 15 ml, respectively) but without remarkable pain relief. Case 2: Her intracranial pressure was low (0 mmH2O on supine position), but, isotope cisternography using DTPA showed only the early appearance of isotope in the bladder but failed to disclose the site of the CSF leak. Epidural blood patch with 30 ml of autologous blood was performed at Th 12-L 1 level which only resulted in severe backache without clinical improvement. In conclusion, we could not find the effectiveness of EBP on the two cases of SIH, although there are many reports on its efficacy.
Adult↗
Characterization of the cytotoxic activity of nitric oxide generating N-nitroso compounds.
The NO-generating abilities of aromatic N-nitroso compounds (nitrosoureas, nitrosamides and nitrosamines), and N-acetyl-S-nitroso-DL-penicillamine at ambient temperature were compared by employing the Griess reaction. 3,3-Dibenzyl-1-(4-tolyl)-1-nitrosourea showed the greatest NO-generating ability among the tested compounds. The NO-generating ability of the aromatic N-nitrosoureas and N-nitrosamides was greater than that of the N-nitrosamines, presumably reflecting differences in electrostatic repulsion between the carbonyl oxygen and nitroso oxygen in these compounds. In addition, a conjugative effect between the aromatic ring carbon and neighboring nitrogen influences the NO-generating ability; the conjugative effect in the case of N-nitrosoureas and N-nitrosamides having an ortho-alkyl substituted aromatic ring, or N-nitrosamines having a bulky N-group, such as tert-butyl, is decreased by an increase in steric hindrance around the nitroso group. The N-NO bond then becomes more stable. The NO-generating ability was related to the reciprocal of the ID50 value for growth inhibition of cultured L-5178 Y cells by the aromatic N-nitroso compounds. On the other hand, NO production from the aliphatic N-nitroso compounds was not observed under our conditions, and these N-nitroso compounds did not show effective cytotoxic activity.
Animals↗
[Study of N-nitroso compounds which have NO-release ability].
Nitric oxide (NO), which plays an important role in the vital functions of organisms, is gaseous and labile molecule. Much attention has been paid to the stability and easily handling of NO donors, for careful handling of NO is required during experimental work. We synthesized a series of aromatic N-nitrosoureas and N-nitrosamides which efficiently liberates NO at room temperature. Generation of NO from the aromatic N-nitroso compounds was chemically confirmed by the trapping of NO as a nitrosyl complex of tetraphenylporphyrinatocobalt (II) and spectrophotometrically quantified by means of the Griess reaction using a newly designed test apparatus. 3,3-Dibenzyl-1-(4-tolyl)-1-nitrosourea showed the greatest NO-generating ability among the synthesized N-nitroso compounds. Further, the NO-generating ability was related to the reciprocal of the ID50 value for growth inhibition of cultured L-5178Y cell by the aromatic N-nitroso compounds.
Cell Division↗
Age-related changes in proliferating cell nuclear antigen levels.
To clarify the effect of aging on rat liver regeneration, we compared proliferating cell nuclear antigen (PCNA) levels in control and regenerating livers from young and aged rats 48 h after partial hepatectomy. The nucleoplasm and cytoplasm from regenerating livers of 2-month and 24 month-old rats were fractionated by phosphocellulose column chromatography, aliquots of fractions were transferred to nitrocellulose filters and the amounts of PCNA in each fraction were measured by an immunostaining method. Two forms of PCNA, L type (eluted at low concentrations of KC1) and H type (eluted at high KC1 concentrations) were observed in the nucleoplasm from both control and regenerating young rat liver. On the other hand, the cytoplasm contained P type (eluted in the pass-through fraction), L type and H type PCNA. In control liver from aged rats, three types of PCNA in the cytoplasm and two types in the nucleoplasm were present at decreased levels. In regenerating liver from young rats, the increases in L type in the cytoplasm and H type in the nucleoplasm were remarkable. However, none of the three PCNA types increased significantly during liver regeneration in aged rats. Treatment with DNase resulted in the disappearance of the H type with a concomitant increase in the P and L types. These results suggest that the H type is a complex form consisting of the P and L types of PCNA and DNA. These results suggest that the increase in the L type in the cytoplasm reflects newly synthesized PCNA production for cellular proliferation and that the increase in the H type in the nucleoplasm is a reflection of binding to DNA and the fundamental role of PCNA itself in liver regeneration in young rats. On the other hand, there was little increase in any of the three types in regenerating liver from 24-month-old rats. Thus, PCNA content may be closely related to the decrease in the rate of cellular proliferation in aged animals.
Aging↗