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Sato Y, Hong SK, Tagiri A, Kitano H, Yamamoto N, Nagato Y, Matsuoka M. A rice homeobox gene, OSH1, is expressed before organ differentiation in a specific region during early embryogenesis. Proc Natl Acad Sci U S A 1996; 93:8117-22. [PMID: 8755613 PMCID: PMC38885 DOI: 10.1073/pnas.93.15.8117] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Homeobox genes encode a large family of homeodomain proteins that play a key role in the pattern formation of animal embryos. By analogy, homeobox genes in plants are thought to mediate important processes in their embryogenesis, but there is very little evidence to support this notion. Here we described the temporal and spatial expression patterns of a rice homeobox gene, OSH1, during rice embryogenesis. In situ hybridization analysis revealed that in the wild-type embryo, OSH1 was first expressed at the globular stage, much earlier than organogenesis started, in a ventral region where shoot apical meristem and epiblast would later develop. This localized expression of OSH1 indicates that the cellular differentiation has already occurred at this stage. At later stages after organogenesis had initiated, OSH1 expression was observed in shoot apical meristem [except in the L1 (tunica) layer], epiblast, radicle, and their intervening tissues in descending strength of expression level with embryonic maturation. We also performed in situ hybridization analysis with a rice organless embryo mutant, orl1, that develops no embryonic organs. In the orl1 embryo, the expression pattern of OSH1 was the same as that in the wild-type embryo in spite of the lack of embryonic organs. This shows that OSH1 is not directly associated with organ differentiation, but may be related to a regulatory process before or independent of the organ determination. The results described here strongly suggest that, like animal homeobox genes, OSH1 plays an important role in regionalization of cell identity during early embryogenesis.
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102
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Kim HJ, Na HS, Nam HJ, Park KA, Hong SK, Kang BS. Sprouting of sympathetic nerve fibers into the dorsal root ganglion following peripheral nerve injury depends on the injury site. Neurosci Lett 1996; 212:191-4. [PMID: 8843105 DOI: 10.1016/0304-3940(96)12811-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Peripheral nerve injury often induces sympathetic nerve fiber sprouting in the dorsal root ganglion (DRG) and injured nerve. Presently, the underlying mechanism and functional significance of the sprouting are unknown. This study was performed to see whether the degree of the sprouting in the DRG was a function of the distance between the DRG and injury site. To this aim, we compared two groups of rats with respect to the sympathetic nerve fibers sprouting in the S1-3 DRG; one group was subjected to unilateral inferior and superior caudal trunk transections at the level between the S3 and S4 spinal nerves (S34 group) and the other group at the levels between the S1 and S2, between S2 and S3 and between S3 and S4 spinal nerves (S123 group). The transections in both groups equally eliminated the inputs from the tail to the S1-3 DRG, but the distance from the S1/S2 DRG to the injury site was different between the two groups. Immunohistochemical staining with tyrosine hydroxylase (TH) antibody of the S1-3 DRG removed from rats a week after the injury revealed that the degree of penetration of TH-positive fibers into the S1 and S2 DRG was much more extensive in the S123 group than in the S34 group, whereas that into the S3 DRG was not significantly different between the two groups. These results suggest that the extent of the sympathetic nerve fiber sprouting in the DRG following peripheral nerve injury is inversely related to the distance between the DRG and injury site.
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103
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Na HS, Kim YI, Yoon YW, Han HC, Nahm SH, Hong SK. Ventricular premature beat-driven intermittent restoration of coronary blood flow reduces the incidence of reperfusion-induced ventricular fibrillation in a cat model of regional ischemia. Am Heart J 1996; 132:78-83. [PMID: 8701879 DOI: 10.1016/s0002-8703(96)90393-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
With a cat model of regional cardiac ischemia, we examined whether the incidence of reperfusion-induced ventricular fibrillation (VF) could be reduced by ventricular premature beat (VPB)-driven intermittent reperfusion. In addition, we assessed whether the effect of the intermittent reperfusion was comparable with that of ischemic preconditioning in suppressing the VF. Of 15 cats subjected to uninterrupted reperfusion after 20-minute occlusion of the left anterior descending coronary artery, 13 (86.70%) had VF, whereas only 1 (7.1%) of 14 cats subjected to the VPB-driven intermittent reperfusion had VF. This incidence of VF was significantly lower than that of the animal group subjected to uninterrupted reperfusion. However, it was not statistically different from that (3 of 15) of the group subjected to a 10-minute episode of the coronary artery occlusion before the 20-minute occlusion (i.e., "ischermic preconditioning"). Our results suggest that the VPB-driven intermittent reperfusion (i.e., "postconditioning") is very effective in preventing reperfusion-induced VF and as good as, if not better than, ischemic preconditioning.
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104
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Abstract
It is unclear how embryo size is genetically regulated in plants. Since cereals have a large persisting endosperm, it is expected that embryo size is affected by endosperm development. Nine single recessive mutations, four reduced embryo mutations representing three loci, REDUCED EMBRYO1, REDUCED EMBRYO2 and REDUCED EMBRYO3, four giant embryo mutations derived from a single locus GIANT EMBRYO, and one endospermless mutation endospermless1-2 were analyzed. Every reduced embryo mutation caused reduction of all the embryonic organs including apical meristems and the enlargement of the endosperm. The giant embryo mutants have a reduced endosperm and an enlarged scutellum. However, shoot and radicle sizes were not affected. All the reduced embryo and giant embryo mutations did not largely affect postembryonic development. Accordingly, the expression of genes analyzed are seed-specific. In reduced embryo and giant embryo mutations, abnormalities were detected in both embryo and endosperm as early as 2 days after pollination. endospermless1-1 resulted in an early loss of endosperm, yielding a giant embryo, suggesting that embryo growth was physically limited by the endosperm. A double mutant between giant embryo-2 and club-shaped embryo1-1, which has a normal endosperm and a minute undifferentiated embryo, resulted in a club-shaped embryo1-1 embryo and a reduced endosperm of giant embryo-2, indicating that GIANT EMBRYO regulates the endosperm development. Double mutants between giant embryo-2 and three reduced embryo mutants exhibited the reduced embryo phenotype in both embryo and endosperm, suggesting that reduced embryo mutations cause the enlarged endosperm. Further, a double mutant of reduced embryo3 and endospermless1-1 showed the enlarged embryo in endospermless seed. This confirms that reduced embryo3 does not regulate embryo size but enlarges endosperm size. Together with the results of the other double mutant analysis, REDUCED EMBRYO1, REDUCED EMBRYO2, REDUCED EMBRYO3 and GIANT EMBRYO are concluded to regulate endosperm development.
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105
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Hong SK, Anestis DK, Hawco NM, Valentovic MA, Brown PI, Rankin GO. Nephrotoxicity of N-(3-bromophenyl)-2-hydroxysuccinimide: role of halogen groups in the nephrotoxic potential of N-(halophenyl) succinimides. Toxicology 1996; 110:17-25. [PMID: 8658556 DOI: 10.1016/0300-483x(96)03328-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Among N-(halophenyl)succinimides. N-(3,5-dichlorophenyl)succinimide (NDPS) is a potent nephrotoxicant as well as an agricultural fungicide. Although two chloride groups on the phenyl ring are essential to induce optimal nephrotoxicity, the role of halogen groups in NDPS nephrotoxicity is not clear. In this study, N-(3-bromophenyl)-2-hydroxysuccinimide (NBPHS) was prepared as a monohalophenyl derivative of N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS), an oxidative and nephrotoxicant metabolite of NDPS. The nephrotoxic potential of NBPHS was evaluated in vivo and in vitro to determine the role of halogen groups in N-(halophenyl)succinimide nephrotoxicity. Male Fischer 344 rats (four/group) were administered a single intraperitoneal (i.p.) injection of NBPHS (0.1, 0.4 or 0.8 mmol/kg) or vehicle (25% dimethyl sulfoxide in sesame oil) and renal function monitored for 48 h. Administration of NBPHS (0.8 mmol/kg) induced nephrotoxicity, while very mild changes or no changes in renal function were observed following administration of 0.4 mmol/kg or 0.1 mmol/kg of NBPHS, respectively. Nephrotoxicity induced by NBPHS (0.8 mmol/kg) was characterized by diuresis, transiently increased proteinuria, glucosuria and hematuria elevated kidney weight and reduced tetraethylammonium (TEA) uptake by renal cortical slices, and was not as marked as nephrotoxicity induced by NDHS (0.1 mmol/kg) or NDPS (0.4 mmol/kg). In the in vitro studies the effects of NBPHS on organic ion accumulation, pyruvate-stimulated gluconeogenesis, and lactate dehydrogenase (LDH) release were measured using renal cortical slices. NBPHS decreased p-aminohippurate (PAH) and TEA accumulation at NBPHS bath concentrations of 0.05 mM and 0.5 mM and 0.5 mM or greater, respectively. Renal gluconeogenesis was inhibited by NBPHS at 1 mM bath concentration, while LDH leakage was not increased at NBPHS bath concentrations up to 1 mM. The results demonstrate that NBPHS is a mild nephrotoxicant in vivo and in vitro, but does not have cytotoxic effects to renal tissues at the concentrations tested. From these results, it appears that halogen groups are essential to the nephrotoxic potential of N-(halophenyl)-2-hydroxysuccinimides or N-(halophenyl)succinimides and play an important role in the mechanism of NDPS nephrotoxicity following NDHS formation.
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106
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Hong SK, Valentovic MA, Anestis DK, Ball JG, Brown PI, Rankin GO. Nephrotoxicity of 4-amino-2-chlorophenol and 2-amino-4-chlorophenol in the Fischer 344 rat. Toxicology 1996; 110:47-58. [PMID: 8658559 DOI: 10.1016/0300-483x(96)03327-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aminophenols and halogenated anilines induce nephrotoxicity and mild hepatotoxicity in rats. In this study, the in vivo and in vitro nephrotoxic potential of 4-amino-2-chlorophenol and 2-amino-4-chlorophenol, monochlorinated aminophenols and potential metabolites of 3-chloroaniline, was evaluated. Hepatotoxicity of both compounds was also examined in vivo. Male Fischer 344 rats (four/group) were administered 4-amino-2-chlorophenol hydrochloride (0.4, 0.8 or 1.0 mmol/kg), 2-amino-4-chlorophenol hydrochloride (0.4, 0.8 or 1.2 mmol/kg) or vehicle intraperitoneally (i.p.) and renal and hepatic function monitored for 48 h. Administration of 4-amino-2-chlorophenol (0.8 mmol/kg) induced nephrotoxicity, while only minor changes in kidney function were observed following administration of 0.4 mmol/kg of 4-amino-2-chlorophenol or 0.8 mmol/kg of 2-amino-4-chlorophenol. Increasing the dose of 4-amino-2-chlorophenol to 1.0 mmol/kg or 2-amino-4-chlorophenol to 1.2 mmol/kg resulted in lethality. Nephrotoxicity induced by 4-amino-2-chlorophenol was characterized by diuresis, increased proteinuria, glucosuria, hematuria, elevated blood urea nitrogen (BUN) concentration and kidney weight, and marked proximal tubular damage, while 2-amino-4-chlorophenol induced milder effects on renal function and transient oliguria instead of diuresis. No hepatotoxicity was observed with either compound at any dose tested. In the in vitro studies, the direct effects of 4-amino-2-chlorophenol or 2-amino-4-chlorophenol on organic ion accumulation, pyruvate-stimulated gluconeogenesis and lactate dehydrogenase (LDH) leakage were determined using renal cortical slices. 4-Amino-2-chlorophenol and 2-amino-4-chlorophenol were almost equally effective in inhibiting organic anion or cation uptake and gluconeogenesis or increasing LDH leakage, although small differences in the minimum effective concentrations were present (minimum effective concentration, 0.01-0.5 mM range). These results demonstrate that 4-amino-2-chlorophenol is a more potent nephrotoxicant than 2-amino-4-chlorophenol in vivo. The results also indicate that the addition of a chloride group to aminophenols enhances renal toxicity.
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107
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Lomovskaya N, Hong SK, Kim SU, Fonstein L, Furuya K, Hutchinson RC. The Streptomyces peucetius drrC gene encodes a UvrA-like protein involved in daunorubicin resistance and production. J Bacteriol 1996; 178:3238-45. [PMID: 8655504 PMCID: PMC178076 DOI: 10.1128/jb.178.11.3238-3245.1996] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The drrC gene, cloned from the daunorubicin (DNR)- and doxorubicin-producing strain of Streptomyces peucetius ATCC 29050, encodes a 764-amino-acid protein with a strong sequence similarity to the Escherichia coli and Micrococcus luteus UvrA proteins involved in excision repair of DNA. Expression of drrC was correlated with the timing of DNR production in the growth medium tested and was not dependent on the presence of DNR. Since introduction of drrC into Streptomyces lividans imparted a DNR resistance phenotype, this gene is believed to be a DNR resistance gene. The drrC gene could be disrupted in the non-DNR-producing S. peucetius dnrJ mutant but not in the wild-type strain, and the resulting dnrJ drrC double mutant was significantly more sensitive to DNR in efficiency-of-plating experiments. Expression of drrC in an E. coli uvrA strain conferred significant DNR resistance to this highly DNR-sensitive mutant. However, the DrrC protein did not complement the uvrA mutation to protect the mutant from the lethal effects of UV or mitomycin even though it enhanced the UV resistance of a uvrA+ strain. We speculate that the DrrC protein mediates a novel type of DNR resistance, possibly different from the mechanism of DNR resistance governed by the S. peucetius drrAB genes, which are believed to encode a DNR antiporter.
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108
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Rankin GO, Beers KW, Nicoll DW, Anestis DK, Hong SK, Hubbard JL, Ball JG, Valentovic MA, Brown PI. Nephrotoxic potential of 2-amino-5-chlorophenol and 4-amino-3-chlorophenol in Fischer 344 rats: comparisons with 2- and 4-chloroaniline and 2- and 4-aminophenol. Toxicology 1996; 108:109-23. [PMID: 8644109 DOI: 10.1016/0300-483x(95)03294-p] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nephrotoxicity occurs following intraperitoneal (i.p.) administration of 2-chloroaniline or 4-chloroaniline hydrochloride to Fischer 344 rats, but the nephrotoxicant chemical species and mechanism of nephrotoxicity are unknown. The purpose of this study was to evaluate the in vivo and in vitro nephrotoxic potential of 2-amino-5-chlorophenol and 4-amino-3-chlorophenol, metabolites of 4-chloroaniline and 2-chloroaniline. A comparison was also made between the nephrotoxic potential of the aminochlorophenols and the corresponding aminophenols to examine the effect of adding a chloride group on the nephrotoxic potential of the animophenols. Male Fischer 344 rats (4/group) were given an i.p. injection of a chloroaniline or aminochlorophenol hydrochloride (1.5 mmol/kg), and aminophenol (1.0 or 1.5 mmol/kg), or vehicle, and renal function monitored at 24 and 48 h. Both aminochlorophenols induced smaller and fewer renal effects that the parent chloroanilenes in vivo. Also, 4-aminophenol was markedly more potent as a nephrotoxicant that 4-amino-3-chlorophenol, while 2-aminophenol and 2-amino-5-chlorophenol induced only mild change in renal function. In vitro, the phenolic compounds reduce p-aminohippurate accumulation by renal cortical slices at bath concentrations of 0.01 mM, while a bath concentration of 0.50 mM or greater was required for the chloroanilines. However, all compounds reduced tetraethylammonium accumulation at bath concentrations of 0.1-0.5 mM or greater. These results indicate that extrarenally-produced aminochlorophenol metabolites do not contribute to the mechanism of chloroaniline nephrotoxicity. Also, the reduced nephrotoxic potential of 4-amino-3-chlorophenol compared to 4-aminophenol could result from an altered ability of the aminochlorophenol to redox cycle or form conjugates.
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109
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Lee KU, Park JY, Hwang IR, Hong SK, Kim GS, Moon DH, Kim SB, Park JS. Glomerular hyperfiltration in Koreans with non-insulin-dependent diabetes mellitus. Am J Kidney Dis 1995; 26:722-6. [PMID: 7485123 DOI: 10.1016/0272-6386(95)90434-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glomerular hyperfiltration (GHF) may play an important role in the pathogenesis of diabetic nephropathy. The prevalence of GHF in non-insulin-dependent diabetes mellitus (NIDDM) is reported to vary in different populations, ranging from 35% in black Americans with new-onset diabetes to less than 5% in whites. We measured glomerular filtration rate (GFR) by 51Cr-EDTA clearance methods in 284 Korean NIDDM patients without overt nephropathy. Glomerular hyperfiltration (defined as GFR > 140 mL/min/1.73 m2) was found in 25% (71 of 284) of the patients. Thirty percent and 15% of the patients with known duration of diabetes less than 5 years and more than 10 years, respectively, showed GHF. Microalbuminuria (defined as urinary albumin excretion rate 20 to 200 micrograms/min) was found in 23% (64 of 284) of the patients. The mean GFR of the microalbuminuric patients was not significantly different from that of the normoalbuminuric patients (121.5 +/- 30.1 mL/min/1.73 m2 v 124.9 +/- 26.4 mL/min/1.73 m2; P = NS). However, when the patients with microalbuminuria were divided according to the presence or absence of retinopathy, the microalbuminuric patients with retinopathy had a lower GFR compared with the microalbuminuric patients without retinopathy (109.6 +/- 35.5 mL/min/1.73 m2 v 130.0 +/- 26.3 mL/min/1.73 m2; P < 0.01). These results show that the prevalence of GHF in Korean NIDDM patients without overt nephropathy is higher than that reported in whites and that it is similar to that in black Americans. The high prevalence of GHF in Korean NIDDM patients may contribute to the relatively higher prevalence of clinical diabetic nephropathy in this population.
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110
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Kim YI, Na HS, Yoon YW, Nahm SH, Ko KH, Hong SK. Mechanical allodynia is more strongly manifested in older rats in an experimental model of peripheral neuropathy. Neurosci Lett 1995; 199:158-60. [PMID: 8584248 DOI: 10.1016/0304-3940(95)12038-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Partial peripheral nerve injury often leads to chronic neuropathic pain characterized by symptoms such as allodynia. In the present study, employing a rat model of experimental neuropathy produced by partial denervation of the tail, we examined whether peripheral nerve injury-induced mechanical and thermal allodynia were affected by the animal's age at the time of the injury. The motive of this study was the demonstration in other neuropathy models of the age effects on the manifestation of neuropathic pain symptoms following partial peripheral nerve injury. We compared two groups of young (n = 23, 7-8 weeks old, 150-200 g) and old rats (n = 14, 16-18 months old, 550-800 g). We found that the older rats exhibited more vigorously the behavioral signs of mechanical allodynia during the first week after the nerve injury. With respect to thermal (cold or warm) allodynia, however, we detected no significant difference between young and old rat groups. The results of the present study, as those of previous studies, support the idea that the age at the time of partial peripheral nerve injury affects the severity of certain neuropathic pain symptoms appearing after the injury. However, the present results argue against the suggestion from previous studies that younger subjects are more vulnerable to partial peripheral nerve injury-induced neuropathic pain symptoms.
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111
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Smith MA, Makino S, Altemus M, Michelson D, Hong SK, Kvetnansky R, Post RM. Stress and antidepressants differentially regulate neurotrophin 3 mRNA expression in the locus coeruleus. Proc Natl Acad Sci U S A 1995; 92:8788-92. [PMID: 7568018 PMCID: PMC41052 DOI: 10.1073/pnas.92.19.8788] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The mechanisms by which stress and anti-depressants exert opposite effects on the course of clinical depression are not known. However, potential candidates might include neurotrophic factors that regulate the development, plasticity, and survival of neurons. To explore this hypothesis, we examined the effects of stress and antidepressants on neurotrophin expression in the locus coeruleus (LC), which modulates many of the behavioral and physiological responses to stress and has been implicated in mood disorders. Using in situ hybridization, we demonstrate that neurotrophin 3 (NT-3) is expressed in noradrenergic neurons of the LC. Recurrent, but not acute, immobilization stress increased NT-3 mRNA levels in the LC. In contrast, chronic treatment with antidepressants decreased NT-3 mRNA levels. The effect occurred in response to antidepressants that blocked norepinephrine uptake, whereas serotonin-specific reuptake inhibitors did not alter NT-3 levels. Electroconvulsive seizures also decreased NT-3 expression in the LC as well as the hippocampus. Ntrk3 (neurotrophic tyrosine kinase receptor type 3; formerly TrkC), the receptor for NT-3, is expressed in the LC, but its mRNA levels did not change with stress or antidepressant treatments. Because, NT-3 is known to be trophic for LC neurons, our results raise the possibility that some of the effects of stress and antidepressants on LC function and plasticity could be mediated through NT-3. Moreover, the coexpression of NT-3 and its receptor in the LC suggests the potential for autocrine mechanisms of action.
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112
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Hwang CK, Kim HS, Hong YS, Kim YH, Hong SK, Kim SJ, Lee JJ. Expression of Streptomyces peucetius genes for doxorubicin resistance and aklavinone 11-hydroxylase in Streptomyces galilaeus ATCC 31133 and production of a hybrid aclacinomycin. Antimicrob Agents Chemother 1995; 39:1616-20. [PMID: 7492117 PMCID: PMC162794 DOI: 10.1128/aac.39.7.1616] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The aklavinone 11-hydroxylase gene and two doxorubicin resistance genes cloned from Streptomyces peucetius subsp. caesius ATCC 27952 were introduced into doxorubicin-sensitive Streptomyces galilaeus ATCC 31133, an aclacinomycin producer. The doxorubicin resistance genes drrA and drrB endowed S. galilaeus with high-level resistance to doxorubicin, indicating that the resistance mechanism for doxorubicin might be different from that for aclacinomycin A. Transformation of S. galilaeus ATCC 31133 with plasmid pMC213 containing the aklavinone 11-hydroxylase gene (dnrF) resulted in the production of many red pigments. A new metabolite was purified, and the position of the newly introduced hydroxyl group was determined. This result indicated that the aklavinone 11-hydroxylase gene was stably expressed in S. galilaeus ATCC 31133 and that it gave rise to a hybrid aclacinomycin A which showed highly specific in vitro cytotoxicity against leukemia and melanoma cell lines.
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113
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Wang KC, Hong SK, Kim IO, Cho BK, Han DH. Infarction of the territory supplied by the contralateral superior cerebellar artery in a case of descending transtentorial herniation. Childs Nerv Syst 1995; 11:432-5. [PMID: 7585676 DOI: 10.1007/bf00717413] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Infarction of the territory supplied by the contralateral superior cerebellar artery in cases of descending transtentorial herniation has not been reported. The authors experienced a primitive neuroectodermal tumor in a patient whose consciousness deteriorated transiently due to descending transtentorial herniation. On the magnetic resonance imaging taken 8 days after the herniation, lesions thought to be infarction of territories supplied by the ipsilateral posterior cerebral artery and the contralateral superior cerebellar artery were noted. The possible mechanism of this peculiar pattern of infarction is discussed.
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114
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Kim YI, Na HS, Han JS, Hong SK. Critical role of the capsaicin-sensitive nerve fibers in the development of the causalgic symptoms produced by transecting some but not all of the nerves innervating the rat tail. J Neurosci 1995; 15:4133-9. [PMID: 7790900 PMCID: PMC6577717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We investigated the role of capsaicin-sensitive small diameter fibers in the development of the thermal and mechanical allodynia in a new rat model for neuropathic pain, produced by transecting some but not all of the nerves innervating the tail. Capsaicin (50 mg/kg, s.c.) injected neonatally prior to the nerve injury produced thermal hypoalgesia in the tail the degree of which was variable across individual rats, presumably as a result of variable degeneration of the small diameter fibers. When subjected to the nerve injury, the animals with moderate thermal hypoalgesia exhibited signs of pain (e.g., tail flick) to normally innocuous mechanical stimuli applied to the tail with von Frey hairs (4.9 mN or 19.6 mN bending force), but not to thermal stimuli given by immersion of the tail into cold (4 degrees C) or warm (40 degrees C) water. The animals with marked thermal hypoalgesia, on the other hand, exhibited no signs of pain either to the mechanical or to the thermal stimuli. These results suggest that the capsaicin-sensitive fibers are critical in the development of both the mechanical and thermal allodynia. It is hypothesized that the destruction of A delta- and C-nociceptive fibers by capsaicin prevented activities induced in these fibers by the nerve injury from producing a central sensitization and thus allodynia.
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115
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Rankin GO, Shih HC, Hong SK, Nicoll DW, Anestis DK, Ball JG, Brown PI, Valentovic MA. Role of chloride groups in the nephrotoxic potential of N-(3,5-dichlorophenyl)-2-hydroxysuccinimide, an oxidative metabolite of N-(3,5-dichlorophenyl)succinimide. Toxicol Lett 1995; 78:49-56. [PMID: 7604399 DOI: 10.1016/0378-4274(94)03232-v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although the addition of chloride groups to the phenyl ring of N-phenylsuccinimide (NPS) is known to enhance the nephrotoxic potential of NPS, the mechanism of this enhancement is unknown. One chlorinated NPS derivative, N-(3,5-dichlorophenyl)succinimide (NDPS), is a potent nephrotoxicant which induces marked proximal tubular necrosis at i.p. doses of 0.4 mmol/kg or greater. The purpose of this study was to compare the nephrotoxic potential of 2-hydroxy-N-phenylsuccinimide (HNPS) and N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS), an oxidative and nephrotoxicant metabolite of NDPS, to determine the importance of the chloride groups for the nephrotoxic potential of NDHS. Male Fischer 344 rats (4/group) were administered a single i.p. injection of HNPS (1.0 or 1.5 mmol/kg), NDHS (0.1 mmol/kg) or vehicle (25% dimethyl sulfoxide in sesame oil), and renal function measured at 24 and 48 h. HNPS was a nonnephrotoxicant at both doses tested, while NDHS induced marked nephrotoxicity characterized by diuresis, increased proteinuria, glucosuria, elevated blood urea nitrogen (BUN) concentration and kidney weight, decreased organic ion accumulation by renal cortical slices and proximal tubular necrosis. In vitro, HNPS reduced p-aminohippurate (PAH) and tetraethylammonium (TEA) accumulation beginning at HNPS bath concentrations of 0.05 and 0.5 mM, respectively. The results of this study indicate that although HNPS has direct effects on renal function in vitro, HNPS is not a nephrotoxicant in vivo at doses up to 15 times the minimal nephrotoxicant dose of NDHS. Therefore, the chloro groups present on NDHS play an essential role in the nephrotoxic potential of NDHS and contribute to aspects of the nephrotoxic mechanism of NDPS beyond NDPS oxidation to form NDHS.
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Mohri M, Torii R, Nagaya K, Shiraki K, Elsner R, Takeuchi H, Park YS, Hong SK. Diving patterns of ama divers of Hegura Island, Japan. Undersea Hyperb Med 1995; 22:137-143. [PMID: 7633275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Daily diving patterns, especially depth-time profiles, were continuously recorded during the entire work shift in four cachido and four funado divers of Hegura Island, Japan. All Hegura divers (cachido and funado alike) were female and habitually wore wet suits. Cachidos dive free and unassisted from a boat or float, whereas funado divers are assisted by weighted descent and during the ascent by being pulled by a partner into a boat on the water surface. Both funado and cachido divers spent 250-280 min/day on the sea at their diving locations; the actual diving time was 100-120 min. The divers made 90-120 dives/day to a depth of 13-22 m, each dive lasting approximately 60 s, considerably longer and deeper than those observed and recorded previously in ama divers in the Chiba and Miura regions. These dive profiles are similar to those reported by Paulev in which he observed apparent signs of decompression sickness when the subject dived to a depth of 15-20 m 100 times in 5 h. The average bottom time for each dive of Hegura funados was 23.6 s which is approximately 10 s longer than that of Korean female ama. The rate of ascent in the funado divers was 1.5 m/s, which is nearly twice that of the cachido divers (0.8 m/s). The dive frequency of Hegura funados (109 dives/day) was greater than the Chiba male funados (23 dives/day). Accordingly, cumulative bottom time of Hegura funado was 48 min/day, whereas that of Chiba funado was 17 min/day.(ABSTRACT TRUNCATED AT 250 WORDS)
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Takeuchi H, Mohri M, Shiraki K, Lin YC, Claybaugh JR, Hong SK. Diurnal renal responses in man to water loading at sea level and 31 atm abs. Undersea Hyperb Med 1995; 22:61-71. [PMID: 7742711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The hyperbaric environment causes a sustained diuresis accompanied by normal water intake and a decrease in insensible water loss. The maintained water intake may be necessary for the maintenance of water balance because of a reduced ability of the kidney to retain water, or may be causal in the diuresis. This problem was studied in four male subjects. Each ingested 1 liter of water (15 degrees C) at 0800 and 2000 h on different days, at 1 atm abs during a predive control, at 31 atm abs, and at 1 atm abs during the postdive control period. Urine was collected 30 min before and 3 h after the drink. Plasma vasopressin (VP) showed a circadian rhythm only at 1 atm abs, higher during the daytime. Because of this, and slightly lower VP levels at hyperbaria, a decrease in VP in response to the water load was significantly detectable only at 1 atm abs during the daytime. At 60 min after all water loads, there were no differences in plasma VP or plasma or urinary osmolality. Variability in the length of time of similarly reduced urine osmolality and increased free water excretion accounted for the increased urine flow during day compared to night (P < 0.05) at 120 and 150 min after the water load. The ability to excrete a water load both day (free water clear-ance, P < 0.05 at 60 min post-drink) and night (free water clearance, P < 0.05 at 60, 90, and 120 min post-drink) at 31 atm abs was enhanced. It is concluded that maintained water intake at hyperbaria is necessary to maintain water balance because there is a reduced ability of the body through renal mechanisms to retain a water load.
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Hong YS, Hwang CK, Hong SK, Kim YH, Lee JJ. Molecular cloning and characterization of the aklavinone 11-hydroxylase gene of Streptomyces peucetius subsp. caesius ATCC 27952. J Bacteriol 1994; 176:7096-101. [PMID: 7961477 PMCID: PMC197087 DOI: 10.1128/jb.176.22.7096-7101.1994] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The gene encoding aklavinone 11-hydroxylase of Streptomyces peucetius subsp. caesius ATCC 27952 was cloned and sequenced. The deduced amino acid sequence of the gene contains at least two common motifs of well-conserved amino acid sequences of several flavin-type bacterial hydroxylases. The hydroxylase gene is apparently transcribed from a single transcriptional start point. The phenotype of a dnrF mutant generated by gene disruption supports the idea that the dnrF gene encodes aklavinone 11-hydroxylase.
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Nakamitsu S, Sagawa S, Miki K, Wada F, Nagaya K, Keil LC, Drummer C, Gerzer R, Greenleaf JE, Hong SK. Effect of water temperature on diuresis-natriuresis: AVP, ANP, and urodilatin during immersion in men. J Appl Physiol (1985) 1994; 77:1919-25. [PMID: 7836219 DOI: 10.1152/jappl.1994.77.4.1919] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Effects of water temperature on diuresis, natriuresis, and associated endocrine responses during head-out immersion were studied in eight men (23.4 +/- 0.3 yr) during four 5-h experimental conditions: air control at 28 degrees C and immersion at 34.5 degrees C [thermoneutral (Tnt)], 36 degrees C [above Tnt (aTnt)], and 32 degrees C [below Tnt (bTnt)]. Esophageal temperature decreased by approximately 0.4 degrees C in bTnt and increased by approximately 0.5 degrees C in aTnt. Cardiac output increased by approximately 80% in aTnt and approximately 40% in bTnt while thoracic impedance, an index of central blood pooling, decreased by 7.5 omega in bTnt (NS vs. Tnt) and 8.8 omega in aTnt (P < 0.05 vs. Tnt and bTnt). Total peripheral resistance decreased at all temperatures (50% in aTnt, 20% in bTnt). Urine flow and Na+ excretion increased by sixfold in bTnt and Tnt but by only threefold in aTnt. Creatinine clearance was unchanged while osmolal clearance (but not free water clearance) increased two-fold with all immersions. Plasma atrial natriuretic peptide (ANP), urinary urodilatin, and urinary guanosine 3',5'-cyclic monophosphate increased while plasma renin activity, aldosterone, and arginine vasopressin (AVP) decreased similarly at all temperatures. bTnt did not potentiate diuresis by selective attenuation of AVP. The overall natriuretic response exhibited a higher correlation with urodilatin (r = 0.45, P < 0.001) than with ANP (r = 0.26, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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Matsumoto A, Hong SK, Ishizuka H, Horinouchi S, Beppu T. Phosphorylation of the AfsR protein involved in secondary metabolism in Streptomyces species by a eukaryotic-type protein kinase. Gene 1994; 146:47-56. [PMID: 8063104 DOI: 10.1016/0378-1119(94)90832-x] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A global regulatory protein, AfsR, involved in secondary metabolism, was found to be phosphorylated by a membrane-associated phosphokinase, named AfsK, of Streptomyces coelicolor A3(2) and S. lividans. The N-terminal portion of AfsK, deduced from the nucleotide (nt) sequence of the afsK gene, which was located downstream from the afsR gene, showed significant sequence similarity to the catalytic domain of eukaryotic Ser/Thr protein kinases (PKs). Consistent with this, experiments with AfsK produced by use of an Escherichia coli host-vector system revealed a self-catalyzed phosphate incorporation into both Ser and Tyr residues of AfsK. The recombinant AfsK phosphorylated the purified AfsR at both Ser and Thr residues. Disruption of the chromosomal afsK gene with the phage vector KC515 resulted in significant, but not complete, loss of actinorhodin production. This result implies the involvement of afsK in the regulation of secondary metabolism. The presence of an additional PK able to phosphorylate AfsR is predicted, because the afsK-disrupted strain still contained an activity able to phosphorylate Ser and Thr residues of AfsR. Southern hybridization experiments showed that nt sequences homologous to afsK, as well as afsR, were distributed among many Streptomyces spp. It is thus concluded that a signal transduction system similar to that found in higher organisms is involved in the regulation of secondary metabolism in the bacterial genus Streptomyces.
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Na HS, Han JS, Ko KH, Hong SK. A behavioral model for peripheral neuropathy produced in rat's tail by inferior caudal trunk injury. Neurosci Lett 1994; 177:50-2. [PMID: 7824181 DOI: 10.1016/0304-3940(94)90042-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We attempted to develop an experimental animal model using rat's tail for understanding the mechanisms involving peripheral neuropathic pain. Under sodium pentobarbital anesthesia, the left inferior caudal trunk of the rat was resected between the S3 and S4 spinal nerves. Latencies of tail-flick induced by the stimulus such as warm (40 degrees C) and cold (4 degrees C) water to the tail were measured for the following 30 weeks. In addition, sensitivity of the tail to mechanical stimulation was tested with von Frey hairs on these rats. Operated rats showed abnormal sensitivity of the tail to normally innocuous mechanical and thermal (warm and cold) stimuli. We interpreted these results as signs of neuropathic pain following nerve injury. The present model offers several advantages in performing behavioral tests; (1) it is easy to apply thermal stimulation to the rat's tail using a water bottle; (2) it is easy to apply the mechanical stimulation with von Frey hairs and to localize sensitive areas in the tail; and (3) blind behavioral studies are possible due to the lack of deformity in the tail after surgery.
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Lee HC, Niu KC, Huang KL, Tsai JD, Shyu RK, Shiraki K, Hong SK, Lin YC. Diving pattern of fishermen in the Pescadores. Undersea Hyperb Med 1994; 21:145-158. [PMID: 8061556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Professional diving fishermen in the Pescadores Archipelago (119.30 degrees W, 23.30 degrees N) dive with a simple hookah system. Although they use modern equipment, such as wet suit, face mask, mouth piece with demand valve, spear gun, weight belt, and fins, their lack of knowledge of diving medicine is apparent. On the average, 180 cases of decompression sickness (DCS) per year were reported to occur in the Pescadores. We conducted studies in 1990 and 1992 on three islands of the Archipelago. At the time of our study, an estimated 140 diving fishermen resided on these three islands. Of the 62 fishermen interviewed, 14 volunteered for the recording of dive profiles using a diver-carried data logger. In the summer of 1990, a group of eight fishermen dived, on the average, to a depth of 17.8 +/- 5.3 m (mean +/- SD; range, 8-27 m) for 26.9 +/- 19.7 min (5-66 min). Although the diving depth was similar to that of the average recollections of 43 divers, 20.1 +/- 4.4 m (15-30 m), the actual diving time was far shorter than that of their recollections, 426 +/- 138 min (240-630 min). The post-typhoon sea floor conditions may have shortened their diving time. In the summer of 1992, a group of six fishermen dived to 20.5 +/- 3.8 m (15-26 m) for 56.4 +/- 21.2 min (18-84 min). Again, the diving depth matched that of their recollection well, 22.2 +/- 2.5 m (20-26 m), but their bottom time was far shorter than they believed, 270 +/- 108 min (120-480 min). They used no decompression procedures, regardless of the bottom time and diving depth. In the 1990 group, 5 out of 10 equivalent single dive bottom times (ESDBT) exceeded U.S. Navy no-decompression (No-D) air dive limits; whereas in the 1992 group, 7 out of 9 ESDBTs exceeded No-D limits. Eight of the 38 discrete dives exceeded the No-D limits, even if we underestimate their decompression stress by disregarding their repetitive dive history. However, no symptoms of DCS were observed in either the 1990 or 1992 groups of 14 divers, despite 63% of the ESDBTs and 21% of discrete dives having exceeded the No-D limits. Adaptation to diving work may have allowed them to exceed the established No-D limits. The existing records of incidence of DCS from this region suggest that previously they must have dived longer or deeper or both during times of abundant resources.
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Park YS, Choi JK, Kim JS, Hong SK. Renal response to head-out water immersion in Korean women divers. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1993; 67:523-7. [PMID: 8149932 DOI: 10.1007/bf00241649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Head-out water immersion (HOI) induces a profound diuresis and natriuresis, which may endanger the body fluid balance of breath-hold divers during prolonged diving work. To investigate if adaptation is acquired by professional breath-hold divers, we have evaluated renal responses to 3-h HOI in 5 Korean women divers (Amas) and 11 nondiving housewives (controls). In both control and diver groups, the average urine flow during 3-h immersion was four times greater and Na+ excretion was 70%-80% greater than the pre-immersion value [urine flow: 3.7 (SD 1.0) ml.min-1 vs 0.9 (SD 0.4), P < 0.001, in controls; 4.3 (SD 0.9) vs 1.1 (SD 0.4), P < 0.001, in divers; Na+ excretion: 270 (SD 176) mumol.min-1 vs 161 (SD 84), P < 0.025, in controls; 303 (SD 31) vs 164 (SD 62), P < 0.005, in divers]. In all cases, the values for a given period were not significantly different between the two groups. The plasma concentrations of Na+ and osmolality, and renal clearance of creatinine did not change significantly. However, the osmolal clearance increased [from 2.0 (SD 0.8) ml.min-1 to 2.8 (SD 0.7), P < 0.05, in the controls; from 2.2 (SD 0.4) to 2.6 (SD 0.4), P < 0.05, in the divers] and free water clearance changed from negative to positive values [from -1.1 (SD 0.5) ml.min-1 to 1.2 (SD 0.3), P < 0.005, in the controls; from -1.2 (SD 0.4) to 1.6 (SD 1.1), P < 0.01, in the divers] during immersion, again the pattern of change being similar in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Stanek KS, Guyton GP, Hurford WE, Park YS, Ahn DW, Qvist J, Falke KJ, Hong SK, Kobayashi K, Kobayashi H. Continuous pulse oximetry in the breath-hold diving women of Korea and Japan. Undersea Hyperb Med 1993; 20:297-307. [PMID: 8286984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Arterial oxygen saturation during breath-hold diving has not previously been measured continuously. We devised a submersible, waterproof, backpack computer to continuously record heart rate, depth, and arterial oxygen saturation (SPO2) as determined by earlobe pulse oximetry. Our measurements showed that one assisted (Funado) diver had reduced SPO2 values immediately after surfacing from 22 dives which lasted 23-76 s, from a mean of 99 +/- 1% SPO2 to 96 +/- 3% SPO2. SPO2 returned to 97 +/- 2% within 15 s after surfacing (P < 0.05 surface value differs from predive base line). Four unassisted (Cachido) divers showed no significant reduction of mean predive SPO2 below 98 +/- 2% at any time during the dive or recovery period in 92 routine dives lasting from 15 to 44 s. Upon surfacing from diving, mean SPO2 was 98 +/- 2% and the mean SPO2 15 s after surfacing was 97 +/- 3% for the unassisted divers. Three Cachido divers were asked to dive and breath hold for as long as possible. Mean SPO2 at the conclusion of breath holding was 73% after an average dive and breath hold lasting 69 s.
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Thornton RM, Krasney JA, Hong SK. Role of vasopressin and atrial natriuretic factor in response to head-out water immersion. J Appl Physiol (1985) 1993; 75:1917-8. [PMID: 8282651 DOI: 10.1152/jappl.1993.75.4.1917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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