Overexpression of TTF-1 and PAX-8 restores thyroglobulin gene promoter activity in ARO and WRO cell lines

BACKGROUND

In anticipation of developing gene therapy against thyroid carcinoma we created an expression vector using the thyroglobulin (Tg) gene promoter. The inhibition of both Tg and thyroid-specific transcription factor (TTF-1 and PAX-8) gene expression, however, has been well documented in thyroid carcinomas. We therefore examined the effects of overexpression of TTF-1 and PAX-8 on Tg gene promoter activity in the human thyroid carcinoma cell lines, ARO (anaplastic) and WRO (follicular).

METHODS

ARO, WRO, and nonthyroid cells were transfected with an expression vector in which beta-galactosidase (beta-gal) is driven by the Tg gene promoter (beta-gal). Tg, TTF-1, and PAX-8 gene expression were also examined by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

ARO and WRO exhibited decreased gene expression of Tg, TTF-1, and PAX-8. Transfection with TG--gal alone exhibited minimal beta-gal expression, whereas cotransfection with TTF-1 and PAX-8 resulted in markedly increased expression. There was no evidence of beta-gal expression with or without TTF-1 and PAX-8 in nonthyroid cells.

CONCLUSIONS

Weak Tg gene promoter activity in ARO and WRO is associated with decreased expression of transcription factors TTF-1 and PAX-8 but can be restored with their overexpression. This model may serve as a template on which to further develop cell-specific gene therapy against thyroid carcinoma.

Neuromuscular interaction between cisatracurium and mivacurium, atracurium, vecuronium or rocuronium administered in combination

We compared the dose-response relationships of cisatracurium, mivacurium, atracurium, vecuronium and rocuronium and examined the interactions of cisatracurium with mivacurium, atracurium, vecuronium and rocuronium in humans by isobolographic and fractional analyses. We studied 180 adult patients during nitrous oxide-fentanyl-propofol anaesthesia. Neuromuscular block was monitored using mechanomyography to detect the twitch response of the ulnar nerve at the wrist. The dose-response curves were determined by probit analysis. The calculated ED50 values and their 95% confidence intervals were 40.9 (38.1-43.7), 49.8 (47.0-52.6), 187.2 (175.1-199.3), 36.6 (34.7-38.5) and 136.4 (129.2-143.6) micrograms.kg-1 for cisatracurium, mivacurium, atracurium, vecuronium and rocuronium, respectively. Corresponding ED95 values were 57.6 (53.5-61.7), 91.8 (88.1-95.5), 253.1 (238.9-267.3), 52.9 (49.1-56.7) and 288.7 (276.2-301.2) micrograms.kg-1, respectively. The interaction between cisatracurium and mivacurium, vecuronium or rocuronium was found to be synergistic, but the interaction between cisatracurium and atracurium was found to be additive. Synergy between cisatracurium and vecuronium or rocuronium was greater than between cisatracurium and mivacurium.

Metabolic modulation of cellular redox potential can improve cardiac recovery from ischemia-reperfusion injury

OBJECTIVE

Ischemia-reperfusion heart injury is an important pathologic condition against which many strategies, mainly involving antioxidants or radical scavengers, have been developed, but without satisfactory results. In the present experiment, modulation of the cytosolic NADH/NAD ratio by pyruvate and aspartate was tested in order to protect the heart from ischemia-reperfusion injury.

METHODS

Effects of pyruvate and aspartate on cardiac function recovery and redox potential were analyzed in the isolated heart of male Sprague-Dawley rats. Hearts were made globally ischemic for 20 min and then reperfused for 30 min.

RESULTS

Pyruvate and aspartate protected against tissue injury and improved contractile function after reperfusion of ischemic hearts, and these substances effectively decreased the tissue and cytosolic NADH/NAD ratio of the myocardium in a dose-dependent manner. Postischemic cardiac functions were negatively related to tissue and cytosolic NADH/NAD ratios. Increased NADH selectively inhibited myocardial xanthine dehydrogenase in vitro. It was thus expected that a decrease of NADH might limit the production of reactive oxygen species through the recovery of xanthine dehydrogenase activity.

CONCLUSION

These results indicate that a decrease of NADH is related to pyruvate and aspartate-induced protection of ischemic myocardium.

Hypnotic activities of N3-benzyl and xylyl substituted arabinofuranosyluracil

N3-Substituted derivatives of arabinofuranosyluracil (1), methyl (2), ethyl (3), propyl (4), butyl (5), allyl (6), benzyl (7), o-, m-, p-xylyls (8, 9, 10) and alpha-phenethyl (11) derivatives, were synthesized and their CNS depressant effects were evaluated by intracerebroventricular (i.c.v.) injection in mice by using hypnotic activity and pentobarbital-induced sleep prolongation as indices. At a dose of 2.0 mumol/mouse, the values of mean sleeping time induced by 7, 8, 9, and 10 were 144, 154, 117, and 33 min, respectively. Although the alkyl (2-6) derivatives did not cause any hypnotic activity, some derivatives tested (5, 7-10) significantly prolonged the pentobarbital-induced sleeping time.

A case of loiasis

The prevalence of Loa loa infections in non-endemic areas such as Korea is very low, even though it is quite common in the endemic regions of West and Central Africa. We describe a patient who presented with temporary localized edema (classical Calabar swellings) after travelling to Cameroon and in whom the diagnosis of loiasis was made by ELISA. This is the second reported case of loiasis in Korea. As international travel is becoming more frequent, Loa loa infection should be considered in the differential diagnosis for patients with eosinophilia and Calabar swellings in Korea.

A unique glucose-dependent apoptotic pathway induced by c-Myc

The lactate dehydrogenase A (LDH-A) gene, whose product participates in normal anaerobic glycolysis and is frequently increased in human cancers, has been identified as a c-Myc-responsive gene. It was of interest, therefore, to compare the effect of glucose deprivation in c-Myc-transformed and nontransformed cells. We observed that glucose deprivation or treatment with the glucose antimetabolite 2-deoxyglucose caused nontransformed cells to arrest in the G0/G1 phase of the cell cycle. In contrast, c-Myc-transformed fibroblasts, lymphoblastoid, or lung carcinoma cells underwent extensive apoptosis. Ectopic expression of LDH-A alone in Rat1a fibroblasts was sufficient to induce apoptosis with glucose deprivation but not with serum withdrawal, suggesting that LDH-A mediates the unique apoptotic effect of c-Myc when glycolysis is blocked. The apoptosis caused by glucose deprivation was blocked by Bcl-2 expression but appeared to be independent of wild-type p53 activity. These studies provide insights on the coupling of glucose metabolism and the cell cycle in c-Myc-transformed cells and may in the future be exploited for cancer therapeutics.

The influence of pregnancy on Behçet's disease

Behçet's disease is a multisystem disorder that affects mainly young adults. Conflicting reports of the effects of pregnancy on the course of Behçet's disease have been reported. We studied 27 pregnant women with Behçet's disease using questionnaires, clinical examination, and laboratory tests. The condition of 18 patients worsened (66.7%) and 9 patients (33.3%) improved during pregnancy. In the deteriorated group, clinical exacerbation of Behçet's disease occurred most commonly during the first trimester (77.8%). They were primarily of the suspected or mucocutaneous type, while in the improved group, the majority of patients were of the incomplete and complete type, or the arthritic and ocular type. Of interest was the fact that all patients in the improved group showed exacerbations related to menstruation or postpartum, which indicated that progesterone may be the major hormone influencing the course of Behçet's disease.

Currarino triad: anorectal malformation, sacral bony abnormality, and presacral mass--a review of 11 cases

Currarino et al, in 1981, described an association of a congenital anorectal stenosis, or another type of low anorectal malformation, an anterior sacral defect, and presacral mass. Eleven patients with this anomaly were treated at the Department of Pediatric Surgery, Seoul National University Children's Hospital from 1984 to 1995. Among these patients, low-type imperforate anus (IA) was seen in three cases and anorectal stenosis was present in eight cases. Presacral masses included seven teratomas, two meningoceles, one dermoid cyst, and one enteric cyst with dermoid cyst. All had a deformed sacrum. Among the eight with anorectal stenoses, posterior sagittal anorectoplasty (PSARP) with diverting colostomy was performed in seven cases, and repeated rectal dilatation was performed in one case. Among the three low-type IA, anoplasty was performed in two cases and PSARP was performed in one case. Although PSARP is a safe and satisfactory method facilitating the excision of the presacral mass, in meningoceles the repair should be performed before correction of anorectal malformation because of the risk of meningitis that can occur when surgeries are done simultaneously. In two cases, untethering of a tethered spinal cord was performed. All patients are continent. Because the incidence of Currarino triad is high when there is an anorectal stenosis (38% in the present series), the Currarino triad should be suspected in anorectal stenosis. Magnetic resonance imaging is a preferred diagnostic method because the incidence of association of tethered cord in this triad is high (18% in the present series).

Ischemic preconditioning reduces Op6 generation and prevents respiratory impairment in the mitochondria of post-ischemic reperfused heart of rat

The present study was performed to test whether the ischemic preconditioning could reduce mitochondrial O2.- production and prevent mitochondrial respiratory impairment upon reperfusion of ischemic hearts. The isolated perfused rat hearts were subjected to 30 min of global ischemia and 20 min of reperfusion. Ischemic preconditioning was performed, involving three 5-min periods of ischemia, each followed by a 5-min reperfusion just before a sustained ischemia. Ischemic preconditioning improved the post-ischemic cardiac function and reduced LDH release and malondialdehyde production upon reperfusion. 02.- generation of mitochondria isolated from the preconditioned hearts was significantly lower than that of mitochondria from the non-preconditioned hearts, and none of the activities of mitochondrial antioxidant enzymes (SOD, catalase, glutathione peroxidase) was altered as a consequence of the ischemic preconditioning alone. The impairment of mitochondrial state 3 respiration induced by ischemia and reperfusion was prevented by ischemic preconditioning. Amytal, a reversible respiratory chain blocker suppressing 02.- production in mitochondria, prevented the ischemia/reperfusion injury. The cardioprotective effect of Amytal could not be distinguished from that of ischemic preconditioning. These results suggest that the cardioprotective effect of ischemic preconditioning against the ischemia/reperfusion injury is attributed partly to the reduction of mitochondrial oxygen radical generation and prevention of the respiratory impairment during ischemia and reperfusion.

Complete nucleotide sequence and tissue-specific expression of the rat phenylethanolamine N-methyltransferase gene

The rat phenylethanolamine N-methyltransferase (PNMT) gene was isolated from a genomic library by cross-hybridization with a bovine PNMT cDNA probe. Complete nucleotide sequence analysis of a genomic clone showed that this gene contained three exons and spanned about 2.8 kb in length. There were the acute-phase response element, TATA, SP1, and GRE sequences. The physicochemical properties of rat adrenal PNMT were different from those of the brainstem PNMT. However, northern blot and reverse transcription-polymerase chain reaction analysis showed that the rat PNMT gene may not express the multiple forms of mRNA. These results suggest that the rat PNMT gene might produce a single enzyme protein, whose activity may be differentially modulated by tissue-specific environment in the central and peripheral systems.

PP1 gamma 2, a testis-specific protein-serine/threonine-phosphatase type 1 catalytic subunit, is associated with a protein having high sequence homology with the 78-kDa glucose-regulated protein, a member of the 70-kDa heat shock protein family

Protein phosphatase 1 gamma 2 (PP1 gamma 2) is a testis-specific isotype of the protein-serine/threonine-phosphatase type 1 catalytic subunit. Three native forms of PP1 gamma 2 were detected in a crude fraction of rat testis by electrophoresis in a nondenaturing polyacrylamide gel. We purified a major native form of PP1 gamma 2 to homogeneity by successive column chromatography on Mono Q-Sepharose, EAH-agarose, protamine-agarose, and G3000SW and by electrophoresis in a nondenaturing polyacrylamide gel. The G3000SW-purified PP1 gamma 2 native form had an apparent molecular mass of 170 kDa. The purified holoenzyme from nondenaturing polyacrylamide gel was composed of the catalytic subunit and two noncatalytic subunits, of 78 kDa and 55 kDa. Partial amino acid sequence analysis of the 78-kDa protein suggested that it is the 78-kDa glucose-regulated protein, a member of the 70-kDa heat shock protein family. The 78-kDa protein may possibly function as a chaperone or by confining substrate specificity of PP1 gamma 2.

Effect of superoxide dismutase on the development of preimplantation mouse embryos

The role of superoxide dismutase (SOD) was tested on preimplantation development of mouse embryos in vitro. The presence of SOD in ovarian antral follicles and in oviductal and uterine secretions was also investigated. Zygotes from superovulated ICR female mice were cultured in modified Whittingham's T6 medium supplemented with SOD (0 to 370 U) or EDTA (100 muM) at 37 degrees C under 5% CO(2) in air. Supplementation of SOD (370 U) significantly promoted the development of zygotes to the blastocyst stage (45%) as compared to that of the controls (1.4%). This favorable effect of SOD was comparable to that of EDTA and completely suppressed by anti-SOD antibody. Blastocysts cultured with SOD consisted of 78.2+/-10.4 blastomeres and possessed as many blastomeres as those (81.6+/-9.3) developing in vivo; blastocysts cultured with EDTA had significantly fewer blastomeres (42.6+/-13.7). These findings suggest that SOD protects embryos against oxidative insults and that it can be an effective substitute for EDTA for supporting mouse embryo development in vitro. The SOD activity was detected in 3 different lumina from mouse reproductive organs, and SOD was identified as a cytosolic Cu,Zn-SOD on photochemically stained polyacrylamide gels. Our results suggest that oxidative injury may be responsible for developmental retardation of preimplantation-stage mouse embryos in vitro and that Cu,Zn-SOD may play a crucial role in protecting embryos against oxygen toxicity in vivo as well as in vitro.

Eighteen-month evaluation of the effects of a 0.4% stannous fluoride gel on gingivitis in orthodontic patients

The purpose of this study was to determine whether conventional toothbrushing and twice daily use of a brush-on 0.4% stannous fluoride (SnF2) gel containing more than 90% available Sn2+ would be more effective for controlling plaque accumulation and gingivitis in the presence of orthodontic appliances than conventional toothbrushing alone. Consecutively treated adolescents who were to receive full-mouth fixed orthodontic appliances were assigned to one of two groups according to age and sex criteria. The first group (control, n = 35) used toothbrushing with a standard fluoride toothpaste, whereas the second group (treatment, n = 30) used toothbrushing supplemented with a 0.4% SnF2 gel used twice daily for the entire 18-month study period. Clinical assessments (Plaque Index, Gingival Index, bleeding tendency, and coronal staining) were made single blind before appliances were placed and 1, 3, 6, 9, 12, and 18 months after appliances were placed. Complete data were obtained for 32 control and 23 SnF2 gel subjects. The results indicated that the SnF2 gel group had significantly lower scores for plaque index (p < 0.01), gingival index (p < 0.001), and bleeding tendency (p < 0.001) at all examinations than did the control group. In the SnF2 group, one subject developed mild coronal staining, and two subjects developed moderate staining. We conclude that the use of a 0.4% SnF2 gel containing more than 90% available Sn2+ is an effective adjunct to mechanical tooth cleaning in preventing gingivitis in adolescents undergoing orthodontic treatment with fixed appliances.

Identification of PP1 catalytic subunit isotypes PP1 gamma 1, PP1 delta and PP1 alpha in various rat tissues

cDNA clones for 4 rat protein phosphatase 1 (PP1) catalytic subunit isotypes, PP1 alpha, PP1 gamma 1, PP1 gamma 2 and PP1 delta, were isolated (K. Sasaki et al., Jpn. J. Cancer Res. 81, 1272-1280, 1990). Antibodies were raised to determine the physiological functions of 4 isotypes. Among these isotypes, the PP1 gamma 2 protein was detected specifically in rat testis (H. Shima et al., Adv. Prot. Phosphatases, vol. 7, in press). On the other hand, PP1 gamma 1, PP1 delta and PP1 alpha were detected as 36kDa, 37kDa and 38kDa proteins in several rat organs by immunoblot analysis. All three isotypes were found in both soluble and particulate fractions. PP1 gamma 1 was predominant in the brain and PP1 delta in the brain, lung and small intestine, but the levels of both were low in the liver and muscle. It became evident that PP1 alpha was not a predominant isotype in any tissue examined.

Cloning and analysis of the pseudogene for human epinephrine synthesizing enzyme, phenylethanolamine N-methyltransferase (PNMT)

1. This gene completely lacks the intervening sequences. 2. This gene is truncated at the 5' end peptide encoding region by 433 base pairs (bp). 3. The 502 bp of this gene containing poly(A) signal are completely identical to the 3' half of mRNA encoding region of functional gene. 4. This gene has a poly(A) tail and is flanked by direct repeat of 6 bp. 5. Here we report for the first time the complete sequence of a human pseudogene for phenylethanolamine N-methyltransferase and this is the first report of cloning of pseudogene for catecholamine biosynthetic enzymes.

Effect of ganciclovir [9-(1,3-dihydroxy-2-propoxymethyl)guanine] on viral DNA and protein synthesis in cells infected with herpes simplex virus

The effect of ganciclovir [9-(1,3-dihydroxy-2-propoxymethyl)guanine] on herpes simplex virus type 1 DNA and protein synthesis was studied. Ganciclovir markedly inhibited the synthesis of viral DNA and gamma proteins in a dose-dependent manner. However, the synthesis of viral beta proteins was significantly increased by ganciclovir in the later stage of infection.

Effect of smokeless tobacco on the replication of herpes simplex virus in vitro and on production of viral lesions in hamster cheek pouch

Previous experiments have shown that combination of herpes simplex virus (HSV) infection and simulated snuff-dipping in hamster buccal pouches enhances the development of micro-invasive squamous cell carcinoma in cheek pouch epithelium. The effect has now been determined of water-extractable components of snuff (snuff-extract) on the growth and the cell-lysing activity of HSV. Various dilutions of snuff-extract in tissue culture medium significantly inhibited the growth of HSV in Vero cell monolayers by inhibiting the viral DNA replication. Moreover, HSV was inactivated and its cell-lysing activity lost when it was incubated with snuff-extract in cell-free condition. Snuff also had a similar anti-herpetic effect in vivo; HSV infection of pouch tissues followed by simulated snuff-dipping resulted in significant inhibition of viral growth. Thus snuff interferes with the DNA synthesis and cytolytic activity of HSV in vitro and in vivo, and this in turn, may increase its oncogenic capacity.