Role of retinoid receptors in the regulation of mucin gene expression by retinoic acid in human tracheobronchial epithelial cells

To investigate which retinoid receptors are critical in the regulation by all-trans-retinoic acid (RA) of the mucin genes MUC2, MUC5AC and MUC5B in cultured normal human tracheobronchial epithelial (NHTBE) cells, we used pan-RAR-, pan-RXR- and RAR- isotype (alpha, beta and gamma)-selective agonists and RARalpha- and RARgamma-selective antagonists (RAR is RA receptor and RXR is retinoid X receptor). RAR-, RARalpha- and RARgamma-selective agonists strongly induced mucin mRNAs in a dose-dependent manner, while the RARbeta-selective retinoid only weakly induced mucin gene expression at very high concentrations (1 microM). The pan-RXR-selective agonist by itself did not induce mucin gene expression, but acted synergistically with suboptimal concentrations of the pan-RAR agonist. A retinoid with selective anti-activator-protein-1 activity only marginally induced mucin gene expression. The RARalpha antagonist strongly inhibited mucin gene induction and mucous cell differentiation caused by RA and by the RARalpha- and RARgamma-selective retinoids. In contrast, the RARgamma antagonist only weakly inhibited RARalpha-selective-retinoid-induced mucin gene expression, but completely blocked mucin gene expression induced by the RARgamma-selective retinoid. Our studies indicate that RARalpha is the major retinoid receptor subtype mediating RA-dependent mucin gene expression and mucous cell differentiation, but that the RARgamma isotype can also induce mucin genes. Furthermore these studies suggest that RARbeta is probably not (directly) involved in RA-induced mucin gene expression.

Formaldehyde exposure levels and serum antibodies to formaldehyde-human serum albumin of Korean medical students

In our study, we estimated formaldehyde exposure levels of Korean medical students during their cadaver dissection practice hours. In addition, we examined the prevalence rates of formaldehyde-specific immunoglobulin E or immunoglobulin G antibodies and compared the results with the symptoms the students experienced as a result of formaldehyde exposure. There were 167 Korean medical students (i.e., subjects) aged 23.8+/-2.5 y (mean+/-standard deviation) and a control group of 67 premedical students aged 20.1+/-2.8 y (mean+/-standard deviation). Concentrations of formaldehyde in the cadaver dissection practice laboratory ranged from 0.194 to 11.245 mg/m3 (3.736+/-3.478 mg/m3 [mean+/-standard deviation]). Students reported by self-administered questionnaires that eye soreness (92.8%) and lacrimation (74.9%) were the most common symptoms they experienced during the laboratory sessions. One (0.6%) of the 167 medical students had a history of wheezing during dissection. Fourteen (8.4%) had specific immunoglobulin G antibody, but none had specific immunoglobulin E antibody. These results suggest that (a) Korean medical students are exposed to formaldehyde at a relatively high levels in their dissection practice hours, (b) specific immunoglobulin G is not related to adverse eye or respiratory symptoms, and (c) specific immunoglobulin E is rarely induced as a result of exposure to formaldehyde.

Chloroplast DNA restriction site variation and phylogeny of the Berberidaceae

Comparative restriction site mapping of the chloroplast genome was performed to examine phylogenetic relationships among 27 species representing 16 genera of the Berberidaceae and two outgroups. Chloroplast genomes of the species included in this study showed no major structural rearrangements (i.e., they are collinear to tobacco cpDNA) except for the extension of the inverted repeat in species of Berberis and Mahonia. Excluding several regions that exhibited severe length variation, a total of 501 phylogenetically informative sites was mapped for ten restriction enzymes. The strict consensus tree of 14 equally parsimonious trees indicated that some berberidaceous genera (Berberis, Mahonia, Diphylleia) are not monophyletic. To explore phylogenetic utility of different parsimony methods phylogenetic trees were generated using Wagner, Dollo, and weighted parsimony for a reduced data set that included 18 species. One of the most significant results was the recognition of the four chromosomal groups, which were strongly supported regardless of the parsimony method used. The most notable difference among the trees produced by the three parsimony methods was the relationships among the four chromosomal groups. The cpDNA trees also strongly supported a close relationship of several generic pairs (e.g., Berberis-Mahonia, Epimedium-Vancouveria, etc.). Maximum likelihood values were computed for the four different tree topologies of the chromosomal groups, two Wagner, one Dollo, and one weighted topology. The results indicate that the weighted tree has the highest likelihood value. The lowest likelihood value was obtained for the Dollo tree, which had the highest bootstrap and decay values. Separate analyses using only the Inverted Repeat (IR) region resulted in a tree that is identical to the weighted tree. Poor resolution and/or support for the relationships among the four chromosomal lineages of the Berberidaceae indicate that they may have radiated from an ancestral stock in a relatively short evolutionary time.

Non-anticoagulant heparin increases endothelial nitric oxide synthase activity: role of inhibitory guanine nucleotide proteins

Heparin, which is widely used clinically, has recently been shown to have specific properties affecting the vascular endothelium. We hypothesized that heparin stimulates endothelial nitric oxide synthase (eNOS) activity by a mechanism independent of its anticoagulant properties and dependent on an inhibitory guanine nucleotide regulatory protein (Gi). We determined the effect of both heparin and N-acetyl heparin (Non-Hep), a heparin derivative without anticoagulant properties, on eNOS activity in cultured bovine aortic endothelial cells and on endothelium-dependent relaxation in isolated vascular rings. The eNOS activity was determined by measuring both citrulline and nitric oxide (NO) metabolite formation. Heparin and Non-Hep dose-dependently increased basal eNOS activity (ED50 1.0 microgram/ml or 0.15 U/ml), an effect that was significantly inhibited by pertussis toxin (100 ng/ml), a Gi-protein inhibitor. Agonist-stimulated (acetylcholine, 10 microM) eNOS activity was potentiated following pre-treatment with both heparin and Non-Hep and reversed by pertussis toxin. Heparin and Non-Hep induced a dose-dependent relaxation in preconstricted thoracic aortic rings, an effect that was significantly inhibited by pertussis toxin, endothelial inactivation (following treatment with sodium deoxycholate) and NG-nitro-L-arginine-methyl ester (L-NAME). We conclude that heparin and non-anticoagulant heparin induce endothelium-dependent relaxation following activation of eNOS by a mechanism involving a Gi-protein. Administration of heparin derivatives without anticoagulant properties may have therapeutic implications for the preservation of eNOS in conditions characterized by endothelial dysfunction.

Heparin preserves nitric oxide activity in coronary endothelium during ischemia-reperfusion injury

BACKGROUND

Brief episodes of ischemia followed by reperfusion adversely affect endothelial vasomotor function. We hypothesized that heparin may impart a protective effect on the coronary endothelium during ischemia-reperfusion injury possibly via the nitric oxide pathway.

METHODS

Eighteen anesthetized dogs were randomly assigned to one of two treatment groups: saline solution or bovine heparin (6.0 mg x kg intravenously). A flow probe and cannula were placed in the left anterior descending artery. Functional recovery of the coronary endothelium was assessed after 15 minutes of ischemia and during 120 minutes of reperfusion after acetylcholine and nitroprusside challenge. In a separate group (n = 10), nitric oxide activity was measured as nitrate/nitrite levels and cyclic guanosine monophosphate levels in the left anterior descending artery.

RESULTS

Control dogs displayed a significant decrease in percent change of left anterior descending artery flow at 15, 30, and 60 minutes of reperfusion (67%+/-8%, 76% +/-11%, and 84%+/-8%) when compared with preischemic values (108+/-6; p < 0.01). Heparinized dogs, however, showed preservation of coronary endothelial function after acetylcholine challenge throughout reperfusion. Heparin-treated dogs also displayed a significant increase in nitrate/nitrite levels during reperfusion (37.3+/-4.1 micromol/L) when compared with the saline group (24.3+/-0.8 micromol/L; p < 0.03). Left anterior descending artery levels of cyclic guanosine monophosphate were also significantly increased after heparin administration (3.0+/-0.3 pmol/mg) when compared with ischemia-reperfusion alone (0.7+/-0.1 pmol/mg; p < 0.03).

CONCLUSIONS

Heparin preserves the vasoregulatory function of the coronary endothelium during brief episodes of ischemia-reperfusion injury, in part, via the nitric oxide pathway. Administration of heparin may have important therapeutic implications in the prevention of coronary endothelial dysfunction associated with reperfusion injury.

Mutations of the STK11 gene in sporadic gastric carcinoma

Gastric carcinoma may occur sporadically or in association with hereditary diseases, such as Peutz-Jehgers syndrome (PJS). The PJS gene (named STK11 or LKB1) was mapped to 19p13.3 and recently cloned. Germ-line mutations of the gene have been detected in familial PJS patients and are predicted to predispose STK11 carriers to the development of a wide range of gastrointestinal and other neoplasms. To elucidate the etiological role of the STK11 gene in sporadic gastric carcinoma tumorigenesis, we analyzed 28 gastric carcinomas (22 of intestinal type and 6 of diffuse type) for STK11 gene mutations. STK11 gene mutations were detected in 3 of 28 gastric carcinomas but were not seen in the corresponding germ-line DNA sequence. In one tumor, a missense mutation, C-to-T transition, was detected at codon 324 resulting in proline to leucine substitution; in the other two, silent mutations were detected at codons 106 and 350, respectively. While these results suggest that somatic STK11 mutations are not common in sporadic gastric carcinomas, they may occur in a subset of these tumors.

17-Beta estradiol regulation of myocardial glutathione and its role in protection against myocardial stunning in dogs

We studied the effect of 2-week treatment with estradiol 17beta on myocardial glutathione concentration in dogs and isolated perfused rat heart subjected to brief coronary ischemia and reperfusion. Estradiol protected against ischemia/reperfusion-induced myocardial systolic shortening and malonylaldehyde production and increased myocardial glutathione concentration and glucose-6-phosphate dehydrogenase enzyme activity. Reduction of myocardial glutathione with buthionine sulfoximine to levels seen in the absence of estrogen reversed the protective effect of estradiol against myocardial dysfunction and lipid peroxidation associated with ischemia/reperfusion. These results suggest that the antioxidant effect of estradiol in ischemia/reperfusion may be mediated by regulation of myocardial glutathione metabolism.

The effect of propofol on isolated human pregnant uterine muscle

BACKGROUND

Propofol is an alternative to thiopental as an intravenous induction agent for cesarean section. Because it has relaxant effects on vascular and other smooth muscles, the authors set out to determine whether propofol has any effect on pregnant human uterine smooth muscle in an isolated preparation.

METHODS

Myometrial specimens were excised from 10 parturients undergoing elective cesarean section. The muscle strips were suspended in tissue baths and isometric tension was recorded. After establishment of rhythmic contractions in the buffer solution as a control, propofol (0.5 to 10 microg/ml) in fat emulsion was applied cumulatively to the bath. The effect of the fat emulsion at equivalent concentrations was also examined.

RESULTS

Propofol concentrations of 2.7 x 10(-6) M (0.5 microg/ml) and 1.1 x 10(-5) M (2 microg/ml) had no significant effect on the active tension developed by muscle contraction. However, propofol at concentration of 5.5 x 10(-5) M (10 microg/ml) reduced the active tension by 45% (P < 0.02) compared with the control value. The fat emulsion had no effects on the active tension.

CONCLUSIONS

These results imply that the decline in the active tension of muscle contraction was most likely caused by propofol and not by the fat emulsion. However, the propofol concentrations needed to produce a significant reduction in the uterine muscle tension appear to be much greater than the free propofol concentrations reported by others during cesarean section.

Transcanalicular laser-assisted revision of failed dacryocystorhinostomy

BACKGROUND AND OBJECTIVE

Despite the high success rate of external dacryocystorhinostomy (DCR), recurrent tearing after DCR can be troublesome. The authors performed transcanalicular revision in 6 patients with failed DCR.

PATIENTS AND METHODS

With the use of a continuous wave Nd:YAG laser with a sclerostomy probe, the internal ostium was reopened by a transcanalicular approach. The authors applied 0.4 mg/ml of mitomycin-C around the opening for 5 minutes intranasally and inserted a silicone tube as a stent.

RESULTS

A total of 7 operations were performed in 6 patients. The operation was successful after the first revision in 5 of the 6 patients, but 1 of the patients required a second procedure.

CONCLUSIONS

The transcanalicular laser-assisted revision has several advantages. It is simple and fast, skin incision is avoided, there is good hemostasis, it is less traumatic, and there is less postoperative morbidity.

Psychoneuroendocrinology and brain imaging in depression

In the past three decades, psychoneuroendocrinologic investigations have generated a great volume of information, particularly in the field of affective disorders, which has formed the basis for designing studies with newer tools such as anatomic and functional imaging. In this article, the authors focus on endocrine imaging in psychiatry and attempt to relate morphometric findings to physiologic neuroendocrine dysfunction in depression.

Heparin and nonanticoagulant heparin preserve regional myocardial contractility after ischemia-reperfusion injury: role of nitric oxide

OBJECTIVES

These studies were performed to determine the effect of heparin and nonanticoagulant heparin on myocardial function after ischemia-reperfusion and to further evaluate the role that the nitric oxide-cyclic guanosine monophosphate pathway plays in mediating the effect of heparin.

METHODS

Fifteen dogs were subjected to 15 minutes ischemia followed by 120 minutes reperfusion and pretreated with either saline solution, bovine heparin (6.0 mg/kg intravenously), or N-acetyl heparin (6.0 mg/kg intravenously), a heparin derivative without anticoagulant properties. The left anterior descending artery was occluded for 15 minutes and regional systolic shortening, a unitless measure of myocardial contractility, assessed during reperfusion. To evaluate the role of nitric oxide, the inhibitor N(omega)-nitro-L-arginine, 1.5 mg/kg intracoronary, was given before heparin administration. Myocardial levels of cyclic guanosine monophosphate, the second messenger of nitric oxide, were also measured in the N-acetyl heparin group using radioimmunoassay.

RESULTS

Regional systolic shortening was significantly decreased in the saline group during 60 and 120 minutes compared with before ischemia (9.2 +/- 1.0 and 9.0 +/- 0.9 vs 12.2 +/- 1.2, p < or = 0.0003). Heparin and N-acetyl heparin-treated dogs, however, showed preservation of systolic shortening throughout reperfusion. Administration of nitro-L-arginine significantly attenuated the protective effect of heparin (9.2 +/- 1.2 vs 12.7 +/- 1.1, p < or = 0.0001) and N-acetyl heparin (9.3 +/- 0.3 vs 12.8 +/- 0.4, p < or = 0.0001) during 120 minutes reperfusion. Myocardial levels of cyclic guanosine monophosphate were also significantly increased in the N-acetyl heparin group compared with saline (199.1 +/- 7.1 vs 103.5 +/- 4.5 pmol/mg, p < or = 0.0001).

CONCLUSIONS

Heparin preserves myocardial contractility after ischemia-reperfusion independent of its anticoagulant properties. Furthermore, the protective effects of heparin during ischemia-reperfusion are mediated, at least in part, through a nitric oxide-cyclic guanosine monophosphate pathway.

Subperiosteal hematoma of the orbit associated with sinusitis

Subperiosteal hematoma of the orbit is a rare but well-recognized entity, usually caused by trauma. Two cases of subperiosteal hematoma associated with sinusitis are presented. A 44-year-old woman experienced the sudden onset of proptosis, and decreased visual acuity. Computed tomographic scanning and magnetic resonance imaging revealed a frontoethmoidal mucocele and a biconvex mass in the upper part of the left orbit. The mucocele was drained during nasal endoscopic surgery and the subperiosteal hematoma was evacuated during superior orbitotomy. A 42-year-old man had a headache and proptosis. Computed tomographic scan revealed sinusitis and subperiosteal orbital hematoma of the left orbit. Subperiosteal orbital hematoma associated with sinusitis is extremely rare but should be suspected in a patient with acute onset of proptosis in whom computed tomographic scanning reveals paranasal sinusitis.

Seroimmunological characteristics of Korean workers exposed to toluene diisocyanate

Since type I allergy caused by specific IgE antibodies may play principal roles and IgG antibody-mediated reactions have been thought to be involved in some parts of the pathogenesis, this study was performed to investigate the role of IgE- or IgG-mediated hypersensitivity reactions in development of toluene diisocyanate (TDI) asthma in Korean workers. For 81 TDI spray painters, self-administrative questionnaires and direct interviews on respiratory symptoms, chest auscultation, and measurements of forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1.0) were performed. The TDI concentration in their working environments was measured. Levels of serum IgE and IgG specific to TDI were estimated by radioallergosorbent test (RAST) and ELISA using p-tolyl isocyanate-human serum albumin (TMI-HSA) as the antigen. When sputum, cough, and dyspnea aggravated by work or wheezing existed, when FVC or FEV1.0 was less than 80% of the normal reference value, or when IgE RAST for TDI was positive, the peak expiratory flow rate (PEFR) was recorded four times per day for over 2 weeks. If decrease of PEFR was over 20% of baseline PEFR and changing pattern of PEFR was closely related to workshift in time, then a diagnosis of TDI asthma was made. Changing patterns of PEFR of 8 (9.9%) workers corresponded to the diagnostic criteria of TDI-related occupational asthma. Levels of the specific IgE were increased in 9 (11.1%) of the 81 subject workers and in 3 (37.5%) of the 8 PEFR-positive workers. Levels of the specific IgG were increased in 9 (11.1%) workers, and in only 1 (12.5%) of the asthmatics sensitive to TDI. Neither elevated TDI-specific IgE levels nor PEFR test positivities were associated with increased IgG levels. The mean titer of the PEFR-test-positive workers was slightly lower than that of the PEFR-negative workers and that of the IgE RAST-positive workers lower than that of the test-negative workers, but there was no statistical significance. These results suggest that IgG is not deeply involved in the pathogenesis of TDI-induced occupational asthma in Korean workers.

Distribution of nitric oxide in the nasal mucosa of the rat: a histochemical study

We evaluated the distribution of nitric oxide (NO) in the rat nasal mucosa using nicotineamide adenosine dinucleotide phosphate (NADPH)-diaphorase histochemistry. The NADPH-diaphorase positive nerve fibers in the nasal mucosa were observed around blood vessels and submucosal glands and in sphenopalatine ganglions. Strong positive reactions for NADPH-diaphorase were observed in ganglions as compared with the other tissues. In septal and turbinate mucosa, positive reactions for NADPH-diaphorase were mainly seen in the anterior portion, and a few positive reactions were observed in the posterior portion. No positive reactions for NADPH-diaphorase were demonstrated in the sinus mucosa. These results suggest that NO may be related to regulation of blood flow, glandular secretion and neurotransmission, and also that NO may play an important role in the defense mechanism of the upper airway system against external environments.

Four cases of dacryocystocele

Dacryocystocele is a rare complication of chronic dacryocystitis. We report four such cases in which epiphora and painless cystic mass located inferior to the medical canthus were manifested. Computed tomographic scanning of the orbit showed a well-demarcated low density mass in the lacrimal sac area, and extending to the nasolacrimal duct. We completely or partially excised the mass and depending on the condition of the canaliculi and puncta, performed dacryocystorhinostomy, canaliculorhinostomy, or conjunctivodacryocystorhinostomy using Jones' tube. Operative findings revealed that the lacrimal sac and nasolacrimal duct were dilated with obliterated proximal and distal portions the cyst. When cysts in the lacrimal sac area develop subsequent to chronic epiphora or are accompanied by punctal agenesis, differential diagnosis should consider the possibility of dacryocystocele.

Transnasal endoscopic excision of an isolated neurofibroma of the nasal septum

Neurofibroma may occur in any parts of myelinated nerves having Schwann cells. However, it is extremely rare in the nasal septum. We have had experience with an isolated neurofibroma of the nasal septum which was successfully removed by transnasal endoscopic excision, and describe the clinical, endoscopic surgical and pathological features.

Breath pentane concentrations during labor and the effect of epidural analgesia on the pentane concentration

Increased lipid peroxidation has been observed in pregnancy and particularly in preeclampsia. Pentane, a by-product of lipid peroxidation, can be measured in exhaled breath, and its measurement is considered a non-invasive method of assessing lipid peroxidation in vivo. We measured pentane levels in the breath of 36 healthy parturient women and examined the effect of epidural analgesia on the pentane level. Single-expiratory breath samples were analyzed by gas chromatography. The breath pentane level was higher during labor (4.88 parts per billion [p.p.b.], 95% confidence interval 3.25-6.51 p.p.b.) than before the induction of labor (3.10 p.p.b., 95% confidence interval 2.01-4.19 p.p.b.). There was a significant decrease in the pentane level after the institution of epidural analgesia (2.27 p.p.b., 95% confidence interval 1.43-3.11 p.p.b.). Our results suggest that labor may be accompanied by an increase in lipid peroxidation, and epidural analgesia reverses this increase.

17 beta-Estradiol prevents dysfunction of canine coronary endothelium and myocardium and reperfusion arrhythmias after brief ischemia/reperfusion

BACKGROUND

Brief myocardial ischemia is associated with myocardial and coronary endothelial dysfunction caused by oxygen free radicals released during reperfusion. Estrogen, known to have antioxidant activity, may prevent these complications.

METHODS AND RESULTS

We assessed the effect of 2 weeks of treatment with 17 beta-estradiol (E, 100 micrograms.kg-1.d-1, n = 12) or placebo (P, n = 15) on myocardial and coronary endothelial function during the first 2 hours of reperfusion in dogs subjected to 15 minutes of ischemia induced by occlusion of the left anterior descending coronary artery (LAD). Our results show that the incidence of ventricular arrhythmias significantly decreased in E (3 of 12) compared with P (11 of 15). Systolic shortening, significantly depressed in P during early reperfusion, was maintained at preischemic levels in E. During reperfusion, the increase in LAD flow to acetylcholine, attenuated in P (60 +/- 6%), was preserved in E endothelium. (151 +/- 28%) and was associated with increased serum nitrite/nitrate concentration. n-Pentane in exhaled gas in vivo, an index of lipid peroxidation, increased significantly during early reperfusion in P (from 9.1 +/- 1.9 to 41.6 +/- 13.0 ppb, P < .05) but not in E (23.0 +/- 6.9 ppb). In vitro, arterial segments from E generated significantly less superoxide anion after hypoxia/reoxygenation than those from P. Ischemic/reperfused LAD segments from E also revealed a better preservation of endothelium-dependent relaxation in vitro (maximum relaxation, 42 +/- 4% versus 24 +/- 4% in P; P < .05).

CONCLUSIONS

Estrogen protects against endothelial and myocardial dysfunction resulting from brief ischemia/reperfusion. This protection may relate to an antioxidant effect of estrogen.

Two Roles of Nonionic Surfactants on the Electrorheological Response

The influence of three nonionic surfactants (Brij 30, GMO, and GTO) on the electrorheological response of various alumina/silicone oil suspensions is investigated. The dependence of the dynamic yield stress on such variables as surfactant type and concentration, water and ion content, and electric field strength and frequency is reported. The prevalent feature common to all formulations is that the yield stress, tau0, initially increases with surfactant concentration, passes through a maximum, and then decreases with surfactant concentration. Below the maximum, the yield stress increases quadratically with the field strength, E, while above the maximum, yield stress increases slower than E2. The increase in the yield stress with surfactant concentration is due to surfactant-enhanced interfacial polarization, which may arise from increased proton transport via neighboring hydrogen bonds. The nonlinear behavior observed at large surfactant concentrations (i.e., tau0 $\not\propto$ E2) arises from field-induced phase separation of a surfactant-rich phase as opposed to field-dependent conductivity of a homogeneous continuous phase.