Lower urinary cotinine level is associated with a trend toward more myopic refractive errors in Korean adolescents

PurposeTo investigate the association between urinary cotinine levels as an objective biological marker for exposure to nicotine and refractive status.Patients and methodsThis cross-sectional study analyzed data from the Korea National Health and Nutrition Examination Survey between 2008 and 2011. A total of 1139 Korean adolescents aged 12-18 years were enrolled. Urinary cotinine concentrations and other potential risk factors for myopia were examined. Correlation analyses and multivariate regression analysis were performed to investigate the association between urinary cotinine level and refractive error.ResultsSpherical equivalent correlated significantly with urinary cotinine concentration (r=0.104, P=0.011). Lower urinary cotinine level was associated with a trend toward more myopic refractive errors (P for trend=0.003). After adjusting for age, sex, area of residence, physical activity, serum 25-hydroxyvitamin D level, parental income level, and receipt of basic livelihood security, subjects with a low urinary cotinine level had a significantly increased risk of myopia <-0.5 D (odds ratio (OR) 1.95, 95% confidence interval (CI) 1.18-3.21), <-3.0 D (OR 2.03, 95% CI 1.29-3.2), and <-6.0 D (OR 2.2, 95% CI, 1.15-4.23) when compared with subjects with a high urinary cotinine level. As urinary cotinine level decreased, the risks of myopia <-0.5 D, <-3.0 D, and <-6.0 D increased significantly (P for trend <0.05).ConclusionA trend toward less myopic refractive error was observed among Korean adolescents with higher urinary cotinine levels. This result provides the epidemiologic evidence implying nicotine as a potential modulator related with refractive development. Further studies with full consideration for myopia-associated risk factors are required to yield clear answers on the direct effect of smoking to the refractive status.

Effects of sirtuin 1 activation on nicotine and lipopolysaccharide-induced cytotoxicity and inflammatory cytokine production in human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Although sirtuin 1 (SIRT1) over-expression and resveratrol exert anti-inflammatory and proinflammatory effects, their effects and the mechanism of action on human gingival fibroblast (HGF)-mediated inflammation are unknown. The aim of this study was to demonstrate the effects of activating SIRT1 using resveratrol and recombinant adenovirus encoding SIRT1 (Ad-SIRT1) on the expression of proinflammatory cytokines and to elucidate its mechanism of action of lipopolysaccharide (LPS) and nicotine stimulated-HGF.

MATERIAL AND METHODS

Cytotoxicity and the production of reactive oxygen species (ROS) were measured using the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. The amount of prostaglandin E2 (PGE2 ) released into the culture medium was measured by radioimmunoassay. mRNA and protein levels were analyzed using RT-PCR and western blotting, respectively.

RESULTS

Nicotine and LPS up-regulated the expression of SIRT1 mRNA and SIRT1 protein in a time- and concentration-dependent manner. Resveratrol and Ad-SIRT1 decreased LPS and nicotine-induced cytotoxicity, ROS and PGE2 production, and expression of cyclooxygenase-2 in HGFs. Resveratrol and Ad-SIRT1 inhibited nicotine and LPS-mediated protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), p38, ERK, JNK, MAPK and nuclear factor-kappa B (NF-κB) activation.

CONCLUSION

This study is the first to show that the anti-inflammatory and cytoprotective effects of SIRT1 activation in HGFs occur through the PKC, PI3K, MAPK and NF-κB pathways.

Chromosomal aberrations in neuroblastoma cell lines identified by cross species color banding and chromosome painting

We have studied cytogenetic rearrangements in karyotypes of five neuroblastoma cell lines [SK-N-AS, SK-N-SH, SH-SY5Y, SK-N-MC, SMS-KCNR] by G-banding, cross species color banding (RxFISH), and fluorescence in situ hybridization (FISH) with chromosome painting probes. Each neuroblastoma cell line had unique modal karyotypic characteristics and showed a variable number of numerical and structural clonal cytogenetic aberrations. The number of rearranged chromosomes in SK-N-AS, SK-N-SH, SH-SY5Y, SK-N-MC, and SMS-KCNR was 11, 3, 7, 14 (tetraploid, 20-21), and 6, respectively. The origins of abnormal chromosomes were effectively analyzed by RxFISH and FISH with multiple chromosome painting probes. The chromosomal origin of the homogeneously staining region in SH-SY5Y was identified as coamplification of chromosome bands 2p13 and 2p24 by chromosome microdissection and FISH. The non-random rearrangements of chromosomes were determined on 1p34 approximately p36, 6q16 approximately q21, 8q24, 9q34, 11q13 approximately q23, 16q23 approximately q24, 17q21, and 22q31. These results may provide useful information for further molecular characterization of neuroblastoma.

Isolation of novel human fetal brain cDNAs mapped to human chromosome bands, 1q25 and 8q24.1

We isolated chromosome band-specific human fetal brain cDNAs by the microdissection mediated cDNA capture method, and localized these cDNA using in situ hybridization histochemistry with developing rat brain sections. Uni-Amp cDNAs were prepared from an 18-week old human fetal brain, and hybridized to human metaphase chromosomes. Eight Uni-Amp cDNAs, hybridized to chromosome band 1q25 or 8q24.1, were recovered by microdissection and PCR amplification with Uni-Amp primers. Among these cDNAs, two novel genes (FB113 of 8q24.1 and FB134 of 1q25) showed a temporospatially interesting expression pattern in the developing rat brains. The expression of FB113 was under dynamic regulation in the developing granule cells of cerebellum and dentate gyrus. FB134 showed a nervous tissue specific expression pattern and an exclusively prominent expression in the developing presubiculum and parasubiculum. By the fluorescence in situ hybridization using human genomic DNAs, FB113 and FB134 were mapped back to the human chromosome bands 8q24.1 and 1q25, respectively. These results indicate that combined application of the microdissection mediated cDNA capture method and in situ hybridization histochemistry can be used for the isolation of chromosomal band-specific genes related to brain development or human genetic diseases.

Establishment and characterization of chromosomal aberrations in human cholangiocarcinoma cell lines by cross-species color banding

Cholangiocarcinoma (CC), a malignant neoplasm of the biliary epithelium, is usually fatal because of difficulty in early diagnosis and lack of availability of effective therapy. Furthermore, little is known about the genetics and biology of CC. Only a few reports concerning cytogenetic studies of CC have been published, and few cell lines have been established. We recently established four CC cell lines, designated as SCK, JCK, Cho-CK, and Choi-CK, and report the first application of cross-species color banding (RxFISH) and multiple chromosome painting for the characterization of the chromosomal rearrangements of these CC cell lines. Each cell line had unique modal karyotypic characteristics and showed a variable number of numerical and structural clonal cytogenetic aberrations. Chromosomes 3, 6, 7, 8, 12, 14, 17, and 18 were commonly involved in structural abnormalities. Homogeneously staining regions were determined in SCK and JCK, and double minute chromosomes were found in Cho-CK. The chromosomal aberrations of the four CC cell lines were effectively analyzed by RxFISH and FISH with multiple chromosome painting probes. The nonrandom rearrangements suggest candidate regions for isolation of genes related to CC.

Establishment and characterization of chromosomal aberrations in human cholangiocarcinoma cell lines by cross-species color banding

Cholangiocarcinoma (CC), a malignant neoplasm of the biliary epithelium, is usually fatal because of difficulty in early diagnosis and lack of availability of effective therapy. Furthermore, little is known about the genetics and biology of CC. Only a few reports concerning cytogenetic studies of CC have been published, and few cell lines have been established. We recently established four CC cell lines, designated as SCK, JCK, Cho-CK, and Choi-CK, and report the first application of cross-species color banding (RxFISH) and multiple chromosome painting for the characterization of the chromosomal rearrangements of these CC cell lines. Each cell line had unique modal karyotypic characteristics and showed a variable number of numerical and structural clonal cytogenetic aberrations. Chromosomes 3, 6, 7, 8, 12, 14, 17, and 18 were commonly involved in structural abnormalities. Homogeneously staining regions were determined in SCK and JCK, and double minute chromosomes were found in Cho-CK. The chromosomal aberrations of the four CC cell lines were effectively analyzed by RxFISH and FISH with multiple chromosome painting probes. The nonrandom rearrangements suggest candidate regions for isolation of genes related to CC.

Characterization of chromosomal aberrations in lung cancer cell lines by cross-species color banding

Using cross-species color banding (RxFISH) and chromosome painting techniques, chromosomal aberrations were investigated in six lung cancer cell lines (NCI-H524, H865, H522, H1373, H358, A549). Each cell line had a variable number of numerical and structural cytogenetic aberrations. While NCI-H524, -H865, and -H522 had near diploidy, NCI-H358, -H1373, and A549 had near triploidy. The origins of the marker chromosomes were further identified by RxFISH and chromosome painting: Nonrandom chromosomal rearrangements were seen on 1p, 3q, 5p10-p15, 6q13-q21, 7q22-q31, 9p32, 15q22-qter, 17p, 17q21-q25, and 21. These abnormal cytogenetic findings indicate that multiple genetic lesions are associated with the development of lung cancer, and thus, these might be possible candidate regions for the abnormal genes involved in lung cancer.

Characterization of chromosomal aberrations in human gastric carcinoma cell lines using chromosome painting

Using chromosome painting, a study of chromosomal abnormalities was performed in six gastric carcinoma cell lines (SNU-484, 601, 620, 638, 668, 719) from Korean patients. Each carcinoma cell line had unique modal karyotypic characteristics and showed a variable number of numerical and structural clonal cytogenetic aberrations. SNU-484, SNU-620, and SNU-668 had near-triploidy; SNU-601, SNU-638, and SNU-719 had near-diploidy. The origins of the marker chromosomes of these cell lines were identified by fluorescence in situ hybridization with constructed painting probes. In all of six cell lines, rearrangement of chromosome 17 resulting in partial deletion of 17p (and/or partial duplication of 17q) was found. The most frequent marker was a partial gain of chromosome 7 with the breakpoints on 7q22 and 7q31. The nonrandom rearrangements of chromosomes were also determined on 1q32, 5q11-q22, 8q, 14q22, 14q34, and 15q15; suggesting that they may be the candidate regions for the isolation of the genes related to gastric cancer.

Chromosomal aberrations in ovarian malignant brenner tumor cell line using chromosome painting

Cytogenetic changes in an ovarian malignant Brenner tumor cell line, SNU-840, were investigated by chromosome painting and G-banding. All chromosome alterations were confirmed by the use of multiple chromosome paintings, which also demonstrated a number of additional alterations.

Electrophysiologic effects of a class I antiarrhythmic agent, cibenzoline, on the refractoriness and conduction of the human atrium in vivo

We investigated the effects of a class I antiarrhythmic drug, cibenzoline, on human atrial muscle in vivo. Electrophysiologic measurements were performed in 44 patients (mean age 49 +/- 15 years), before and after an intravenous infusion of cibenzoline 1.4 mg/kg in 5 min. Extrastimuli at a basic cycle length (BCL) of 500 ms were delivered from the right atrial appendage. The effective refractory period of the right atrium (ERP-A), the conduction time from the high right atrium to the coronary sinus, maximum conduction delay (Max. CD), repetitive atrial firing zone (RAFZ), fragmented atrial activity zone (FAAZ), and conduction delay zone (CDZ) were measured. Patients were divided into two groups according to whether repetitive atrial firing (RAF) was induced (group A, n = 18) or not (group B, n = 26). Cibenzoline increased ERP-A from 198 +/- 25 to 214 +/- 26 ms (p < 0.05) and decreased Max. CD from 55 +/- 23 to 43 +/- 19 ms (p < 0.05). There were significant decreases in the RAFZ (10 +/- 17 to 4 +/- 10 ms, p < 0.05), the FAAZ (20 +/- 25 to 12 +/- 18, ms p < 0.05), and the CDZ (41 +/- 21 to 32 +/- 19 ms, p < 0.05). Cibenzoline significantly increased ERP.A (186 +/- 25 to 212 +/- 26 ms, p < 0.05) in group A, but not in group B. There were significant decreases in the RAFZ [25 +/- 19 to 9 +/- 15 ms (p < 0.05) and FAAZ 22 +/- 29 to 11 +/- 21 ms, (p < 0.05)] in group A, but not in group B. The results suggest that cibenzoline can suppress paroxysmal atrial fibrillation by prolongation of ERP-A and may also have preferential effects on the substrate of atrial fibrillation and RAF.

Visceral heterotaxy syndrome induced by retinoids in mouse embryo

Visceral heterotaxy syndrome causes abnormal arrangement of thoracoabdominal organs and severe complex cardiac anomalies by abnormal laterality. The purpose of the present study is to analyze the incidence and pattern of heterotaxy syndrome in etretinate and all-tran retinoic acid treated pregnant DDY mice. Pregnant DDY mice were intragastrically given a single dose of 15 mg/kg of etretinate at day 6, 7 of gestation, 30 mg/kg of etretinate at day 7 of gestation and 20 mg/kg of all-trans retinoic acid at day 7 of gestation. The incidence of visceral heterotaxy was highest in the etretinate 15 mg/kg treated group on day 7 of gestation (38.5%). The major cardiovascular anomalies in heterotaxy syndrome were common atrium, common atrioventricular valve, atrioventricular septal defect, transposition of great arteries, pulmonary atresia, pulmonary artery hypoplasia and aortic arch anomalies. Atrial situs of heterotaxy syndrome were right isomerism, solitus-like, inversus-like and left atrial aplasia, but right isomerism was observed most frequently. The results suggest that retinoic acid exerts a significant effect on the determination of atrial situs during the development of mouse embryo.

Radiofrequency catheter ablation of atrioventricular accessory pathways in Wolff-Parkinson-White syndrome with drug-refractory and symptomatic supraventricular tachycardia--its high effectiveness irrespective of accessory pathway location and properties

Radiofrequency catheter ablation of atrioventricular accessory pathways was performed in 125 cases of the Wolff-Parkinson-White syndrome (type-A:54, type-B: 29, concealed: 42) complicated with drug-refractory and symptomatic atrioventricular reentrant tachycardia and/or paroxysmal atrial fibrillation. A total of 135 accessory pathways were identified: 50 left free-wall manifest, 34 left free-wall concealed, 21 right free-wall manifest, 2 right free-wall concealed, 15 posteroseptal manifest, 10 posteroseptal concealed, 2 right anteroseptal manifest and 1 right anteroseptal concealed. Accessory pathway conduction was successfully eliminated in 133 of these 135 accessory pathways (99%). Two right posteroseptal pathways were eventually ablated with direct current. Successful ablation required a mean 5.2 applications of radiofrequency current, a mean total energy of 2615 J and a mean fluoroscopic time of 52 min. The mean number of applications, applied energy and fluoroscopic time were greater in the right free-wall pathways than in the left free-wall pathways, and in the concealed pathways than in the manifest pathways. None of the procedures produced complications. During a mean follow-up period of 11.5 months, 1 right free-wall accessory pathway recurred and was ablated successfully in a repeat session. These results suggest that radiofrequency catheter ablation of accessory pathways is highly effective and safe irrespective of the accessory pathway location and properties, although these factors can affect the difficulty of this procedure. This technique may be an alternative to surgical therapy for Wolff-Parkinson-White syndrome with drug-refractory and symptomatic supraventricular tachyarrhythmias.

Electrophysiologic characteristics at initiation of ventricular tachycardia and ventricular fibrillation in a canine infarct model

Local ventricular activation time and the conduction time during sinus rhythm at the induction of ventricular tachycardia (VT) and ventricular fibrillation (VF) were investigated using a canine model of chronic myocardial infarction. Of 26 dogs studied, 15 had inducible VT, 10 had inducible VF, and 1 had no inducible arrhythmias. Bipolar local ventricular electrograms were recorded during sinus rhythm from 136 sites in 10 dogs with VT and 164 sites in 11 dogs with VF. Mean activation time in dogs with inducible VT was significantly longer than in dogs with inducible VF. Furthermore, simultaneous local ventricular electrograms were recorded during the induction of VT (74 episodes) or VF (38 episodes) from the infarct border zone at the endocardium (B-EN), the epicardium (B-EP), and normal sites (N-EN, N-EP). During VT induction, the activation time at N-EN and N-EP was significantly longer than during VF induction (N-EN: 94 +/- 21, 70 +/- 19 ms; N-EP: 83 +/- 21, 64 +/- 10 ms; p < 0.05). Conduction time was measured at the initiation of VT or VF induced by orthodromic or antidromic pacing. The conduction times of the last paced beat between N-EN and B-EP (35 +/- 11, 62 +/- 24 ms), N-EN and N-EP (35 +/- 12, 14 +/- 13 ms), B-EN and B-EP (16 +/- 10, 38 +/- 25 ms), and B-EP and N-EP (77 +/- 27, 44 +/- 12 ms) were significantly different in dogs with inducible VT (p < 0.05), but not in dogs with VF.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of early versus late programmed ventricular stimulation in acute myocardial infarction

To determine the influence of timing on the prognostic value of programmed ventricular stimulation after acute myocardial infarction (AMI), 32 patients were studied on day 19 (early study) and again on day 36 (late study) after AMI using up to 3 extrastimuli. At the early study, sustained monomorphic ventricular tachycardia (VT) was induced in 12 patients (38%), sustained polymorphic VT in 8 (25%), nonsustained monomorphic VT in 1 (3%), nonsustained polymorphic VT in 1 (3%) and no inducible arrhythmia in 10 (31%). At the late study, sustained monomorphic VT, nonsustained monomorphic VT and nonsustained polymorphic VT were induced in 8 patients (25%) each, and no inducible arrhythmia in 8 (25%). Of the 12 patients who had inducible sustained monomorphic VT at the early study, 7 had noninducibility of sustained monomorphic VT at the late study. Of the 20 patients who had noninducibility of sustained monomorphic VT at the early study, 3 had inducible sustained monomorphic VT at the late study. During the follow-up period (mean +/- standard deviation 21 +/- 8 months), there were 2 sudden cardiac deaths and 3 occurrences of sustained VT. Univariate analysis revealed both inducibilities of sustained monomorphic VT at the early study (p = 0.045) and at the late study (p less than 0.001) to be predictive of sudden cardiac death or clinical occurrence of sustained VT. However, inducibility of sustained monomorphic VT at the late study had a higher sensitivity (100%), specificity (89%), positive predictive value (63%) and negative predictive value (100%) than at the early study (80, 70, 33 and 95%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on the initiation of sustained ventricular tachycardia by programmed stimulation

We analyzed the initiation of sustained monomorphic ventricular tachycardia (VT) by programmed ventricular stimulation (PVS) in 50 consecutive patients who had clinical VT or aborted sudden cardiac death with remote myocardial infarction. In 25 of 50 patients, the first induced QRS complex of VT was morphologically identical to the succeeding QRS complexes of VT (type I). In 25 other patients, the first VT beat had a different morphology (type II). Type I had a significantly longer VT cycle length than type II (333 +/- 65 msec and 293 +/- 66 msec, P = 0.036). Type II VT initiation required more aggressive stimulation protocol than type I (type I: type II; number of extrastimulus required for induction 2.5 +/- 0.9 : 3.0 +/- 0.6, P = 0.026; shortest extrastimuli coupling interval 244 +/- 28 msec : 220 +/- 23 msec, P = 0.002). The interval between the last extrastimulus and the onset of the first VT beat was 408 +/- 88 msec in type I and 336 +/- 75 msec in type II (P = 0.004). Furthermore, there was good correlation between the VT cycle length and the interval from last extrastimulus to the onset of nonpaced beat in type I but not in type II.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of verapamil on myocardial infarct size estimated by serial 201-thallium single-photon emission tomography]

To investigate the effects of intravenous verapamil (V) in coronary thrombolytic therapy, we serially observed the time course of perfusion of the myocardium by 201-thallium (Tl) SPECT in patients who were successfully reperfused within 6 hours from the onset. 201-Tl SPECT was attempted serially on the 1st-2nd day, the 7th-10th day and 28th-30th day. In addition to this, we calculated the count ratio of radioactivity of 99mTc-PYP (CR) in the infarcted myocardium to sternum to evaluate intracellular uptake of calcium during reperfusion. The infarct size, estimated by % Defect decreased significantly in the patients treated with V, while it remained unchanged in the patients without it. In the patients with V, the left ventricular ejection fraction was more favourable, and exercise-induced ischemia determined by redistribution of 201-Tl SPECT in the chronic phase was found more frequently. CR showed no difference between reperfused myocardium irrespective of the treatment. In conclusion, verapamil was considered to enhance myocardial salvage carried out by reperfusion, and not to affect the influx of intracellular calcium into the injured myocytes.

Prognostic significance of sustained monomorphic ventricular tachycardia induced by programmed ventricular stimulation using up to triple extrastimuli in survivors of acute myocardial infarction

The prognostic significance of sustained monomorphic ventricular tachycardia (VT) induced by programmed ventricular stimulation using up to 3 extrastimuli was evaluated in 133 consecutive survivors of acute myocardial infarction (AMI) at a mean interval of 1.8 +/- 1.1 months after onset. This was compared with hemodynamic and angiographic abnormalities shown by cardiac catheterization and ventricular ectopic activity detected by Holter monitoring. Sustained monomorphic VT was induced in 25 (19%) patients, sustained polymorphic VT in 11 (8%) patients, nonsustained monomorphic VT (greater than or equal to 10 beats) in 12 patients (9%) and nonsustained polymorphic VT in 9 patients (7%). Multivariate logistic regression analysis of clinical, angiographic, hemodynamic and electrocardiographic variables showed that the presence of a left ventricular aneurysm (p = 0.005) and Lown grade 4B ventricular ectopic activity (p less than 0.001) were independent predictors of inducibility of sustained monomorphic VT. During a mean follow-up of 21 +/- 13 months, there were 8 (6%) sudden cardiac deaths and 3 (2.3%) spontaneous occurrences of life-threatening sustained VT. The 2-year probability of freedom from sudden cardiac death or sustained ventricular tachyarrhythmias was 53 +/- 13% for patients with inducible sustained monomorphic VT, 70 +/- 10% for those with a left ventricular ejection fraction less than 40% and 58 +/- 13% for those with Lown grade 4B ventricular ectopic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical significance of the technetium-99m/thallium-201 overlap in acute myocardial infarction]

The region of overlap of thallium-201 (Tl) and technetium-99m pyrophosphate (Tc) was evaluated as a scintigraphic prognosticator of future necrosis. Serial time courses of myocardial perfusion according to Tl and left ventricular wall motion evaluated by two-dimensional echocardiography (2D echo) were used in 22 patients. In all, dual energy emission computed tomography (dual-SPECT) showed the Tl/Tc overlap on identical slices on the third post-infarction day. According to the results of dual-SPECT, the patients were categorized in three groups: nine with large Tl/Tc overlap (group A); five with small Tc accumulation and small Tl/Tc overlap (group B); and eight with large Tl defect and Tc accumulation, which are concordant with each other (group C). Tl-201 SPECT and 2D echo were attempted serially on the 1st and 2nd days, the 7th-10th days and the 28th-30th days. To estimate infarct size with Tl-201 SPECT, we measured pixel counts of eight short-axis images with the 40% cut-off level and computed "% defect". To evaluate the viability of the myocardium, "% Tl uptake" was computed from the ROIs both in the centers of the infarct areas and their border zones. 2D echoes of the left ventricular short axis at the chordae tendineae level were recorded to identify the time course of percent fractional area change (% FAC) of the ischemic left ventricular wall. The scintigraphic results were compared with the serial changes of regional ejection fraction in the areas of infarcts and ischemic lesions. The % defect remained unchanged in group C (29.2 +/- 11.5----25.7 +/- 8.3%); whereas those of groups A and B decreased significantly (21.2 +/- 11.3----9.9 +/- 6.3%, 13.8 +/- 2.6----5.4 +/- 2.9%, respectively). In groups A and B, % FAC improved significantly in the centers of the infarct areas and the border zones, but not in group C. Exercise-induced ischemia determined by redistribution of Tl at the chronic phase was observed more frequently in groups A and B than in group C. These findings indicated that more myocardium can be saved from necrosis in group A than in group C. In conclusion, it is suggested that there is considerable viable myocardium in patients with large Tl/Tc overlap on dual-SPECT.

A large myxoma of the right atrium demonstrated by thallium-201

A rare case of right atrial myxoma in which thallium-201 gave a good delineation of the tumor was presented. In this case, the feeding arteries were seen to be highly developed on coronary arteriogram. The amount of blood containing thallium-201 supplied to the tumor through the feeding arteries was so great that the tumor was considered to be visualized by thallium-201 imaging.

In vitro differential developmental toxicity of vitamin A congeners

Several forms of vitamin A were tested in the in vitro hydra assay for their developmental toxicity hazard potential and site of action on progressive ontogenesis. Retinol, retinyl acetate, retinaldehyde, all trans retinoic acid, and 13 cis retinoic acid were tested fully, and each was established clearly as being able to perturb development of artificial hydra "embryos" at, or near, adult toxic treatment levels. All forms of vitamin A tested interfered with differentiation, but, although the alcohol, acetate, and aldehyde forms (group I) prevented the initial stages of differentiation from occurring, the acid forms (group II) allowed the initial stages of differentiation to occur but not the final differentiation of tentacle buds. Group I compounds produced the developmental toxicity endpoint after as little as 24 h of transient exposure on the first day of development, but had no permanent effect on development at their minimal affective developmental concentration (D-MAC) when exposure began after the first day of development. In contrast, transient 24-h exposure to group II forms did not interfere with development. At, or even above, a concentration greater than the D-MAC, more continuous exposure to them was required to interfere with differentiation. Consistent with tests of other chemicals, the concentrations needed to produce effects in hydra bore no relation to those needed to produce effects in mammals.

[Dobutamine stress thallium myocardial scintigraphy compared with two-dimensional echocardiography]

To assess the relationships among wall motion abnormality, myocardial ischemia and ST change in patients with myocardial infarction (MI), dobutamine stress thallium (Tl) myocardial scintigraphy, and two-dimensional echocardiography (2DE) and electrocardiography were simultaneously performed. Sixteen patients with anterior MI who underwent 2DE and ECG were studied at baseline and during dobutamine infusion with incremental doses of two to 40 micrograms/kg/min. The stress endpoints were chest pain, significant ST changes, tachycardia (greater than or equal to 110/min), and complicated arrhythmias. At the maximal tolerable dose of dobutamine, Tl scintigraphy was completed, and then repeated again four hours later. Left ventricular wall motion was evaluated using superimposed wall tracings of the configuration on 2DE, and was expressed as regional % area changes. Myocardial ischemia was quantified by SPECT and measured as regional % Tl uptake. Dobutamine stress testing was well tolerated by all patients, and no complications occurred. Hemodynamic changes included: heart rate increased from 61 +/- 9 to 113 +/- 11 beats/min, left ventricular end-diastolic volume (2DE) decreased from 93 +/- 27 to 59 +/- 33 ml, and mean blood pressure and ejection fraction were unchanged. In 11 of the 16 patients, redistributions on planar and SPECT images were observed. Although redistributions were observed in the areas adjacent to infarcts in patients with significant ST elevation in V3, additional wall motion abnormalities were not observed. The shape of the ST elevation had no relation to myocardial ischemia. In some cases, wall motion abnormality can be improved in spite of ischemia. Thus, this new combined method is useful for evaluating the relationship between ischemia and wall motion dynamics.

Pituitary atrophy in Korean (epidemic) hemorrhagic fever: CT correlation with pituitary function and visual field

Eleven patients with Korean (epidemic) hemorrhagic fever were each studied three times with high-resolution CT in order to demonstrate necrosis of the pituitary gland and to correlate the CT findings with the patients' pituitary function and visual fields. Seven of the 11 patients showed varying degrees of progressive decrease in the height of the pituitary gland: one severe, two moderate, and four mild. The visual fields of all the patients were checked at the time of the third (last) follow-up CT. Six of the 11 patients had bitemporal superior quadrantanopsia. In five patients, the decreased height (atrophic change) of the pituitary gland and the visual-field defect were coincidental. The visual-field defects in those patients were not improved on follow-up examination 5 weeks later. Two patients in whom a 1-year follow-up examination was performed showed no interval changes in the defects. Pituitary function tests were performed in nine of the 11 patients (six with atrophic pituitary glands and three without atrophic changes) at the time of the third CT. Five of the six patients with atrophy showed decreased pituitary reserve function for follicle-stimulating hormone, cortisol, or human growth hormone, while only one patient showed decreased reserve function for cortisol among the three patients without atrophic change. The pituitary atrophic changes observed on follow-up sellar CT are thought to be the result of the ischemic necrosis of the gland. The high probability (five of seven) of visual-field defects in those patients with atrophic glands suggests optochiasmatic and pituitary ischemia as the basic pathogenesis.

Regeneration by dissociated adult Hydra cells: a histologic study

Adult Hydra attenuata with vitally stained gastrodermal cells were dissociated into their component cells which were then randomly reaggregated into pellets by low-speed centrifugation. Representative examples of these preparations, which develop into normal adult hydra if left undisturbed, were examined fresh at low magnification and at higher magnification in fixed, stained, and sectioned specimens. The actual pellet stage lasts less than 1 hour because the adult ectodermal and gastrodermal cells rapidly sort themselves into an inner and outer layer and seem to secrete a new mesoglea immediately thereafter. The "embryo" becomes trilaminar and attains a central cavity by extruding a large amount of cellular debris at the end of the first day. At about this same time, new tentacles begin to differentiate from rapidly dividing and undifferentiated interstitial cells. Regulation of tentacle number and position occurs at the end of two days, and the body form is essentially reestablished within 60 hours by further differentiation of the hypostomes and body wall. Complete separation of the preparation into individual polyps does not occur until about 190 hours of development.

Relationship of developmental stage to effects of vinblastine on the artificial "embryo" of Hydra

Three milligrams of vinblastine sulfate per liter of culture medium prevented normal development of all reaggregated artificial hydra "embryos" at the 66-hour stage of regeneration. One milligram of vinblastine per liter of medium had no effect on development, and 100 mg did not markedly accelerate the developmental disruption beyond the pace of the 2 mg/liter concentration which was the lowest effective concentration. Treatment with vinblastine through the first few hours of development was sufficient to produce the toxic endpoint at 66 hours of incubation, but effects were delayed in appearance when treatment was initiated later in development. Early development of exposed preparations proceeded normally even in the presence of rather high concentrations of the test substance, and the pellet was resistant to the effects of vinblastine treatment begun after 24 hours of development. From these results, it would appear that interference with cell division is not the primary means by which vinblastine perturbs this developing system.