NO- and NO2-carrying molecules potentiate photorelaxation in rat trachea and aorta

Photorelaxation elicited by ultraviolet light (366 nm) was investigated on isolated rat thoracic aorta and trachealis. Rat tracheal smooth muscle but not aorta did not show UV-induced photorelaxation. Both streptozotocin, NO-carrying molecule and N omega-nitro-L-arginine, NO2-carrying molecule significantly enhanced photorelaxation, concentration-dependently, in rat trachealis and aorta. Methylene blue (10 microM) inhibited the potentiation action of streptozotocin and N omega-nitro-L-arginine in both tissues. Superoxide dismutase (300 U/ml) enhanced streptozotocin- and N omega-nitro-L-arginine-potentiated photorelaxation in rat trachealis, while pyrogallol (0.1 mM), a potent O2- generating agent, inhibited streptozotocin-potentiated photorelaxation in trachealis. Streptozotocin was much more effective than N omega-nitro-L-Arginine in potentiating of photorelaxation elicited by UV light in both tissues. From these findings, we conclude that streptozotocin and N omega-nitro-L-arginine produce EDRF like labile substance(s) by UV irradiation.

Endothelial potentiation of relaxation response to ascorbic acid in rat and guinea pig thoracic aorta

The role of the endothelium was evaluated in the relaxation of rat and guinea pig aortic rings induced by ascorbic acid. Ascorbic acid relaxed rat and guinea pig aortic rings that were previously contracted with submaximal dose of phenylephrine (PE), in a concentration dependent manner. Removal of the endothelium significantly reduced the sensitivity but not the magnitude of the response to ascorbic acid. Methylene blue, but not propranolol, blocked the endothelial augmentation of vascular relaxation to ascorbic acid. Vessels precontracted with potassium chloride (high K+) were also relaxed by ascorbic acid. Methylene blue also inhibited the response to ascorbic acid in the intact vessels precontracted with high K+. A23187 and acetylcholine, but not ADP, variably caused endothelium dependent component relaxation in guinea pigs, whereas all of these three probes constantly caused it. In Ca(2+)-free medium, Ca(2+)-induced contraction of high K(+)-depolarized rat aorta was inhibited by the presence of ascorbate, which was more pronounced in endothelium intact rings than in endothelium denuded ones. PE-induced contraction in the presence of different concentrations of ascorbate reduced both the sensitivity and the maximal contractile force in rat aorta. Ascorbic acid (0.125-32 mM) did not change the pH in the medium. From these findings, it is speculated that 1) receptor- and potential-operated Ca2+ channels may be modulated by ascorbate, 2) endothelium has a significant role in promoting relaxation induced by ascorbic acid.

Human fetal heart development after mid-term: morphometry and ultrastructural study

A total of 44 normally developed human fetal hearts aged from 17 to 40 weeks gestation were provided for routine ultrastructural and morphometric studies. For morphometric analysis, the maximal thicknesses of the anterior, lateral and posterior wall of both ventricles and that of interventricular septum were measured and the left-to-right thickness ratios calculated. The cross-sectional areas of both ventricles in the plane of the greatest heart diameter were measured with computerized image analysis system. Data were analyzed using linear regression and one-way analysis of variance. Myofibril formation occurred by attachment of thin filaments into amorphous Z materials which were presented in sarcolemmal plaques, sarcoplasmic condensations, desmosomes and in Z lines. From these Z centers, myofibrils radiated many directions and branched and anastomosed with further development. This pattern of myofibrillar development continued throughout the whole fetal period. A transverse tubule system was clearly evident in later fetal development. It occurred by invagination of sarcolemma into myocardial cells and formation of subsarcolemmal caveolae. Mitochondria, well-developed Golgi complexes, glycogen granules and well-developed microvessels were found throughout the whole fetal period. Binucleated myocytes appeared by 32 weeks gestation and this suggests that myocyte hyperplasia may cease before birth in humans. The growth of both ventricular walls, the interventricular septum and that of both ventricular cross-sectional areas showed linear regression, and the left-to-right wall thickness ratios were nearly constant. Also, there were no differences in morphometric data between the left and right ventricles. In conclusion, development of the myocyte is an ongoing process which may be continued in the post-natal period in humans, and our statistical results do not support the theory of the right ventricular dominance during the fetal period.

Two upstream elements activate transcription of a major histocompatibility complex class I gene in vitro

Expression of major histocompatibility complex (MHC) class I genes exhibits unique tissue and developmental specificity. In an effort to study molecular mechanisms of MHC class I gene regulation, an in vitro transcription system has been established. In B cell nuclear extracts a template DNA containing the mouse H-2Ld promoter sequence accurately directed RNA polymerase II-dependent transcription of a G-free cassette. A conserved class I regulatory complex previously shown to moderately enhance promoter activity in vivo enhanced transcription in vitro by 2-3 fold. Much of this enhancement was accounted for by a 40 bp fragment within the complex, which was capable of activating a basal H-2Ld promoter in either orientation. Farther downstream, another element called site B was identified, which independently activated MHC class I transcription in vitro by 2-4 fold. Site B bound a specific nuclear factor(s) through an NF-1 binding site but not through a neighboring CCAAT site. The functional significance of site B in vivo was demonstrated in transfection experiments in which site B enhanced MHC class I promoter activity to a degree comparable to that seen in vitro. With the identification of the two upstream activators, MHC class I genes may serve as a model to study roles of sequence-specific DNA-binding proteins in transcription in vitro.

Positive and negative transcriptional regulatory elements in the early H4 histone gene of the sea urchin, Strongylocentrotus purpuratus

The early H4 (EH4) histone gene of the sea urchin, Strongylocentrotus purpuratus, is shown to contain at least five positive-responding sequence elements and one negative-responding site which control the level of in vitro transcription in an embryonic nuclear extract. The positive acting elements are: 1) the UHF-1 region, located between -133 and -102 (the site of a strong footprint, due at least in part to the binding of an 85 kD protein factor termed UHF-1); 2) the H4 specific element (H4SE), situated between -62 and -39; 3) a sequence corresponding to a TATA box between -33 and -26 (TAACAATA); 4) the transcriptional initiation site; and 5) an internal sequence element found between +19 and +50. Deletion of, or base changes in, the UHF-1, H4SE, initiation, or internal sequence sites resulted in significant decreases in transcription. Base substitutions in the TATA-like sequence had much less effect, resulting in no more than a 2-fold decrease in transcription, and there was no evidence that alternative initiation sites are utilized in the mutant templates. The negative element (termed the UHF-3 site) is contained within a footprinted region between nucleotides -75 and -56. Base substitutions in this area result in templates that were transcribed at a level 1.2-2.0-fold higher than the wild-type gene. Transcription levels of double UHF-1/H4SE and UHF-1/INR mutants were those expected from additive effects of the individual mutations and there was no suggestion of synergism.

Endoscopic laser treatment of Dieulafoy's lesion

Dieulafoy’s disease is a distinctive arteriovenous malformation of the stomach, which presents with massive or recurrent gastrointestinal bleeding.

A case of Dieulafoy’s disease in an adult female, in which an endoscopic Nd: YAG (neodymium: yttrium aluminum garnet) laser was used successfully in controlling bleeding, is presented here.

Renal handling of uric acid under cyclosporin A treatment

The renal handling of uric acid during cyclosporin A (CyA) treatment was investigated by clearance studies using 24-h urine collections in 28 paediatric renal transplant recipients (CyA group), and the results were compared with those of 19 renal transplanted children treated with azathioprine and prednisolone (AZA group), 35 children with chronic renal failure (CRF) and 10 children with normal renal function (N group). Serum uric acid levels were significantly higher in the CyA group (567 +/- 156 mumol/l) compared with the AZA group (378 +/- 98), the CRF group (415 +/- 119) and the N group (290 +/- 68). Mean uric acid clearances in each group measured 3.9 +/- 2.8 ml/min per 1.73 m2 (CyA), 5.6 +/- 3.4 (AZA), 4.0 +/- 2.2 (CRF) and 8.4 +/- 3.7 (N). Calculation of the net tubular uric acid reabsorption per millilitre glomerular filtration rate revealed a significantly increased value of 0.53 +/- 0.15 mumol/ml in the CyA group (P less than 0.01) compared with 0.34 +/- 0.08, 0.29 +/- 0.15 and 0.27 +/- 0.07 mumol/l for the AZA, CRF and N groups respectively. We therefore conclude that CyA treatment is associated with an increased net tubular reabsorption of uric acid, which may lead to hyperuricaemia.

[Analysis--of family-planning in urban low-income brackets based on Daejon and Daegu Cities]

Since the inception of the national family planning program in 1962, the main emphasis has been placed on the provision of contraceptive services and information, education, and communication (IEC) activities through home visits by family planning field workers and through government designated private physicians. This approach has been a powerful management system for the national program, particularly in the rural area. However, new issues in the national family planning program emerged with the subsequent socioeconomic changes since 1962. An increasing number of the rural population began to migrate to the urban area, and, therefore, beginning in the 1970s, more weight had to be given to the family planning service for the urban area; in particular, for those in the low-income brackets. In an effort to increase contraceptive acceptors among the urban low-income people, the government has implemented various special projects for them since 1974, through maximum utilization of community leaders including Tong and Ban Chiefs and mothers' clubs, and family planning workers in their areas. Thus, this paper analyzes the current status of family planning and fertility behavior of urban low-income wives as a part of program evaluation. Also, this paper is based on an analysis of the 1984 Family Planning Survey data, which was conducted in July 1984 and responded to by 600 married women aged 15-44 in the low-income areas of the Daejon and Daegu cities. The survey data revealed that the contraceptive practice rate was 77.0%, which was much higher than 70.3% of the national practice rate in the same year, and the approval rate for the 1 or 2 children of the low-income areas was much higher than that of other urban areas. Based on the results of the analysis, the following recommendations are suggested for the better program implementation: 1) improvement of program management system for recruiting new acceptors in their 20s for birth spacing; 2) development and inducement of innovative incentive schemes and IEC activities for increasing the proportion of the 1 child families; and 3) strengthening the utilization of community resources including mothers' clubs.

Prevention of perinatal transmission of hepatitis B virus: a comparison between the efficacy of passive and passive-active immunization in Korea

In a study to compare the prophylactic efficacy of passive and passive-active immunization against hepatitis B virus (HBV) among newborn infants of HBV carrier mothers positive for hepatitis B e in Korea, both regimens resulted in effective protection against development of hepatitis B surface antigen (HBsAg): 10 of 12 recipients of hepatitis B immune globulin (HBIG) and 25 of 29 recipients of HBIG and vaccine during nine months of follow-up. Among untreated controls in the same population just before the present study, 12 of 16 developed HBsAg within nine months of birth. Seven recipients of HBIG and vaccine and four untreated infants who had HBsAg in their blood at birth were excluded. The declining antibody levels in infants who received only HBIG as compared with the rising antibody levels in infants who received HBIG followed by three doses of HBV vaccine suggest that long-term protection will be seen only in the latter group.