Repeated prenatal corticosteroid administration delays astrocyte and capillary tight junction maturation in fetal sheep

Glucocorticoids are powerful regulators of cell differentiation and maturation. Their synthetic counterparts, the corticosteroids, are used widely in obstetric practice to enhance fetal lung maturation in cases of threatened preterm birth. Here we examined the effects of repeated corticosteroid administration on astrocyte and capillary tight junction development in the fetal sheep brain, selecting the corpus callosum for analysis. Pregnant ewes were given saline or betamethasone (0.5 mg/kg) at 104, 111, 118 and 124 days gestation. Lambs were delivered at term, terminally anaesthetized and transcardially perfused. Transverse semi-thin sections of the corpus callosum were cut and immuno-stained with antibody against glial fibrillary acidic protein (GFAP). Ultra-thin sections were examined in the electron microscope. The percentage area of GFAP staining was reduced in the corticosteroid-treated group compared to control (5.2 vs. 8.7%, P<0.05). The expression of GFAP in peri-capillary and parenchymal astrocytes was also reduced compared to control (peri-capillary: 3.0 vs. 9.5 microm2; parenchymal: 14.6 vs. 29.4 microm2, P<0.05). Furthermore, capillary tight junction maturation was delayed compared to control. Immature 'type II' junctions were more common in the corticosteroid-treated group (63 vs. 22%, P<0.05), whereas more mature 'type III' junctions were less common (27 vs. 65%, P<0.05). Our data suggest that repeated corticosteroids delay both astrocyte and capillary tight junction maturation. The implications for clinical practice are as yet unknown.

Genetic analysis of recent Taiwanese isolates of a variant of coxsackievirus A24

Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v) reappeared in Taiwan in 1990 and 1994, following the first two epidemics of 1985--86 and 1988--89. To analyze the genetic diversity of recent CA24v in Taiwan, 7 Taiwanese strains isolated during the 1990--94 period were studied together with one Japanese and two Thai strains isolated in 1993. A fragment of 674 nucleotides between the carboxy terminal 3A and the amino terminal 3D polymerase, including the entire 3C protease (3C(pro)), was amplified by a reverse transcription-polymerase chain reaction (RT-PCR) and the nucleotide sequences were determined. In the 549 nucleotides (183 amino acids) of the entire 3C(pro), we found nucleotide differences at 80 positions between 10 strains and the prototype strain, EH24/70, one of the earliest strains of CA24v. Most of the nucleotide changes were synonymous substitutions and only nine amino acid changes were found. The nucleotide sequence homologies among 71 strains worldwide were 88-100%. These 71 nucleotide sequences were then analyzed by Neighbor-joining method and phylogenetically separated into three distinct genotypes. Genotype I consisted of early strains isolated in 1970--71 from Singapore and Hong Kong. Genotype II included isolates from Singapore and Thailand obtained in 1975. Genotype III comprised strains from the eastern hemisphere isolated in 1985--94 from Japan, Taiwan, China, Hong Kong, Thailand, Singapore, Pakistan and Ghana. They were further divided chronologically into six clusters. The recent isolates from Taiwan obtained in 1985/1986, 1988/1989 and 1990--94 were classified into genotype III Clusters 1, 5, and 6 respectively. The evolutionary rate was re-estimated to be 3 x 10(- 3) 30 years after the emergence of the virus.

Repeated prenatal corticosteroid administration delays myelination of the corpus callosum in fetal sheep

Glucocorticoids regulate oligodendrocyte maturation and the myelin biosynthetic pathways. Synthetic glucocorticoids, the corticosteroids have been successfully used in clinical practice as a single course to enhance lung maturation and reduce mortality and morbidity in preterm infants with no long-term neurologic or cognitive side effects. However, a trend has arisen to use repeated courses despite an absence of safety data from clinical trials. We examined the effects of clinically appropriate, maternally administrated, repeated courses of corticosteroids on myelination of the corpus callosum using sheep as a large animal model. The corpus callosum is a major white matter tract that undergoes protracted myelination, underpins higher order cognitive processing and developmental damage to which is associated with, for example, cerebral palsy, mental retardation and attention deficit hyperactivity disorder. Pregnant ewes were given saline or betamethasone (0.5 mg/kg) at 104,111,118 and 124 days gestation, stages equivalent to the third trimester in humans. Lambs were delivered at 145 days (term), perfused and the corpus callosum examined light and electron microscopically. Total axon numbers were unaffected (P>0.05). However, myelination was significantly delayed. Myelinated axons were 5.7% in the experimental group and 9.2% in controls (P<0.05); conversely, unmyelinated axons were 88.3 and 83.7% (P<0.05). Myelinated axon diameter and myelin sheath thickness were also reduced (0.68 vs. 0.94 and 0.11 vs. 0.14 microm, P<0.05). Our data suggest that repeated prenatal corticosteroid administration delays myelination of the corpus callosum and that further safety data are needed to evaluate clinical practice.

[Synthesis and bioactivity of some 3,4-diacyloxybenzopyrans]

Considerable attention is now being given to the potassium channel openers of benzopyrans as potential therapeutical agents for hypertension. In order to search for novel antihypertensive with high efficacy and low toxicity, integrating structural features of cromakalim and praeruptorin C, twenty-four compounds of 3,4-diacyloxybenzopyrans were designed and synthesized. Some of them exhibited hypotensive activity in Sprague Dawley rats.

Influence of Calcination Procedure on Porosity and Surface Fractal Dimensions of Silica Xerogels Prepared under Different Evaporation Conditions

Silica xerogels were prepared under three different solvent evaporation conditions before gelation and two calcination procedures after aging and drying, using a hydrochloric acid-catalyzed tetraethyl orthosilicate system with acetone as the solvent. The influence of calcination procedures on the percentage porosity and surface fractal dimensions of the resultant xerogels is investigated. The evaluation of percentage porosity and surface fractal dimensions based on field emission gun-scanning electron microscopy indicates that calcination generally causes an increase in percentage porosity and surface fractal dimensions. Calcination at 700 degrees C without an intermediate stay at 600 degrees C leads to larger extent of further condensation that hinders the increase of porosity and surface fractal dimensions, in comparison with calcination with an intermediate stay. The difference in porosity and surface fractal dimensions derived from calcination procedures is also influenced by the solvent evaporation conditions before gelation in preparation of the samples. When the solvent evaporation rate is slower, the difference is slight because further condensation in the resultant finer gel textures proceeds more efficiently. Copyright 2000 Academic Press.

Effect of corticosteroids on brain growth in fetal sheep

OBJECTIVE

To compare the effects of single and repeated courses of corticosteroids on brain growth in fetal sheep.

METHODS

Pregnant sheep were given intramuscular betamethasone (0.5 mg/kg) at 104 days' gestation followed at 111, 118, and 124 days by equivalent volumes of sterile normal saline (n = 12) or betamethasone (n = 12). Controls received equivalent volumes of sterile normal saline at all four intervals (n = 12). Lambs were delivered at 125 (preterm) or 145 (term) days. After perfusion, we measured weights (grams) for whole brain, cerebrum, cerebellum, and brain stem, volumes (milliliters) for whole brain and cerebrum, and maximum cerebral anterior-posterior length, width, and depth (centimeters).

RESULTS

In the single-injection group at preterm, there were no significant differences (P = .070) in whole-brain weight between the corticosteroid-treated animals (38.0 +/- 1.81 g) and controls (42.5 +/- 1.65 g). Cerebral length and depth were significantly reduced in the corticosteroid group (P < .05); other measures were not significantly different. At term, whole-brain weight was significantly lower (47.5 +/- 1.70 g; P = .022) compared with controls (53.4 +/- 1.73 g). All other measures were significantly reduced (P < .05) except cerebral and brain-stem weights and cerebral length. In the group that received repeated injections at preterm, whole-brain weight was significantly reduced (35.5 +/- 1.65 g; P = .005) compared with controls (42.5 +/- 1.65 g). All other measures were significantly reduced (P < .05) except cerebellar and brain-stem weights. At term, whole-brain weight was also significantly reduced (42.4 +/- 1.52 g; P = .001) compared with controls (53.4 +/- 1.73 g) as were all other measures (P < .05).

CONCLUSION

Administration of single and repeated courses of corticosteroids to pregnant sheep retarded fetal brain growth.

Effect of exogenous corticosteroids on the developing central nervous system: a review

Corticosteroid therapy is used in a variety of developmental clinical settings. Prenatally, maternal administration of corticosteroids is used primarily in the prevention of respiratory distress syndrome. Postnatally, corticosteroids are used to treat a variety of infant diseases such as autoimmune hemolytic anemia and hypoglycemia. Treatment regimes often involve repeated administration, on a weekly basis prenatally and daily postnatally, despite an absence of safety data from randomized clinical trials. A large number of animal studies, the majority of which used rodents, have shown that both repeated prenatal or neonatal administration of exogenous corticosteroids has a wide range of detrimental effects on the structure and function of the developing central nervous system (CNS). None of these studies included long-term follow-up. Despite the reported detrimental effects on CNS development, a number of animal studies have shown that pretreatment with corticosteroids nevertheless protect the brain from hypoxia-ischemic injury; however, clinically such treatment is no longer favored. Studies using large animal models and with long-term follow-up should be undertaken to establish the relative risks and benefits of the repeated application of exogenous corticosteroids.

Reversal of tumor multidrug resistance by 2-phenyl-3-(3',5'-dimorpholinomethyl-4'-hydroxy)-benzoyl-indole (HWL-12)

AIM

To explore the reversal of multidrug resistance (MDR) by indole derivative HWL-12.

METHODS

Cytotoxicity was determined by tetrazolium (MTT) assay. The function of P-gp was examined by Fura 2-AM assay. Cellular accumulation of doxorubicin (Dox) was measured by fluorescence spectrophotometry.

RESULTS

HWL-12 10 mumol.L-1 markedly increased Fura-2 accumulation and was 17.2-fold reversal of MDR in MCF-7/ADR cells. The cellular Dox accumulation in MDR cells was increased in the presence of HWL-12 on the MCF-7/ADR cells. No effect was observed for Dox accumulation in the presence of high Ca2+ (addition of CaCl2) or low Ca2+ (addition of egtazic acid).

CONCLUSION

HWL-12 has a potent MDR reversal action which was associated with the increase of cellular Dox accumulation in MDR cells and not related with calcium ion concentration.

Improvement of hepatitis B virus DNA vaccines by plasmids coexpressing hepatitis B surface antigen and interleukin-2

DNA vaccines encoding a viral protein have been shown to induce antiviral immune responses and provide protection against subsequent viral challenge. In this study, we show that the efficacy of a DNA vaccine can be greatly improved by simultaneous expression of interleukin-2 (IL-2). Plasmid vectors encoding the major (S) or middle (pre-S2 plus S) envelope proteins of hepatitis B virus (HBV) were constructed and compared for their potential to induce hepatitis B surface antigen (HBsAg)-specific immune responses with a vector encoding the middle envelope and IL-2 fusion protein or with a bicistronic vector separately encoding the middle envelope protein and IL-2. Following transfection of cells in culture with these HBV plasmid vectors, we found that the encoded major protein was secreted while the middle protein and the fusion protein were retained on the cell membrane. Despite differences in localization of the encoded antigens, plasmids encoding the major or middle proteins gave similar antibody and T-cell proliferative responses in the vaccinated animals. The use of plasmids coexpressing IL-2 and the envelope protein in the fusion or nonfusion context resulted in enhanced humoral and cellular immune responses. In addition, the vaccine efficacy in terms of dosage used in immunization was increased at least 100-fold by coexpression of IL-2. We also found that DNA vaccines coexpressing IL-2 help overcome major histocompatibility complex-linked nonresponsiveness to HBsAg vaccination. The immune responses elicited by HBV DNA vaccines were also modulated by coexpression of IL-2. When restimulated with antigen in vitro, splenocytes from mice that received plasmids coexpressing IL-2 and the envelope protein produced much stronger T helper 1 (Th1)-like responses than did those from mice that had been given injections of plasmids encoding the envelope protein alone. Coexpression of IL-2 also increased the Th2-like responses, although the increment was much less significant.

Swyer-James syndrome associated with Noonan syndrome: report of a case

A 28-year-old man with Noonan syndrome associated with unilateral hyperlucent lung is reported. He had the typical craniofacial appearance and short stature of Noonan syndrome; he had mild mental retardation, atrophic testis, mild funnel chest and kyphosis. cardiovascular abnormalities included asymmetric hypertrophic cardiomyopathy and a significantly different caliber of the left and right pulmonary arteries. The unilateral hyperlucent lung was shown to result from acquired nondestructive emphysema caused by nonvalvular obstruction of the bronchi (Swyer-James syndrome or Macleod's syndrome). To the authors' knowledge, this is the first reported case of Noonan syndrome associated with Swyer-James syndrome.

A molecular study of ocular herpes simplex infection in Kaohsiung, Taiwan. Part I: Cleavage pattern analysis

In order to investigate the relationship between genotypes of herpes simplex virus (HSV) and its clinical pictures in herpes simplex virus keratoconjunctivitis (HSK), fifty nine strains of HSV isolates, collected in the Kaohsiung Medical College Hospital during January 1981 to July 1991, and F strain (ATCC VR-73), a standard HSV-1, were studied. The viruses were isolated from HSK patients. All 59 strains were identified as HSV-1 using immunofluorescence monoclonal antibody method. The HSV DNAs were extracted and digested by restriction enzymes, BamH I, Kpn I and Sal I, followed by electrophoresis, and photographing. Six kinds of DNA cleavage patterns were found in Taiwan. The majority were E subtype (56.4%) then A subtype (27.3%), D subtype (7.3%), F subtype (5.4%), G subtype (1.8%) and H subtype (1.8%). Subtypes B and C were not found in this study. The cleavage patterns of two recurrent cases belonged to E and A subtypes. The identical cleavage patterns of two bilateral infections all belonged to the E subtype.

Prominent proliferative response of peripheral blood mononuclear cells to a recombinant non-structural (NS3) protein of hepatitis C virus in patients with chronic hepatitis C

The proliferative response of peripheral blood mononuclear cells (PBMC) to a recombinant non-structural (NS3) protein of hepatitis C virus (HCV) was studied in 41 patients with chronic hepatitis C. Of them, 28 had chronic persistent hepatitis (CPH) and 13 chronic active hepatitis (CAH). The positive proliferation rate of PBMC to the recombinant NS3 protein, T9Ag, was 66% in the 41 patients (77% in CAH versus 61% in CPH; P > 0.05) when stimulation index (SI) = 4 was set as the cut-off value. However, mean SI of CAH patients was significantly higher than that of CPH patients (8.3 +/- 5.2 versus 5.1 +/- 3.6; P < 0.05). Six other chronic hepatitis patients who were repeatedly negative for anti-HCV antibody but positive for serum HCV RNA also had an SI of > or = 4.0. The frequency of cellular immune response to the T9Ag is among the highest results obtained by using HCV antigens tested so far. Our studies thus indicate that NS3 is an immunologically important region of HCV for T cells. Moreover, the proliferative response to T9Ag may help to establish hepatitis C etiology in chronic hepatitis patients who are seronegative with currently available anti-HCV assays.

[The re-evaluation of the prevalence of trachoma in primary school children in Kaohsiung City]

For years, trachoma screening has been a routine part of the health examination program for all primary school children. In order to ascertain the current prevalence of trachoma in primary school children, we used clinical examination, immunofluorescein-monoclonal antibody and McCoy cell culture technique to examine 771 children from 5 primary schools in Kaohsiung City. Using the results of the McCoy cell culture as a judgement standard, we found that 118 children (15.3%) had chlamydia trachomatis infections. The infection rates of children were statistically insignificant for sex, grade and location of school of children. Among the 118 infected children, most had none or mild (96.6%) conjunctival inflammation. Only 3 children (0.4%) had conjunctival cicatrization complications. These results showed that the repeated reinfections among these children were quite few. The McCoy cell culture was used to test the result of clinical diagnosis made by the senior ophthalmologists. The sensitivity of the clinical diagnosis was 50% and the predictive positive rate was 26.6%. It revealed that the diagnosis of trachoma made by clinical observation only was unreliable. The results of immunofluorescein-monoclonal antibody test showed that 120 children (15.6%) had trachomatous infections. Its sensitivity was 68.4%, and specificity was 91.7%. It revealed that more care should be taken in quality control of laboratory techniques. From these results, we conclude: 1) the trachomatous infections of primary school children in Kaohsiung City are not serious; the repeated infections among

Expression of the Epstein-Barr virus DNA polymerase in Escherichia coli for use as antigen for the diagnosis of nasopharyngeal carcinoma

Epstein-Barr virus (EBV) encoded DNA polymerase (POL) was cloned and over-expressed in Escherichia coli. Western blot analysis confirmed the presence of antibody to this POL protein in sera from nasopharyngeal carcinoma (NPC) patients. By Western blot analysis, moderate to high concentration of IgG POL-specific antibodies were present in 43 of 48 NPC sera and only 4 of 48 healthy, seropositive controls. The POL-specific IgG antibodies appear as early as stage I of NPC, suggesting that the recombinant POL protein can be a useful diagnostic marker for early diagnosis of the disease. It was also found that human sera containing high titer of cytomegalovirus (CMV) antibodies or herpes simplex virus type 1 (HSV-1) antibodies did not cross-react with the recombinant EBV POL, despite the homology shared by DNA polymerase proteins of these viruses.

Analysis of T-lymphocyte subpopulations in inflammatory bowel diseases by three-color flow cytometry

In order to better define changes in the relative proportion of peripheral blood T-lymphocyte subpopulations in patients with inflammatory diseases of the bowel, we performed simultaneous three-color fluorescence-activated cytometric (FACS) analysis using fluorophore-conjugated monoclonal antibodies with specificity for CD4, CD8, Leu 8, and CD45RA on 22 normal control subjects, 28 patients with Crohn's disease (CD), 15 patients with ulcerative colitis (UC), and 11 patients with intestinal inflammation secondary to etiologies other than inflammatory bowel disease (NIBD). This staining combination allowed enumeration of distinct T-cell subpopulations as follows: virgin CD4+, recall antigen helper T cells, nonspecific B-cell helper T cell, virgin CD8+, cytotoxic effector and suppressor effector and recall antigen cytotoxic T cells based on a synthesis of published functional analyses. No differences in the proportion of CD4+ or CD8+ cells or in the CD4+/CD8+ ratios were evident when UC and NIBD patients were compared to normal subjects. A significant reduction in the proportion of CD4+ cells and an increase in CD8+ cells was observed, however, in the CD group. When two-color analysis was performed, several significant differences in the proportions of circulating lymphocytes were seen. Specifically, these included significant increases in the number of CD4+, Leu 8- (P < 0.01) cells in all disease groups and an increase in CD4+, CD45RA+ cells in the NIBD group. Conversely, significant decreases in the proportions of CD8+, Leu 8+ (P < 0.01) cells were evident in the Crohn's disease group.(ABSTRACT TRUNCATED AT 250 WORDS)

Study on some biological and antigenic characteristics of CA24v isolates in Taiwan in 1985-1989

In order to understand the relationship between the CA24v isolates which caused two epidemics of acute hemorrhagic conjunctivitis (AHC) in 1985-1986 and 1988-1989 in Taiwan, biological and antigenic characteristics were studied with four CA24v strains, L077/85, V116/86, 590/88 and 722/89, which were isolated during the epidemics. The prototype strain, EH24/70, was used for comparison. In terms of cross neutralization, kinetic neutralization, plaque assay and protein electrophoresis, no obvious differences were found between the isolates from the two epidemics though differences were found between these isolates and the prototype.

[The effects of exercise on the arterial potassium and ventilatory response under hyperoxic, normoxic, and hypoxic conditions]

BACKGROUND

Exercise leads to an increase in plasma potassium, the animal experiments showed that potassium infusion stimulated ventilation and abolished by peripheral chemodenervation and also showed that combined effects of potassium and hypoxia were greater than the sum of the individual effects. This study proposed to investigate plasma potassium and its correlation with exercise, and to investigate the effects of hypoxia and hyperoxia on potassium and ventilation during steady state exercise.

METHODS

Ten male subjects exercised on a cycle ergometer. Each performed (1) incremental exercise test; (2) steady state exercise test with a work rate of about 75% of anaerobic threshold under hyperoxic (FiO2 100%), normoxic (FiO2 21%) and hypoxic (FiO2 12%) conditions, respectively.

RESULTS

Arterial plasma potassium concentration rose from a pre-exercise level of 3.97 +/- 0.40 mEq/L to the post-exercise level of 5.11 +/- 0.49 mEq/L. The increase in plasma potassium during exercise correlated well with the increase in lactate (r = 0.72, p < 0.05) and the decrease in pH (r = 0.69, p < 0.05). During the steady state exercise test, switching the subject from room air to hypoxic (12% O2) conditions led to a significant rise in both plasma potassium (p < 0.05) and ventilation (p < 0.05) with good correlation between the potassium increase and the increase in ventilation (r = 0.85, p < 0.05). Switching the subject from room air to hyperoxic (100% O2) condition resulted in a significant decrease in ventilation (p < 0.05) without significant change in plasma potassium (p > 0.01).

CONCLUSIONS

It was concluded that (1) exercise can lead to an increase in arterial potassium, hydrogen ion, lactate in men; (2) hypoxia can stimulate the peripheral chemoreceptor and increase plasma potassium level. Potassium may, therefore, be an important factor by which the magnitude of the peripheral chemoreflex response is augmented during exercise.

Platelet derived growth factor (PDGF), androgens and inflammation: possible etiologic factors in the development of prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is characterized by varying degrees of epithelial and stromal hyperplasia in association with inflammation. Although androgens are known to be important for the growth and function of the prostate, their role in the development of BPH is unclear. The release of platelet-derived growth factor (PDGF) in response to inflammation suggests that PDGF may participate in the development of BPH. Cultured prostate cells derived from patients with BPH were examined for the presence of functional PDGF and androgen receptors. The cells expressed PDGF receptors and responded to PDGF stimulation by the activation of the PDGF signal transduction pathway and a dose-dependent stimulation of cell proliferation. Even though the cells expressed androgen receptors, dihydrotestosterone failed to elicit a mitogenic response. While the role of androgens in BPH remains unclear, these results suggest that inflammation and, specifically, PDGF may be important etiologic factors in the development of BPH.

Molecular epidemiology of a variant of coxsackievirus A24 in Taiwan: two epidemics caused by phylogenetically distinct viruses from 1985 to 1989

In order to know the phylogenetic relationship and the route of transmission of a variant of coxsackievirus A24 (CA24v), an agent that caused four sequential outbreaks of acute hemorrhagic conjunctivitis from 1985 to 1989 in Taiwan, the nucleotide sequence variations in the virus-encoded proteinase 3C region (549 nucleotides) were studied with 19 isolates. The prototype strain (EH24/70), four isolates from Japan, and two isolates from Hong Kong were used for comparison. The nucleotide sequences of the Taiwan strains from the 1985-1986 and 1988-1989 epidemics were closely related within each epidemic, while they were more distantly related between strains from two epidemics. Phylogenetic analysis by the unweighted pairwise grouping method of the arithmetic average revealed that the 19 Taiwan isolates had diverged into two groups, 1985-1986 and 1988-1989 groups. The time at which these two groups diverged was estimated to be around May 1982, more than 3 years prior to the first appearance of the CA24v epidemic in Taiwan. On each occasion, the viruses caused a 2-year epidemic and then disappeared. The Taiwan isolates from 1985 to 1986 were closely related to the Japan isolates from 1985 to 1986 and the Taiwan isolates from 1988 to 1989 were phylogenetically close to the 1989 Japan isolates, indicating that Taiwan and Japan had two common-source outbreaks. However, none of the 1988 Taiwan isolates were phylogenetically close to the 1988 Japan or Hong Kong isolates. The evidence revealed that Taiwan has had two repeated but discontinuous introductions of CA24v since its first appearance in Taiwan in 1985. None of the other CA24v strains have been detected so far.

[Blood lactate changes during incremental exercise in chronic obstructive pulmonary disease]

In order to evaluate whether the lactic acidosis is developed during incremental exercise test in COPD. 12 untrained subjects with COPD performed incremental maximal cycle ergometer tests. Ventilation (VE); O2 uptake (VO2), CO2 output (VCO2); and end-tidal CO2 fraction (FETCO2) were measured. Arterial lactate concentration and blood gas analysis were measured at rest, maximal exercise and recovery of exercise from an indwelling arterial catheter. of the degree of airway obstruction. (2) T40 and BEecf correlated well with lactate change (r = 0.83; 0.84, P < 0.05). (3) The change of VE, and RQ correlated with the lactate change (r = 0.81; 0.83, 0.72, P < 0.05), but not the VE/VO2, VE/VCO2, nor FETCO2, (r = 0.24; 0.06; 0.46, P > 0.05). We concluded that the blood lactate increased markedly in patients of COPD during increment exercise, and it was well corrected with the change of VE, VCO2 and RQ. The increased lactate could be indicated by the concomitant change of T40 and BEecf.

Interaction of berbamine compound E6 and calmodulin-dependent myosin light chain kinase

The interaction of the berbamine compound E6 and calmodulin (CaM)-dependent myosin light chain kinase (MLCK) has been studied. The experimental results showed that the inhibition of MLCK activity was increased with increasing amounts of E6 and was overcome completely by the addition of excessive CaM. The stimulatory activity of MLCK induced by CaM was gradually inhibited by the increasing concentrations of compound E6, showing that the inhibition of MLCK activity by compound E6 was concentration dependent; and the Ki was 0.95 microM. Compound E6 diminished the fluorescence intensity of dansyl-labeled CaM and the intensity was increased gradually by the addition of different amounts of CaM. Compound E6 had no effect on the activity of MLCK fragments produced by limited trypsinization, and it is a novel and considerably potent calmodulin antagonist.

The downstream regulatory sequence of the adenovirus type 2 major late promoter is functionally redundant

Mutagenesis of promoter sequences and oligonucleotide competition assays have been used to demonstrate the late-phase-specific stimulation of the adenovirus type 2 major late promoter is mediated by functionally redundant elements located between positions +75 and +125. These octamer motif-related sequences are recognized by multiple factors.