Inhibition of restriction endonuclease activity by DNA binding fluorochromes

Activity of type II restriction endonuclease is affected by many common factors including buffer composition and sequences flanking the recognition site (Brabec et al., Eur.J. Biochem. 216, 183, 1993). The successful development of Optical Mapping (Schwartz et al., Science, 262, 110, 1993; Meng et al., Nature Genet. 9, 432, 1995; Wang and Schwartz, PNAS, 1995 Cai et al., PNAS, 92, 5164, 1995) relied on optimization of light microscope-based imaging of fluorescently labeled DNA molecules during restriction endonuclease digestion. Little was known about the effects of commonly used DNA-fluorochromes on restriction endonuclease activity. Thus, we developed an enzyme activity assay using lambda bacteriophage DNA or adenovirus-2 DNA to evaluate the effects of five DNA binding fluorochromes (4'-6-daimidine-2-phenylindole (DAPI), ethidium bromide (EtdBr), ethidium bromide homodimer (EthD-1), bis-benzimide (H33258) and benzothiazolium-4-quinolinium dimer (TOTO-1)) on the enzymatic activities of eleven type II restriction endonucleases (Asc I, Csp I, Dra I, EcoR I, Hha I, Hind III, Not I, Rsr II, Sfi I, SgrA I and Sma I). We found that the minor groove binding fluorochrome, DAPI, did not measurably inhibit activity of this group, with the exception of Dra I. Similarly, another minor groove binding fluorochrome H33258 inhibited Dra I and Not I (slightly). The three intercalating fluorochromes EtdBr, EthD-1 and TOTO-1, however, variably inhibited the other enzymes. Since Beta-mercaptoethanol (Beta-ME) is used to discourage photodamage of stained DNA molecules, we also assessed its effect on restriction endonuclease activity. Interestingly, Dra I, Hind III, Sfi I and Sma I retained full activities at high concentration of Beta-ME (5%), but Asc I, Csp I, Not I, Rsr II and SgrA I showed varying sensitivities to the Beta-ME. Isoschizomers Csp I and Rsr II behaved differently to both fluorochromes and Beta-ME. The results presented here should provide a basis for further development of new Optical Mapping-based techniques requiring fluorescence labeling of other actively imaged enzymatic reactions.

Alpha-adrenergic preservation of myocardial pH during ischemia is PKC isoform dependent

alpha-adrenergic stimulation of patients with ischemic heart disease should intuitively impose a destructive stress. However, therapeutic alpha1-adrenergic receptor mediated cardioadaptation prior to myocardial ischemia protects ventricular mechanical function, promotes electrophysiologic stability, and preserves myocyte viability. Prior to an anticipated cardiac ischemic insult, alpha1-adrenergic preconditioning attenuates ischemic myocardial acidosis by a protein kinase C-(PKC) dependent mechanism. The alpha1-adrenoceptor can directly stimulate calcium-independent nPKC isoforms via diacylglycerol (DAG) or indirectly stimulate calcium-dependent cPKC isoforms through the release of intracellular calcium via inositol triphosphate, (IP3). We hypothesized that alpha1-adrenergic limitation of ischemic acidosis is mediated by the family of calcium-dependent PKC isoforms. [31P]NMR spectra were obtained in isolated, buffer perfused rat hearts treated with alpha1-adrenergic stimulation [phenylephrine (PE) 50 microM, 2 min]; PKC blockade [chelerythrine chloride, (Chel) 20 microM]; or stearoyl-arachidonoyl glycerol (SAG, a DAG analogue, 100 microM, 2 min) administered 10 min prior to ischemia. Control hearts were perfused under normoxic conditions for 20 min. All hearts were then subjected to global ischemia (20 min, 37.5 degrees C). Developed pressure (DP) and heart rate were recorded continuously. pHi was obtained from chemical shift of inorganic phosphate. Immunohistochemical staining was utilized to delineate the translocation and activation profiles of specific PKC profiles established with each stimulus. Pre-ischemic alpha1-adrenergic stimulation did attenuate the myocellular hydrogen ion accumulation during sustained normothermic ischemia (6.90 +/- 0.13 vs control 6.54 +/- 0.10; P < 0.05). General PKC inhibition abrogated this effect (end-ischemic pH 6.17 +/- 0.10; P < 0.05 vs control and PE). Ischemic acidosis was not attenuated following selective nPKC stimulation (SAG, 6.48 +/- 0.08; NS vs control). Myocellular immunohistochemical staining revealed translocation of the calcium-independent PKC-epsilon isoform in the calcium-dependent PKC (SAG) group, but not in response to alpha1-adrenergic stimulation. The results suggest that (1) alpha1-adrenoceptor stimulation limits ischemic acidosis, (2) alpha1-adrenergic stimulated attenuation of ischemic acidosis is PKC dependent, (3) direct nPKC stimulation with SAG does not limit ischemic acidosis, and (4) SAG stimulates nPKC-epsilon isoform activation where alpha1-adrenergic stimulation does not. We conclude that alpha1-adrenergic stimulation limits ischemic acidosis by a cPKC-dependent mechanism and that the mobilization of the IP3 arm by receptor stimuli suppresses PKC-epsilon thus permitting the limitation of ischemic acidosis.

A single endotoxin challenge induces delayed myocardial protection against infarcation

Sublethal endotoxemia attenuates cardiac functional injury from global ischemia but it is unknown whether endotoxemia can protect myocardium against infarction. Furthermore, increases in myocardial catalase and heat shock protein (HSP) following endotoxemia have been associated with cardiac ischemic protection. We therefore hypothesized that a 72-hr pretreatment with endotoxin (ETX) would reduce myocardial tissue necrosis in association with augmented catalase activity and stress protein expression. Rabbits were treated with normal saline or lipopolysaccharide (Salmonella typhimurium) at 10, 5, and 1 microgram/kg doses. Three days after saline or ETX injection they were subjected to 45 min of coronary artery occlusion followed by 3 hr of reperfusion. Area of necrosis (tetrazolium staining) was normalized to anatomic risk zone size (Evans blue staining). Catalase activity was measured by a standard assay and HSP 72 was assessed by immunohistochemistry. During regional ischemia and reperfusion there were no differences in heart rate or mean arterial blood pressure between groups. ETX treated rabbits had the same risk zone size as controls. Infarct size was reduced in the ETX treated rabbits at the 10 and 5 microgram/kg doses compared with control rabbits (17.5 +/- 1.5% and 22.2 +/- 3.1% vs 45.3 +/- 2.5%; P < 0.05) but no protective effect was observed at the 1.0 micrograms/kg dose (38.0 +/- 4.6%; P > 0.05 vs control). Catalase activity was not different between control and ETX (5 microgram/kg) treated groups (997.8 +/- 59.1 U/g vs 1099.6 +/- 69.3 U/g myocardium; P > 0.05) but endotoxin induced expression of myocardial HSP 72. We conclude that a single challenge with endotoxin can induce delayed myocardial protection against infarction in vivo. This delayed cardioprotective response involves enhanced stress protein expression without changes in myocellular catalase activity.

[Immunohistochemical double labelling studies on liver tissues superinfected with hepatitis C virus and hepatitis B virus]

OBJECTIVE

To explore the relatiship between hepatitis C virus (HCV) and hepatitis B virus (HBV) replication in liver tissue of patients superinfected with HCV and HBV.

METHODS

The expresion and distribution of HCVAg and HBVAg in paraffin-embeded liver tissue from 25 autopsy cases were studied with immunohistochemical double labelling techniques using monoclonal anti-HCV NS3 and anti-HCV NS5 as well as polyclonal anti-HBs and anti-HBc.

RESULTS

HBsAg and HCV NS3 or NS5 antigen were detected at the same section in 11 and 12 cases, and HBcAg and HCV NS3 or NS5 antigen in each 10 cases, respectively. Nearly all of the specimens with single labelling stained positive tissue for HC-VAg or HBVAg were also those positive with double labelling studies for HCVAg and HBVAg. The distribution of HCV and HBV infected hepatocytes was characterized as diffuse and single or cluster scattered in liver lobular. There were no differences in expression related to replication such as membranous, cytoplasmic type of HBsAg or cytoplasmic type of HBcAg and the cases positive for HCV NS3Ag or HCV NS5Ag between the group of HCV superinfected with HBV and the group infected with single HCV or HBV (chi 2 = 0.154 and 0.198, P > 0.05).

CONCLUSION

The results suggested that there was no interference or suppression each other in liver tissues superinfected with HCV and HBV.

Laser demonstration of diode-laser-pumped neodymium-doped strontium fluorovanadate

The laser properties of diode-laser-pumped neodymium-doped strontium fluorovanadate samples cut perpendicular to the x(a) and y axes have been investigated. A slope efficiency of 36% for the 1.065-µm laser line and a lasing threshold of 6.8 mW have been measured for the x(a)-axis-cut crystal. Data are also presented for the laser's performance as a function of crystal temperature and for the variation of the central peak wavelength with the incident pump power.

Normal range estimation for repeated immunologic measures

A method for estimating a normal range from a set of immunologic measurements on control subjects when there may be more than one observation per subject is described. The method is nonparametric, makes efficient use of all observations, and is very simple to apply. It is illustrated on a set of 152 CD38 measurements from 58 healthy men.

Omniplane transesophageal echocardiography imaging planes exploration

One hundred and twenty-four patients with heart disease were examined by omniplane TEE in order to systematically research every views of omniplane TEE, and further explore anatomy and image feature of each view. The result showed that omniplane TEE transducer can be rotated in probe from 0 degree to 180 degrees, obtain many views at various angles behind the heart and fully demonstrate the structure and pathology of the heart and great vessels. It was useful for clinical diagnosis because of getting more information about the heart and great vessels. As omniplane TEE probe was little rotated in esophagus, it lessened esophagus stimulation. Meanwhile, it was suitable for three-dimensional reconstruction of left ventriculum.

Determination of the in vivo post-antibiotic effects of ciprofloxacin and rifampicin

A modified rabbit meningitis model is described for determining the PAE in vivo, which utilised a self-standing device for repeatedly sampling pure CSF. The model allowed the PAEs of ciprofloxacin and rifampicin on Escherichia coli ATCC 25922 to be determined following PAE induction in vitro, or in vivo in CSF after intrathecal injection or during the last 1.5 h of a 7 h iv continuous infusion. The estimated volumes of distribution of ciprofloxacin and rifampicin in CSF were 0.68 +/- 0.24 mL and 0.74 +/- 0.04 mL, respectively, and the terminal elimination half lives were 1.8 +/- 0.5 h and 2.2 +/- 0.3 h, respectively. PAEs of approximately 2 h were obtained in vivo and in vitro after exposing E. coli to 3 x MIC of ciprofloxacin in vitro and to 1 x MIC of drug in vivo. When the organism was exposed to rapidly declining concentrations in vivo, only a minimal PAE was observed for both antibiotics. Moreover, a PAE of 3.1 +/- 1.3 h of rifampicin was obtained in vivo, being smaller than the 4.8 h PAE observed in vitro, which might be explained by the binding of 45 +/- 6.5% rifampicin to proteins in the CSF.

Superficial carcinomas of the esophagus and gastric cardia. A clinicopathological analysis of 141 cases

From January 1970 to June 1992, 141 patients with superficial esophageal and cardiac carcinomas (SEC and SCC) underwent surgical treatment. Of the 141 patients 128(90.8%) had slight symptoms related to swallowing, and the remaining 13(9.2%) were asymptomatic. Balloon cytology and esophagoscopy proved very useful for the diagnosis of SEC and SCC, and Lugol's solution staining technique was an effective auxiliary diagnostic measure. Lymph node metastasis was not found in patients with epithelial (EP) cancer. However, it was present in one (2.9%) of 34 patients with muscularis mucosal (MM) invasion, and in 5 (8.6%) of 58 patients with submucosal (SM) cancer. The 5-year survival rates of the patients with SEC and SCC were 75.5% and 71.4%, respectively (P > 0.05). The different depth of tumor invasion including EP, MM and SM cancers showed significant differences in the 5-year survival rate (P < 0.05). Although the prognosis for the patients with lymph node metastasis is poor, we should advocate extended lymph node dissection in surgical treatment of the patients in whom MM and SM cancers are suspected.

Differentiation of murine embryonal carcinoma in vitro and in vivo with N,N-dimethyl acetamide

Polar solvents such as N,N-dimethyl acetamide (DMA) are known inducers of tumor cell differentiation in vitro. Nothing is known about their ability to induce differentiation in vivo. Using PCC4 AZArL murine embryonal carcinoma (EC) cells we examined the time course and dose response relationship of DMA induced EC differentiation in vitro. The effective continuous dose range of 0.1% to 0.15% gave a linear increase in differentiation index with the probability of attaining complete differentiation. EC tumors were raised subcutaneously in the flanks of strain 129 mice and DMA injected intraperitoneally at a dose calculated to attain tissue levels of between 0.1% and 0.15%. DMA induced significant differentiation primarily into neuroepithelium when compared to negative controls, but DMA was not as effective as retinoic acid. The extent of differentiation was dosage dependent, but the maximal dose of DMA was limited by toxicity mainly to the liver and lymphoid tissues. A graduated dosage schedule of DMA treatment reduced toxicity. These preliminary studies suggest that "differentiation therapy" with polar solvents such as DMA may be an effective adjunct to standard therapies.

Potential gene therapy strategies in the treatment of cardiovascular disease

Gene therapy is the introduction of new genetic material into somatic cells to synthesize missing or defective proteins. Efficient methods for the introduction of genetic material into cells are available, both in vitro and in vivo. These strategies involve chemical, physical, and viral-mediated mechanisms of gene transfer. Application of these gene transfer techniques has led to the development of potential gene-based treatment strategies that could combat vascular and myocardial disease. Gene therapy in the treatment of cardiovascular disease promises to alter atherosclerotic risk factors, prevent vascular thrombotic disease, retard progression of disease in the peripheral vasculature, provide drug delivery systems, and prevent myocardial infarction in patients with coronary artery disease. This exciting technology will eventually become the ultimate intervention in the treatment of cardiovascular disease.

Mechanisms of immature myocardial tolerance to ischemia: phenotypic differences in antioxidants, stress proteins, and oxidases

BACKGROUND

Previous work has suggested tolerance to ischemic injury in newborn myocardium. Although various mechanisms for this protection have been proposed, a link between oxidant-antioxidant factors, stress protein expression, and protection from cardiac ischemia/reperfusion (I/R) injury has not been made in newborn myocardium. We hypothesized total newborn myocardial resistance to I/R is related to decreased oxygen radical producing potential, increased free radical scavenging capacity and augmented stress protein expression. The purposes of the study were to examine in newborn and adult rat hearts (1) functional recovery from I/R, (2) catalase and xanthine oxidase (XO) activities, and (3) heat shock protein 72 (HSP 72) expression.

METHODS

Isolated rat hearts (7 to 10 days versus 60 days) were perfused on a nonworking Langendorff apparatus at 60 mm Hg (Krebs-Henseleit buffer, pH 7.4, 37 degrees C) and subjected to 20 minutes of global ischemia and 40 minutes of reperfusion. Left ventricular developed pressure was recorded by using a left ventricular catheter. Catalase and XO were measured by means of standard assays, and HSP 72 was assessed with in situ immunohistochemistry.

RESULTS

Newborn rat hearts had greater percentage functional recovery of left ventricular developed pressure after I/R (66.0% +/- 4.2% versus 44.3% +/- 3.5%; p < 0.05). The newborn myocardium also had increased catalase activity (1027.9 +/- 20.6 units/gm versus 707.3 +/- 38.7 units/gm; p < 0.05), whereas the activity of XO was decreased relative to the adult (0.23 +/- 0.01 mU/gm versus 7.6 +/- 1.4 mU/gm; p < 0.05). Furthermore, the expression of HSP 72 was greater in the newborn than the adult control.

CONCLUSIONS

Relative to adult hearts, newborn rat hearts are more tolerant to a global ischemic insult followed by reperfusion. This improved functional recovery is associated with decreased oxidant production potential (XO), increased scavenging capacity (catalase), and augmented stress protein expression (HSP 72).

[Diagnosis and treatment of interrupted aortic arch: report of 6 cases]

Six patients with interrupted aortic arch were operated on from Nov. 1986 to Jun. 1992. 4 patients were type A and 2 type B. The result was good except a patients of type A died early after operation. Two-stage operation was performed for 4 patients of type A, and 2 patients of type B accepted posterolateral incision. The aortic arch was constructed with artificial vessel. Cardiopulmonary bypass was set up with patients lying on back, then PDA was ligated and VSD closed. Pulmonary artery trunk reconstruction and VSD closing were performed. Three months after operation a patient died of septicemia caused by infection of incision.

Dysfunction of cGMP-mediated pulmonary vasorelaxation in endotoxin-induced acute lung injury

Endothelial-dependent and -independent cGMP-mediated mechanisms of pulmonary vasorelaxation were studied in endotoxin-induced acute lung injury in the rat. Concentration-response curves were generated (10(-9) to 10(-6) M) for acetylcholine (ACh), A23187, and sodium nitroprusside (SNP) and for 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) (10(-9) to 10(-4) M) in isolated pulmonary arterial rings preconstricted with phenylephrine 6 h after endotoxin treatment (20 mg/kg ip). Endotoxin treatment produced significantly increased lung neutrophil accumulation (myeloperoxidase assay, 28 +/- 6 units/g lung tissue vs. 1.8 +/- 1 in controls) and lung leakage (lung/blood 125I-labeled albumin ratio, 0.06 +/- 0.01 vs. 0.028 +/- 0.01 in controls) as well as histological evidence of pulmonary vascular endothelial damage. The concentration-response curves demonstrated that pulmonary vasorelaxation by mechanisms that require generation of cGMP by either endothelial-dependent (both receptor-dependent, ACh, and receptor-independent, A23187) or endothelial-independent (SNP) pathways were significantly impaired after endotoxin treatment. Relaxation by stimulation with the cGMP analogue 8-BrcGMP was not different from control. Pulmonary vascular smooth muscle is able to relax in response to cGMP after endotoxin treatment, but relaxation by endothelial-dependent and -independent pathways that require generation of cGMP is significantly impaired.

Optical mapping of lambda bacteriophage clones using restriction endonucleases

Optical mapping is an emerging single molecule approach for the rapid generation of ordered restriction maps, using fluorescence microscopy. We have improved the size resolution of optical mapping by imaging individual DNA molecules elongated and fixed onto derivatized glass surfaces. Averaged fluorescence intensity and apparent length measurements accurately determined the mass of restriction fragments 800 basepairs long. We have used optical mapping to create ordered restriction maps for lambda clones derived from the mouse pygmy locus.

[Identification of chaihu guizhi ganjiang decoction by three dimensional HPLC]

The Chaihu Guizhi Ganjiang Decoction was identified by three dimensional HPLC. The result showed that the constituents in this decoction, namely Radix Bupleuri; Ramulus Cinnamomi; Radix Glycyrrhizae and Radix Scutellariae could all be identified clearly.

[Effects of Sichuan herba Epimedii on the concentration of plasma middle molecular substances and sulfhydryl group of "yang-deficiency" model animal]

The effects of tonifying the kidney and strengthening the "Yang" produced by the extracts of Chinese herbs Epimedium wushanense and E. pubescens were studied in this paper. The results showed that both two herbs could decrease the concentration of plasma middle molecular substances and increase the concentration of plasma sulfhydryl group of "Yang-deficiency" model mice, thus suggesting that the above-said tonifying and strengthening effects of Herba Epimedii may result from its effects on middle molecular substances and sulfhydryl group, so as to strengthen the body resistance and eliminate the invading pathogenic factors.

Intravenous ascorbate as a tumor cytotoxic chemotherapeutic agent

Ascorbic acid and its salts (AA) are preferentially toxic to tumor cells in vitro and in vivo. Given in high enough doses to maintain plasma concentrations above levels that have been shown to be toxic to tumor cells in vitro, AA has the potential to selectively kill tumor cells in a manner similar to other tumor cytotoxic chemotherapeutic agents. Most studies of AA and cancer to date have not utilized high enough doses of AA to maintain tumor cytotoxic plasma concentrations of AA. Data are presented which demonstrate the ability to sustain plasma levels of AA in humans above levels which are toxic to tumor cells in vitro and suggests the feasibility of using AA as a cytotoxic chemotherapeutic agent.

Isolation of chicken hsp90 beta gene promoter

In order to define the mechanisms responsible for the differential expression of chicken hsp90 alpha and beta genes, a portion of the chicken hsp90 beta genomic sequence, including 3081 bp upstream from the transcription initiation site and 2718 bp of structural gene sequence which covers 7 exons and 6 introns was investigated. The transcriptional initiation site was determined by primer extension, RNAase and S1 nuclease mapping, Northern blot and cloning of 5' end of cDNA. The first intron, as in other hsp90 genes, is located just before the ATG initiation codon. Three Sp1 sites are located near the TATA box. The apparent major divergence with the hsp90 alpha promoter is that, in the hsp90 beta promoter, the only CAAT box and HSE element are located at about 3 and 2 kb upstream the TATA box, respectively. These features may explain why chicken hsp90 beta mRNA is generally less abundant than alpha and is not inducible by heat shock or serum/growth factor stimulation.

Preconditioning of isolated rat heart is mediated by protein kinase C

Catecholamines have been implicated in the phenomenon of ischemic preconditioning. We have previously demonstrated that ischemic preconditioning against postischemic mechanical dysfunction in the isolated rat heart is mediated by the alpha 1-adrenergic receptor. The purpose of this study was to delineate the signal transduction of preconditioning distal to the alpha 1-adrenergic receptor. Our results suggest that (1) transient ischemia and alpha 1-adrenergic receptor-induced preconditioning is inhibited by protein kinase C (PKC) antagonists, (2) functional protection against global ischemia/reperfusion injury can be induced by infusion of diacylglycerol, the second messenger of the alpha 1-adrenergic pathway, and (3) transient ischemia and alpha 1-adrenergic preconditioning are both characterized by similar translocation of PKC-delta to the sarcolemma of myocardium. These findings suggest that PKC is an effector of preconditioning in the isolated rat heart.

Clinical assessment of biplanar transesophageal echocardiography--a report of 125 cases

One hundred and twenty-five patients with cardiovascular disease were examined by biplanar transesophageal echocardiography (BTEE), including 67 with rheumatic heart disease (7 monitored during operation), 22 with aortic diseases, 20 with congenital heart diseases, and 16 with other kinds of heart disease. The results showed that BTEE was not influenced by corpulent and pulmonary emphysema and was better than transthoracic echocardiography at imaging the interatrial septum, left atrium and left atrial appendage, thoracic aorta, and mitral artificial valve and at intraoperative monitoring. BTEE was also better than single-plane transesophageal echocardiography, because BTEE could be used to observe the heart and thoracic aorta in transverse and longitudinal planes, thus enlarging the transmission "window" as well as allowing the entire lesion to be imaged. This study suggests that BTEE will have good prospects in clinical application.