Direct interaction between two Escherichia coli transcription antitermination factors, NusB and ribosomal protein S10

The Escherichia coli proteins NusB and ribosomal protein S10 are important for transcription antitermination by the bacteriophage lambda N protein. We have used sucrose gradient co-sedimentation and affinity chromatography with immobilized ribosomal protein S10, a glutathione S-transferase-S10 fusion protein, and NusB to show that NusB binds directly and very selectively to S10. The interaction is non-ionic and has an estimated Kd value of 10(-7) M. We hypothesize that NusB binds to N-modified transcription complexes primarily by interacting with S10.

PCR detection of HCV RNA among French non-A, non-B hepatitis patients

Hepatitis C virus (HCV) cDNA was amplified from serum of 26/40 French chronic non-A, non-B hepatitis patients by the nested polymerase chain reaction. Compared with anti-C100, viral cDNA represents a more reliable marker of active HCV replication.

Influence of occlusion on the fluoride distribution in rat molar cementum

This study was undertaken to examine the influence of occlusion on the fluoride distribution in cementum following an experiment in which the occlusion in rats was locally altered by extracting the upper left molar. These and control rats with normal occlusion were given water containing 0 or 100 ppm fluoride for 12 weeks. The fluoride distributions in cementum from both first lower molars of the same animal were compared. The fluoride concentrations had increased throughout the tissue as a result of increased fluoride administration, irrespective of any changes in occlusion. They were, as usual, generally highest at or near the cementum surface and decrease towards the interior of the tissue. Where there had been a change in occlusion, the thickness of cementum was less than that of the contralateral tooth, but, despite this, the fluoride profiles in contralateral teeth were similar in both experimental and control rats. In the experimental rats, on the other hand, the total fluoride tended to be lower, and the mean fluoride tended to be higher in left molars without antagonists. These findings were never seen in the control rats. It was concluded that the alteration in occlusion influenced the fluoride distribution in the cementum through its effect on the rate of cementum formation.

Surface-bound biomembranes incorporating receptors: electrochemical and structural characterization

A generic method is described for forming surface-bound structures that incorporate protein receptors in a membrane-like environment. Silane reagents (octadecyltrichlorosilane and dimethyloctadecylchlorosilane) were used to produce primed substrates bearing full and partial monolayers, respectively. Biomembranes were formed by dialysis of detergent-solubilized membranes in the presence of two different alkylsilanized substrates: Si/SiO2 electrodes and glass microspheres. Electrochemical analysis of the capacitance was used to determine apparent thickness and degree of surface coverage at each stage in the deposition process. Elemental analysis on glass beads gave the hydrocarbon incorporation. Glass bead substrates were also examined by Fourier transform infrared spectroscopy to evaluate the alkylsilanized substrate before and after dialysis. Both vertebrate rhodopsin and the nicotinic acetylcholine receptor could be incorporated into structures with composition and dimensions similar to natural bilayer membranes. The techniques reported here are applicable for coupling membrane receptors to a variety of transducing substrates used in biosensors.

Inhibitory effect of tetrandrine on lens proteins-induced ocular inflammation in rabbits

Ocular inflammation was induced by 25 microliters of lens proteins (62.5mg/ml) injected into anterior chamber of the rabbit eye. Tetrandrine (Tet) (50mg/kg ip) and Indomethacin (Ind) (20 mg/kg ip) showed marked inhibition on this ocular inflammation. Maximum inhibition rate of Tet and Ind was 65% and 66% and their anti-inflammation action lasted 5 and 4 h, respectively. In the early phase of ocular inflammation (at 2 h) the total content of prostaglandin E(PGES) in the iris was reduced by Tet and Ind. Ind showed a greater effect than Tet on PGES. Tet also inhibited leukocyte chemotaxis significantly at late phase of inflammation. No significant effect was observed on the IOP recovery following reduction by 20% NaCl iv. Topical instillation of 50 microliters of 2% Tet did not display any inhibition of ocular inflammation. These results indicate that Tet is an effective ocular antiinflammatory agent without producing ocular hypertension. The antiinflammatory mechanism of Tet in early phase (at 2 h) was related to inhibition of PGES synthesis. The relationship between ocular anti-inflammation and calcium antagonism of Tet was discussed.

Studies of Muc-1 mucin expression and polarity in the mouse mammary gland demonstrate developmental regulation of Muc-1 glycosylation and establish the hormonal basis for mRNA expression

Muc-1 is a major mucin glycoprotein expressed on the surface of mammary epithelial cells. It has attracted considerable attention as it is expressed in an aberrant form on many breast tumor cells. Here we describe studies using a recently obtained cDNA probe of Muc-1 expression during lactogenic development in the mouse. Northern blot analysis demonstrated that Muc-1 is expressed at all stages of lactogenic development but its levels are increased very significantly during mid-pregnancy and into lactation. The basis of this was examined using CID-9 mammary epithelial cell cultures. It was found that in the presence of insulin Muc-1 mRNA levels were increased by both hydrocortisone and prolactin, with the combination of the three hormones supporting maximum expression. Muc-1 mRNA levels were also modulated by culturing cells on a basement-membrane-like extracellular matrix that promoted mRNA levels 5- to 10-fold above levels in cells cultured on plastic tissue culture dishes. Immunocytochemical studies using monoclonal antibodies to carbohydrate epitopes on Muc-1 demonstrated that while Muc-1 was found at all developmental stages, it became increasingly sialylated during the course of pregnancy and into lactation. Additionally, we found that while Muc-1 is tightly polarized to the apical surface of the epithelium of lactating and pregnant mice it exhibited a less-polarized distribution on a small proportion of ductal cells in virgin mice. We conclude that the expression of Muc-1 is regulated at several different levels and by a number of different factors. We speculate that this may reflect different functional roles for Muc-1 at different stages of mammary development.

Serum angiotensin-converting enzyme activity in pregnancy-induced hypertension

Angiotensin-converting enzyme (ACE) activity was measured in the serum of 33 pregnant women with normal blood pressure or pregnancy-induced hypertension (PIH) using sensitive hippuric acid colorimetric micromethods. Mean serum ACE activity in 17 PIH patients (73.25 +/- 18.81 U/ml) was significantly higher than that in normotensive pregnant women (16 cases; 52.36 +/- 9.91 U/ml; p less than 0.01). Mean arterial blood pressure was correlated with the level of serum ACE activity in all pregnant women (y = 69.089 + 0.49x, r = 0.562, p less than 0.01). In PIH patients, the gestosis index and the degree of edema also had a statistically significant correlation with the level of serum ACE activity (y = -0.560 + 0.056x, r = 0.549, p less than 0.05; y = -1.760 + 0.043x, r = 0.629, p less than 0.01). The amount of 24-hour urinary protein was independent of the level of serum ACE activity. It seems that a disturbance in the regulation of ACE activity may be one of the factors responsible for the development of PIH.

The protective effect of puerarin against myocardial reperfusion injury. Study on cardiac function

In order to find out if puerarin could protect the hearts from myocardial reperfusion injury after cardiac arrest, twelve dogs divided into two equal groups were placed on moderately hypothermic cardiopulmonary bypass and their hearts were subjected to 140 min of cold cardioplegic arrest and 60 min of reperfusion. In the control group, the hearts were perfused with a crystalloid cardioplegic solution (CPS) through the aortic root every 20 min during arrest. In the treated group, the hearts received CPS containing puerarin (2 mg/kg). Cardiac hemodynamic variables were monitored throughout the experiments. Left ventricular function curves were formed before ischemia and after 60 min of reperfusion. The results showed that the recovery of left ventricular function in the treated group was significantly better than that in the controls (81 +/- 11% versus 39 +/- 7%, P less than 0.01). Compared with preischemic values, the increase of coronary blood flow (CBF) at cardiac arrest in the puerarin-treated group was higher than that in the control group (214 +/- 11 versus 177 +/- 4 ml/min, P less than 0.01). The data indicate that puerarin has protective effects on the cardiac function after prolonged arrest and reperfusion.

[Chemical constituents of Ledebouriella seseloides Wolff]

Eleven compounds were isolated from the methanolic extraction of the radix of Ledebouriella seseloides. They were identified as beta-sitosterol, bergapten, hamaudol, daucosterine sec-O-glucosylhamaudol, 5-O-methylvisamminol, cimifugin, sucrose, 4-O-beta-glucopyranosyl-5-O-methyl-visamminol, prim-O-glucosylcimifugin and mannitol by physico-chemical constants and spectroscopic analysis.

Precancerous lesions of the human esophagus: multiparametric study of esophageal biopsies from a high-risk population in Linxian, China

Histopathology, morphometry, tritiated thymidine incorporation and immunohistochemistry were studied in 221 esophageal biopsies from subjects with cytologica hyperplasia in Linxian, China. A spectrum of 7 morphologic entities were found: (1) normal/near normal (NN); (2) basal cell hyperplasia 0 (BHO); (3) simple hyperplasia (SH); (4) mixed basal and spinous cell hyperplasia (MBS); (5) basal cell hyperplasia 1 (BH1); (6) dysplasia (D); and (7) non-proliferative lesion (NP). Forty percent of the biopsies had combinations of histologic types. The thickness of the epithelium was increased in SH, MBS, and BH1, but not in BHO and NP. Elongation of papillae was frequently seen in SH, MBS, BH1, and D. Papillary bleeding was very prevalent in the esophageal specimens studied. A variety of cellular changes were found in peripapillary areas especially when bleeding occurred. [3H]-thymidine labeling index was dramatically increased in the entire epithelium in dysplasia, and also increased in cell layer 3 of MBS, BH1 and D. Blood group antigen LeY and lectin WGA showed consistent positivity in cellular membranes of the squamous cells, and these changes occurred before gross morphologic alterations. These findings provide a hypothesis for the sequence of pathogenetic events leading to esophageal carcinoma, and define each step with corresponding biomarkers for cancer prevention studies.

Multibacterial artificial plaque. A model for studying carious process

A multibacterial artificial plaque was established in vitro on enamel slabs incubated in mixed culture of Streptococcus sanguis, Streptococcus mutans (serotype c), Streptococcus salivarius, Lactobacillus casei and Actinomyces viscosus. Typical structure same as natural plaque was seen under microscope. The caries-like lesion produced under the plaque was observed in enamel sections. The lesion was similar in appearance to natural ones under optic and scanning electron microscopes. The acids produced in both culture media and artificial plaque were similar in composition and type to those produced in natural plaque after sugar attack. It is suggested that this kind of plaque model may be useful in studying carious process in vitro, because it is easily controlled either by changing the composition of bacteria or by adding different kinds of nutrient in the media. Moreover, the results will be easier to explain than those produced in natural ones.

Enzyme chemistry of dithiohemiacetals: synthesis and characterization of S-D-dithiomandeloylglutathione as an alternate substrate for glyoxalase I

Both the D- and L-forms of S-dithiomandeloylglutathione (1) have been synthesized by a dithioester-interchange reaction between GSH and S-carboxy-methyl(D,L)-dithiomandelate. Kinetic and product analysis studies indicate that yeast glyoxalase I efficiently catalyzes the stereoselective conversion of D-1 to GSH-phenylglyoxal dithiohemiacetal (2), isolated as a disulfide adduct between 2 and a second molecule of GSH. This observation suggests that dithioester substrate analogues should be generally useful as mechanistic probes of enzyme catalyzed reactions involving thiohemiacetal intermediates.

[A follow-up study of HBV infection in a village of Beijing rural area]

From 1982 to 1988, a follow-up study on HBV infection was carried out in a village of Beijing rural area. The negative conversion rates of HBsAg; anti-HBs; anti-HBc were 2.9%; 2.1%; 1.2% per year respectively. It was seemed that the negative conversion of HBsAg; anti-HBs increased with age. The present of anti-HBc was favorable to keeping anti-HBs. For all of the three markers, the higher the titre, the lower the negative conversion rates. It was concluded that the essential factor influencing the natural outcome of HBV markers was the level of HBV duplication. Those who were susceptible to HBV in 1982 were infected at the rate of 20.3% in this period. Analysis indicated that source of the Infection perhaps seems not to be in their family.

[Pharmacological studies on the comparison between the drainage and certified Fel Ursi]

A comparison between the drainage and certified Fel Ursi was studied by pharmacological methods. The results demonstrated that the drainage Fel Ursi was similar to the certified products in anti-inflammatory, antipyretic, sedative, anticonvulsive, antispasmodic and bacteriostatic actions.

[Statistical analysis of age-related macular degeneration (AMD) in the differentiation of symptoms and signs]

Ninety-eight individuals according with entry criterion were allowed to participate in the study. Their clinical symptoms and signs were classified to seven symptoms by means of epidemiology. The results indicated syndrome of vital energy in patient group had more significant than controlled group, the others had not. In the syndrome of deficiency of vital energy, the frequency that the corpalent tongue or margin and tip of the tongue look jagged and the pulse lost its vitality emerged in the patient group surpassed significantly the controlled group. So, we initially considered that traditional Chinese medicine syndrome of AMD patient is mainly the deficiency of vital energy. The happening and development of AMD is probably related to the physique of deficiency of vital energy, it is a key point of determination of treatment with traditional chinese medicine based on differentiation of symptoms and signs.

Nitrate-inducible formate dehydrogenase in Escherichia coli K-12. I. Nucleotide sequence of the fdnGHI operon and evidence that opal (UGA) encodes selenocysteine

The fdnGHI operon of Escherichia coli encodes nitrate-inducible formate dehydrogenase. We report here the entire nucleotide sequence of fdnGHI. The sequence contains three open reading frames of sizes appropriate to encode the three subunits of formate dehydrogenase-N. fdnG contains an in-frame UGA codon that specifies selenocysteine incorporation, and the predicted amino acid sequence of FdnG shows similarity to two other bacterial formate dehydrogenase enzymes. FdnH contains 4 cysteine clusters typical of those found in iron-sulfur proteins. FdnG also contains a cysteine cluster. Evidence from sequence and spectral analyses suggest that FdnI encodes cytochrome bFdn556. Implications for the membrane topology of formate dehydrogenase-N and its mechanism of proton translocation are discussed.

ICI 181,037: a novel eukalemic diuretic with antiarrhythmic activity

ICI 181,037, the most active compound from a series of 1,1-diarylcarbin-1-ol-2 amines, was evaluated for diuretic and cardiovascular activity. In saline-loaded rats, the magnitude of water diuresis and saluresis produced by ICI 181,037 (10 mg/kg, p.o.) was equal to that of hydrochlorothiazide. Water diuresis and saluresis produced by ICI 181,037 were enhanced with SKF 525A, ampicillin or neomycin plus lincomycin, suggesting that ICI 181,037 is an active diuretic. In conscious dogs, the saluretic activity of ICI d-181,037 (5 mg/kg, p.o.) was about 80% of the corresponding hydrochlorothiazide value, whereas the l-isomer demonstrated only minimum saluretic activity. In both rats and dogs, the concurrent kaliuresis after ICI 181,037 or its enantiomers was minimal as compared to hydrochlorothiazide. Following chronic dosing with diuretic doses, the basal levels of plasma potassium in dogs were not altered. In amphibian in vitro models for mimicking mammalian nephron, ICI 181,037 and its enantiomers demonstrated antinatriferic and antichloriferic activities, suggesting multiple renal sites of action for this agent. Racemic ICI 181,037 and its isomers reversed ouabain-induced arrhythmia in dogs and/or reduced the ouabain-induced mortality in mice after intravenous administration. It is concluded that ICI 181,037, particularly its d-isomer, is a novel eukalemic diuretic and possesses antiarrhythmic activity.

Persistent ethanol drinking increases liver injury induced by trinitrotoluene exposure: an in-plant case-control study

On the basis of a general survey conducted in a munitions plant, a case-control study was made on the various risk factors of liver damage induced by trinitrotoluene (TNT) exposure in the plant. One-hundred male cases with occupational TNT liver damage were paired with 100 male controls, one-by-one, for occupation, age and duration (years) of employment. A total of 55 possible risk factors were statistically analysed with a single factor analysis. On the basis of the single analysis, nine factors including drinking, smoking and education were further analysed with a conditional logistic regression model. A calculation was made on the odds ratio (OR) of each factor selected into the model. According to the estimated parameter of the established logistic model, the relative risk of the risk factors could be worked out. Finally, two factors, the amount of ethanol drunk on each occasion and the frequency of drinking every week were selected into the model at the level of a = 0.05. The result showed that these two factors have a dose-response relationship with their OR of occupational TNT liver damage, but there is no connection between smoking and occupational TNT liver damage and no interaction between drinking and smoking. The above results have revealed that people exposed to TNT and with a long history of heavy drinking, have a greater risk of suffering from chronic liver impairment than those that do not drink.

Electrochemical identification of dopachrome isomerase in Drosophila melanogaster

A principal reaction in the eumelanin biosynthetic pathway is the conversion of dopachrome (DC) to dihydroxyindole(s). Dopachrome isomerase (DI), the enzyme that catalyzes this reaction, was detected for the first time in larvae of D. melanogaster. Unlike the enzyme from B16 mouse melanoma cells which converts dopachrome to 5,6-dihydroxyindole-2-carboxylic acid (DHICA), the insect enzyme forms 5,6-dihydroxyindole (DHI). The activity of the insect DI was linear through 15 min incubation, and the amount of DHI produced was proportional to the amount of enzyme that was incorporated into the reaction mixtures.