Effect of cell line on in vitro metal ion cytotoxicity

OBJECTIVES

The choice of cell line for in vitro biological tests which assess the cytotoxicity of dental materials remains controversial, yet this issue is important because these tests are widely used to rate the biocompatibility of new and existing materials, and many different cell lines are commonly used. The purpose of the current study was to quantify the responses of four cell lines (Balb/c 3T3, L929, ROS 17/2.8 and WI-38) to 14 metal ions which are released from dental materials, and relate these responses to the metabolic activity and population doubling times of these cells.

METHODS

Succinic dehydrogenase (SDH) activity was used to monitor metabolic activity and cytotoxic response.

RESULTS

The cell lines responded differently to most metal ions. In general, the Balb/c 3T3 line was the most sensitive, and the WI-38 line was the least sensitive. However, there were many exceptions depending on the metal ion. The passage number of the cells also affected the cytotoxic response. It was concluded that the cytotoxicity of materials which release metal ions will be significantly different depending on which cell line is selected and its passage number.

SIGNIFICANCE

Based on the findings that cell lines ranked the toxicities of the metal ions similarly, it seems reasonable to use these types of in vitro tests to rank the cytotoxicities of materials. However, if these types of tests are used to predict in vivo cytotoxicity, care should be taken to choose conditions and cells which are relevant.

Bidirectional transcription from the human immunoglobulin VH6 gene promoter

The human immunoglobulin (Ig) heavy chain VH6 gene promoter contains an imperfect octamer (AgGCAAAT) and is not dependent on the Ig heavy chain enhancer for activity; reporter constructs containing this promoter are very active in non-B cells. In experiments designed to characterize regions upstream of the transcriptional start site that are important for promoter function, we produced a series of deletion constructs, including one containing sequences between -74 and -146. Surprisingly, this fragment had promoter activity in both orientations. Inspection of the VH6 promoter sequence indicated that there was a possible TATA box in the proper orientation upstream of the imperfect octamer. The -74 to -146 fragment functioned as a promoter in the reverse orientation in three B cell lines and in non-B (HeLa) cells, with a much higher level of activity seen in the HeLa cells. To determine if the promoter could work in both directions simultaneously, reporter genes were positioned up- and downstream of a VH6 promoter fragment. Reporter gene activity was found for both genes in B cells and HeLa cells. Using a reverse transcriptase-polymerase chain reaction procedure (RT-PCR), we found a transcript corresponding to sequences upstream of the VH6 promoter in RNA from both the lymphoblastoid cell line ML-1, which actively transcribes the VH6 promoter, and the REH cell line, which does not. No transcripts were found in the KB epithelial cell line. Two or three mRNA 5' ends were found that mapped between -137 to -143 from the authentic VH6 transcription site, 31-37 nucleotides upstream of the putative TATA box. Inspection of the sequence upstream of the VH6 promoter demonstrated the presence of an open reading frame capable of coding for 96 amino acids. The VH6 promoter represents the second Ig promoter with bidirectional activity.

Analysis of the imperfect octamer-containing human immunoglobulin VH6 gene promoter

The octamer sequence ATGCAAAT is highly conserved in the promoter of immunoglobulin heavy and light chain genes and is one of the sequence motifs involved in the control of transcription of these genes. The promoter region of an human immunoglobulin heavy chain variable gene, the sole member of the VH6 gene family, was found to differ from other VH gene promoters: it contains neither the conserved octamer motif nor a heptamer sequence, and generally bears little resemblance to other VH gene transcriptional control regions. An imperfect octamer sequence with a single nucleotide substitution (AgGCAAAT) is located 108 bp upstream of the ATG translation start site, and 81 bp upstream of the transcription initiation site. We sought to determine which sequence elements within the VH6 promoter were responsible for transcription initiation by creating progressive deletions of a 1 kb fragment from this region and testing their ability to function as promoter elements in B and non-B cells (HeLa). The minimum fragment required for full promoter function was 110 bp, but a fragment with only 65 bp retained 30-50% activity in B cells. Similar levels of transcription were seen when the -146 bp promoter containing two point mutations in the imperfect octamer was tested. Mutation of a possible pyrimidine box sequence located downstream of the TATA box was shown to have only a minor effect (10-30%) on transcription when three nucleotides were changed. Surprisingly, CAT activity was not B cell-specific, as all constructs had virtually the same activity in several B cell lines and in HeLa cells. Removal of the TATA box led to a 50% reduction in CAT activity, and the region upstream of the TATA box functioned as a promoter in both orientations. The transcriptional activity of the VH6 promoter was virtually enhancer independent: only a minor increase was observed when the immunoglobulin or SV40 enhancer was added to the promoter construct. Electrophoretic mobility shift assays of transcription factor binding to the region around the imperfect octamer indicated that binding was weak when nuclear extracts from either B cells or HeLa cells were used. The amount of complex shifted was increased by mutating the imperfect octamer to a perfect one. Chimeras produced between the VH6 promoter and a B cell-specific promoter from a member of the human VH2 gene family demonstrated that the lack of tissue specificity was due to the absence of a repressor of non-B cell transcription in the VH6 promoter. These results indicate that the VH6 promoter is relatively simple, requiring little more than the TATA element and the imperfect octamer, and transcription from this promoter lacks B cell specificity and is not dependent on the enhancer element.

Solute absorption from the airways of the isolated rat lung. IV. Mechanisms of absorption of fluorophore-labeled poly-alpha,beta-[N(2-hydroxyethyl)-DL-aspartamide]

The pulmonary absorption kinetics of a single molecular weight distribution (MWD) of fluorophore-labeled poly-alpha,beta-[N(2-hydroxyethyl)-DL-aspartamide] (F-PHEA), a hydrophilic and biocompatible synthetic polypeptide, were studied in the isolated, perfused rat lung (iprl) as functions of administered polymer concentration, dose, vehicle, and presence and absence of fluorophore. The MWD was characterized before and after absorption by measurement of weight- and number-averaged molecular weights (Mw and Mn, respectively) using high-performance gel-permeation chromatography. Values for Mw and Mn were 8.6 and 5.3 kD before, and 6.7 and 4.7 kD after, absorption into the perfusate; there was no significant metabolism and the MWD of the absorbed polymer was independent of both dose and sampling time over a 3-hr period. F-PHEA failed to show any evidence of aggregation in solution or changes in dose distribution within the airways as functions of increasing polymer concentration and dose. A concentration ranging study indicated the presence of a saturable, carrier-mediated transport process for F-PHEA with a maximum absorption rate, Vmax, of approximately 180 micrograms or 0.027 mumol/hr. Coadministration of fluorophore-free PHEA was capable of depressing the absorption of F-PHEA. The transport process for F-PHEA appeared to have a molecular weight limit of about 7 kD for this hydrophilic polymer.

[A study on P21(ras) in human lung cancer and body fluid of cancer patients]

The McAb of anti-P21(ras) has been used to screen 9 cases of human lung cancer tissues, 18 cases of samples and 2 cases of hydrothorax samples of lung cancer patients by means of PAGE-immunoblots. The expression of ras gene was found in 8 cases of human lung cancer among which the expression of 4 cases was higher than that of normal control. P21(ras) has not been detected in serum and hydrothorax samples of cancer patients. The present study indicated that there was P21(ras) in human lung cancer and normal control and the expression level of ras gene in lung cancer was related to the differentiation of cancer.

Texture analysis of ultrasonic images of the prostate by means of co-occurrence matrices

As speckle on ultrasonic B-scan may reveal information relative to tissue structure, the present work attempts to discriminate the various prostatic tissues (normal tissue, benign prostatic hypertrophy and cancer) by means of texture analysis. We select regions of interest by their homogeneous appearance. A pre-processing stage is required to obtain stationary samples. The method used measures the second-order statistics, namely co-occurrence matrices. Fairly good tissue signatures have been obtained with parameters derived from these matrices. Of 37 images processed, 78 percent of the samples were classified with success, which is a high score considering that the images cannot be discriminated visually. However, while such results are obtained when wide regions of interest are investigated (64 x 64 pixels), they are not as good with smaller sample sizes, i.e., when the pathological area is very small.

Late results of mitral valve repair for mitral regurgitation due to degenerative disease

From June 1981 to August 1992, 184 patients with mitral regurgitation due to degenerative disease underwent mitral valve repair. The mean age was 57 years, and 74% were men. One-third of the patients were in atrial fibrillation, and 71% were in New York Heart Association classes III and IV. The mitral regurgitation was due to prolapse of the posterior leaflet in 97 patients (53%), prolapse of the anterior leaflet in 42 (23%), and prolapse of both leaflets in 45 (24%). The degree of myxomatous changes was assessed intraoperatively as mild in 125 patients (68%), moderate in 27 (15%), and severe in 32 (17%). Mitral valve repair was accomplished largely by techniques described by Carpentier. Ring annuloplasty was performed in 160 patients (66 with Carpentier ring and 94 with Duran ring). There was one operative death, and 5 patients experienced life-threatening complications. Patients were followed up from 5 to 132 months (mean, 41 months). The actuarial survival at 8 years was 88% +/- 4%. The freedom from stroke at 8 years was 94% +/- 2%, and the freedom from transient ischemic attacks was 86% +/- 6%. Age greater than 60 years was the only factor associated with higher risk of thromboembolic complications by logistic regression analysis. The actuarial freedom from reoperation at 8 years was 95% +/- 2%. Advanced myxomatous changes in the leaflets of the mitral valve was the only significant factor associated with a higher risk of reoperation. Most patients were in New York Heart Association class I at the last follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study on the transcriptional expression of oncogenes in human primary brain tumors]

The c-myc, L-myc, N-myc, Ha-ras, c-fos, and v-erbB oncogenes were used as probes to detect the total RNA of 5 cases of normal human brain tissues and 29 cases of brain tumor tissues by RNA dot hybridization analysis. The results showed that the increasing expressions of cerbB and c-fos were the highest, being 88.2% and 82.4%, respectively, the next was c-myc with an increased expression of 46.1%; the increasing expressions of L-myc (29.3%) and N-myc (31.6%) were observed in a few samples only. There was no significant difference of Ha-ras gene expression between normal brain and brain tumor. In addition, we observed the increasing expression of more than one oncogene in one sample. These results suggest that c-erbB and c-fos oncogenes may play an important role in the pathogenesis of human primary brain tumors, and that multiple genetic changes are implicated in genesis of human brain tumors.

[The appliance of image analysis in the diagnosis of oral Lichen Planus and it's malignant change]

After the Feulgen dying,if the normal oral mucous,oral Lichen planus as well as the pathological cut sheets with atypical dysplasia and malignant change in defferent degrees,use the image analysis technique to measure the morphologic parameters of the nucleus(including nuclear surface area,perimeter maximum nuclear diameter,minimum nulear diameter,equivalent circle diameter,morphological factor) and the amount of DNA,5CER acts as an indes of distinguishing malignancy or benignancy,the value of 5CER in malignant is more than 10% and in benignant is less than 10%.The result of the analysis from the optical microscope differs from the optical microscope differs form the image analysis.There are so many personal factors in the qualitative analysis by optical microscope that it because quite imperative to research for a new diagnosing way.The synchronization of quantitative analysis and qualitative analysis can correct the personal errors in qualitative analysis.It will be very useful for directing the clinical practice and the judgment of prognosis.

Clinical and hemodynamic assessment of the Hancock II bioprosthesis

The Hancock II bioprosthesis was used for heart valve replacement in 614 patients from 1982 to 1990. Aortic valve replacement (AVR) was performed in 376 patients, mitral valve replacement (MVR) in 195, and aortic and mitral valve replacement (DVR) in 43. The mean age was 62.7 years, and 78% of all patients were in New York Heart Association functional class III or IV before operation. Coronary artery bypass graft was necessary in 232 patients and replacement of ascending aorta in 55. There were 31 operative deaths (AVR, 4%; MVR, 6%; DVR, 9%). Follow-up was complete in 98.5% of the patients and extended from 12 to 103 months, with a mean of 49 months. At the last follow-up, 85% of the patients were in New York Heart Association class I or II. The actuarial survival at 8 years was 79% +/- 3% for AVR, 68% +/- 4% for MVR, and 65% +/- 10% for DVR. The freedom from stroke at 8 years was 93% +/- 2% for AVR, 83% +/- 5% for MVR, and 90% +/- 5% for DVR. At the end of 8 years 96% +/- 1% of all patients were free from endocarditis, 92% +/- 1% were free from primary tissue failure, and 89% +/- 3% were free from reoperation. The actuarial freedom from valve-related death at 8 years was 98% +/- 1% for AVR, 86% +/- 5% for MVR, and 91% +/- 6% for DVR. Hemodynamic assessment was obtained by Doppler echocardiography in all operative survivors and demonstrated satisfactorily effective valve orifices and transvalvular gradients. The clinical results obtained with the Hancock II bioprosthesis have been gratifying, particularly in the aortic position. This bioprosthesis is our biological valve of choice.

Influence of medicinal herbs on phagocytosis by bovine neutrophils

Twenty-six herbal preparations made from 24 medicinal herbs, categorized as antipyretics in Chinese materia medica, were tested in vitro to determine their effects upon phagocytosis of 32P-labelled Staphylococcus aureus by neutrophils isolated from bovine blood and milk. The percentage of phagocytosis was determined after incubating (1 hour at 37 degrees C) 1.25 x 10(7) neutrophils, 1 x 10(8) 32P-labelled S. aureus and 10% skimmed milk with herbal solutions. Concentrations of herbal preparations tested were 100%, 10% and 1% (v/v). When compared with PBSS (0.01 M phosphate buffered saline solution) controls, most of the herbs at high concentrations inhibited phagocytosis while at lower concentrations phagocytosis was increased. All 26 herbal preparations significantly increased blood neutrophil activity at their proper concentrations. The most active herbs in promoting blood neutrophil phagocytosis were observed for Herba verbenae, Flos chrysanthemi, Flos lonicerae, Radix sophorae flavescentis, Herba houttuyniae, Radix isatidis, Herba patriniae, Berberini sulfatis at the lowest concentration and for Folium hibisci at the high concentration with the increased percentage of more than 40.0% in comparison with PBSS control. Of the 19 herbal preparations tested with milk neutrophils, 18 herbs greatly increased phagocytosis at suitable concentrations. The most active preparations in stimulating milk neutrophil functions included Folium hibisci, Flos chrysanthemi, Radix bupleuri, Radix stellariae, Herba houttuyniae, Herba senecionis scandentis, Caulis lonicerae and Flos lonicerae which increased phagocytosis by over 35.0%.

[Biochemical and immunological characterization of desmosomal proteins]

Desmosmoes were dissolved by incubation at 100 degrees C for 30 minutes in lysis buffer containing 9.5 M urea. SDS-PAGE revealed seven high molecular weight (> 67 kd) bands and some keratins. Seven of these were considered to be major bands. Bands 1 and 2 with M(r) values of 250 kd and 215 kd, called desmoplakins I and II. Polypeptide bands 3, 4a 4b, 5 and 6 had M(r) values of 165kd, 130kd, 115kd, 83kd and 75kd, respectively. 2-2.5mg of Desmoplakin I was obtained by a preparative electrophoresis; the purity reached 93.1%. The isoelectric pH range was between 6.8 and 7.2, and the amino acid compositions displayed a relatively high content of glycine. It was found that McAb Desmoplakin I recognized specifically the 250kd antigenic band by immunoblotting.

[The construction of rich genomic library of bovine Y chromosome]

According to the fundamentals of DNA renatured kinetics, we made a study in which genomic DNA from male cattle was completely digested with Sau 3A, while female DNA was sheared to an average size of 500 bp fragments. The Y derived DNA sequence rich library of bovine has been contracted with pUC19 plasmid as vector and JM109 as host bacteria by reassociation of male and female DNA. Male and female DNA probes, were used. The result of colony hybridization showed that out of 1000 recombinants analysed, 6 were found to be stronger signal with male probe. Analysis of Pvu' I digested DNA fragment revealed that most of the inserts were in the 90-300 bp.

The effect of warm heart surgery on postoperative bleeding

The effects of normothermic systemic perfusion (35 degrees to 37 degrees C; n = 73) were compared with those of moderately hypothermic systemic perfusion (25 degrees to 29 degrees C; n = 73) with respect to blood loss, transfusion requirements, and platelet levels in 146 patients undergoing isolated, primary coronary artery bypass grafting. In addition, most patients were given an antifibrinolytic medication during operation as follows: tranexamic acid (10 gm intravenously; n = 63), epsilon-aminocaproic acid (15 gm intravenously; n = 63), or no drug as a control. (n = 20). Normothermic patients tended to bleed less at 24 hours (warm, 864 +/- 42 ml and cold, 918 +/- 68 ml), but these differences were not statistically significant. Patients receiving either tranexamic acid or epsilon-aminocaproic acid, regardless of perfusion temperature, bled less after 6, 12, and 24 hours than did cold control patients (p less than 0.05). Warm control patients also bled less than did cold control patients after 6 or 12 hours (p less than 0.05), and neither drug further reduced blood loss in these patients. Circulating platelet levels were better preserved in patients receiving either tranexamic acid or epsilon-aminocaproic acid and in patients with warm perfusion and no drug than in cold control patients. Normothermic systemic perfusion, tranexamic acid, and epsilon-aminocaproic acid each reduced postoperative blood loss and preserved platelets.

[Effects of insulin on expression of oncogenes in CWE mouse brain]

By RNA dot blot hybridization, we observed the expression of c-myc, c-fos, Ha-ras and erbB genes in normal brain of CWE mouse after the injection of insulin. Transcription of the c-myc and c-fos genes is greatly increased, which peaks approximately 2 h after insulin stimulation, decreases in 6 h and returns to the initial levels within 48 h. The alteration in Ha-ras transcription appears more complex; its expression decreases first but increases subsequently. We also detected the expression of erbB gene which decreases after the injection of insulin. The results suggest that c-myc, c-fos, Ha-ras and erbB might be directly involved in growth control. Their protein products might play a role in intracellular signal transduction.

Enzyme-based bilayer conducting polymer electrodes consisting of polymetallophthalocyanines and polypyrrole-glucose oxidase thin films

Bilayer conducting polymer electrodes, which consist of a polymetallophthalocyanine (PMePc) and polypyrrole incorporating glucose oxidase (PPy-GOx), were prepared on the glassy-carbon electrode by the successive electrochemical deposition of two different polymers. The bilayer film electrodes showed catalytic behavior, which included an enhanced amperometric response current with the substrate and a significantly shifted oxidation potential (approximately 700 mV) of the response current. The bilayer electrodes also showed a fast response time and good stability with the substrate. A bilayer microelectrode, which was prepared by using both PCuPc and PPy-GOx polymer films, also showed a good amperometric response with the substrate.

[The expression of oncogenes in the development of human brain]

Seven oncogenes (c-myc, L-myc, N-myc, v-erbB, c-fos, Ha-ras and mos) were used as the probe to detect the total RNA of every part (cerebellum, temporal folium, frontal folium and occipital folium) in human brain from 2 cases of 6 mon fetus and the total RNA in fetal development (4 mon, 5 mon, 6 mon, 7 mon, and newborn) of human brain tissue by RNA dot hybridization analysis. The results showed that most oncogenes were expressed at high level in cerebellum and occipital folium of 6 mon fetus and at low level in temporal folium; there was similar expression of c-myc, L-myc and N-myc in fetal development of human brain tissue, and the highest level was in the 5 mon fetal brain. There was no expression of erbB gene in normal human brain. The high level expression of Ha-ras and c-fos genes was in the middle and later stages of fetal development. These results suggested that c-myc, L-myc, N-myc, erbB, Ha-ras, c-fos and mos genes might play an important role in the fetal development of human brain.

[Effects of stimulation of renal afferent nerve on renal excretion of water, sodium and potassium]

The present study was designed to investigate the effect of stimulation of the renal afferent nerve (RAN) on renal excretory function and its mechanism. In pentobarbital-anesthetized, sino-aortic denervated and vagotomized (SAD+VD) cats, stimulation of the RAN caused a significant rise in arterial pressure. In the denervated kidney urine volume (Vu) and sodium excretion (UNa V) were greatly increased, no changes in potassium excretion (UK V) and glomerular filtration rate (GFR) were observed. In the innervated kidney, UNa V was greatly increased, but Vu, UK V and GFR were not different from those observed during the control period. When arterial pressure was held constant at the control level, stimulation of the RNA reduced the Vu, UK V of both the innervated and denervated kidneys and GFR in the innervated but not in the denervated kidney. Transection of spinal cord at C7 level did not abolish the changes in Vu, UNa V, and UK V in the innervated kidney, but completely eliminated the changes in the excretory function in the denervated kidney. These data suggest that when arterial pressure is controlled, stimulation of the RAN causes a decrease in Vu, UNa V, UK V in SAD+VD cats and that these responses in the innervated kidney can be performed at the spinal level.

Operative risks and long-term results of operation for left ventricular aneurysm

A review of 336 consecutive patients who underwent repair of left ventricular aneurysm from 1978 to 1989 disclosed that partial resection of the aneurysm and conventional closure of the ventriculotomy was performed in 281 patients, inverted T closure in 17, and endocardial patch in 38. These two latter techniques were developed in an attempt to restore normal left ventricular geometry. The operative mortality was 6.8% (23 patients). A stepwise logistic regression analysis of various preopeative clinical, hemodynamic, and angiographic variables revealed that left ventricular ejection fraction of 0.20 or less, age greater than 60 years, previous myocardial revascularization, lack of angina, and New York Heart Association functional class IV were independent predictors of operative mortality. The technique of repair was not a predictor of outcome, but when patients with poor left ventricular function were analyzed separately, the operative mortality was reduced from 12.5% to 6.5% when newer techniques were employed. Patients were followed up during a mean of 6.3 years. There have been 51 late deaths, 45 cardiac. Cox regression analysis indicated that poor left ventricular function and left main coronary artery stenosis were the only two predictors of late mortality. The actuarial survival at 10 years was 63% +/- 4%. Most patients (88%) are in New York Heart Association class I or II. These data indicate excellent long-term results after repair of left ventricular aneurysm. Newer techniques of repair are valuable in patients with poor left ventricular function.

[Effect of (-)-stepholidine on blood pressure and alpha-adrenoceptor agonists-, KCl- and CaCl2-evoked contractions of aortic strips]

Iv (-)-SPD lowered the blood pressure in anesthetized rat, the ED50 value was 5.1 +/- 2.5 mg.kg-1. In the experiments of rat and rabbit aortic strips, (-)-SPD 0.3-100.0 mumol.L-1 inhibited the contraction initiated by clonidine (alpha 2) and phenylephrine (alpha 1) and shifted the dose-response curve to the right parallely without change in maximum response. The inhibitory ratio of (-)-SPD acting on alpha 2/alpha 1 adrenergic receptors was about 7.2, and (-)-SPD thus was predominant inhibition on alpha 2 adrenergic receptors. In the experiment of aortic strips from reserpinized rabbits, the inhibition of (-)-SPD on contraction evoked by clonidine was diminished markedly. The results suggest that (-)-SPD stimulated mainly the alpha 2-adrenergic receptors of presynaptic nerve endings. Moreover (-)-SPD 1 mumol.L-1 inhibited the release of intracellular Ca2+ initiated by NE. (-)-SPD 3-30 mumol.L-1 blocked the voltage-dependent Ca2+ channel.