Effect of seating force on film thickness of new adhesive luting agents

This study examined the effect of seating force on the film thickness of new adhesive luting agents. The method was in compliance with American National Standards/American Dental Association Specification No. 8 for zinc phosphate cement. The materials tested were zinc phosphate cement, glass ionomer cement, polycarboxylate cement, and a resinous cement with a dentinal bonding agent. All materials were manipulated exactly as described in the manufacturer's instructions, and an electronic gauge with an accuracy of 0.5 micron was used. Each class of material was measured 10 times at six different seating forces. Analysis of variance and multiple comparisons testing disclosed that the seating force and class of material strongly influenced the film thicknesses of luting agents. A mathematical model describing the response of zinc phosphate cement within the range tested was reported.

The effect of adhesive luting agent-dentinal surface interactions on film thickness

This study investigated the effect of luting agent-dentinal surface interactions on the film thicknesses of new adhesive luting agents. The method was in compliance with American National Standards Institution/American Dental Association (ADA) Specification No. 8 for zinc phosphate cement. In the control groups the luting agents were placed between two glass plates, as described in ADA Specification No. 8, but in the test groups the luting agents were positioned between a glass and a dentinal plate. The materials selected were zinc phosphate cement, glass ionomer cement, polycarboxylate cement, and a resinous cement with a dentinal bonding agent. A two-way analysis of variance was performed, and t tests were computed to compare glass with the dentinal plate within each material. Zinc phosphate and glass ionomer cements exhibited a significant decrease in film thickness when measured in contact with dentin, as compared with contact with the glass plate. However, polycarboxylate cement and the resinous cement with its dentin bonding agent showed a slight nonsignificant increase when contacting dentin, as compared with the glass plate. An explanation was offered and suggestions were made regarding future research.

Genetic engineering of a Lymantria dispar nuclear polyhedrosis virus for expression of foreign genes

A bacterial lacZ gene was inserted into an isolate of the Lymantria dispar nuclear polyhedrosis virus (LdMNPV). The transfer vector was constructed by site-directed mutagenesis of the translation start site of the LdMNPV polyhedrin gene, within the BglII E fragment of the viral genome. A multiple cloning sequence was inserted at this start site and used for the insertion of the lacZ gene into the transfer plasmid. Liposome transfection was used to cotransfect L. dispar tissue culture cells with viral DNA and the transfer plasmid. Recombinant LdMNPV isolates were purified by isolation of plaques producing beta-galactosidase but not polyhedra. Restriction enzyme fragment profiles were used to determine the site of the lacZ gene insertion, and DNA sequencing of the 5' and 3' ends of the lacZ gene insert and the adjoining polyhedrin promoter and coding regions was performed to identify its precise location. Expression of the lacZ gene was examined by studying virus-induced protein using [35S]methionine pulse-labelling, SDS-PAGE fractionation and autoradiography. Expression of beta-galactosidase was examined in tissue culture cells using colorimetric assays. The maximum rate of beta-galactosidase production was approximately 50 international units (IU)/10(6) tissue culture cells/day between 3 and 4 days post-infection (p.i), and the peak total expression was 158 IU/10(6) cells 5 days p.i. beta-Galactosidase activity was first detected 48 h p.i. in haemolymph samples from fourth instar L. dispar larvae injected with 10(6) p.f.u. of virus. The peak beta-galactosidase activity in larval haemolymph samples was 1931 IU/ml of haemolymph at 11 days p.i., just prior to death.

Nonconditional logistic regression analysis of risk factors in rheumatic heart disease

The prognostic risk factors in 4323 patients with rheumatic heart disease, admitted from 1970 to 1990, were analysed. The overall mortality was 31.75% in this group of patients. Single factor analysis indicated that cardiac functional classification, time of death, month of death, cardiothoracic ratio, valvular lesions, cardiogenic shock, digitalis-induced arrhythmias, intercurrent pneumonia, pleurorrhea, and hypotension were related to the overall mortality and cardiac death. Multiple factor logistic analysis indicated that for the overall mortality, the independent prognostic factors included presence of cardiac functional classification, cardiothoracic ratio and cardiogenic shock; for cardiac death, the independent factors included cardiac functional classification, cardiothoracic ratio, cardiogenic shock, digitalis-induced arrhythmias and valvular lesions. The data analysis showed that these five factors were contributory to rheumatic heart disease with synergism.

Film thickness of new adhesive luting agents

This study determined and compared the film thicknesses of new adhesive luting agents. The method was in compliance with American National Standards Institution/American Dental Association (ADA) Specification No. 8 for zinc phosphate cement. Each of the 20 materials tested was manipulated exactly as described in the manufacturers' instructions. An electronic gauge with an accuracy of 0.5 micron was recalibrated after each recording, and each luting agent was measured 10 times. The mean film thickness and standard deviation were calculated for each luting agent; an analysis of variance and a multiple comparison test were also performed. Nine materials satisfied the ADA type I specification for film thicknesses less than 25 microns, and these included a hydroxyapatite cement, glass ionomer cements, zinc phosphate cements, and polycarboxylate cements. Five other materials met the ADA type II specification for film thicknesses of less than 40 microns, and these included a glass ionomer cement, a resinous cement, a zinc phosphate cement, and glass ionomer-resinous hybrids. Six resinous cements recorded film thicknesses greater than 40 microns, and suggestions were made regarding future development and research.

Detection of human cytomegalovirus antigen and DNA in lymph nodes and peripheral blood mononuclear cells of patients with angioimmunoblastic lymphadenopathy with dysproteinemia

The cause of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) remains unknown. It is characterized by acute onset, severe constitutional symptoms, cervical or generalized lymphadenopathy, lymphopenia, and polyclonal hypergammaglobulinemia, all of which are highly suggestive of a viral origin. Using immunohistochemical methods, employing murine monoclonal antibody as the primary antibody, we detected human cytomegalovirus antigen in the lymph nodes of eight of 11 patients with AILD. Cytomegalovirus DNA was also detected in the peripheral blood mononuclear cells by DNA dot hybridization in all five of the patients with AILD who were tested using this technique. None of the lymph nodes from the 11 patients stained positive for the rubella virus antigen. Based on the above evidence and the similarity of the immunologic abnormalities found in both AILD and cytomegalovirus infection, the possible role of cytomegalovirus as one of the causative agents for AILD is proposed.

HPLC determination of a chemically modified nonantimicrobial tetracycline: biological implications

Chemically modified tetracycline (4-de-dimethylamino tetracycline), like commercially available tetracyclines, is known to inhibit experimentally induced pathologic collagen breakdown. A method for measurement of chemically modified tetracycline in small volumes (50 microliters) of rat serum was developed using reversed-phase HPLC; this was necessary because this tetracycline analog lacks antimicrobial activity and, therefore, cannot be measured with standard bioassays. This method uses the same solution for extraction and elution thus providing a simple and rapid assay for both drugs. Using this technique, the concentration of chemically modified tetracycline and tetracycline were determined in rat serum at different times after oral administration. The serum concentration of chemically modified tetracycline was much higher than that for tetracycline, and its serum half-life was greater. The IC50 of chemically modified tetracycline and tetracycline, as inhibitors of collagenase from rat polymorphonuclear leukocytes, was determined and found to be 4.1 x 10(-8) M (0.02 micrograms/ml) and 2.4 x 10(-4) M (120 micrograms/ml), respectively. Based on the serum levels of these drugs after oral administration, and their IC50 values, chemically modified tetracycline is potentially a far more potent inhibitor of excess collagenase activity than tetracycline, during pathologic conditions, and may have the added advantage of not producing some of the typical complications of long-term antibiotic therapy.

[A systematic study on comprehensive utilization of fibers of radix Ophiopogonis]

The components, toxicology, bioactivity and application of fibers of Radix Ophiopogonis (RO) were studied. The components of its fibers and roots are similar. In a clinical study with 100 aged patients, the aging syndromes were markedly improved. No side-effect was found.

Observation of the beat between two independent light sources by a method of time-delayed laser-induced double gratings

A novel method of time-delayed laser-induced double gratings has been proposed to study the beat between two independent light sources. Our experimental results indicate that we can obtain good interference patterns even when the coherence time of the laser source is only a few picoseconds. This new technique can be used to measure the frequency difference between two laser fields.

[A study on the development of vertebral column in reference to the gestational ages of fetuses]

The anteroposterior radiographs and ultrasound measurements of vertebral columns ranging from 12 to 33 weeks' gestation were studied. Two kinds of regressive equations were developed: one for estimating the length of cervical, thoracic and lumbar regions of vertebral column in accordance to gestational ages, and the other for estimating the gestational ages on the basis of the length of cervical, thoracic and lumbar regions of vertebral column. The normal values with confidence interval in accordance to the length of lumbar vertebral column for estimating the gestational ages were obtained. Also presented were the adjusted values of intercept between the data of ultrasound measurement and X-ray measurement. The ossification centers of neural arch appeared first in the upper cervical vertebrae, then they extended towards the lower vertebrae. Ossification centers for the vertebral centra appeared first in the lower thoracic/upper lumbar region and then extended to the lower and upper centra, respectively. Combining the length of lumbar vertebral column with the appearance time of the ossification centers of cervical vertebral centra, sacral vertebral centra and sacral neural arch, the authors set a standard for assessing the developmental condition of 12-23 weeks' fetuses.

Force-interval relationship and its response to ryanodine in streptozotocin-induced diabetic rats

Post-quiescent potentiation (PQP), an enhanced contraction following a long pause that occurs as a result of increased Ca2+ release from intracellular stores, and post-stimulation potentiation (PSP), an enhanced contraction following a rapid series of contractions that is believed to be related to increased Ca2+ influx, were measured in streptozotocin-treated Wistar, spontaneously hypertensive (SHR), and Wistar-Kyoto (WKY) diabetic heart tissues. Decreased PQP values were found in Wistar and SHR diabetic papillary muscles (PM) in comparison with the same strain controls, which suggests a diminished degree of releasable Ca2+ from sarcoplasmic reticulum (SR) in these tissues. Decreased PSP was found in SHR diabetic PM, which may be related primarily to a depressed sarcolemmal (SL) Na(+)-Ca2+ exchange in this tissue. PSP was not decreased in diabetic Wistar or WKY cardiac preparations, indicating that Ca2+ entry via channels must be involved in the PSP mechanism. Ryanodine depressed PQP in Wistar and SHR PM, and SHR left atria in both control and diabetic tissues. It abolished PQP and SHR diabetic tissues but had no effect on WKY control and diabetic tissues. The data suggest that the ryanodine effect differs in the various strains of rat. These differences may be due to differences in the SR sensitivity to ryanodine among the strains. Diabetic SR with impaired Ca2+ uptake may contribute to these phenomena. Ryanodine depressed PSP of Wistar and SHR diabetic PM but had no effects on tissues from controls. The influence of ryanodine on diabetic SL Na(+)-Ca2+ exchange requires further investigation.

Altered inotropic responses in diabetic cardiomyopathy and hypertensive-diabetic cardiomyopathy

To understand the mechanisms of diabetic cardiomyopathy and the consequences of combined hypertension and diabetes, cardiac tissue responses to various inotropic agents were measured in experimental diabetes. Streptozotocin was injected into Wistar rats, spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKYs). Six weeks after the injection diabetic rats showed a subsensitivity to beta adrenergic stimulation in ventricular tissue and a supersensitivity and hyper-responsiveness to Ca++ and alpha adrenergic stimulation (except in WKYs) in ventricular tissues and left atria. A supersensitivity to BAY K 8644 in SHR left atria and a hyper-responsiveness to verapamil in ventricular strips were also noted. These alterations may be due to a change in receptor number or to postreceptor alterations. Diabetic SHRs exhibited greater changes in several of the drug responses (responses to isoproterenol, phenylephrine and BAK 8644) were more hyperlipidemic and had a high mortality as compared with Wistar rats and WKY diabetics. These findings confirm that the combination of hypertension and diabetes results in greater cardiac pathology than is seen with either disease alone.

[An investigation on the resources of medicinal fungi in Sichuan]

This paper reports the classification, distributional traits, new distribution, specific species of medicinal fungi, as well as the status of anticancer medications and edible and medicinal fungi in Sichuan. Rational suggestions have been made with regard to the cultivation, development and utilization of those important species with proven curative effect.

Rapid diagnosis of Campylobacter pylori infection by urea test paper

Antral biopsy specimens from 106 patients were examined by culture, Gram stain and silver stain for Campylobacter pylori. Biopsies were also examined by a urea test paper test (UTPT). Of 106 patients studied C. pylori was detected in 68 (64.2%) by Gram stain, silver stain and culture. The UTPT was positive in 63 (59.4%) specimens. Five had false negative results using the UTPT with no false positive subjects. Thus, UTPT has a sensitivity of 92.6% (63/68) and a specificity of 100%. Of the 63 specimens that were UTPT positive, 45 were positive within 1 min, 58 were positive within 5 min. The remainder became positive between 5 and 15 min. There was a negative correlation between the time required for positive UTPT and the number of C. pylori per pit as seen on silver stained sections (P less than 0.05). UTPT is a rapid and sensitive method for detecting C. pylori in gastric mucosa. This enables early therapy, if indicated, before discharge from hospital. Moreover, the urea test paper method is cheap and easily stored.

[Separation and purification of the toxic protein of Bacillus sphaericus Ts-1]

Bacillus sphaericus strain Ts-1 is highly insecticidal to larvae of the mosquito. It's insecticidal component is toxic proteins. The toxin was extracted from spore-crystal complexes by disruption in a Sonicator Cell Disruptor Model W-220F followed by treatment with 0.05 mol/L NaOH. Fraction recovered from chromatography of the spore-crystal complexes on column of Sephadex G-200 were assayed against mosquito larvae and the toxic fractions from gel chromatography were subjected to SDS-PAGE. The toxic proteins in B. sphaericus Ts-1 spore-crystal complex migrated in position corresponding to 42kD and 43kD. Bioassay of the two purified proteins prepared by PAGE indicated that they were all toxic to mosquito larvae. Toxic protein was further purified by DEAE-cellulose chromatography. The toxic protein with a molecular weight of 42kD was obtained.

A long-term study of 370 autotransplanted premolars. Part IV. Root development subsequent to transplantation

The purpose of the present study was to analyse the extent of root development subsequent to transplantation in a material of 370 transplanted premolars. Before transplantation, the grafts were classified according to stage of root development (i.e. quarters of root length and constriction of the apical foramen) and length of tooth development (measured in mm from the cusp tip to the apical foramen). At radiographic controls the extent of root formation was registered. These figures were compared to the final tooth length of 288 non-transplanted premolars from the present material as well as to tooth length determinations of 534 premolars extracted for orthodontic purposes. Furthermore, intra-individual and inter-individual differences in tooth length were examined in a skull material with 40 pairs of premolars. These method studies indicated that root growth was probably determined genetically with great right-left accuracy and variation related to location of premolar (maxilla or mandible) and sex. A statistical analysis of the transplant material revealed that stage as well as length of tooth development assessed prior to transplantation were significantly related to final tooth length after transplantation. In most cases of transplantation performed at early stages of root development, a reduction in the final root length was seen. When a qualitative analysis of root development was performed in teeth with incomplete root formation at the time of transplantation, and where a homologous non-transplanted premolar was present, it was found that 14 per cent showed total arrest of root formation, 65 per cent partial arrest whereas 21 per cent showed no arrest (i.e. normal root formation). Premolars in ectopic position in the mandible before transplantation showed a significantly reduced root growth compared to matched pairs with normal position of the tooth graft. The present study indicated that no, partial or total damage to the Hertwig's epithelial root sheath was probably the explanatory factor for variations in root growth.

A long-term study of 370 autotransplanted premolars. Part II. Tooth survival and pulp healing subsequent to transplantation

The purpose of the present investigation was to determine the long-term prognosis of autotransplanted premolars with respect to tooth survival and pulpal healing. The material consisted of 195 patients aged 7 to 35 years, with a total of 370 autotransplanted premolars with observation period ranged from 1 to 13 years. Teeth transplanted with incomplete and complete root formation showed 95 per cent and 98 per cent long-term survival respectively: Pulp healing as evaluated by sensibility testing and radiographic signs of partial pulp canal obliteration was usually verified 6 months after transplantation. The frequency of pulpal healing (versus pulp necrosis), appeared to be closely related to stage of root development at time of transplantation. Teeth transplanted with incomplete and complete root formation showed 96 per cent and 15 per cent pulp healing respectively. Another and associated factor which could equally well predict pulpal healing was the diameter of the apical foramen of the graft. Finally, in teeth with completed root formation, the use of bursa with internal cooling and no extra-alveolar storage prior to transplantation seemed to increase the chance for pulpal healing. The present study indicates, that the size of the apical foramen and possibly the avoidance of bacterial contamination during the surgical procedure are explanatory factors for pulpal healing.

A long-term study of 370 autotransplanted premolars. Part I. Surgical procedures and standardized techniques for monitoring healing

Tooth autotransplantation has recently become a method of treating certain orthodontic problems. Over a 13-year period 370 premolar transplants were monitored by electrometric pulp sensibility testing and radiographic examination for pulp and periodontal ligament healing as well as root growth. This article describes the surgical technique as well as the precision of sensibility testing and radiographic examination for evaluating transplant healing. The sensibility response was found markedly related to the stage of tooth development but not to the type of premolar. The precision of sensibility testing (i.e. deviation of two consecutive measurements at a few weeks' interval) was found to range from 15-36 per cent for the different stages. Film holders were used to standardize the intraoral radiographic exposures. The precision percentage for the measuring technique of tooth length and crown width based on a single radiograph read twice (reading error) ranged from 1.1 to 1.8 with only small variations among the different types of premolar. The precision percentage of the radiographic exposure technique evaluated from two consecutive radiographs (measuring plus exposure error) was found to range from 1.2 to 4.2, again with small variations among the different premolars. The accuracy of the radiographic technique (i.e. deviation of radiographically determined tooth dimensions from the true values) was found to range from 2.0 to 2.9 with only small variation between the various types of premolar. In conclusion the evaluation of electrometric sensibility testing should take into account the stage of root formation of premolars.

A long-term study of 370 autotransplanted premolars. Part III. Periodontal healing subsequent to transplantation

The purpose of the present investigation was to determine the long-term prognosis of autotransplanted premolars with respect to periodontal healing. The subjects consisted of 195 patients aged 7 to 35 years, with a total of 370 autotransplanted all operated and followed with a standard technique. The observation period ranged from 1 to 13 years. Periodontal healing as demonstrated radiographically was complete in most cases after 8 weeks. Root resorption occurring after transplantation was divided into surface-, inflammatory- and replacement resorption (ankylosis). Root resorption occurred in 52 of the transplanted teeth and was usually diagnosed within 6 months. Root resorption was found to be significantly related to increasing stage of root development and the stage of eruption at the time of transplantation. Subsequent orthodontic movement of teeth with completed root formation at the time of transplantation resulted in a slight increase in the frequency of both surface and inflammatory resorption. The present study indicates that trauma to the PDL of the transplant is the explanatory factor for the development of root resorption.

Comparative inhibition of ras p21 protein synthesis with phosphorus-modified antisense oligonucleotides

A rabbit reticulocyte lysate translation assay was used to quantitatively compare a series of antisense oligodeoxyribonucleotides (11-mers) having different internucleoside linkages and various degrees of complementarity (100-80%) with the start codon and downstream 8 bases of Balb-ras p21 mRNA. The oligomers had either contiguous phosphodiester, or alternating methylphosphonate-phosphodiester, or contiguous methylphosphonate, or contiguous phosphorothioate linkages. Under the conditions used for the assay, all of the test compounds when present in about 10(3)-10(4) excess over mRNA (15 nM mRNA) inhibited protein synthesis to a degree which was dependent on both the concentration and sequence of the oligomer. At low concentrations (12.5-25 microM), the phosphorothioate analogs were the most potent inhibitors of p21 protein synthesis; however, a sequence non-specific effect for these oligomers was dominant at higher concentrations of oligomer (100-200 microM). The methylphosphonate oligomers appeared to be slightly more discriminant. Relative hybridization strengths were assessed by melting (Tm) studies using a DNA oligomer target to mimic the mRNA.

Novel inhibitors of enkephalin-degrading enzymes. II: N5'-substituted-4-thioxohydantoic acids as aminopeptidase inhibitors

Some 2-substituted-(2'-aminophenyl)-4-thioxohydantoic acids (o-amino PTC-amino acids) have antinociceptive activity when administered (icv) alone (IC50 = 0.04-0.87 microM/animal) and show a striking prolongation of the antinociceptive action of (D-Ala-2 D-Leu5)-enkephalin (DADL) in combination. The effects are thought to be mediated via opioid receptors since they are naloxone-reversible. Although inhibitors of the enkephalin degrading puromycin-insensitive, bestatin-sensitive aminopeptidase (possibly aminopeptidase M) their action is weak (IC50 = 32 microM leucine, 536 microM, glycine) and they might be considered to have a direct antinociceptive effect on opioid receptors. The titled compounds constitute novel 'lead' compounds for the development of potent aminopeptidase M inhibitors.

The results of radiation therapy in advanced carcinoma of the lung in the Beijing region of China

From 1958 to 1973, 682 patients with lung cancer were treated by radiation therapy in the Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China. The clinical presentation, sex, age, histology and stage and palliative effects of radiation therapy were reported. The 1-, 3- and 5-year survival rates were 40.62, 8.94 and 3.81%, respectively. The prognostic factors such as staging, histology, combination with chemotherapy and response of tumours are discussed. The causes of failure are also analysed. It is suggested that improving the local control rate of squamous cell carcinoma would increase the survival rate.