Economical template fabrication for provisional fixed partial dentures.
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Dental Impression Technique↗
Biomedical subjects
J C Chang
Publications and source records attributed to J C Chang.
Attachment of wrought wire clasp to metal framework.
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Acrylic Resins↗
Cloning and nucleotide sequence of an extracellular alpha-amylase gene from Aeromonas hydrophila MCC-1.
A gene encoding the extracellular alpha-amylase of Aeromonas hydrophila MCC-1 was cloned and expressed using its own promoter on the recombinant plasmid pCA101. Subcellular fractionation of Escherichia coli JA221 carrying pCA101 revealed that approximately 60% of the amylase activity was localized in the periplasmic space. The extracellular amylase was purified to homogeneity, identified as an alpha-type and its amino-terminal sequence was determined. Nucleotide sequence analysis predicted a 443 amino acid ORF and 24 amino acids at the amino terminus of the sequence that are not found in the secreted protein. This 24 amino acid sequence has many of the characteristics common to known signal peptides. The predicted amino acid sequence has considerable similarity with mammalian, invertebrate and Streptomycete alpha-amylases. Most of the amino acid residues that are involved in catalytic activity, substrate binding and calcium binding in several alpha-amylases were also present in A. hydrophila alpha-amylase at the corresponding positions.
Aeromonas hydrophila↗
Bond strength of composite to alloy treated with bonding systems.
PURPOSE: The in-vitro bond strengths of a composite bonded to a nickel-chromium-beryllium alloy treated by eight bonding systems were measured after three storage conditions. MATERIALS AND METHODS: Nickel-chromium-beryllium alloy samples were treated by eight commercial bonding systems including adhesive composite cements, all-purpose bonding agents, and silica-coating systems. A composite was bonded to the alloy samples. Sample groups were stored in water for 24 hours at 23 degrees C, or thermocycled, or stored for 6 months at 23 degrees C and then debonded in tension. RESULTS: Bond strengths after 24 hours storage were: adhesive composite cements, 14.2 to 22.1 MPa; all-purpose bonding agents, 11.4 to 14.6 MPa; and silica-coating systems, 18.6 to 20.2 MPa. Bond strengths after thermocycling were: adhesive composite cements, 12.6 to 20.6 MPa; all-purpose bonding agents, 9.9 to 17.7 MPa; and silica-coating systems, 11.1 to 19.2 MPa. Bond strengths after 6 months were: adhesive composite cements, 12.0 to 13.1 MPa; all-purpose bonding agents, 8.7 to 14.1 MPa; and silica-coating systems, 14.8 to 18.4 MPa. CONCLUSIONS: Only two bonding systems showed decreased bond strength after thermocycling, as compared with 24 hours' storage; whereas four bond systems showed decreased bond strength after 6 months' storage. Bond strengths measured after thermocycling were not predictive of those measured after 6 months' storage.
Analysis of Variance↗
Multiorgan procurement from non-heart-beating donors by use of Osaka University cocktail, Osaka rinse solution, and the portable cardiopulmonary bypass machine.
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Animals↗
Relining dentures with metal bases.
Metal bases are common in both complete and removable partial dentures. Before the introduction of adhesive denture base material, relining of these bases was almost impossible. This article presents a case on the technique of relining a partial denture metal base, using a 4-META resin (Acrylic Solder). With this technique, metal base can be relined easily in the dental office.
Acrylic Resins↗
Prevention and control of melanoma skin cancer in Missouri.
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Adult↗
Dissection of the enhancer activity of beta-globin 5' DNase I-hypersensitive site 2 in transgenic mice.
The beta-globin locus control region (LCR) consists of four erythroid-specific DNase I-hypersensitive sites, which are necessary for high-level expression of the beta-like globin genes in erythroid tissues. One of these sites, designated 5'HS-2, functions as an erythroid-specific enhancer element in transfection and transgenic mouse experiments. Recent transfection experiments and studies of DNA-protein interactions have localized the 5'HS-2 enhancer to 18 nucleotides that contain a binding site for both the erythroid-specific factor nuclear factor erythroid 2 (NFE-2) and for activator protein 1 (AP-1). To define the sequences necessary for in vivo enhancer activity, several deletion mutants of 5'HS-2 were linked to the human beta-globin gene and their activity was tested in transgenic mice. Three upstream fragments of 5'HS-2 [341, 374, and 412 base pairs (bp)], each of which contained the NFE-2/AP-1 sequences, resulted in beta-globin expression at levels equivalent to or higher than those observed with the entire 732-bp 5'HS-2 fragment. In contrast, a 358-bp downstream portion of 5'HS-2, which lacked the NFE-2/AP-1 sequences, resulted in beta-globin expression at the low levels seen with the beta-globin gene alone. Removal of the NFE-2/AP-1 sequences by a 67-bp internal deletion resulted in similar low levels of beta-globin expression. A 100-bp 5' fragment that contained the NFE-2/AP-1 sequences resulted in beta-globin expression that was higher than the beta-globin gene alone but lower than the entire 5'HS-2 fragment or the three larger upstream fragments. These studies demonstrate that the NFE-2/AP-1 sequences are essential for enhancer activity of 5'HS-2 but that other sequences are required for full activity in vivo.
Animals↗
Simultaneous ectopic pregnancy with intra-uterine gestation after in vitro fertilization and embryo transfer.
A case of combined intra-uterine and tubal ectopic pregnancy is described following in vitro fertilization and the transfer of two four-cell and one two-cell embryos. This phenomenon is known to be related to ovarian stimulation by gonadotropin therapy, and there is an increased risk with tubal disease. Techniques applied at the time of embryo transfer, the use of culture medium with 50% fetal cord serum to convey the embryos to the uterus, the catheterization method, and the position of the patient during transfer are presented. The risk of multiple pregnancies and combined intra-uterine and ectopic gestations increases with numbers of transfers and large volume of transfer medium. We would therefore recommend that after IVF-ET treatment in women with tubal disease, intensive care should be taken in the early follow-up period to rule out the possibility of ectopic pregnancy. In this case, a viable ongoing intra-uterine pregnancy was confirmed after surgery for right ampullary ectopic pregnancy. And a 2,925 g male in excellent condition was delivered by Cesarean section without complications.
Adult↗
A 36-base-pair core sequence of locus control region enhances retrovirally transferred human beta-globin gene expression.
The locus control region of the human beta-globin cluster consists of four major DNase I hypersensitive sites (HS). When linked to globin genes, the locus control region confers a high level of erythroid-specific expression of these genes in transgenic mice or transfected erythroid cell lines. We have examined the effect of one of these sites, HS2, on human beta-globin gene expression in a murine erythroleukemia cell line (MEL) after retrovirus-mediated gene transfer. We incorporated a 732- or 412-base-pair (bp) segment of HS2 in the retroviral construct carrying the human beta-globin gene. These fragments rendered the viruses unstable as the human beta-globin gene was rearranged or deleted in all the packaging cell lines examined. On the other hand, when a 36-bp fragment containing the NFE-2/AP-1 binding consensus in this region was inserted into the retroviral construct, we recovered 6 stable packaging cell lines of 12 examined, similar in percentage to the construct with the beta-globin gene alone. The virus titers of the packaging cell lines from these two constructs were similar. We infected MEL cells with viruses produced from three packaging cell lines of each of the two constructs and measured the ratio of human beta-globin to mouse alpha-globin mRNA after hexamethylenebisacetamide induction. The overall level of expression increased 2-fold from 6.0% to 12.7% with the addition of this 36-bp enhancer.
3T3 Cells↗
One-year dietary toxicity study with methidathion in beagle dogs.
The purpose of this study was to determine the chronic toxicity of methidathion, an organophosphate insecticide, in dogs. Groups of beagle dogs, four/sex/dose, were fed methidathion at constant dietary concentrations of 0, 0.5, 2, 4, 40, or 140 ppm for 1 year. The equivalent daily dosages were approximately 0, 0.02, 0.07, 0.15, 1.4, and 4.7 mg/kg. There were no deaths or adverse clinical signs associated with the treatment. Weekly body weights and weight gains were not affected. Mean daily food consumption was reduced in male dogs given the 140-ppm diet. Major treatment-related effects were cholestasis, chronic inflammation in the liver, and cholinesterase (ChE) inhibition. The liver effects were indicated by gross and microscopic pathologic findings as well as moderate increases in serum bile acids and enzyme activities (alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, and alkaline phosphatase) in all dogs receiving greater than or equal to 40 ppm. RBC ChE was inhibited in males at greater than or equal to 40 ppm and in females and 140 ppm. Brain ChE was inhibited in both sexes at 140 ppm; the magnitude of inhibition relative to control was slightly greater with the cerebellar fraction than with the cerebral fraction. Serum ChE was not affected at any dose level. In conclusion, liver was the target organ in beagle dogs given greater than or equal to 40 ppm (equivalent to 1.4 mg/kg/day) methidathion in diet for 1 year. The no-observable-effect level was 4 ppm (0.15 mg/kg/day) for both liver cholestasis and ChE inhibition.
Animals↗
The distribution of the DHFR genes in trimethoprim-resistant urinary tract isolates from Taiwan.
Between July 1987 and June 1989, 1054 urinary isolates of enterobacteria from Kaohsiung, Taiwan were studied for their trimethoprim resistance. Trimethoprim resistance was defined as MIC greater than 4 micrograms/ml and high-level resistance by MIC greater than 1000 micrograms/ml. The incidence of trimethoprim resistance increased from 33.6% in 1987 to 42.1% in 1989. Among the resistant strains studied, 90% were resistant to high levels of trimethoprim. An increase in the proportion of resistant strains (33.9-46.3%) exhibiting high-level non-transferable trimethoprim resistance was noted. The distribution of the dihydrofolate reductase (DHFR) genes by colony hybridization in 374 trimethoprim-resistant isolates revealed the presence of type I and type V DHFR genes in most of these isolates (45.4% and 10.4% respectively). Type I was predominant in Escherichia coli whereas type V was frequently seen in Enterobacter spp. None showed homology with the type II and type III DHFR probe DNA. In addition, transposon Tn7 was present in 7.8% of 374 trimethoprim-resistant enterobacteria.
DNA Transposable Elements↗
Gender and histologic type variations in smoking-related risk of lung cancer.
We conducted a registry-based case-control study to examine the relation between smoking and lung cancer by gender and histologic type. Our analyses were based on 14,596 cases and 36,438 age-matched controls. Relative risk associated with ever-smoking, and level of smoking was consistently higher in females than males for all lung cancers combined (ever-smoking odds ratios: 12.7 for females and 9.1 for males) and for each histologic type except adenocarcinoma. Female-male differences in relative risk were larger in younger age groups. The largest estimates of the attributable fraction due to smoking were observed for small cell carcinoma (97% in females and 91% in males); conversely, the smallest value was noted for adenocarcinoma (86% in females). Although our study was unable to measure absolute risk, our findings, other recent studies, and contemporary female smoking patterns raise concerns that female smokers may assume a proportionally greater burden of lung cancer morbidity and mortality in the future.
Adenocarcinoma↗
Cloning of a creatinase gene from Pseudomonas putida in Escherichia coli by using an indicator plate.
A genomic library of Pseudomonas putida DNA was constructed by using plasmid pBR322. Transformants of Escherichia coli in combination with Proteus mirabilis cells grown on creatinase test plates were screened for creatinase activity; transformants were considered positive for creatinase activity if a red-pink zone appeared around the colonies. One creatinase-positive clone was further analyzed, and the gene was reduced to a 2.7-kb DNA fragment. A unique protein band (with a molecular weight of approximately 50,000) was observed in recombinant E. coli by minicell analysis.
Cloning, Molecular↗
Effects of pentoxifylline in the hamster zona-free oocyte spermatozoa penetration assay and on spermatozoa transmembrane migration motility.
The effects of pentoxifylline on capacitation, acrosome reaction and motility of spermatozoa in vitro were evaluated by the hamster zona-free oocyte penetration assay and the transmembrane migration method, respectively. The improvement in penetration capacity by the addition of pentoxifylline 40 min before coincubation had a trend toward statistical significance (0.05 less than less than 0.1) in normal fertile men and had statistical significance (p less than 0.05) in asthenospermic patients. There was no improvement by the addition of pentoxifylline 16 h before coincubation. Pentoxifylline significantly increased sperm motility in both normal (p less than 0.001) and asthenospermic patients (p less than 0.05) in the transmembrane migration method. This study showed that pentoxifylline could be used as a stimulant of in vitro sperm motility in male infertility.
Animals↗
Rupture of rudimentary horn pregnancy.
A rare case of rupture of an noncommunicating rudimentary horn pregnancy is reported. The pregnancy proceeded to 25 gestational weeks, when the rudimentary horn ruptured. The patient had signs and symptoms of massive hemoperitoneum. An emergency exploratory laparotomy revealed rupture of the gravid rudimentary horn and the fetus was lying free in the peritoneal cavity, was delivered breech and died 2 hours later. This reproductive complication was treated successfully by prompt exploratory laparotomy. Some of the factors associated with pregnancy in a rudimentary horn are discussed.
Adult↗
Clinical analysis of surgical treatment for tuboovarian abscess.
The role of copious irrigation and drainage in the treatment of tuboovarian abscess (TOA) is crucial, especially for the patients who want to remain fertile. Some have used vaginal drainage via posterior colpotomy for patients with TOA, whereas others preferred irrigation using large-bore drains. In this study, we reported 31 cases of TOA. We found that for women who want to conceive again the best method of treatment is conservative surgery plus low pressure sump tube drainage.
Abscess↗
Prevalence of transposons encoding kanamycin, ampicillin and trimethoprim resistance in isolates from urinary tract infections detected using DNA probes.
Drug resistant Gram-negative bacteria causing urinary tract infections were collected. Kanamycin, ampicillin or trimethoprim-resistant strains were analyzed separately for the presence of Tn5, Tn3, or Tn7 by colony hybridization. Of these isolates, kanamycin-resistant transposons were present in 38.2% of 60 kanamycin-resistant isolates. A 3.3 kb fragment containing SacI-BamHI transposase of Tn3 and 42.6% showed a positive reaction in 129 ampicillin-resistant clinical isolates. Among the 75 trimethoprim-resistant isolates studied, 52% were shown to contain Tn7 when probed with a 1 kb BamHI fragment of Tn7. Results from Southern hybridizations demonstrated that these antibiotic resistant genes had been born on plasmids in some clinical isolates.
Ampicillin Resistance↗