Development of a nondestructive compliance test for resilient denture liners

PURPOSE

Resilient denture liners are prescribed for patients who cannot adjust to hard-based dentures because of a thin mucosa or severe alveolar ridge resorption. A nondestructive test to evaluate compliance of new soft liner materials will be useful in clinical trials. The purpose of this study was to evaluate a nondestructive compliance testing technique designed to characterize long-term, silicone-based resilient denture liner materials.

MATERIALS AND METHODS

Samples of thicknesses of 1.1, 2.2, 3.3, and 4.4 mm of 2 materials (MPDS-SL [Lai Laboratories, Inc, Burnsville, MN] and Molloplast-B [Buffalo Dental, New York, NY]) were assessed for compliance using a closed-loop servohydraulic testing system, applying a 3 lb force following a squarewave pattern; force and position values were recorded using a storage oscilloscope. The oscilloscope values were analyzed using computer software to determine compliance values. The effect of material thickness was examined by testing wedges of the 2 materials.

RESULTS

The testing technique used showed that differing thicknesses had significantly different compliance values (p <.0001). In the materials used to evaluate the technique, MPDS-SL behaved more elastically than did Molloplast-B (p <.0001). Material thicknesses beyond 2.2 mm did not increase compliance, although MPDS-SL had a steeper thickness-compliance curve than Molloplast-B.

CONCLUSIONS

The method used to test compliance proved to be sufficiently sensitive to distinguish between 2 materials and between varying thicknesses. The sensitivity and nondestructive nature of this test show its suitability for clinical evaluation of resilient denture liners.

[STR polymorphisms in five Chinese ethnic groups(2)]

Population genetic studies were performed in Chinese Han, Hui, Mongolian, Tibetan and Uygur. Allele frequency distributions were analyzed for ten loci, i.e., D3S1358, VWA, CSF1PO, FGA, THO1, TPOX, D5S818, D13S317 and D7S820 by GeneScan. The results showed that there were 60 STR alleles and 149 genotypes in Han; 63 STR alleles and 144 genotypes in Hui; 69 STR alleles and 173 genotypes in Mongolian; 77 STR alleles and 168 genotypes in Tibetan; 70 STR alleles and 148 genotypes in Uygur. Significant differences were identified among ethnic groups (African-American, US-Caucasian and Chinese-Oriental), but similarity was found among the five Chinese populations, and immunogenomics and pharmacogenomics studied in this report. These findings indicated that the nine STR loci and amelogenin locus were very useful for individual identification in forensic science.

Infection of human dendritic cells by dengue virus causes cell maturation and cytokine production

Dengue virus (DV) infection is a major problem in public health. It can cause fatal diseases such as Dengue hemorrhagic fever and Dengue shock syndrome. Dendritic cells (DC) are professional APCs required for establishing a primary immune response. Here, we investigated the role of human PBMC-derived DC in DV infection. Using different techniques, including plaque assay, flow cytometry analysis, nested RT-PCR, and confocal microscope and electron microscope examinations, we show that DV can enter cultured human DC and produce virus particles. After entrance, DV could be visualized in cystic vesicles, vacuoles, and the endoplasmic reticulum. The DV-infected DC also showed proliferation and hypertrophy of the endoplasmic reticulum as well as the swollen mitochondria. In addition, the DV-stimulated DC could express maturation markers such as B7-1, B7-2, HLA-DR, CD11b, and CD83. Furthermore, the infection of DC by DV induced production of TNF-alpha and IFN-alpha, but not IL-6 and IL-12. Although DC underwent spontaneous apoptosis in the absence of feeding cytokines, this process appeared to be delayed after DV infection. Our observations provide important information in understanding the pathogenesis of DV infection.

Utilization of oriented peptide libraries to identify substrate motifs selected by ATM

The ataxia telangiectasia mutated (ATM) gene encodes a serine/threonine protein kinase that plays a critical role in genomic surveillance and development. Here, we use a peptide library approach to define the in vitro substrate specificity of ATM kinase activity. The peptide library analysis identified an optimal sequence with a central core motif of LSQE that is preferentially phosphorylated by ATM. The contributions of the amino acids surrounding serine in the LSQE motif were assessed by utilizing specific peptide libraries or individual peptide substrates. All amino acids comprising the LSQE sequence were critical for maximum peptide substrate suitability for ATM. The DNA-dependent protein kinase (DNA-PK), a Ser/Thr kinase related to ATM and important in DNA repair, was compared with ATM in terms of peptide substrate selectivity. DNA-PK was found to be unique in its preference of neighboring amino acids to the phosphorylated serine. Peptide library analyses defined a preferred amino acid motif for ATM that permits clear distinctions between ATM and DNA-PK kinase activity. Data base searches using the library-derived ATM sequence identified previously characterized substrates of ATM, as well as novel candidate substrate targets that may function downstream in ATM-directed signaling pathways.

[HLA-DRB alleles polymorphism in Han, Hui, Uygur and Tibetan populations in northwestern China]

According to the 11th THW standard, we designed a pair of primers by which a segment of 256bp of HLA-DRB1, B3, B4, and B5 could be amplified simultaneously. Twenty-seven oligonucleotide probes were designed and synthesized for 39 loci on DRB1, 3 on DRB3, 1 on DRB4 and 3 on DRB5. A PCR-SSO DNA typing protocol was built, which met the standard of HLA class II DNA typing in 11th IHW. With this method, 186 of Chinese (Han) in Xi'an, 169 of Hui in Ningxia, 200 of Uygur in Xinjiang, and 188 of Tibetan in Tibet were detected with a comparison study. The genetic distribution of 46 loci of DRB in four ethnic healthy populations were surveyed. No diversity has been found between Han and Hui in DRB. DRB1 * 02(16.9%), DRB1 * 07 (13.1%), and DRB1 * 09(12.0%) were the higher frequent loci in Han. More DRB loci were detected in Tibetan but without higher loci as in Han and Hui. The DRB polymorphism of Uygur population was similar to Caucasian. A discriminative highest frequency of DRB1 * 07(23.8%) was found in Uygur, which implied a selection happened.

Lupane-glycoside of Acanthopanax trifoliatus forma tristigmatis leaves

This report contains the first characterization of acanthodiolglycoside which belongs to pentacyclic lupane triterpene glycoside.

Failure of the all-polyethylene patellar component after total knee arthroplasty

From 1991 to 1996, 953 cases of porous-coated anatomic modular knee prostheses with all-polyethylene patellar components were implanted. Among them, 4 cases had breakage of the patellar component at the peg-button interfaces. One had loosening of the patellar component by cutting out the patellar bony bed. Heavy body weight, weakness of the pegs of the all-polyethylene patellar component, and osteonecrosis of the patella were conceived as the causes of failure.

Plant alkaloid tetrandrine and its analog block CD28-costimulated activities of human peripheral blood T cells: potential immunosuppressants in transplantation immunology

BACKGROUND

T lymphocyte activation mediated by CD28 costimulation plays a critical role in graft rejection. Plant alkaloid tetrandrine, purified from a Chinese antirheumatic herb, is a potent immunosuppressant. Here, we examined its effects on several CD28-costimulated T-cell activities. In addition, such effects were readily compared with the effects of three tetrandrine analogs.

METHODS

T lymphocytes were purified from whole blood by negative selection. The stimuli that mimic CD28 costimulation included both anti-CD3 + anti-CD28 monoclonal antibody and PMA+anti-CD28 monoclonal antibody. The determination of CD28-costimulated cell proliferation was performed by tritium uptake, cytokine production by ELISA, cell surface interleukin 2Ra and CD69 expression by flow cytometry, and mixed leukocyte reaction by tritium uptake. Drug cytotoxicity was determined by trypan blue exclusion, propidium iodide staining, and MTT colorimetric assays.

RESULTS

Tetrandrine inhibited CD28-costimulated T-cell proliferation and cytokine production through a mechanism different from that of cyclosporine. In addition, tetrandrine down-regulated both T helper 1 and T helper 2 cytokine production in CD4+ and CD8+ T-cell subpopulations. By examining cytokine production and T-cell activation marker expression, we further demonstrated that, among tetrandrine and its analogs tested, dauricine was the most potent suppressor of CD28-costimulated T-cell activities. Furthermore, the different immunosuppressive activities of these compounds were not associated with their cytotoxic capacities. Finally, the unparalleled inhibitory potency of dauricine on both mixed leukocyte reaction and CD28-costimulated T-cell proliferation suggests that dauricine preferentially targeted CD28-costimulated T-cell activities.

CONCLUSIONS

This is the first report to show that tetrandrine and its analogs potently inhibited both PMA+CD28-costimulated and CD3 + CD28-costimulated activation of human peripheral blood T cells. Based upon their structural similarity and different immunosuppressive potency, these in vitro data also provide very useful information for further identification and development of more potent and less toxic immunosuppressants to achieve transplantation success.

Effects of processing parameters on physical properties of the silicone maxillofacial prosthetic materials

OBJECTIVES

Maxillofacial prostheses are commonly fabricated using dental stone molds. However, for evaluating physical properties, maxillofacial materials are most often cured in metal molds. A-2186 is a silicone-based maxillofacial prosthetic material. Because its cure may be inhibited by traces of impurities, its physical properties may be different when it contains additives and is cured in dental stone molds, compared to when it is cured in metal molds without additives. This study's purpose is to determine and compare the physical properties of A-2186 cured in stainless steel molds and stone molds. The effects of additives and cure conditions on the physical properties were also studied.

METHODS

Hardness, tensile strength, ultimate elongation, and tear strength of A-2186 cured in dental stone molds, stainless steel molds, and with and without additives were determined. The bonding strength of A-2186 to four adhesives was determined by the peel test. All comparisons were made using analysis of variance (ANOVA).

RESULTS

Hardness, tensile strength and ultimate elongation of A-2186 cured in stainless steel molds are significantly higher than those cured in stone molds. Adding a small amount of a pigment, a kaolin and a fiber reduces hardness, tensile strength, ultimate elongation and tear strength. Except for Hydrobond, the bond strength of the adhesives to A-2186 was not significantly affected by the cure conditions and additives.

SIGNIFICANCE

Physical properties of A-2186 are affected by the additives commonly used in fabricating maxillofacial prostheses, and use of stone molds for curing degrades A-2186's mechanical properties. In fabricating clinical prostheses, special attention should be exercised to avoid contamination of A-2186 with impurities that could inhibit curing and produce inferior prostheses.

Effects of anti-rheumatic herbal medicines on cellular adhesion molecules

OBJECTIVE

To test the hypothesis whether herbal medicines ameliorate inflammatory diseases via the modulation of cellular adhesion molecules (CAMs).

METHODS

Human neutrophils, synovial fibroblasts, and endothelial cells were incubated with different concentrations of Tripterygium Wilfordii Hook-f (TWH-f) or Tetrandrine in the presence or absence of interleukin 1 (IL1). The amount of soluble E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cellular adhesion molecule-1 (VCAM-1) secreted by cells were determined by ELISA. The cell surface expression of these three CAMs was detected by flow cytometry.

RESULTS

TWH-f at high concentration (50 ng/ml) has a significant (p<0.05) inhibitory effect on both the secretion and the expression of the cellular adhesion molecules. However, Tetrandrine did not demonstrate the same effects.

CONCLUSIONS

The cellular adhesion molecules of the endothelium and leucocytes may constitute excellent targets for the development of new anti-inflammation medicines. These results indicate that TWH could be a potential therapeutic agent in the treatment of inflammatory diseases.

Plant alkaloid tetrandrine downregulates protein kinase C-dependent signaling pathway in T cells

Tetrandrine, a purified traditional Chinese medicinal herb that acts as an immunosuppressant and a Ca2+ channel blocker, has been clinically used to treat patients with arthritis, silicosis and hypertension. Since T cells play a critical role as autoreactive and pathogenic population in autoimmune diseases, in this study, we examined the immunosuppressive effect of tetrandrine on human peripheral blood T cells. We showed that tetrandrine inhibited phorbol 12-myristate 13-acetate (PMA) + ionomycin-induced T cell proliferation, interleukin-2 secretion and the expression of the T cell activation antigen, CD71. Further investigation of the molecular mechanism demonstrated that tetrandrine inhibited the expression of the protein kinase C-dependent interleukin-2 receptor alpha chain and CD69 but not the expression of the Ca2+-dependent CD40 ligand and CD69. Interestingly, when tetrandrine and cyclosporin A were added together, significant synergism in the suppression of T cell activation was observed. Moreover, of the several tetrandrine analogues studied, hernandezine was the most potent inhibitor of protein kinase C signaling events. These results also suggest that the protein kinase C-inhibitory capacity of tetrandrine and its analogues may not be associated with their function as Ca2+ channel blockers. Lastly, we showed that, within therapeutic concentrations, tetrandrine and its analogues could induce cellular apoptosis, which is defective in autoimmune diseases. In conclusion, our findings provide novel information about the molecular mechanism of the immunosuppressive effect of tetrandrine and its analogues in human peripheral blood T cells.

Mechanism of immunosuppression of the antirheumatic herb TWHf in human T cells

OBJECTIVE

To investigate the immunosuppressive mechanism of Tripterygium wilfordii Hook-F (TWHf) in human T cells. TWHf, a traditional Chinese medicinal herb for rheumatoid arthritis, has been shown to inhibit the function of immune effector cells such as neutrophils, macrophages, and B lymphocytes.

METHODS

T cell survival was evaluated with trypan blue exclusion assay, morphologic changes with Wright's stain, the induction of endonuclease activity with DNA fragmentation assay, and the subdiploid DNA content with flow cytometry. T cell activation was measured with interleukin 2 (IL-2) ELISA and the expression of several surface molecules with flow cytometry.

RESULTS

At high dosages, TWHf caused inhibition of T cell proliferation and this mechanism was mediated through the induction of apoptosis. TWHf, in noncytotoxic dosages, was as potent as cyclosporin A and more potent than prednisolone and cyclophosphamide in inhibiting IL-2 production from activated T cells. TWHf also inhibited both phorbol 12-myristate 13-acetate induced IL-2Ralpha expression and ionomycin induced CD40 ligand expression. TWHf did not reverse downregulated expression of CD3 and CD4 by phorbol ester stimulation.

CONCLUSION

This is the first evidence that the immunosuppressive mechanism of TWHf in T cells was mediated through both downregulation of T cell receptor signaling pathway and induction of cellular apoptosis, which is defective in autoimmune diseases.

Cell surface markers and circulating cytokines in graft versus host disease

Graft versus host disease (GVHD) remains the major obstacle to the widespread application of allogeneic bone marrow transplantation (BMT) despite improvement in drug prophylaxis. T cells in the donor bone marrow recognize and react against host alloantigens and thereby initiate GVHD, but the precise mechanisms by which host tissues are damaged remain unclear. In the current study, we determined the cytokine secretion, cell population distribution, and cell surface markers expression by ELISA and flow cytometer, to understand further the pathophysiology of GVHD. Our results demonstrated that there was no significant change in the cell ratio of B-and T- lymphocytes, and helper/suppressor cells during GVHD development when compared to the condition before transplantation. Furthermore, the percentage of natural killer cells, the interleukin-2 receptor (IL-2R) or the HLA-DR antigen on both CD4 and CD8 positive cells presented no significant difference between pre-transplantation and during GVHD. The serum cytokine secretion of IL-1, TNF-alpha, IL-2, ICAM-1, endothelin, TGF-beta showed no difference before BMT and during GVHD. However, when patients in the developing of GVHD, there was significant difference in the serum levels of soluble IL-2R (slL-2R), epidermal growth factor (EGF), and platelet derived growth factor (PDGF). In addition, with patients who develop GVHD, the mixed lymphocyte reaction also presented a significant difference. This study indicated that some serum cytokines such as sIL-2R, growth factors, and the mixed lymphocyte reaction may be used as parameters for the early detection of the development of GVHD.

The design, synthesis and activity of pentapeptide pp60c-src inhibitors containing L-phosphotyrosine mimics

Efficient syntheses of 4-(R,S-hydroxyphosphonomethyl)-L-phenylalanine and 4-carboxy-L-phenylalanine within the context of the pentapeptide Ac-Ile-X-Gly-Glu-Phe-NH2 (wherein X = the unnatural amino acid) illustrate the use of a divergent synthetic strategy from an advanced common peptide intermediate to more readily access peptide-based tyrosine kinase inhibitors. The key intermediate, Ac-Ile-Phe(4-formyl)-Gly-Glu(O-tBu)-Phe-NH2, was synthesized by a facile palladium-catalyzed carbonylation of Ac-Ile-Phe(4-iodo)-Gly-Glu(O-tBu)-Phe-NH2. Oxidation of Ac-Ile-Phe(4-formyl)-Gly-Glu(O-tBu)-Phe-NH2 with tetrabutylammonium permanganate or addition of di-t-butylphosphite, both followed by trifluoroacetic acid deprotection, gave the target pentapeptide inhibitors wherein X = 4-carboxy-L-phenylalanine or 4-(R,S-hydroxyphosphonomethyl)-L-phenylalanine, respectively. These two peptides gave somewhat more potent inhibition of the tyrosine kinase pp60c-src than the corresponding pentapeptide wherein X = L-phenylalanine, demonstrating that appended functionalities at the 4-position are accepted and can enhance binding through added interactions within the catalytic region of the active site.

Primary pyogenic abscess of the psoas muscle

During a six-year period, eleven persons with primary pyogenic abscess of the psoas muscle were treated at the Mackay Memorial Hospital. Five were males and six were females and their average age was 47.2 years (range 6-83 years). The abscess was identified by CT in 7 patients, MRI in 2 and ultrasonography in 1. One abscess was found during laparotomy. Treatment included extraperitoneal drainage of the abscess in 7 patients and CT guided aspiration in 3. One patient improved after antibiotic therapy and they all recovered after treatment. The diagnosis of primary pyogenic abscess requires a high index of suspicion and the best treatment is early operative drainage and administration of systemic antibiotics.

Effect of epidermal growth factor on glutamine metabolic enzymes in small intestine and skeletal muscle of parenterally fed rats

Exogenous epidermal growth factor (EGF) markedly increases the in vivo uptake of glutamine by small intestine during total parenteral nutrition (TPN). Since glutamine is the major oxidative fuel for the small intestine and is synthesized mainly in skeletal muscle, we investigated whether EGF would induce changes in the activity of the enzymes that mediate glutamine degradation (glutaminase) and synthesis (glutamine synthetase) in the two tissues. Male Sprague Dawley rats were randomized into three groups: group I (chow) were fed rat chow and water and libitum, group II (TPN) received a standard formula of TPN, and group III (TPN-EGF) received the same TPN as group II and injections of EGF (0.1 microgram/ gm body weight (bw)) subcutaneously twice daily. TPN was given for 2 wk; when EGF was administered along with TPN, the glutaminase activity of intestinal mucosa and the glutamine synthetase activity of skeletal muscle were increased, respectively, by 25% and 24% (P < 0.05, versus TPN group). These data suggest a mechanism whereby EGF enhances the intestinal utilization of glutamine by changing the activities of glutamine metabolic enzymes in the small intestine and skeletal muscle during TPN.

RelA is a potent transcriptional activator of the CD28 response element within the interleukin 2 promoter

T-cell activation requires two different signals. The T-cell receptor's recognition of a specific antigen on antigen-presenting cells provides one, and the second signal comes from costimulatory molecules such as CD28. In contrast, T cells that are stimulated with antigen in the absence of the CD28 costimulatory signal can become anergic (nonresponsive). The CD28 response element (CD28RE) has been identified as the DNA element mediating interleukin 2 (IL-2) gene activation by CD28 costimulation. Our previous work demonstrates that the Rel/NF-kappa B family proteins c-Rel, RelA (p65), and NFKB1 (p50) are involved in the complex that binds to the CD28RE. We also showed that c-Rel, but not NFKB1 (p50), can bind to the CD28RE and activate CD28RE-driven transcription in cotransfection assays. However, the role of RelA (p65) in CD28 signaling has not yet been addressed. We provide evidence that RelA (p65) itself bound directly to the CD28RE of the IL-2 promoter and other lymphokine promoters. In addition, RelA (p65) was a potent transcriptional activator of the CD28RE in vivo. We show that a RelA (p65)-c-Rel heterodimer bound to the CD28RE and synergistically activated the CD28RE enhancer activity. We also demonstrate that activated Raf-1 kinase synergized with RelA (p65) in activating the CD28RE enhancer activity. Interestingly, a soluble anti-CD28 monoclonal antibody alone, in the absence of other stimuli, also synergized with RelA (p65) in activating the CD28RE. Furthermore, we show that RelA (p65) activated expression of the wild-type IL-2 promoter but not the CD28RE-mutated IL-2 promoter. A combination of RelA (p65) and NFKB1 (p50) also activated the IL-2 promoter through the CD28RE site. These results demonstrate the functional regulation of the CD28RE, within the IL-2 promoter, by Rel/NF-kappa B transcription factors.

CD28 signaling causes a sustained down-regulation of I kappa B alpha which can be prevented by the immunosuppressant rapamycin

CD28, an important T cell surface molecule, mediates a costimulatory signal in the activation of T cell immune responses. CD28 signaling is resistant to the immunosuppressant cyclosporin A (CsA) but sensitive to the immunosuppressant rapamycin. CD28 costimulation induces transcription from the interleukin (IL)-2 promoter via the CD28 response element. The levels of c-Rel, a CD28 response element-binding factor, were found previously to be increased by CD28 costimulation. Therefore, we focused our present study on the mechanism(s) of c-Rel up-regulation by CD28 signaling in Jurkat T cells. In this paper, we showed that CD28 costimulation accelerated the kinetics of nuclear translocation of c-Rel. We showed that CD28 signaling, distinct from other stimuli such as phorbol 12-myristate 13-acetate, IL-1, and tumor necrosis factor-alpha, caused a sustained down-regulation of the inhibitor I kappa B alpha in Jurkat T cells. However, the levels of two other c-Rel inhibitors, namely NFKB1 (p105) and NFKB2 (p100), were not affected. Remarkably, the CD28-mediated down-regulation of I kappa B alpha was prevented by rapamycin but not by CsA. The counter-regulation of I kappa B alpha by CD28 signaling and rapamycin observed in Jurkat T cells is also reproducible in primary T cells. In contrast, the phorbol 12-myristate 13-acetate/ionomycin-mediated down-regulation of I kappa B alpha was prevented by CsA but not by rapamycin. Our data suggest that I kappa B alpha is the down-stream target of both CD28 signaling and rapamycin; a continued down-regulation of I kappa B alpha by CD28 costimulation leads to enhanced nuclear translocation of c-Rel, which in turn causes a sustained up-regulation of IL-2 gene expression.

Effect of CD28 signal transduction on c-Rel in human peripheral blood T cells

Optimal T-cell activation requires both an antigen-specific signal delivered through the T-cell receptor and a costimulatory signal which can be delivered through the CD28 molecule. CD28 costimulation induces the expression of multiple lymphokines, including interleukin 2 (IL-2). Because the c-Rel transcription factor bound to and activated the CD28 response element within the IL-2 promoter, we focused our study on the mechanism of CD28-mediated regulation of c-Rel in human peripheral blood T cells. We showed that CD28 costimulation accelerated the kinetics of nuclear translocation of c-Rel (and its phosphorylated form), p50 (NFKB1), and p65 (RelA). The enhanced nuclear translocation of c-Rel correlated with the stimulation of Il-2 production and T-cell proliferation by several distinct anti-CD28 monoclonal antibodies. This is explained at least in part by the long-term downregulation of I kappa B alpha following CD28 signalling as opposed to phorbol myristate acetate alone. Furthermore, we showed that the c-Rel-containing CD28-responsive complex is enhanced by, but not specific to, CD28 costimulation. Our results indicate that c-Rel is one of the transcription factors targeted by CD28 signalling.

Tetrapeptide tyrosine kinase inhibitors. Enantioselective synthesis of p-hydroxymethyl-L-phenylalanine, incorporation into a tetrapeptide, and subsequent elaboration into p-(R,S-hydroxyphosphonomethyl)-L-phenylalanine

A convenient enantioselective synthesis of p-hydroxymethyl-L-phenylalanine was developed which produces a 4/1 ratio of L/D enantiomers resulting from a chiral phase-transfer-catalyzed alkylation. This amino acid was coupled into the p56(1)ck tyrosine kinase substrate Ac-Leu-Pro-Tyr-Ala-NHCH3 as a replacement for Tyr and can subsequently be elaborated into a variety of potential tyrosine kinase inhibitor designs of general structure Ac-Leu-Pro-AA-Ala-NHCH3, wherein AA is an unnatural amino acid. The contaminating D enantiomer was readily removed after coupling to L-Ala-NHCH3 of this sequence. The utility of the p-hydroxymethyl functionality in an efficient divergent synthetic strategy leading to various inhibitor designs is illustrated with the synthesis of Ac-Leu-Pro-AA-Ala-NHCH3, wherein AA is p-(R,S-hydroxyphosphonomethyl)-L-phenylalanine.

Measuring polymerization shrinkage of photo-activated restorative materials by a water-filled dilatometer

A water-filled dilatometer specifically designed for determining the polymerization shrinkage of photo-activated composite restorative materials was used to measure the polymerization shrinkage of three visible light-activated composites. Polymerization shrinkage values ranged from 1.82% for P-50 to 2.15% and 2.19% for Herculite XRV and Prisma APH, respectively. Shrinkage data obtained in this investigation were compared with the published data, and the factors which affect shrinkage measurements were reviewed. It was concluded that maintaining a constant temperature environment (+ or - 0.02 degrees C) for the dilatometer during the shrinkage test was the most critical factor for successful application of the dilatometer.

Intercostal arteriovenous fistula due to pleural biopsy

A 32 year old woman had a pleural biopsy for a left pleural effusion, which showed caseating granuloma typical of tuberculosis. When the fourth biopsy specimen was removed considerable bleeding occurred from the puncture site. Four days later a bruit was audible over the punctured area, radiating to the back. Eight days after the procedure the patient had a massive bleed into the left pleural space. Selective aortic angiography showed an arteriovenous fistula between the 9th intercostal artery and vein and a pseudoaneurysm in the intercostal punctured area. Thoracotomy showed bleeding from the site of the pleural biopsy. The intercostal vessels were ligated and pleural decortication was performed, and the patient recovered uneventfully.