Arthroplasty of the hip in patients with aplastic anemia

BACKGROUND

Patients with aplastic anemia are now living longer and therefore are at increased risk for the development of osteonecrosis of the hip. However, studies on the results of arthroplasty for the treatment of osteoarthritis of the hip in patients with aplastic anemia are lacking.

METHODS

Twenty-six primary hip prostheses (one bipolar prosthesis fixed with cement, two bipolar prostheses fixed without cement, three hybrid total hip prostheses, and twenty total hip prostheses fixed without cement) were implanted, between March 1990 and May 1992, in nineteen patients who had been diagnosed with aplastic anemia. A specific prospective protocol was followed for the perioperative transfusion of platelets and blood. Twenty-five hips were replaced because of osteonecrosis of the femoral head, and one was replaced because of a femoral neck fracture. The patients were followed prospectively, with preoperative and serial postoperative Harris hip ratings as well as radiographs, for a minimum of six years or until death.

RESULTS

No patient had excessive perioperative bleeding or a postoperative infection. After a mean duration of follow-up of seventy-nine months (range, seventy-two to ninety-five months), two patients had died with the original implant in place. No patients were lost to follow-up. The mean Harris hip score was 55 points (range, 42 to 68 points) preoperatively and 87 points (range, 56 to 95 points) at the time of the latest follow-up. At the time of this writing, no hip had been revised. One patient with a bipolar prosthesis had radiographic evidence of femoral loosening and will probably require revision. A second patient had some medial protrusion of a bipolar prosthesis, with mild symptoms. All of the acetabular components that had been fixed without cement and all of the other femoral components appeared to be stable on radiographs after a minimum of seventy-two months of follow-up.

CONCLUSIONS

Total hip arthroplasty can be performed safely in patients with aplastic anemia. In the present intermediate-term study, the durability of implant fixation was maintained and the clinical results demonstrated a sustained increase in function of the hip.

Expression and characterization of the flavoprotein domain of gp91phox

Truncated forms of gp91(phox) were expressed in E. coli in which the N-terminal hydrophobic transmembrane region was replaced with a portion of the highly soluble bacterial protein thioredoxin (TRX). TRX-gp91(phox) (306-569), which contains the putative FAD and NADPH binding sites, showed NADPH-dependent NBT (nitroblue tetrazolium) reductase activity, whereas TRX-gp91(phox) (304-423) and TRX-gp91(phox) (424-569) were inactive. Activity saturated at about a 1:1 molar ratio of FAD to TRX-gp91(phox) (306- 569), and showed the same Km for NADPH as that for superoxide generating activity by the intact enzyme. Activity was not inhibited by superoxide dismutase, indicating that it was not mediated by superoxide, but was blocked by an inhibitor of the respiratory burst oxidase, diphenylene iodonium (DPI). In the presence of Rac1, the cytosolic regulatory protein p67(phox) stimulated the NBT reductase activity, but p47(phox) had no effect. Truncated p67(phox) containing the activation domain (residues 199- 210) stimulated activity approximately 2-fold, whereas forms mutated or lacking this region failed to stimulate the activity. Our data indicate that: 1) TRX-gp91(phox) (306-569) contains the binding sites for both pyridine and flavin nucleotides; 2) this flavoprotein domain shows NBT reductase activity; and 3) the flavin-binding domain of gp91(phox) is the target of regulation by the activation domain of p67(phox).

Activation domain in P67phox regulates the steady state reduction of FAD in gp91phox

An activation domain in p67(phox) (residues 199-210) is critical for regulating NADPH oxidase activity in cell-free system [10] To determine the steady state reduction of FAD, thioacetamide-FAD was reconstituted in gp91(phox), and the fluorescence of its oxidised form was monitored. Omission of p67(phox) decreased the steady state reduction of the FAD from 28% to 4%, but omission of p47(phox) had little effect. A series of the truncated forms of p67(phox) were expressed in E.coli to determine the domain in p67(phox) which is essential for regulating the steady state of FAD reduction. The minimal length of p67(phox) for for regulating the steady state of FAD reduction is shown to be 1-210 using a series of truncation mutants which indicates that the region 199-210 is also important for regulating electron flow within flavocytochrome b(558). The deletion of this domain not only decreased the superoxide generation but also decreased the steady state of FAD reduction. Therefore, the activation domain on p67(phox) regulates the reductive half-reaction for FAD, consistent with a dominant effect on hydride/electron transfer from NADPH to FAD.

Synthesis and cytotoxic evaluation of a series of gamma-substituted gamma-aryloxymethyl-alpha-methylene-gamma-butyrolactones against cancer cells

PURPOSE

The main objective of this investigation was to explore the cytotoxic structure-activity relationships of gamma-substituted gamma-aryloxymethyl-alpha-methylene-gamma-butyrolactones against cancer cells.

METHODS

The target compounds were synthesized in two steps commencing with aryl-OH which was treated with a bromomethyl ketone followed by the Reformatsky-type condensation.

RESULTS

Seven types of alpha-methylene-gamma-butyrolactones were evaluated in vitro against 60 human cancer cell lines derived from nine cancer cell types. The average values of log GI50 indicated that for the aryl portion, potencies of these alpha-methylene-gamma-butyrolactones are in a decreasing order of quinolin-2(1H)-one (or 2-hydroxyquinoline, 21, -5.89) > quinoline (19, -5.79) > 2-methylquinoline (20, -5.69) >8-hydroxyquinoline (17,-5.64) > 2-naphthalene (16, -5.59) > benzene (15, -4.90). The same order was obtained for both log TGI and log LC50. However, for the gamma-substituent, the potencies are in a decreasing order of biphenyl (16f-21f) > phenyl and 4-substituted phenyl (16b-e-21b-e) > methyl (16a-21a).

CONCLUSIONS

Unlike cardiovascular activities of alpha-methylene-gamma-butyrolactones in which a gamma-methyl substituent is necessary for vasorelaxing effect while a phenyl or a halogen-substituted phenyl is prefer for the antiplatelet activities, a gamma-biphenyl substituent proved to be the best for their cytotoxicities against various cancer cell lines tested.

Comparison of acquired cystic kidney disease between hemodialysis and continuous ambulatory peritoneal dialysis

OBJECTIVES

ACKD has been described mainly in patients treated with hemodialysis(HD), and there are only a few reports about the prevalence of ACKD in continuous ambulatory peritoneal dialysis (CAPD) patients. Therefore, we compared the prevalence of ACKD in patients receiving HD and CAPD, and evaluated the possible factors which may affect the development of ACKD.

METHODS

Forty nine HD and 49 CAPD patients who had received dialysis therapy for at least 12 months were enrolled in this cross-sectional study. Patients who had a past history of polycystic kidney disease and had acquired cystic kidney disease on predialysis sonographic exam were excluded. Detection of ACKD was made by ultrasonography and ACKD was defined as 3 or more cysts in each kidney.

RESULTS

The prevalence of ACKD was about 31% (30/98) and there was no significant difference between HD and CAPD patients(27% vs. 34%, p > 0.05). The prevalence of ACKD was not associated with age, sex, primary renal disease, the levels of hemoglobin, BUN, and serum creatinine. However, the duration of dialysis was significantly related to the development of ACKD (presence of ACKD, 74.4 +/- 42.4 months vs. absence of ACKD, 37.8 +/- 24.1 months, p < 0.05).

CONCLUSION

The prevalence of ACKD is not different according to the mode of dialysis, and the major determinant of acquired cyst formation is duration of dialysis.

The p67(phox) activation domain regulates electron flow from NADPH to flavin in flavocytochrome b(558)

An activation domain in p67(phox) (residues within 199-210) is essential for cytochrome b(558)-dependent activation of NADPH superoxide (O2(-.)) generation in a cell-free system (Han, C.-H., Freeman, J. L. R., Lee, T., Motalebi, S. A., and Lambeth, J. D. (1998) J. Biol. Chem. 273, 16663-16668). To determine the steady state reduction flavin in the presence of highly absorbing hemes, 8-nor-8-S-thioacetamido-FAD ("thioacetamido-FAD") was reconstituted into the flavocytochrome, and the fluorescence of its oxidized form was monitored. Thioacetamido-FAD-reconstituted cytochrome showed lower activity (7% versus 100%) and increased steady state flavin reduction (28 versus <5%) compared with the enzyme reconstituted with native FAD. Omission of p67(phox) decreased the percent steady state reduction of the flavin to 4%, but omission of p47(phox) had little effect. The activation domain on p67(phox) was critical for regulating flavin reduction, since mutations in this region that decreased O2(-.) generation also decreased the steady state reduction of flavin. Thus, the activation domain on p67(phox) regulates the reductive half-reaction for FAD. This reaction is comprised of the binding of NADPH followed by hydride transfer to the flavin. Kinetic deuterium isotope effects along with K(m) values permitted calculation of the K(d) for NADPH. (R)-NADPD but not (S)-NADPD showed kinetic deuterium isotope effects on V and V/K of about 1.9 and 1.5, respectively, demonstrating stereospecificity for the R hydride transfer. The calculated K(d) for NADPH was 40 microM in the presence of wild type p67(phox) and was approximately 55 microM using the weakly activating p67(phox)(V205A). Thus, the activation domain of p67(phox) regulates the reduction of FAD but has only a small effect on NADPH binding, consistent with a dominant effect on hydride/electron transfer from NADPH to FAD.

Biological effects of man-made mineral fibers (II)--their genetic damages examined by in vitro assay

In order to study and compare genetic damage induced by 10 kinds of man-made mineral fibers (JFM fibers) in cells, human lung epithelial cells (A549) were exposed to JFM fibers and chrysotile for 1 h, then single-cell gel electrophoresis (SCGE) assay was used to detect DNA strand breaks, DNA-DNA interstrand crosslink and the ability of DNA to repair; The results showed that all 10 JFM fibers could induce DNA strand breaks, DNA-DNA interstrand crosslinks and inhibit the ability of DNA repair. When human embryo lung (HEL) cells were exposed to JFM fibers and chrysotile for 24 h respectively, the chromosomal aberration was analyzed and the results showed that chrysotile and most of JFM fibers at 5.0 micrograms/ml induced structural chromosomal aberration, but all of these effects were lower than that of chrysotile and were different among them, suggesting that 10 types of JFM fibers had genotoxicity with different degree in vitro, but all of them were lower than that of chrysotile.

Structural elements within the methylation loop (residues 112-117) and EF hands III and IV of calmodulin are required for Lys(115) trimethylation

Calmodulin is trimethylated by a specific methyltransferase on Lys115, a residue located in a six amino acid loop (LGEKLT) between EF hands III and IV. To investigate the structural requirements for methylation, domain exchange mutants as well as single point mutations of conserved methylation loop residues (E114A, Glu114-->Ala; L116T, Leu116-->Thr) were generated. E114A and L116T activated cyclic nucleotide phosphodiesterase (PDE) and NAD+ kinase (NADK) similar to wild-type calmodulin, but lost their ability to be methylated. Domain exchange mutants in which EF hand III or IV was replaced by EF hand I or II respectively (CaM1214 and CaM1232 respectively) showed a modest effect on PDE and NADK activation (50 to 100% of wild-type), but calmodulin methylation was abolished. A third domain exchange mutant, CaMEKL, has the methylation loop sequence placed at a symmetrical position between EF hands I and II in the N-terminal lobe [residues QNP(41-43) replaced by EKL]. CaMEKL activated PDE normally, but did not activate NADK. However, CaMEKL retained the ability to bind to NADK and inhibited activation by wild-type calmodulin. Site-directed mutagenesis of single residues showed that Gln41 and Pro43 substitutions had the strongest effect on NADK activation. Additionally, CaMEKL was not methylated, suggesting that the introduction of the methylation loop between EF hands I and II is not adequate for methyltransferase recognition. Overall the data indicate that residues in the methylation loop are essential but not sufficient for methyltransferase recognition, and that additional residues unique to EF hands III and IV are required. Secondly, the QNP sequence in the loop between EF hands I and II is necessary for NADK activation.

Biological effects of man-made mineral fibers (I)--Reactive oxygen species production and calcium homeostasis in alveolar macrophages

10 types of standard mineral fiber samples (JFM fibers) were tested for their cytotoxicity in alveolar macrophages (AM) in vitro experiments, in which UICC chrysotile B was used as a positive control. The cytotoxicity included the production of superoxide anion radical and hydrogen peroxide, depletion of glutathione (GSH) and increase of intracellular free calcium. The results showed that chrysotile and most of the 10 mineral fibers could increase the production of superoxide anion and hydrogen peroxide, deplete the concentration of GSH and increase the level of free intracellular Ca2+ in AM. But all the effects of JFM fibers were lower than that induced by UICC chrysotile B. Although the cytotoxicity of JFM fibers were lower than that of asbestos, these mineral fibers should be used with highly care for workers in industries.

[Studies on cytotoxicity of man-made mineral fiber to alveolar macrophage]

OBJECTIVE

To compare the difference in cytotoxicity to human alveolar macrophage caused by ten kinds of man-made mineral fiber.

METHODS

Ten kinds of man-made mineral fiber prepared by Japan Fibrous Materials Research Association (JFM) were used with alveolar macrophage extracted from guinea pigs in vitro as the target cells. Changes in the production of O2- and H2O2, levels of glutathione and cellular free calcium ion (Ca2+) in alveolar macrophage were determined.

RESULTS

Most of the 10 kinds of JFM fiber could cause increased production of O2- and H2O2, reduction of levels of glutathione and increase of cellular free calcium ion (Ca2+) in alveolar macrophage, to a extent less than that caused by chrysotile.

CONCLUSION

In general, the cytotoxicity of JFM fiber was less than that of chrysotile. Although these mineral fiber could be used as substitutes for asbestos, they still could cause certain harm to human bodies.

Regulation of the neutrophil respiratory burst oxidase. Identification of an activation domain in p67(phox)

Superoxide generation by the neutrophil respiratory burst oxidase (NADPH oxidase) can be reconstituted in a cell-free system using flavocytochrome b558 and the cytosolic proteins p47(phox), p67(phox), and Rac. p47(phox) functions as an adaptor protein; it increases the affinity of p67(phox) and Rac in the NADPH oxidase complex, but is not essential when high concentrations of these proteins are used (Freeman, J. L., and Lambeth, J. D. (1996) J. Biol. Chem. 271, 22578-22582), implying that p67(phox) and/or Rac directly regulates enzyme activity. Herein, we describe an activation domain in p67(phox) that is essential for NADPH oxidase activity. A series of C-terminal truncation mutants of p67(phox) showed that residues 211 to the C terminus (residue 526) are not needed for cell-free activity. However, shorter truncations were inactive, pointing to an activation domain within the region spanning residues 199-210. p67(phox) mutated at single amino acid residues within this region showed diminished activity, and p67(phox) V204A was completely inactive. The effects of mutations on activity were independent of p47(phox), and mutations did not affect the binding of p67(phox) to Rac. In the presence of wild-type p67(phox), the V204A mutant was a potent inhibitor of superoxide generation, and inhibition was partially reversed by high concentrations of p67(phox), but not by p47(phox) or Rac. The V204A mutant competed with native p67(phox) for translocation to neutrophil plasma membrane, indicating that p67(phox) V204A assembles to form an inactive complex. The data imply a direct activation of flavocytochrome b558 by an activation domain in p67(phox).

Acute lymphoblastic leukemia with maturation--a new entity with clinical significance

The diagnosis of 'ALL with maturation' (ALLm) is proposed. One hundred and one patients with untreated ALL were entered into this study. The diagnosis of ALLm was made when more than 20% of all nucleated elements in the bone marrow showed maturation beyond prolymphocytes by light microscopic examination. The mature-appearing leukemic cells showed the same immunophenotype to remaining lymphoblasts. The number of ALLm cases was 19 (18.8%). The mean age at presentation of ALLm was 29 +/- 18, older than that of 18 +/- 16 of the remaining typical ALL (ALLt) (P = 0.015). Remission was induced with daunorubicin, vincristine, prednisone and L-asparaginase. Only two of 19 ALLm patients achieved CR after 4 weeks induction chemotherapy. In contrast, 57 of 82 (69.5%) ALLt patients achieved CR after the same induction chemotherapy. There was no significant difference in immunophenotype of ALLm compared with ALLt. Labeling index of DNA topoisomerase IIalpha (TopoLI) was studied by immunohistochemistry. Initial TopoLI of ALLm (221 +/- 147) was much lower than that of ALLt (609 +/- 262, P = 0.005). Furthermore, the remaining leukemic cells after chemotherapy were not labeled with anti-DNA topoisomerase IIalpha. The P53 protein was expressed in nine of 18 ALLm cases (50.0%) and P-glycoprotein was not expressed in ALLm cases. Twelve of 19 ALLm cases were studied for carrying bcr/abl fusion by karyotyping and/or fluorescent in situ hybridization. Only two cases revealed bcr/abl fusion. In conclusion, ALLm is a separate entity of ALL which has a very poor clinical course and is independent of other prognostic factors. The morphologically mature leukemic cells are in resting GO phase.

A quantitative comparison of machined commercially pure titanium and titanium-aluminum-vanadium implants in rabbit bone

Screw-shaped implants made from rods of commercially pure titanium (grade 1) and titanium-aluminum-vanadium (grade 5) were machined, and the implant surface structures were numerically described before being placed in rabbit tibiae for healing periods of 1 months, 6 months, and 12 months. Quantitative comparisons of the removal torque (Ncm) necessary to loosen the implants from the bone bed were performed. Short-term (1 month) observations revealed no significant differences between the two tested materials. However, after 6 and 12 months, the commercially pure titanium implants were significantly more stable in the bone bed, as compared to the alloy samples. After 6 months, the commercially pure titanium had a mean removal torque of 29 Ncm versus 23 for the alloy (P = .01), and after 12 months, the mean removal torque was 38 Ncm for commercially pure titanium as compared to 35 Ncm for the alloy (P = .01). Quantifications of the bone tissue response to the materials did not show any significant differences; however, the commercially pure titanium showed a tendency to have a higher percentage of bone in contact with the implant as compared to the alloy screws. Bone volumes in the threads were similar. The absence of any quantitative light microscopic difference after 1 month following placement may relate to the fact that there was a sparse amount of bone, since the tissue was in the organization/granulation phase. After 6 and 12 months of follow-up, substantial bone formation had occurred, resulting in significantly increased removal torques for the commercially pure titanium samples.

Quantitative and qualitative investigations of surface enlarged titanium and titanium alloy implants

Screw shaped implants of commercially pure (c.p.) titanium and titanium-6aluminum-4vanadium (Ti6A14V) were blasted with particles of TiO2 of mean sizes of 25 microns (Group I) and 75 microns (Group II) and inserted in rabbit bone for 3 months. The surface roughness of the implants was examined and quantified with an optical scanning 3-dimensional instrument (TopScan 3D system), revealing the two alloy surfaces in each group had similar surface roughness. Biomechanical (removal torque) tests showed the c.p. titanium implants to be significantly more stable in the bone bed than those of Ti6A14V. In Group I, the c.p. titanium implants demonstrated a mean removal torque of 38 N cm while the Ti6A14V demonstrated a mean removal torque of 27 N cm (P = 0.004). Group II implants revealed a mean removal torque of 70 N cm for the c.p. ti and 50 N cm for the alloy samples (P = 0.003). The removal torque values were converted to shear forces/strengths by three calculation methods, based on (a) the entire length of the implant surface in the cortical region, (b) the thickness of the cortical bone measured in close vicinity to the thread peaks and (c) the bone-metal contact length measured on the non-unscrewed neighbouring implants. Group I: (a) the c.p. ti implants revealed a mean shear force of 4 vs a mean of 3 N/mm2 for the alloy samples. Shear strengths based on (b); were 8 for c.p. ti vs 6 N/mm2 for the alloy. The mean shear strength/force if calculated according to (c) revealed 23 for c.p. ti vs 18 N/mm2 for the alloy. Corresponding numbers for Group II; (a) c.p. ti 8 compared to 6 N/mm2 for the alloy, (b) c.p. ti demonstrated a mean value of 17 vs 11 N/mm2 for the alloy. According to method (c); c.p. ti had a mean shear strength of 26 vs 22 N/mm2 for the alloy samples. Histomorphometrical comparisons were performed on 10 microns thick undecalcified ground sections in the light microscope. In both Group I and Group II, the calculations of the mean bone-to-metal contact demonstrated more bone in contact to the c.p. titanium implants than to the Ti6A14V ones. Whereas comparisons of the bone volume inside the threads demonstrated slightly higher bone volumes around the alloy samples, no statistically significant difference was obtained between the two materials histomorphometrically.

Ionization and solubilization of 4 alkyl benzoic acids and 4 alkyl anilines in sodium taurodeoxycholate solutions

PURPOSE

The aqueous solubility and the extent of solubilization and ionization constant in sodium taurodeoxycholate (NaTDC) solutions of a series of benzoic acid and aniline derivatives were measured as a basis to characterize and thereby help predict the nature of the interaction of drugs with bile aggregates.

METHODS

The aqueous solubility and the solubilization of two series of compounds, 4-alkyl benzoic acids and 4-alkyl anilines, was measured as a function of NaTDC in 0 and 150 mM NaCl. The ionization constants were determined in water and in 50 mM NaTDC at sodium chloride concentration of 0, 75 and 150 mM by spectrophotometric titration. The diffusion coefficients of NaTDC and the solutes were measured by pulsed-field gradient spin echo NMR spectroscopy.

RESULTS

The aqueous solubilities decreased with increasing alkyl chain length in both series, and the aniline derivatives had larger solubilities than the benzoic acid derivatives. The number of moles of solute solubilized per mole of bile salt ranged from 0.17 to 0.31 for the benzoic acid derivatives and from 1.3 to 3.0 for the aniline derivatives. The pKa values of the benzoic acid derivatives in the presence of NaTDC were higher relative to the controls, and the difference in the pKa (delta pKa,obs) increased with increasing chain length. With the aniline derivatives, the pKa values were also shifted to higher values in NaTDC relative to the control but only in the absence of salt. The presence of the solute caused a decrease in the diffusion coefficient of NaTDC, and the diffusion coefficients of the solutes decreased with increasing alkyl chain length. With the hexyl derivative, the diffusion coefficient of the solute was smaller than the diffusion coefficient of the bile salt. The chemical shift of the protons attached to carbon 18 and 19 of the salt were decreased to a greater extent in the presence of the solutes than the protons attached to carbon 26.

CONCLUSION

Both the solubilization and ionization behavior of solutes were affected by the presence of bile salt aggregates. The surface potential and effective polarity of NaTDC aggregates were found to be dependent on the alkyl chain length for these two homologous series of solutes. The solubilization ratio was largely independent of alkyl chain length, but the unitary partition coefficient was dependent on both alkyl chain length as well as ionization state. The derivatives reduced the diffusivity of the micelles suggesting the formation of larger size aggregates and the solutes (hexyl derivatives) appear to favor association with the larger sized aggregates. The phenyl ring of the solutes appears to be oriented parallel to the plane of the steroid frame with preferential positioning near the hydrophobic rings.

Altered methylation substrate kinetics and calcium binding of a calmodulin with a Val136-->Thr substitution

Calmodulin is trimethylated on Lys115 by a specific calmodulin methyltransferase. Previously, it was shown that the cam2 mutant (Ile136-->Thr) of Paramecium has a decreased level of methylated Lys115 [Lukas, T. J., Friedman, M. W., Kung, C. & Watterson, D. M. (1989) Proc. Natl Acad. Sci. USA 86, 7331-7335]. To investigate how this substitution affects calmodulin structure, function and recognition by the calmodulin methyltransferase, a calmodulin with a Thr136 substitution ([Thr136]calmodulin) was expressed in Escherichia coli in an unmethylated form for in vitro enzyme activator, calcium binding and methylation kinetic analyses. [Thr136]calmodulin was indistinguishable from wild-type calmodulin in saturating (1 mM) calcium in its ability to activate calmodulin-dependent enzymes and in its steady-state kinetic properties with isolated calmodulin methyltransferase. However, [Thr136]calmodulin did show two defects: a complete inability to be methylated in the absence of calcium; and defective calcium binding. As a result, an approximate 10-fold shift in the K0.5 values for calcium dependence of enzyme activation (shifted from 1.1 microM to 9.1 microM of Ca2+ for NAD kinase) and methylation (from 0.71 microM to 7.2 microM of Ca2+ in 0.15 M K+, 2 mM Mg2+) were observed. Non-denaturing electrophoresis and Tyr138 spectroscopic measurements suggest a difference in the conformation of the calcium-depleted structures of normal calmodulin and [Thr136]calmodulin. Overall, the results suggest that the mutation in this conserved position in the COOH-terminal hydrophobic core lowers calcium-binding affinity and alters the calcium-depleted structure leading to decreased methylation at physiological Ca2+ concentrations.

A 1-year radiographic evaluation of marginal bone around dental implants

The aim of this study was to report alveolar bone loss during the first 12 months after implant abutment connection. Marginal bone loss around 62 endosseous root-form implants in 62 patients was measured on periapical radiographs. Changes in bone density were measured by the digital subtraction image radiographic method. At 3-month intervals for 1 year, bone loss around the four types of implants used (standard series, mini series, and hexlock implants of the Steri-Oss system; and 3i standard implants) was investigated. Rapid bone loss around all four implant types occurred in the first 3 months. Most of the implants showed resorption of alveolar bone beyond the polished neck at 12 months. The bone level stabilized at the first thread of the implants with no correlation to either the time of exposure of the polished neck or the type of implant. Bone density decreased at the marginal bone and increased at the newly formed alveolar crest.

Phase properties of mixtures of ceramides

Ceramides have been proposed to have a central role in the function of the stratum corneum. Ceramides also influence the phase properties of model skin lipid mixtures, but the relevance of this to the stratum corneum function is controversial. Because the stratum corneum contains several classes of ceramides, the type of ceramides used in model mixtures of stratum corneum lipid lamellae may be important. Thus, the properties of alpha-hydroxy fatty acid containing (HFAC) and nonhydroxy fatty acid containing (NFAC) ceramides and their mixtures have been investigated. Ceramides were obtained by the conversion of purified bovine brain cerebrosides. Isolated, anhydrous HFAC underwent an endothermic solid to liquid transition at 92 degrees C. With hydration, an endothermic transition at 71.8 degrees C was observed which was accompanied by a reduction in the birefringence. The enthalpy increased from 66 to 89 J/g with a 20-d storage time. These thermal properties are very similar to those observed with hydroxy fatty acid containing cerebrosides. In contrast, anhydrous nonhydroxy fatty acid containing ceramides underwent a broad endothermic transition over the temperature range of 50-90 degrees C. When hydrated, the initial endothermic transition was interrupted by an exothermic transition that was followed immediately by a second endothermic transition. During these thermal changes, there was a loss of birefringence, and with completion of the second endothermic transition, a nonbirefringent liquid was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and kinetic characterization of the calmodulin methyltransferase from sheep brain

The methyltransferase that catalyzes the trimethylation of lysine 115 in calmodulin has been purified from sheep brain. The enzyme is a monomer with an apparent molecular weight of 38,000 on the basis of gel filtration chromatography and SDS-polyacrylamide electrophoresis. In the presence of calcium the methyltransferase exhibited a Km of 100 nM for unmethylated calmodulin and a kcat of 0.0278 s-1. The enzyme was able to use calcium-depleted calmodulin as a substrate, albeit with less efficiency. The methylation of calcium-depleted calmodulin was inhibited by increases in ionic strength, whereas methylation of calcium-saturated calmodulin was not affected. This suggests a difference in the mode of interaction of calcium-saturated and calcium-depleted calmodulins with the enzyme. As with calmodulin's interactions with other calmodulin-dependent enzymes, the oxidation of the methionines of calmodulin by performic acid treatment decreases the ability of the methyltransferase to recognize and methylate calmodulin. A calmodulin-binding peptide based on the calmodulin-dependent protein kinase II sequence and the naphthalenesulfonamide W-7 inhibit the calmodulin methyltransferase-calmodulin interaction in a calcium-dependent manner. Removal of the NH2-terminal lobe (residues 1-77) does not affect the ability of the calmodulin methyltransferase to recognize and methylate lysine 115. Thus, the determinants for calmodulin methyltransferase binding reside solely in the COOH-terminal lobe of calmodulin. Further, structural features within this region, in particular, the hydrophobic cleft, that are manifested upon calcium binding may contribute to the interaction of calmodulin with the enzyme.

Allogeneic bone marrow transplantation for the patients with hemopoietic stem cell disorders: CUMC experience

Bone marrow transplantation from an HLA-identical sibling is increasingly used as a curative therapy for patients with hemopoietic stem cell disorders including acute leukemia, chronic myelogenous leukemia and severe aplastic anemia. Between March 1983 and March 1991, we performed 86 cases of allogeneic bone marrow transplantation (BMT) for the patients with hemopoietic stem cell disorders: 25 acute myelogenous leukemia (AML); 15 acute lymphoblastic leukemia (ALL); 20 chronic myelogenous leukemia (CML); and 26 severe aplastic anemia (SAA). Ten out of 25 AML are in disease free survival (DFS). The causes of death were recurrence of leukemia (12), acute GVHD (3), sepsis (1) and veno-occlusive disease (1). Nine of 15 ALL are in unmaintained remission. Thirteen out of 20 CML are in DFS. Among 26 SAA, 21 are enjoying DFS, but 1 died of engraftment failure, 3 of graft rejection followed by cytomegalovirus (1) and aspergillus pneumonia (1). Comparing the survival between standard [less than or equal to CR1: 9/14 (64%)] and high risk [greater than or equal to CR1: 1/11 (9%)] AML, our data suggest that preparative regimen for high risk AML was not potent enough to eradicate the minimal residual disease in advanced AML. Although our cases are limited and the follow-up period is short, our result of ALL [overall: CCR (60%), standard risk (adult less than or equal to CR1, children less than or equal to CR2; 8/11 (73%) and high risk; 1/4 (25%)] and CML [overall: 65%, CP; 9/10 (90%), AP; 4/6 (67%), BP; 0/4 (0%)] are optimistic. It is of our interest that the incidence of death related with IP (1/33: 3%) and with AGVHD 94/33: 12%) were much less than that of other's observation but the explanation for this still remains to be clear.

Suicide by burning in Korea

Of 2,143 admissions following suicide attempts over a seven year period (1980-1986) in Seoul, Korea, there were 38 cases (1.8%) of suicide by burning. These cases were matched by age and sex with a control group of suicide attempts in general and were investigated for psychosocial differences from other suicide attempters. No significant differences were found in social factors such as education, religion, marital status, seasonal change and occupation. The majority of suicide attempts by burning were in a public place (73.7%) and were eventually fatal despite intensive medical treatment (78.9%). Half (52.7%) suffered from significant mental disorders and marital disharmony.

Immunomodulation therapy for severe aplastic anemia--ALG versus ALG plus cyclosporin A

Immunosuppressive treatment of aplastic anemia has been increasingly used as an alternative treatment to bone marrow transplantation. In this study, the additive effect of Cyclosporin A (CSA) (5mg/kg/day, at least 3 months) for maintenance of immunosuppression after antilymphocyte globulin (ALG) therapy (40mg/kg/day for 4 days) was compared to the previous ALG alone treatment (15mg/kg/day for 10 days). A high dose of methylprednisolone (20mg/kg/day for 5 days and 10mg/kg/day for 5 days) to the ALG group and a low dose of methylprednisolone (2mg/kg/day for 5 days) to the ALG plus CSA group were administered simultaneously. The results were as follows: 1) Sixteen (69.6%) out of twenty-three patients treated with ALG plus Cyclosporin A showed higher responses (CR: 48%, PR: 22%). On the contrary, nine out of nineteen in the ALG group showed lower responses (CR: 21%, PR: 26%). 2) Our data showed a tendency that male patients in age ranging from sixteen to thirty years showed an excellent response to ALG therapy (12/23: 52.2%). 3) The ALG plus CSA group revealed a faster response compared to the ALG alone group (15/16 within 6 months). 4) We speculate that ALG plus CSA therapy might be the treatment of choice for patients with a moderate degree of aplastic anemia. 5) Adding CSA to ALG increased the chance of infection, such as those with URI-like symptoms, but it did not affect the mortality rate. Our data suggest that the ALG plus CSA regimen may be a more useful therapeutic modality for patients with severe aplastic anemia who cannot be candidates for bone marrow transplantation and a randomized multicenter study is needed for confirmation of our preliminary study.