[Coronary artery bypass surgery in aged patients]

From January 1993 through December 1996, 749 patients underwent isolated coronary artery bypass grafting. Of these patients, 578 patients were older than 60 years old. We classified them into three groups; Group A were the 60 to 69 year age group (337 patients), Group B were the 70 to 79 year age group (224 patients) and Group C were over 80 years age group (17 patients). Emergency cases and preoperative LV dysfunction cases were more frequently in Group C, but mortality did not differ among three groups. Duration of intubation, ICU stay and hospital stay were longer in Group C than other groups and complications (PMI, arrhythmia and reoperation for bleeding) were more frequently in Group C. Coronary artery bypass surgery can be performed in aged patients, especially for patients over 80 years old, with acceptably low mortality and significant functional benefit but a high incidence of complications necessitates careful postoperative management in aged patients.

The use of a multitracer technique for the studies of the uptake and retention of trace elements in rats

The uptake by, and distribution and retention of radioactive isotopes in various organs of Wistar rats were examined using the multitracer technique. A hydrocholoric acid solution (pH 3) of a carrier-free radioactive multitracer was prepared from gold foil irradiated with a 14N beam of 135 MeV nucleon. The solution was administered orally to 12 7-week-old male rats. Urine and faeces were collected and each group of three rats was killed at 1, 2, 3 or 6 days after administration. The percentage of administered dose of the 17 elements, Mn, Co, Zn, As, Rb, Sr, Y, Eu, Gd, Er, Tm, Yb, Lu, W, Re, Ir and Pt in the organs blood and excreta were determined using gamma-ray spectrometry. Each element revealed its characteristic distribution among the different organs, including the blood. These results are discussed and compared with those of single-tracer experiments, and the advantages of the multitracer technique are presented.

Effect of a titanium surface on bone marrow-derived osteoblastic cells in vitro

The initial interaction between a titanium implant and the surrounding cancellous bone tissue was investigated by means of in vitro cultures of bone marrow-derived osteoblastic clone TMS-12 cells. Proliferation of TMS-12 cells cultured on a titanium surface was significantly reduced compared with that of control cells cultured directly on plastic, but alkaline phosphatase activity was the same as control cells. Co-culture of spleen cells with TMS-12 cells in the presence of a 1 alpha,25-dihydroxyvitamin D3 on titanium resulted in significant inhibition of tartrate-resistant acid phosphatase activity compared to control cultures on plastic. More prostaglandin E2 (PGE2) was produced by cells grown on a titanium surface than on plastic tissue-culture plates. On the other hand, mouse calvaria-derived osteogenic MC3T3-E1 cells, known to proliferate well on titanium, released similar amounts of PGE2 on titanium surfaces as on plastic tissue culture plates, indicating additional marked differences between the two osteoblastic cell types in response to a titanium surface. These results suggest that the reaction of bone marrow-derived osteoblastic cells to a titanium surface may fundamentally differ from that of calvaria-derived osteoblastics even though both cells are from bone tissue.

Pharmacokinetic stereoselectivity of troglitazone, an antidiabetic agent, in the KK mouse

Troglitazone, an oral antidiabetic agent, is an equal mixture of four stereoisomers involving two asymmetric centres. In the present study, the stereoselectivity of in vitro epimerization in plasma and organ homogenate and in vivo plasma disposition in the KK mouse, an animal model of non-insulin-dependent diabetes, was examined. In the incubation experiments at 37 degrees C, there was a fivefold to eightfold acceleration of epimerization at the 5 position of the thiazolidine ring in KK mouse plasma compared with that in buffer. However, no inversion at the 2 position of the chroman ring was observed. In addition, there was an approximately 1.3-fold difference in the epimerization rates among stereoisomers at the 2 position of the chroman ring. However, there were no differences in the values of the equilibrium constants of epimerization, and the ratio of epimerization among stereoisomers at the 5 position of thiazolidine ring was almost unity. The acceleration of epimerization is thought to be due to the high degree of protein binding because of the relationship between the initial epimerization rate and the dilution ratio of the plasma. Although acceleration of epimerization was also observed in the 20% homogenates of liver, kidney, and intestine of the KK mouse, the degree of stereoselectivity was lower than in plasma. The analysis of the plasma disposition after intravenous administration of troglitazone stereoisomers, using a kinetic model, indicated that the metabolic clearance in the liver showed a 2.5-fold maximum difference among stereoisomers and that the stereoselectivity of epimerization was low.

Postoperative stability after sagittal split ramus osteotomy with condylar-positioning appliance and screw fixation: asymmetric versus symmetric cases

OBJECTIVE

The purpose of this study was to evaluate postoperative stability in prognathic patients with mandibular asymmetry who were treated with sagittal split ramus osteotomy of the mandible.

STUDY DESIGN

Ten asymmetric (group I) and 11 symmetric (group II) patients were examined. An appliance for repositioning the proximal segment was applied, and the bony segments were fixed with titanium screws. Cephalograms were obtained preoperatively, 2 to 3 days postoperatively, and 3 and 6 months after surgery. Changes in the positions of the standard points were examined on lateral cephalograms, and changes in the widths of the gonion points were examined on posteroanterior cephalograms.

RESULTS

Statistical analysis revealed no significant difference between the two groups. In addition, there was no significant difference between the postoperative changes in the widths of the gonion points on the deviated and nondeviated sides in group I.

CONCLUSIONS

This study suggests that application of an appliance for repositioning the proximal segment can minimize postoperative skeletal changes in patients with asymmetry.

Stability after surgical correction of mandibular prognathism using the sagittal split ramus osteotomy and fixation with poly-L-lactic acid (PLLA) screws

PURPOSE

This study was designed to examine skeletal stability after surgical correction of mandibular prognathism using a sagittal split ramus osteotomy (SSRO) and fixation with poly-L-lactic acid (PLLA) screws.

PATIENTS AND METHODS

Twenty patients with Class III malocclusion were treated with bilateral SSRO and mandibular setback. Ten underwent fixation with titanium screws (group I) and the other 10 with PLLA screws (group II). Cephalograms were obtained 2 or 3 days postoperatively, and at 3, 6, and 12 months after the operation. Changes in the position of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms.

RESULTS

Certain tendencies for overjet and overbite were noted to have decreased more markedly, and changes in the position of the skeletal points were greater in group II than in group I. However, statistical analysis showed no significant differences between the two groups.

CONCLUSION

Our results suggest that fixation of the bony segments with PLLA screws after SSRO may be used effectively in properly selected cases.

Determination of protein binding of troglitazone stereoisomers by fluorometric titration

Determination of the protein binding of troglitazone is difficult because of its high adsorption to filters and membranes and the instability of the stereoisomers. We attempted to assess the protein binding of four stereoisomers of troglitazone in the plasma and albumin from several species by the method using fluorescent probes. The inhibition constants (Ki) for the stereoisomers of troglitazone were obtained from the decreases in fluorescence intensity of dansylsarcosine caused by competitive inhibition. Each stereoisomer of troglitazone displaced dansylsarcosine, a typical specific fluorescent probe for the diazepam binding site on human serum albumin (HSA). The highest binding affinity for dansylsarcosine was observed with HSA (dissociation constant, Kd,1 = 0.5 microM), while it was lowest in the mouse (Kd,1 = 18 microM). The Ki values for KK and ddY mouse plasma and mouse and rat albumin were in the range 2-15 microM, and there were no large variations among stereoisomers, the maximum differences being twofold. For human plasma and albumin, the displacement could not be accounted for by a simple competitive inhibition. Comparison between unbound fraction (fu) values calculated from thus obtained Ki values and those of a mixture of the four stereoisomers determined by high-performance frontal analysis showed that the fu values obtained by fluorometric titration were higher, while the relative differences among the stereoisomers in terms of animal species and strain were comparable for the two methods. Small differences in protein binding among stereoisomers of troglitazone may not be the major reason for their stereoselective pharmacokinetics.

Pharmacokinetics of troglitazone, an antidiabetic agent: prediction of in vivo stereoselective sulfation and glucuronidation from in vitro data

Sulfation and glucuronidation, the major routes of metabolism of troglitazone, an antidiabetic agent, were examined in vitro using hepatic cytosol and microsomes prepared from KK mice, an animal model of non-insulin-dependent diabetes mellitus. Stereoselectivity was observed for both conjugation reactions, and the metabolic intrinsic clearance of glucuronidation was about 3- to 100-fold higher than that of sulfation for each stereoisomer. In addition, the metabolic intrinsic clearance of glucuronidation exhibited an 8-fold difference among stereoisomers. The predicted metabolic clearance for each stereoisomer, calculated from the in vitro data based on a dispersion model, was comparable to the measured metabolic clearance in vivo, ranging from 27 to 93%. We also attempted to predict the in vivo metabolic clearance from in vitro metabolism data, to investigate species differences in the stereoselectivity of the conjugation reactions in normal animals, i.e., ddY mice and rats. For ddY mice the in vivo hepatic glucuronidation clearance was 170-fold higher than the corresponding sulfation clearance, whereas for rats the sulfation clearance was 6-fold higher than the glucuronidation clearance. The hepatic sulfation clearance in mice and rats predicted from in vitro metabolism data was 5.3- and 1.1-fold higher, respectively, than that in vivo, calculated from the plasma disposition of parent drug and biliary excretion of metabolites. For glucuronidation, the predicted values in mice and rats were 1.0- and 0.33-fold higher, respectively. These results suggest that semiquantitative extrapolation of in vitro stereoselective metabolism of troglitazone, by conjugation, to the in vivo situation is possible.

RLF2, a subunit of yeast chromatin assembly factor-I, is required for telomeric chromatin function in vivo

In the yeast Saccharomyces cerevisiae, telomere repeat DNA is assembled into a specialized heterochromatin-like complex that silences the transcription of adjacent genes. The general DNA-binding protein Rap1p binds telomere DNA repeats, contributes to telomere length control and to telomeric silencing, and is a major component of telomeric chromatin. We identified Rap1p localization factor 2 (RLF2) in a screen for genes that alleviate antagonism between telomere and centromere sequences on plasmids. In rlf2 mutants, telomeric chromatin is perturbed: Telomeric silencing is reduced and Rap1p localization is altered. In wild-type cells, Rap1p and telomeres localize to bright perinuclear foci. In rlf2 strains, the number of Rap1p foci is increased, Rap1p staining is more diffuse throughout the nucleus, Rap1p foci are distributed in a much broader perinuclear domain, and nuclear volume is 50% larger. Despite the altered distribution of Rap1p in rlf2 mutant cells, fluorescence in situ hybridization to subtelomeric repeats shows that the distribution of telomeric DNA is similar in wild-type and mutant cells. Thus in rlf2 mutant cells, the distribution of Rap1p does not reflect the distribution of telomeric DNA. RLF2 encodes a highly charged coiled-coil protein that has significant similarity to the p150 subunit of human chromatin assembly factor-I(hCAF-I), a complex that is required for the DNA replication-dependent assembly of nucleosomes from newly synthesized histones in vitro. Furthermore, RLF2 is identical to CAC1, a subunit of yeast chromatin assembly factor-I (yCAF-I) which assembles nucleosomes in vitro. In wild-type cells, epitope-tagged Rlf2p expressed from the GAL10 promoter localizes to the nucleus with a pattern distinct from that of Rap1p, suggesting that Rlf2p is not a component of telomeric chromatin. This study provides evidence that yCAF-I is required for the function and organization of telomeric chromatin in vivo. We propose that Rlf2p facilitates the efficient and timely assembly of histones into telomeric chromatin.

Congenital midline sinus of the upper lip: case report and review of literature

A case report of a congenital midline sinus of the upper lip in a 5-year-old girl is presented. The patient complained of intermittent swelling around the frenulum of the upper lip. The sinus was located on the midline of the philtrum just below the base of the columella. Excision of the sinus tract via an intraoral approach gave a satisfactory result. Microscopic examination of the resected sinus revealed it to be lined by stratified squamous epithelium with sebaceous glands and hair follicles. Fifteen other cases have been reported in the English literature and are reviewed. There are two postulates that can account for the formation of the upper lip sinus based on two major theories of the development of the face: the fusion theory and the merging theory. However, the etiology of this rare congenital sinus remains obscure.

[Early establishment of bone marrow hypoplasia by antileukemic chemotherapy with concurrent rhG-CSF in a case of acute myelogenous leukemia complicated with intestinal perforation]

We report a case of 53-year-old man with acute myelogenous leukemia (M2) showing a karyotype of t(7;11) (p15;p15), del(10) (q11;q12), who was complicated with perforation of a duodenal ulcer during the antileukemic chemotherapy using behenoyl ara-C, daunorubicin, 6-mercaptopurine and prednisolone. As his bone marrow still showed high cell density and leukemic proliferation at the time of intestinal perforation, the therapeutic regimen was changed to a combination of behenoyl are-C and mitoxantrone, and daily rhG-CSF was concurrently administered for the purpose of early establishment of bone marrow hypoplasia. On the 8th day after the therapeutic regimen had been changed, his bone marrow became nearly aplastic, and complete remission was obtained on the 24th day. This case may indicate that the concurrent administration of cell-cycle specific antileukemic drugs and rhG-CSF is available for AML patients with emergent need of leukemic cell reduction.

Biodistribution of trace elements in normal, aluminum-overloaded and cadmium-overloaded mice. An application of the radioactive multitracer technique

The radioactive multitracer technique was applied to simultaneous evaluation of biobehavior of many trace elements in normal, Al-overloaded and Cd-overloaded mice. The tissue and subcellular distributions of Be, Sc, V, Mn, Fe, Co, Zn, As, Se, Rb, Sr, Y, Zr, Ru, and Rh were examined by using a multitracer solution, prepared from an Ag target irradiated with heavy ions, in 9 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidney, skeletal muscle, and bone) and blood. Their tissue and subcellular distributions were evaluated by gamma-ray spectrometry in terms of tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, percent of dose/g) and fractionation percentage (the radioactivity percentage of nuclear fraction, mitochondrial fraction, microsomal fraction or supernatant fraction, percent), respectively. Comparative biobehavior of these elements in brain and liver is reported. Aluminium- and Cd-induced synergistic interactions were observed among these trace elements in their liver uptake behavior.

High-affinity calcium-binding site in the gama-carboxyglutamic acid domain of bovine factor VII

The calcium-mediated interaction of factor VIIa with tissue factor is considered to be the primary trigger of blood coagulation. To determine the role of calcium ions in the action of factor VII, we prepared monoclonal antibodies whose binding to factor VII was calcium-dependent. A monoclonal antibody designated C6 strongly inhibited factor VII-induced clotting at a molar ratio of factor VII to antibody of 1:1. The half-maximal binding of factor VII to the C6 antibody was observed at a concentration of calcium ions of 80 microM. Proteolytic fragments of factor VII were assayed for their ability to inhibit competitively the binding of 125I-factor VII to immobilized C6 antibody. The binding was inhibited by increasing amounts of factor VII, by a fragment that contained the gamma-carboxyglutamic acid (Gla) domain linked to first epidermal growth factor-like domain, and by a Gla domain peptide (residues 1-41), over a range of concentration of 10(-9) to 10(-7) M. The antigenic site recognized by the monoclonal antibody C6, which was generated upon the high-affinity binding of calcium ions, was located in the Gla domain. The C6 antibody inhibited the activation of factor X and the amidolytic activity of factor VIIa in the presence of tissue factor. These results demonstrate that a high-affinity calcium-binding site(s) is located in the Gla domain of factor VII, which is concerned with the initiation of tissue factor-mediated blood coagulation by factor VIIa.

Bone uptake of vanadium in mice: simultaneous tracing of V, Se, Sr, Y, Zr, Ru and Rh using a radioactive multitracer

The radioactive multitracer technique, which enables simultaneous tracing of a number of elements in a variety of bio-systems and an accurate comparison of their biobehavior, was employed in a study on uptake behavior of trace elements in various mice tissues, focusing on uptake of V by bone. We found that the bone uptake behavior of trace V closely resembles that of trace Sr and Y. It is suggested that V is a bone-seeking element which probably plays an important role in bone formation. The multitracer technique was thus shown to be useful for comparative studies of behavior of trace elements in living organisms.

Identification of type I and type II serine/threonine kinase receptors for growth/differentiation factor-5

Growth/differentiation factor-5 (GDF-5) is a member of the bone morphogenetic protein (BMP) family, which plays an important role in bone development in vivo. Mutations in the GDF-5 gene result in brachypodism in mice and Hunter-Thompson type chondrodysplasia in human. BMPs transduce their effects through binding to two different types of serine/threonine kinase receptors, type I and type II. However, binding abilities appear to be different among the members of the BMP family. BMP-4 binds to two different type I receptors, BMP receptors type IA (BMPR-IA) and type IB (BMPR-IB), and a type II receptor, BMP receptor type II (BMPR-II). In addition to these receptors, osteogenic protein-1 (OP-1, also known as BMP-7) binds to activin type I receptor (ActR-I) as well as activin type II receptors (ActR-II and ActR-IIB). Here we investigate the binding and signaling properties of GDF-5 through type I and type II receptors. GDF-5 induced alkaline phosphatase activity in a rat osteoprogenitor-like cell line, ROB-C26. 125I-GDF-5 bound to BMPR-IB and BMPR-II but not to BMPR-IA in ROB-C26 cells and other nontransfected cell lines. Analysis using COS-1 cells transfected with the receptor cDNAs revealed that GDF-5 bound to BMPR-IB but not to the other type I receptors when expressed alone. When COS-1 cells were transfected with type II receptor cDNAs, GDF-5 bound to ActR-II, ActR-IIB, and BMPR-II but not to transforming growth factor-beta type II receptor. In the presence of type II receptors, GDF-5 bound to different sets of type I receptors, but the binding was most efficient to BMPR-IB compared with the other type I receptors. Moreover, a transcriptional activation signal was efficiently transduced by BMPR-IB in the presence of BMPR-II or ActR-II after stimulation by GDF-5. These results suggest that BMPR-IB mediates certain signals for GDF-5 after forming the heteromeric complex with BMPR-II or ActR-II.

A new condylar positioning appliance for two-jaw osteotomies (Le Fort I and sagittal split ramus osteotomy)

We have presented a new appliance for easy, rapid, and exact repositioning of the proximal segment of the mandible in two-jaw osteotomies (Le Fort I and sagittal split ramus osteotomy).