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).

Prediction of the human pharmacokinetics of troglitazone, a new and extensively metabolized antidiabetic agent, after oral administration, with an animal scale-up approach

We have attempted to predict the human pharmacokinetics of troglitazone after oral administration based on animal data. Troglitazone is a new antidiabetic agent that exhibits a high-metabolic clearance and is metabolized mainly in the liver to sulfate and glucuronide conjugates. The prediction of the area under the plasma concentration-time curve (AUCp.o.) and bio-availability (F) in humans after oral administration was initially attempted by use of allometric equations involving the oral plasma clearance of total (CLp.o.) or unbound drug (CLp.o.,fu), or the hepatic intrinsic clearance of unbound drug (CLuint) and animal body weight. The exponents in the allometric equations between the clearances and body weights were 0.63 to 0.82 with high correlation coefficients (r > .98), and there was no marked difference in predictability by the three methods. Next, the prediction of the range of plasma profiles after oral administration to humans was attempted by the following series of steps: (1) calculation of the exponent and coefficients in the allometric relationships between body weight and parameters, such as total body plasma clearance (CLi.v.) and various distribution volumes (Vss, V beta and Vc) based on animal data; (2) estimation of the absorption rate constant (ka) from allometric relationship to body weight, and estimation of F value from the predicted AUCp.o. (3) description of the plasma concentration-time profiles after oral administration by an equation involving the allometric exponents and coefficients, ka, F and body weight. The observed and simulated plasma profiles were similar and the predicted AUCp.o. values were 60 to 120% of those observed. These methodologies will be useful for predicting the human pharmacokinetics after oral dosing from animal data.

Rapid rewarming causes an increase in the cerebral metabolic rate for oxygen that is temporarily unmatched by cerebral blood flow. A study during cardiopulmonary bypass in rabbits

BACKGROUND

Jugular venous hemoglobin desaturation during the rewarming phase of cardiopulmonary bypass is associated with adverse neuropsychologic outcome and may indicate a pathologic mismatch between cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2). In some studies, rapid rewarming from hypothermic cardiopulmonary bypass results in greater jugular venous hemoglobin desaturation. The authors wished to determine if rewarming rate influences the temperature dependence of CBF and CMRO2.

METHODS

Anesthetized New Zealand white rabbits, cooled to 25 degrees C on cardiopulmonary bypass, were randomized to one of two rewarming groups. In the fast group (n = 9), aortic blood temperature was made normothermic within 4 min. In the slow group (n = 9), aortic blood temperature was made normothermic over 25 min. Cerebral blood flow (microspheres) and CMRO2 (Fick) were determined at baseline (25 degrees C), and at brain temperatures of 28 degrees, 31 degrees, 34 degrees, and 37 degrees C during rewarming.

RESULTS

Systemic physiologic variables appeared similar between groups. At a brain temperature of 28 degrees C, CMRO2 was 47% greater in the fast rewarming group than in the slow group (2.2 +/- 0.5 vs. 1.5 +/- 0.2 ml O2.100 g-1. min-1, respectively; P = 0.01), whereas CBF did not differ (48 +/- 18 vs. 49 +/- 8 ml.100 g-1.min-1, respectively; P = 0.47). Throughout rewarming, CBF increased as a function of brain temperature but was indistinguishable between groups. Cerebral metabolic rate for oxygen differences between groups decreased as brain temperatures increased.

CONCLUSIONS

Cerebral venous hemoglobin desaturation with rapid rewarming is caused by an increase in CMRO2 that is temporarily greater than the increase in CBF. This mismatch may indicate a transient abnormality in flow-metabolism coupling, or the effect of temperature gradients on oxygen transfer from hemoglobin to brain.

Multitracer study on uptake and excretion of trace elements in rats

The multitracer technique was first applied to the investigation of the uptake and excretion behaviour of trace elements in rats. A multitracer solution, prepared by irradiation of a gold target with a 14N-beam from the RIKEN Ring Cyclotron, was orally administered to male Wistar rats. The uptake and excretion rates of 23 elements, Be, Mn, Co, Zn, As, Rb, Sr, Y, Zr, Ce, Pm, Eu, Gd, Tb, Er, Tm, Yb, Lu, Hf, W, Re, Ir and Pt, were simultaneously determined under strictly identical experimental conditions. For some of the elements, the results obtained were consistent with previous reports on uptake and excretion of the elements in animals. For the other elements, unique behaviour was revealed for the first time as described in the present work. These results show that the multitracer technique has excellent reliability and versatility for a comparative study of the uptake and excretion of many different elements in animals.

A new appliance for condylar positioning (clamp system)

A new appliance for condylar positioning during sagittal split ramus osteotomy (SSRO) of the mandible is presented. The application procedure and our method of condylar repositioning are described.

Dual brain stem projection from the cortical masticatory area in guinea-pig

The cortical masticatory area (CMA) in the guinea pig is subdivided into the anterior and posterior parts (A-CMA and P-CMA), based on the pattern of the CMA-induced rhythmical digastric EMG burst and the cytoarchitecture. The anterograde tracing of horseradish peroxidase from the A-CMA and P-CMA revealed, in addition to a common projection to the region around the trigeminal motor nucleus and the parvicellular reticular formation bilaterally, a massive projection to the ipsilateral superior colliculus (SC) from the A-CMA but not from the P-CMA. The results suggest a dual brain stem projection system from the CMA: the direct pyramidal route from the P-CMA and the SC-mediated indirect route from the A-CMA.

A class of single-stranded telomeric DNA-binding proteins required for Rap1p localization in yeast nuclei

We have identified a class of proteins that bind single-stranded telomeric DNA and are required for the nuclear organization of telomeres and/or telomere-associated proteins. Rlf6p was identified by its sequence similarity to Gbp1p, a single-stranded telomeric DNA-binding protein from Chlamydomonas reinhardtii. Rlf6p and Gbp1p bind yeast single-stranded G-strand telomeric DNA. Both proteins include at least two RNA recognition motifs, which are found in many proteins that interact with single-stranded nucleic acids. Disruption of RLF6 alters the distribution of repressor/activator protein 1 (Rap1p), a telomere-associated protein. In wild-type yeast cells, Rap1p localizes to a small number of perinuclear spots, while in rlf6 cells Rap1p appears diffuse and nuclear. Interestingly, telomere position effect and telomere length control, which require RAP1, are unaffected by rlf6 mutations, demonstrating that Rap1p localization can be uncoupled from other Rap1p-dependent telomere functions. In addition, expression of Chlamydomonas GBP1 restores perinuclear, punctate Rap1p localization in rlf6 mutant cells. The functional complementation of a fungal gene by an algal gene suggests that Rlf6p and Gbp1p are members of a conserved class of single-stranded telomeric DNA-binding proteins that influence nuclear organization. Furthermore, it demonstrates that, despite their unusual codon bias, C. reinhardtii genes can be efficiently translated in Saccharomyces cerevisiae cells.

In vivo biological behavior of a water-miscible fullerene: 14C labeling, absorption, distribution, excretion and acute toxicity

BACKGROUND

Water-soluble fullerenes have recently been shown to exhibit considerable in vitro biological activity including cytotoxicity, site-selective DNA cleavage and inhibition of HIV protease. To assess the potential of these compounds as drugs, studies on the in vivo behavior of fullerenes are needed. We therefore set out to synthesize a radiolabeled, water-soluble fullerene, in order to obtain data on the oral absorption, distribution and excretion of this class of compounds.

RESULTS

We synthesized a 14C-labeled water-soluble [60]fullerene using dipolar trimethylenemethane, which undergoes cycloaddition to [60]fullerene. When administered orally to rats, this compound was not efficiently absorbed and was excreted primarily in the feces. When injected intravenously, however, it was distributed rapidly to various tissues, and most of the material was retained in the body after one week. The compound was also able to penetrate the blood-brain barrier. Acute toxicity of the water-miscible fullerene was found to be quite low.

CONCLUSIONS

Although the water-soluble fullerenes (and possibly their simple metabolites) are not acutely toxic, they are retained in the body for long periods, raising concerns about chronic toxic effects. The fact that fullerenes distribute rapidly to many tissues suggests that they may eventually be useful to deliver highly polar drugs through membranes to a target tissue, however, and they may even have applications in the delivery of drugs to the brain. Recent advances in fullerene synthetic chemistry may also make it possible to control fullerene absorption/excretion profiles in the future.

Production of functional human bone morphogenetic protein-2 using a baculovirus/Sf-9 insect cell system

A clone of a human Bone Morphogenetic Protein-2 (hBMP-2) cDNA was obtained from a cDNA library established from human dental pulp cells. After subcloning hBMP-2 cDNA into Autographa californica nuclear polyhedrosis virus, the recombinant baculovirus was transfected to Sf-9 cells. Immuno-reactive recombinant hBMP-2 (rhBMP-2) was detected by a polyclonal antibody against Xenopus BMP-2 in the transfected insect cells but not in the culture media. Three days after treatment with the lysate of the transfected Sf-9 cells, increase in alkaline phosphatase activity of a murine stromal cell line, ST2, was detected. Subcutaneous implantation of rhBMP-2 produced in the insect cells induced formation of cartilage, bone and bone marrow in the rats. The present data indicated that the rhBMP-2 preparation produced in the insect Sf-9 cells had a comparable activity to that produced in mammalian cells.

[Cell cycle arrest induced by epidermal growth factor on human squamous cell carcinoma cell lines]

Although human squamous cell carcinoma (SCC) cell lines frequently contain an elevated number of epidermal growth factor (EGF) receptor accompanied with amplification of EGF receptor/c-erbB gene, it is well known that EGF inhibits the growth of these cells in culture at doses that stimulate the growth of epidermal keratinocytes and dermal fibroblasts. To study this growth inhibitory effect of EGF on the SCC cell lines, 3H-thymidine incorporation into DNA and cell cycle distribution were analyzed. In HSC-1 and NA cells, which contain the highest number of EGF receptor among these SCC cell lines, the inhibition of 3H-thymidine incorporation was apparent 2 to 4 hours after treatment with 100 ng/ml of EGF and reached more than 95% inhibition after 24 hours. Two-color cell cycle analysis using fluorescein isothiocyanate (FITC)-conjugated anti-Bromodeoxyuridine (BrdU) antibody and propidium iodide revealed that this inhibitory effect was due to cell cycle arrest not only in G1 but also in G2 phase. This effect was well correlated to the sensitivity to the growth inhibitory effect of EGF among the 4 SCC cell lines. These observations suggest that the SCC cells contain altered machineries which regulate the normal cell growth in both G1 and G2 phases, and the EGF affects these machineries via overexpressed its receptor.

TEL+CEN antagonism on plasmids involves telomere repeat sequences tracts and gene products that interact with chromosomal telomeres

In Saccharomyces cerevisiae, circular plasmids that include either a centromere (CEN-plasmids) or a telomere sequence (TEL-plasmids) segregate more efficiently than circular ARS-plasmids. In contrast, circular plasmids that include both telomere and centromere sequences were unstable, a property we term TEL+CEN antagonism. TEL+CEN antagonism required a telomere repeat tract longer than 49 bp although the distance and relative orientation of the centromere and telomere sequences was not critical. TEL+CEN antagonism was alleviated in strains carrying different rap1 alleles including rap1ts, rap1s, and rap1t alleles. Mutations SIR2, SIR3, SIR4, NAT1 and ARD1, genes that influence transcriptional silencing at telomeres and at the silent mating type loci, abolished TEL+CEN antagonism Mutation of SIR1 also partially alleviated TEL-CEN antagonism. In some sir mutant strains short yeast artificial chromosomes (YACs), which are normally unstable, became more stable, suggesting that the same mechanism that caused TEL+CEN antagonism on circular plasmids may contribute to the instability of short linear plasmids.

Expression on outer membranes of mannose residues, which are involved in osteoclast formation via cellular fusion events

Osteoclast, the bone-resorbing cell, is formed from hematopoietic precursors via cell-cell fusion. To evaluate the possibility that under certain specific conditions mannose residues may be expressed on the mammalian cell surface, we examined the action of pradimicin derivatives, which bind specific sugars such as the mannose residue, on the formation of osteoclast induced in the coculture of mouse spleen cells with mouse stromal cells, a process in which cell-cell fusion is involved. Osteoclast formation was inhibited by treatment of this coculture system with pradimicin at the later stage (day 4-7), and this inhibition was specifically abrogated by mannose-rich yeast mannan. During the 8-day cocultivation, osteoclast formation was blocked by the pradimicin on days 6 and 7, when mononuclear preosteoclasts fused into multinucleated osteoclasts. With an interactive laser cytometer ACAS570, fluorescein isothiocyanate-labeled pradimicin was observed to bind osteoclast progenitors at the fusion stage and to have no binding affinity for osteoclast progenitors at the early stage (day 0-3) or for osteoclasts, which were formed after performing fusion between mononuclear preosteoclasts. These results suggest that mannose residues were expressed on outer membranes of monocytes under pathophysiological conditions and that they were involved in the osteoclast formation via cellular membrane fusion events.

A new repositioning system for the proximal segment in sagittal split ramus osteotomy of the mandible

A new repositioning system for the proximal segment in sagittal split ramus osteotomy (SSRO) of the mandible was developed. Preparation and application of the system are described.

Effect of freeze-dried poly-L-lactic acid discs mixed with bone morphogenetic protein on the healing of rat skull defects

Porous poly-L-lactic-acid discs were prepared by a freeze-drying method (FDPLLA). During preparation of the discs, semipurified bone morphogenetic protein (BMP) was mixed with the poly-L-lactic acid (500 micrograms BMP per disc). The discs were implanted in the skull defects of rats and retrieved after 2 or 4 weeks. With the FDPLLA/BMP discs, new bone formation was observed at 2 weeks after implantation. On the other hand, plain FDPLLA discs failed to produce new bone formation even at 4 weeks after implantation. Calcium content of the retrieved FDPLLA/BMP discs was statistically higher than that of plain FDPLLA discs. These results suggest that FDPLLA may be an effective delivery system for BMP and that the FDPLLA/BMP disc may potentially have usefulness as a bone graft substitute.

Enhancement of telomere-plasmid segregation by the X-telomere associated sequence in Saccharomyces cerevisiae involves SIR2, SIR3, SIR4 and ABF1

We have previously shown that circular replicating plasmids that carry yeast telomere repeat sequence (TG1-3) tracts segregate efficiently relative to analogous plasmids lacking the TG1-3 tract and this efficient segregation is dependent upon RAP1. While a long TG1-3 tract is sufficient to improve plasmid segregation, the segregation efficiency of telomere plasmids (TEL-plasmids) is enhanced when the X-Telomere Associated Sequence (X-TAS) is also included on the plasmids. We now demonstrate that the enhancement of TEL-plasmid segregation by the X-TAS depends on SIR2, SIR3, SIR4 and ABF1 in trans and requires the Abf1p-binding site within the X-TAS. Mutation of the Abf1p-binding site within the X-TAS results in TEL-plasmids that are no longer affected by mutations in SIR2, SIR3 or SIR4, despite the fact that other Abf1p-binding sites are present on the plasmid. Mutation of the ARS consensus sequence within the X-TAS converts the X-TAS from an enhancer element to a negative element that interferes with TEL-plasmid segregation in a SIR-dependent manner. Thus, telomere associated sequences interact with TG1-3 tracts on the plasmid, suggesting that the TASs have an active role in modulating telomere function.

[Transcranial Doppler monitor in the case of selective cerebral perfusion]

Six patients underwent ascending aorta and aortic arch replacement for aneurysmal disease between 1991.12-1992.2 using the cardiopulmonary bypass technique with selective cerebral perfusion from right axillary artery. For four patients, intraoperative transcranial Doppler monitorings of left MCA flow velocity were done. We added left carotid artery perfusion for 5 patients because of old age; 1, intraoperative finding of anisocoria; 1 and low left MCA flow velocity on the TCD monitor; 3. After the addition of left side perfusion, the left MCA flow velocity on the TCD monitor recovered to normal level in the 3 patients. TCD reflected the cerebral perfusion state every minutes and seemed to be very useful monitor in selective cerebral perfusion. It also suggested that unilateral cerebral perfusion does not supply enough blood flow in contralateral side of brain in many cases. To another patient who also underwent aortic arch replacement, we examined preoperatively left MCA flow velocity on the TCD monitor under left carotid artery compression. This "carotid artery compression test" was thought to suggest the degree of right to left intracranial collateral blood flow via Willis's circle. TCD image, when the left carotid artery was clamped, was compared with the result of preoperative "carotid artery compression test". But we can't evaluate the results quantitatively now.

Plant regeneration from protoplasts of peppermint (Mentha piperita L.)

Enzymatically isolated leaf-derived protoplasts of peppermint (Mentha piperita L.) were cultured in modified B5 medium containing 1 mg/l NAA, 0.4 mg/l BA, 0.5% sucrose, 0.5 M mannitol and 0.1% Gelrite (first medium). After 30 d culture at 25°C in the dark, protoplasts formed colonies consisting of about 100 cells. Gelrite medium blocks were transferred into liquid medium to promote further growth. Colonies of 0.5 mm transferred to 0.2% Gelrite solidified medium (same components as first medium) formed green calli (1-2 mm) under incubation in the light. Green calli transferred to differentiation medium (B5, 0.1 mg/l NAA, 5 mg/l BA, 2% sucrose, 0.2 M mannitol, 0.2% Gelrite) developed shoot buds after 3-4 weeks. Whole plants were recovered following rooting of shoots in B5 medium without hormones.

[6 cases of CABG post coronary stent]

In recent years, percutaneous transluminal coronary angioplasty (PTCA) has been actively carried out as a therapeutic method of the ischemic cardiopathies, and Stent therapy has been clinically applied as settlement method of problematical points of the acute occlusion and dissection of the coronary artery by PTCA. We experienced 6 cases necessitated coronary artery bypass graft (CABG) after insertion of Palmaz-Schatz Stent until March 1992. The emergent bypass was carried out in 3 of 6 cases because thrombotic occlusion developed although Stent was inserted in thrombotic occlusion after PTCA, while 2 cases were not life-saved because of the cardiac function was worsened before operation. Other 3 cases were life-saved by expectant treatment even though stenosis developed again after Stent therapy. Stent therapy is a useful method, while severity in cases using CABG and operative complexity are expected by development of new problematical point in the future.

Monitoring bovine embryo viability with early pregnancy factor

The viability of the bovine embryo was monitored by measuring the early pregnancy factor (EPF). The EPF activity was measured by the rosette inhibition test before and after artificial insemination (AI) at natural estrus (n = 14), and after superovulatory treatment followed by embryo removal on day 7 after AI (n = 5). In the cows inseminated artificially at natural estrus, there were significant differences (p < 0.01) in the rosette inhibition titer (RIT) between pregnant and non-pregnant cows on day 13-16 and day 20-25 after AI. In the 8 pregnant cows, the RIT remained more than 5 from day 6-9 after AI. In the 6 non-pregnant cows, two patterns were observed. In one pattern, RIT rose transiently to more than 5 and decreased to less than 4 thereafter. In the other pattern, RIT remained less than 4 throughout the experimental period. The former pattern suggested early embryonic death, while the latter suggested that fertilization had not taken place or that early embryonic death had occurred before the first blood collection on day 6-9 after AI. In the cows superovulated followed by embryo removal on day 7 after AI, the RIT values were all less than 4 on the day of AI (day 0), rose to more than 5 on day 3 and thereafter then until the day of embryo removal on day 7. In 4 cows, the RIT decreased to less than 4 by 3 days after embryo removal, and in the remaining one cow, the RIT decreased to less than 4 by 7 days after embryo removal. These findings suggest that the measurement of EPF activity is useful for monitoring the viability of bovine embryos.

Telomere-mediated plasmid segregation in Saccharomyces cerevisiae involves gene products required for transcriptional repression at silencers and telomeres

Plasmids that contain Saccharomyces cerevisiae TG1-3 telomere repeat sequences (TRS plasmids) segregate efficiently during mitosis. Mutations in histone H4 reduce the efficiency of TRS-mediated plasmid segregation, suggesting that chromatin structure is involved in this process. Sir2, Sir3 and Sir4 are required for the transcriptional repression of genes located at the silent mating type loci (HML and HMR) and at telomeres (telomere position effect) and are also involved in the segregation of TRS plasmids, indicating that TRS-mediated plasmid segregation involves factors that act at chromosomal telomeres. TRS plasmid segregation differes from the segregation of plasmids carrying the HMR E silencing region: HMR E plasmid segregation function is completely dependent upon Sir2, Sir3 and Sir4, involves Sir1 and is not influenced by mutations in RAP 1 that eliminate TRS plasmid segregation. Mutations in SIR1, SIN1, TOP1, TEL1 and TEL2 do not influence TRS plasmid segregation. Unlike transcriptional repression at telomeres, TRS plasmids retain partial segregation function in sir2, sir3, sir4, nat1 and ard1 mutant strains. Thus it is likely that TRS plasmid segregation involves additional factors that are not involved in telomere position effect.

Transduction mechanisms in the olfactory and vomeronasal organs of turtles

It is generally believed that odorants bind to receptor proteins and activate cAMP-dependent channels located in olfactory cilia. In the present paper, we discuss whether or not this mechanism holds for in vivo transduction in the olfactory and vomeronasal organs of a turtle: (1) Elimination of salts from the olfactory epithelium did not affect the responses to odorants; changes in concentration of NaCl or CaCl2 did not affect the olfactory responses. (2) The sensitivity of the vomeronasal system to various general odorants was essentially similar to that of the olfactory system, although the vomeronasal cells have no cilia. Elimination of salts from the surface of the vomeronasal organ, similar to the olfactory system, did not affect responses to odorants. (3) Liposomes having certain lipid compositions responded to odorants with a sensitivity comparable to that in the olfactory system. The liposomes containing phosphatidylserine (PS) exhibited strong responses, especially to fatty acids. (4) Application of PS-containing liposomes to the olfactory epithelium greatly enhanced the responses to fatty acids. The results suggest that the cation channels located at olfactory cilia may not contribute to in vivo olfactory transduction. The results also suggest that lipids in olfactory receptor membranes are important in odor reception.

The p53 tumor-suppressor gene and ras oncogene mutations in oral squamous-cell carcinoma

The frequencies of mutations in the p53 tumor-suppressor gene and ras proto-oncogenes were investigated systematically in surgically resected oral squamous-cell carcinomas (SCCs) using single-strand conformation polymorphism (SSCP) and/or dot-blot hybridization analysis of DNA fragments which had been amplified by the polymerase chain reaction (PCR). p53 gene mutations, within the region of exons 5 to 8, were detected in 17 out of 27 (63%) tumor specimens. The role of p53 mutations in cell-line establishment was investigated. p53 gene mutations were detected in 5 out of 6 tissue samples from which cell lines were established and in 4 out of 5 specimens from which cell lines could not be established, suggesting that the presence of p53 gene mutations is not by itself sufficient for cell-line establishment. Tumor samples were also analyzed for point mutational activation of the ras proto-oncogenes. One out of 30 (3%) tumors showed an activating point mutation in codon 12 of H-ras, this being consistent with reports from Europe and USA but not with any from India. Compared to frequencies of the other genetic changes so far reported for oral SCC, the p53 mutations have been observed most often to undergo genetic change. p53 gene mutation is thus intimately involved in the genesis of oral SCC and consequently should be useful as a marker for the diagnosis of this neoplasm.

[Studies on acute surgical therapy for DeBakey III aortic dissection: especially on the CT images and the operative indication]

Nine patients with DeBakey type III aortic dissection (type III a; 6, type III b; 3) that underwent acute surgical therapy were studied with particular emphasis on the preoperative CT images and operative indication. It took 6 approximately 192 hours (mean 40.6 +/- 56.0) from onset of the disease to the operation. The reasons why operations were required in acute phase were prolonged pain; 2, fluid retensionin in thoracic cavity; 3, increasing fluid retension; 3, shock state; 1, anuria; 1.6 (75%) of 8 thoracic aortic dissection cases showed intra-thoracic fluid retension in chest roentogenogram or CT image. We performed prosthetic interposition of descending thoracic aorta in 8 patients and Y-graft interposition of abdominal aorta in a patient. During the operations, we found fluid retension in the thoracic and pericardial cavity in 83% (5 cases) of 6 non-ruptured cases. To diagnose ruptured aneurysm, CT image played very important role. But we could not discriminate between ruptured aneurysm and intrapleural serous fluid retension on the CT image. Puncture of intra-thoracic fluid is effective procedure to diagnose rupture of the aneurysms but it is impossible in some cases and traumatic tap may lead misdiagnosis. Therefore we think moderate or increasing fluid retension in the thoracic cavity should be added to the operative indication of acute DeBakey type III aortic dissection and that the early operation will make mortality rate lower.

Yeast telomere repeat sequence (TRS) improves circular plasmid segregation, and TRS plasmid segregation involves the RAP1 gene product

Telomere repeat sequences (TRSs) can dramatically improve the segregation of unstable circular autonomously replicating sequence (ARS) plasmids in Saccharomyces cerevisiae. Deletion analysis demonstrated that yeast TRSs, which conform to the general sequence (C(1-3)A)n, are able to stabilize circular ARS plasmids. A number of TRS clones of different primary sequence and C(1-3)A tract length confer the plasmid stabilization phenotype. TRS sequences do not appear to improve plasmid replication efficiency, as determined by plasmid copy number analysis and functional assays for ARS activity. Pedigree analysis confirms that TRS-containing plasmids are missegregated at low frequency and that missegregated TRS-containing plasmids, like ARS plasmids, are preferentially retained by the mother cell. Plasmids stabilized by TRSs have properties that distinguish them from centromere-containing plasmids and 2 microns-based recombinant plasmids. Linear ARS plasmids, which include two TRS tracts at their termini, segregate inefficiently, while circular plasmids with one or two TRS tracts segregate efficiently, suggesting that plasmid topology or TRS accessibility interferes with TRS segregation function on linear plasmids. In strains carrying the temperature-sensitive mutant alleles rap1grc4 and rap1-5, TRS plasmids are not stable at the semipermissive temperature, suggesting that RAP1 protein is involved in TRS plasmid stability. In Schizosaccharomyces pombe, an ARS plasmid was stabilized by the addition of S. pombe telomere sequence, suggesting that the ability to improve the segregation of ARS plasmids is a general property of telomere repeats.

[Surgical therapy of aortic regurgitation due to aortitis syndrome--effectiveness and extended indication of Bentall's operation]

Fourteen patients with aortic regurgitation due to aortitis syndrome that underwent surgical therapy were studied with particular emphasis on the long term merits of Bentall's operations over the conventional valve replacement. They were divided into two groups; Group A: 6 aortic valve replacements (AVRs) and Group B: 8 Bentall's operations. Post operative complications related to aortitis syndrome developed in 3 cases; a case of paravalvular leakage (Group A) and two cases of aneurysm formation at the coronary artery anastomotic sites (Group B). We speculated that these complications were due to abnormal healing and recurrent inflammatory process of the disease. Therefore we think that conventional valve replacement is not suited to cope with these problems. Since 1984, we have adopted the policy to perform Bentall's operations for all patients with aortitis requiring valve replacement. Bentall's operation required longer aortic cross-clamp time (212.1 +/- 53.9 min) than AVRs (73.0 +/- 25.0) and was more aggressive. However no patients with our current technique to reimplant the coronary artery button and distal graft to aorta anastomosis, which has been used since 1984, has developed pseudoaneurysm or valvular leakage. We conclude that our modified Bentall's operation is effective even for patients who have active aortitis syndrome or need redo operations.

Causes of oral tongue cancer treatment failures. Analysis of autopsy cases

Eighty-three autopsy cases of squamous cell carcinoma of the oral tongue were reviewed to identify retrospectively the causes of treatment failure. The cure rate for the primary cancers at autopsy was 48.2% (40 of 83). Regional lymph node metastases were found in 71.1% (59 of 83). Regional metastases and/or juxtaprimary recurrence frequently spread continuously and diffusely, forming bulky neck tumors in 38.6% (32 of 83). The incidence of distant lymph node metastasis (below the clavicle) and hematogenous metastasis was 35.4% (29 of 82) and 58.5% (48 of 82), respectively. The lung was the most common site of hematogenous metastases (52.4%, 43 of 82). Hematogenous metastasis occurred more frequently in the younger age group (less than 40 years of age; P = 0.03). Distant lymph node metastases were identified in the lung hilar, bifurcation, and paratracheal nodes in 89.7% (26 of 29) and had a statistically significant association with lung hematogenous metastasis. Univariate analysis revealed that gross appearance, tumor stage, clinical stage, presence of cervical lymph node metastasis, and interval from N0 to NX were significant predictors of survival time (duration from initial treatment to death). Rupture of the neck vessels was fatal in eight patients (9.6%), and hypercalcemia was seen in six (7.2%). Pulmonary infection was the direct cause of death in 33.7% of patients (28 of 83). Secondary malignant lesions occurred in 22.9% (19 of 83).

Malignant melanomas of the oral cavity: heterogeneity of pathological and clinical features

Data on 35 patients with oral malignant melanomas were pooled and the pathological features and the clinical course were examined in detail. Of these 35 cases, 27 (77.1%) showed a two-phase growth pattern, with both a vertical and a radial growth phase. Moreover, these 27 cases were classified into three subtypes according to gross features of the vertical growth phase; nodular, flat elevated and ulcerated types. Almost two-thirds of the cases were of the melanotic type. Malignant melanomas without a radial growth phase were found in 8 instances, all of which showed a nodular growth pattern, 1 being of melanotic type and 7 amelanotic. Mean latent insidious periods were evaluated for the cases with different growth phases. Cases with a radical growth phase exhibited the longest mean latent period (35.7 months), and a median survival time of 23.5 months. Cases without a radial growth phase showed a short mean latent period (2.1 months), and a median survival time of 7.5 months. The thickness of invasion ranged from 2 to 9 mm. Although 77.1% of the cases depicted similar pathological patterns to acral lentiginous melanomas of the skin, oral malignant melanomas demonstrated heterogeneity in morphological features, developmental process and biological behaviour. The histogenesis of oral melanomas is briefly discussed.