Cdc20 is critical for meiosis I and fertility of female mice

Chromosome missegregation in germ cells is an important cause of unexplained infertility, miscarriages, and congenital birth defects in humans. However, the molecular defects that lead to production of aneuploid gametes are largely unknown. Cdc20, the activating subunit of the anaphase-promoting complex/cyclosome (APC/C), initiates sister-chromatid separation by ordering the destruction of two key anaphase inhibitors, cyclin B1 and securin, at the transition from metaphase to anaphase. The physiological significance and full repertoire of functions of mammalian Cdc20 are unclear at present, mainly because of the essential nature of this protein in cell cycle progression. To bypass this problem we generated hypomorphic mice that express low amounts of Cdc20. These mice are healthy and have a normal lifespan, but females produce either no or very few offspring, despite normal folliculogenesis and fertilization rates. When mated with wild-type males, hypomorphic females yield nearly normal numbers of fertilized eggs, but as these embryos develop, they become malformed and rarely reach the blastocyst stage. In exploring the underlying mechanism, we uncover that the vast majority of these embryos have abnormal chromosome numbers, primarily due to chromosome lagging and chromosome misalignment during meiosis I in the oocyte. Furthermore, cyclin B1, cyclin A2, and securin are inefficiently degraded in metaphase I; and anaphase I onset is markedly delayed. These results demonstrate that the physiologically effective threshold level of Cdc20 is high for female meiosis I and identify Cdc20 hypomorphism as a mechanism for chromosome missegregation and formation of aneuploid gametes.

Aneuploidy, an abnormal number of chromosomes, is a common defect in sperm and egg cells that is responsible for human infertility, miscarriage, and congenital birth defects. Although these developmental outcomes are prevalent in human reproduction, little is known about the molecular defects that may cause aneuploidy in germ cells. In this study, we identify Cdc20, a critical activator of the APC/C E3 ubiquitin ligase that initiates sister chromosome separation by ordering the destruction of cyclin B1 and securin, as a female infertility gene. We show that female mice with low amounts of Cdc20 have normal fitness but almost exclusively produce aneuploid embryos that fail to thrive and die early in development. The aneuploidy primarily results from chromosome segregation errors in primary oocytes that may be caused by inefficient APC/C-mediated destruction of mitotic cyclins and securin during metaphase I. Thus, our studies reveal that primary oocytes are highly dependent on Cdc20 for accurate chromosome segregation and raise the possibility that Cdc20 insufficiency may be a cause of infertility in otherwise healthy women.

Two new variants of G6PD deficiencies in Singapore

Identification of mutations in G6PD gene is performed as an epidemiologic investigation of G6PD deficiency in many countries. In order to understand the hereditary background of G6PD deficiency in a population, screening of mutations is required not only in exonic regions but also for intron and promoter regions. One hundred male neonatal samples diagnosed as with G6PD deficiency by newborn screening in Singapore were used in this study. The multiplex PCR using the multiple tandem forward primers and common reverse primer (MPTP) method was carried out to detect the common 11 mutations in south-east Asia such as Gaohe 95A>G, Orissa 131C>G, Vanua-Lava 383T>C, Mahidol 487G>A, Mediterranean 563C>T, Coimbra 592C>T, Viangchan 871G>A, Chatham 1003G>A, Union 1360C>T, Canton 1376G>T and Kaiping 1388G>A. Samples whose mutations were unidentified by MPTP method were scanned at cording region, intron and promoter region by direct sequencing.Out of 100 samples, 90 samples (90.0%) were identified with one of the above mentioned common mutations. Eight out of 10 samples whose mutations were unidentified by MPTP method carried exonic mutations which had been previously reported such as Murcia 209A>G, Quing Yuan 392G>T, Nankang 517T>C, Chinese5 1024C>T. Two novel mutations were identified in these samples: one had a novel mutation (25C>T); the remaining sample carried a 49 bp deletion in intron 12.

Operation of a 500 MHz high temperature superconducting NMR: towards an NMR spectrometer operating beyond 1 GHz

We have begun a project to develop an NMR spectrometer that operates at frequencies beyond 1 GHz (magnetic field strength in excess of 23.5 T) using a high temperature superconductor (HTS) innermost coil. As the first step, we developed a 500 MHz NMR with a Bi-2223 HTS innermost coil, which was operated in external current mode. The temporal magnetic field change of the NMR magnet after the coil charge was dominated by (i) the field fluctuation due to a DC power supply and (ii) relaxation in the screening current in the HTS tape conductor; effect (i) was stabilized by the 2H field-frequency lock system, while effect (ii) decreased with time due to relaxation of the screening current induced in the HTS coil and reached 10(-8)(0.01 ppm)/h on the 20th day after the coil charge, which was as small as the persistent current mode of the NMR magnet. The 1D (1)H NMR spectra obtained by the 500 MHz LTS/HTS magnet were nearly equivalent to those obtained by the LTS NMR magnet. The 2D-NOESY, 3D-HNCO and 3D-HNCACB spectra were achieved for ubiquitin by the 500 MHz LTS/HTS magnet; their quality was closely equivalent to that achieved by a conventional LTS NMR. Based on the results of numerical simulation, the effects of screening current-induced magnetic field changes are predicted to be harmless for the 1.03 GHz NMR magnet system.

Induction of apoptosis of detached oral squamous cell carcinoma cells by safingol. Possible role of Bim, focal adhesion kinase and endonuclease G

The protein kinase C (PKC) inhibitor safingol increased rounding and detachment of human oral squamous cell carcinoma (SCC) cells in monolayer cultures. When dissociated cells were incubated in the presence of safingol, cell adhesion was prevented and cell viability was lost gradually, while most cells survived in the absence of safingol even if their attachment was blocked by coating the culture plates with polyhydroxyethyl methacrylate. Flow cytometric analysis and agarose gel electrophoresis of cellular DNA revealed an increase in the proportion of sub-G(1) cells and DNA fragmentation, indicating that safingol induced apoptosis of dissociated cells. During the induction of apoptosis in cell suspensions by safingol, there was an increase of the pro-apoptotic BH-3 only protein Bim and decrease of pro-survival Bcl-2 family proteins Bcl-xL and mitochondrial pro-apoptogenic factor endonuclease G translocated to the nucleus. The level of phosphorylated focal adhesion kinase (FAK) required for cell survival also rapidly decreased, followed by a decrease in the protein level. The introduction of siRNA against PKCalpha into SAS cells resulted in an increase of Bim, a decrease of Bcl-xL, the translocation of endonuclease G, and a decrease in the phosphorylation of FAK. These results suggest that Bim, Bcl-xL, FAK and endonuclease G are involved in safingol-induced apoptosis of detached oral SCC cells. Safingol can be used to induce apoptosis with cell detachment, anoikis, of oral SCC cells.

BubR1 N terminus acts as a soluble inhibitor of cyclin B degradation by APC/C(Cdc20) in interphase

BubR1 is an essential mitotic checkpoint protein with multiple functional domains. It has been implicated in mitotic checkpoint control, as an active kinase at unattached kinetochores, and as a cytosolic inhibitor of APC/C(Cdc20) activity, as well as in mitotic timing and stable chromosome-spindle attachment. Using BubR1-conditional knockout cells and BubR1 domain mutants, we demonstrate that the N-terminal Cdc20 binding domain of BubR1 is essential for all of these functions, whereas its C-terminal Cdc20-binding domain, Bub3-binding domain, and kinase domain are not. We find that the BubR1 N terminus binds to Cdc20 in a KEN box-dependent manner to inhibit APC/C activity in interphase, thereby allowing accumulation of cyclin B in G(2) phase prior to mitosis onset. Together, our results suggest that kinetochore-bound BubR1 is nonessential and that soluble BubR1 functions as a pseudosubstrate inhibitor of APC/C(Cdc20) during interphase to prevent unscheduled degradation of specific APC/C substrates.

Purification and characterization of recombinant lipid storage protein-2 from Drosophila melanogaster

Lipid storage protein 2 (Lsd 2) is a conserved insect protein that belongs to the small PAT family of proteins. PAT proteins are found associated to the lipid droplets of adipocytes and play significant roles in the regulation of triacylglycerides metabolism. Here we describe the expression and purification of Lsd2, its reconstitution in lipoprotein particles, the location of putative lipid binding sites and its secondary structure. This study provides the starting point for future studies on the mechanism of function of Lsd2. The similarities and differences between Lsd1 and Lsd2, the only PAT proteins found in insects, are discussed.

Identification of Piccolo as a regulator of behavioral plasticity and dopamine transporter internalization

Dopamine transporter (DAT) internalization is a mechanism underlying the decreased dopamine reuptake caused by addictive drugs like methamphetamine (METH). We found that Piccolo, a presynaptic scaffolding protein, was overexpressed in the nucleus accumbens (NAc) of the mice repeatedly administrated with METH. Piccolo downexpression by antisense technique augmented METH-induced behavioral sensitization, conditioned reward and synaptic dopamine accumulation in NAc. Expression of Piccolo C2A domain attenuated METH-induced inhibition of dopamine uptake in PC12 cells expressing human DAT. Consistent with this, it slowed down the accelerated DAT internalization induced by METH, thus maintaining the presentation of plasmalemmal DAT. In immunostaining and structural modeling Piccolo C2A domain displays an unusual feature of sequestering membrane phosphatidylinositol 4,5-bisphosphate, which may underlie its role in modulating DAT internalization. Together, our results indicate that Piccolo upregulation induced by METH represents a homeostatic response in the NAc to excessive dopaminergic transmission. Piccolo C2A domain may act as a cytoskeletal regulator for plasmalemmal DAT internalization, which may underlie its contributions in behavioral plasticity.

Function and structure of lipid storage droplet protein 1 studied in lipoprotein complexes

Triglycerides (TG) stored in lipid droplets (LDs) are the main energy reserve in all animals. The mechanism by which animals mobilize TG is complex and not fully understood. Several proteins surrounding the LDs have been implicated in TG homeostasis such as mammalian perilipin A and insect lipid storage proteins (Lsd). Most of the knowledge on LD-associated proteins comes from studies using cells or LDs leaving biochemical properties of these proteins uncharacterized. Here we describe the purification of recombinant Lsd1 and its reconstitution with lipids to form lipoprotein complexes suitable for functional and structural studies. Lsd1 in the lipid bound state is a predominately alpha-helical protein. Using lipoprotein complexes containing triolein it is shown that PKA mediated phosphorylation of Lsd1 promoted a 1.7-fold activation of the main fat body lipase demonstrating the direct link between Lsd1 phosphorylation and activation of lipolysis. Serine 20 was identified as the Lsd1-phosphorylation site triggering this effect.

Repeated bacteraemia caused by Streptococcus mutans in a patient with Sjogren's syndrome

Streptococcus mutans, considered to be a pathogen for dental caries, is known to cause bacteraemia and infective endocarditis. Herein, an unusual case of repeated bacteraemia caused by S. mutans identified in a 71-year-old male is described. The patient visited Itami City Hospital with the major complaint of a fever, and a subsequent clinical examination led to a diagnosis of possible infective endocarditis without specific vegetation formation around the heart valve. A bacteriological examination of blood taken at the first visit showed the presence of S. mutans. Antimicrobial treatment was provided, which successfully eliminated the pathogenic bacteria from the blood. However, the patient returned and was hospitalized twice more with a recurrent fever, and S. mutans was again detected. Analyses of the biological properties of the S. mutans isolates showed that they possessed cariogenic properties and had a low susceptibility to phagocytosis by human polymorphonuclear leukocytes. Since the patient had Sjögren's syndrome, in which a reduction of saliva secretion is a characteristic feature, a great number of dental caries lesions were identified. The findings indicated that S. mutans present in those dental caries lesions caused repeated bacteraemia in this case.

Evaluation of cholesterol content and impact on antigen exposure in the outer lipid bilayer of adult schistosomes

Developing and adultSchistosoma mansoniandS. haematobiumintact worms do not bind specific antibodies, likely because of structural and biochemical modifications of the outer lipid bilayer. We have estimated the amount of cholesterol in the apical membrane of adult schistosomes via extraction with the membrane-impermeable, cholesterol-binding drug, methyl-β-cyclodextrin (MBCD), followed by filipin staining of the worms, and evaluation of the amount of cholesterol released in the medium by a commercially available, enzymatic colorimetric assay. Positive correlations between amount of released cholesterol, MBCD concentration, and worm number and age provided evidence for the sensitivity and validity of the newly developed method. Treatment with 40 mmMBCD for 2 h at 37°C led to total loss of cholesterol from the worm outer membrane, as assessed by filipin staining, and the released cholesterol values were used to estimate the amount of cholesterol per worm and per an approximate surface area unit. Additionally, total depletion of outer membrane cholesterol was associated with exposure of surface membrane antigens to specific antibody binding in 50% and 70% ofS. haematobiumandS. mansoniworms, respectively. These findings together suggest that cholesterol is an essential, but not the sole, factor in sequestration of surface membrane antigens in schistosomes.

Induction of endonuclease G-mediated apopotosis in human oral squamous cell carcinoma cells by protein kinase C inhibitor safingol

PKC inhibitor safingol suppressed the growth of human oral squamous cell carcinoma (SCC) cells significantly at concentrations that inhibit PKC isoforms. Safingol inhibited the translocation of PKC following treatment with 12-o-tetradecanoylphorbol 13-acetate (TPA) in PKC alpha-EGFP-transfected cells, but not in PKC beta-EGFP- transfected cells, indicating selective inhibition for PKC alpha in oral SCC cells. Flow cytometric analysis and DNA analysis by agarose gel electrophoresis revealed an increase in the proportion of sub-G(1) cells and DNA fragmentation in safingol-treated cells. Mitochondrial membrane potential was decreased, and cytochrome c was released from mitochondria. However, the safingol-induced cell death was not accompanied by activation of caspase 3 and cleavage of poly (ADP-ribose) polymerase (PARP). The broad-spectrum caspase inhibitor BD-fmk failed to prevent safingol-induced cell death. Another apoptogenic factor endonuclease G, but not apoptosis-inducing factor (AIF), was also released from mitochondria and translocated to the nucleus. These results suggest that PKC alpha inhibitor safingol induces an endonuclease G- mediated apoptosis in a caspase-independent manner.

Different real-time PCR assays could lead to a different result of detection of varicella-zoster virus in facial palsy

Real-time PCR is a useful tool for rapid detection of viral genomic DNA. However, there are many types of real-time PCR, and this variation may induce different results. The sensitivity of two different real-time PCR assays was evaluated for the detection of the varicella-zoster virus (VZV) genome: LightCycler PCR and TaqMan PCR. Auricular skin cells and saliva were sampled from 201 patients with facial nerve paralysis. A hundred and seventy-one of these patients were diagnosed clinically with Bell's palsy, and the remaining 30 with Ramsay Hunt syndrome. In 30 specimens obtained from Ramsay Hunt syndrome patients, VZV DNA was detected in 26 skin and 3 saliva specimens using the LightCycler PCR, while 28 skin and 9 saliva specimens were positive using the TaqMan PCR. None of the patients with Bell's palsy were positive for VZV by the LightCycler PCR, whereas five of these patients were positive by the TaqMan PCR. The TaqMan PCR assay has a better sensitivity compared to the LightCycler PCR for the detection of VZV genome from patients with facial palsy. Further study is required to develop a more sensitive real-time PCR.

A very rare anatomic variation of the right ventricular branch: right ventricular descending branch from the anterior interventricular branch

The anterior interventricular branch of the left coronary artery has the most constant distribution in the human heart and rarely gives off right ventricular branches. Here we report a case with a right ventricular branch which diverged from the anterior interventricular branch and descended on the anterior right ventricular wall parallel to the anterior interventricular sulcus; we termed it the "right ventricular descending branch." This artery gave a collateral artery to the occluded anterior interventricular branch at the apex, and had prevented anterior myocardial infarction. The right ventricular descending branch should be precisely identified in order to perform successful myocardial revascularization procedures such as coronary artery bypass grafting and percutaneous coronary intervention, especially in a patient with anterior interventricular branch occlusion.

[Emergency coronary artery bypass grafting for acute coronary syndrome with preoperative intraaortic balloon pumping; comparative surgical outcome and long-term results]

With recent technical improvements in catheter interventional therapy, percutaneous coronary intervention (PCI) has now become the treatment of first choice for acute coronary syndrome (ACS). The objective of the present study was to evaluate critically the timing of coronary artery bypass grafting (CABG) for severe ACS with preoperative intraaortic balloon pumping (IABP). Since 1994, a total of 70 patients have gone emergency or urgent CABG for ACS. Of 70 patients, 50 patients required preoperative IABP. There were 22 patients (17 men, 5 women) with acute myocardial infarction (AMI), with a mean age of 67.7 years, and 28 patients (19 men, 9 women) with unstable angina pectoris (UAP), with a mean age of 69.2 years. There was a significant difference, between AMI and UAP, in the prevalence of emergency operation (95.5% vs 25.0%), in preoperative cardiogenic shock (81.8% vs 17.9%), in the level of preoperative CPK-MB (196.7 IU/l vs 2.0 IU/l) and in preoperative ejection fraction (41.8% vs 47.3%). Two patients in AMI required percutaneous cardiopulmonary support (PCPS). Thirteen patients in AMI and 22 patients in UAP presented left main trunk (LMT) disease. Of the 13 LMT patients in AMI, 4 patients were AMI due to acute occlusion in the LMT. The AMI patients received 2.45 distal anastomoses on average, while the UAP patients 3.14 distal anastomoses (p = 0.019). Excluding the mean number of distal anastomoses, there was no difference in the intraoperative technical factors, such as aortic cross clamping duration, cardiopulmonary bypass duration, rate of complete revascularization, between AMI and UAP. There were postoperative significant differences in low cardiac output syndrome (LOS) [45.6% in AMI vs 3.6% in UAP] and in prolongation of mechanical ventilation (59.1% in AMI vs 14.3% in UAP). The hospital mortality was 9.1% (2/22) in AMI, and 3.6% (1/28) in UAP, with no significant difference. Of these 3 patients, 1 patient died from perioperative cerebrovascular accident (CVA), another from LOS, and the other from postoperative mesenteric ischemia, with an overall mortality of 6.0% (3/50). The overall patency rate of the grafts was 100% in AMI and 96.6% in UAP. The 5-year-survival rate excluding in-hospital death was 72.5% in AMI, and 89.6% in UAP. The 5-year-cardiac event-free rate was 77% in AMI and 89.4% in UAP. The overall survival rate, and cardiac event-free rate, at 5 years was 80.8%, and 83.8%, respectively. In conclusion, for ACS cases, especially UAP cases of LMT, in which symptoms, findings of ischemia and hemodynamics are stabilized by medical intervention including IABP; emergency surgery could be avoided immediately after coronary angiography. Recovery in the ischemic myocardium is intended by IABP, and urgent surgery should be performed after sufficient and precise preoperative examinations. An improvement not only in the perioperative but also long-term results can be expected by performing complete revascularizations.

Comparison between the cross-sectional area of bone-patellar tendon-bone grafts and multistranded hamstring tendon grafts obtained from the same patients

This study intraoperatively compared the cross-sectional area (CSA) and graft-tunnel fit of bone-patellar tendon-bone (BTB) and multistranded hamstring tendon (STG) grafts harvested from the same patient. Twenty-two patients with a mean age of 26 years were the subjects of the study. Each BTB graft was harvested from the central third of the patellar tendon. Tripled or quadrupled semitendinosus tendon with or without gracilis tendon was used as a STG graft. CSAs of both grafts in the same patients were intraoperatively measured using a custom-made area micrometer during primary ACL reconstruction and revision surgery or during combined ACL and PCL reconstruction. Graft-tunnel fit was calculated by dividing the CSA of the graft by that of the tibial bone tunnel. The average CSA of STG grafts was significantly greater than that of BTB grafts. The average value of graft-tunnel fit for the STG grafts% was also greater than that of the BTB grafts%. Thus STG grafts have a larger CSA and closer graft-tunnel fit than BTB grafts in a clinical setting.

Identification of the HLA-A24 peptide epitope within cytomegalovirus protein pp65 recognized by CMV-specific cytotoxic T lymphocytes

Among cytomegalovirus (CMV) tegument proteins, phosphoprotein 65 (pp65) has been identified as the important target antigen of the cytotoxic T lymphocyte (CTL) response against the virus. We synthesized seven CMV-pp65-derived peptides carrying an HLA-A24-binding motif, and investigated the ability of these peptides to induce CMV-specific CTL. We identified one nonamer peptide (pp65113-121; VYALPLKML) able to bind HLA-A24 and induce CTL responses in vitro in peripheral blood mononuclear cells (PBMC) from CMV-seropositive individuals. The peptide-specific CTLs generated were capable of recognizing pp65 expressed on CMV-infected fibroblasts as well as pp65113-121 peptide bound to the surface of C1R-A*2402 cells in an HLA-A24-restricted manner. The pp65113-121 peptide thus might be considered a synthetic peptide vaccine in HLA-A24-positive individuals.

Beneficial effect of replacing of angiotensin-converting enzyme inhibitor with angiotensin II antagonist for heart failure patients

OBJECTIVE

Angiotensin-converting enzyme (ACE) inhibitors and beta-blockers improve prognosis inpatients with chronic heart failure. Some patients, however, show little response to combined treatment with an ACE inhibitor and a beta-blocker. In addition, the ACE inhibitor cannot completely suppress angiotensin II production. Our objective was to examine whether replacing the ACE inhibitor with an angiotensin II antagonist can improve the condition of patients with chronic heart failure.

METHODS

In 11 patients with chronic heart failure treated with an ACE inhibitor and a beta-blocker, who have had severe left ventricular dysfunction or high plasma level of natriuretic peptides, left ventricular dimension, and fractional shortening, plasma atrial and brain natriuretic peptide (ANP and BNP) levels were determined before and 3 months after the change of treatment.

RESULTS

After substituting the ACE inhibitor with an angiotensin II antagonist, patients showed New York Heart Association functional class improvement, and significant decrease in left ventricular dimension and BNP.

CONCLUSION

In patients with severe chronic heart failure treated with an ACE inhibitor and a beta-blocker, replacing the ACE inhibitor with an angiotensin II antagonist may be effective. However, this has to be confirmed by an adequately powered randomized controlled study.

Correlation between age and vital organ function following deep hypothermic circulatory arrest

BACKGROUND

We investigated the correlation bet-ween perioperative variables such as patients' age and vital organ function after operation on thoracic aorta using deep hypothermic circulatory arrest (DHCA).

METHODS

Ninety-five patients who underwent replacement of thoracic aorta under DHCA for acute or chronic aortic dissection and aortic aneurysm, and survived more than 10 days were divided into group I (age less than 60, n=17), group II (between 60 and 69, n=39), and group III (over 70, n=39). Concomitant procedures such as aortic root replacement and coronary artery bypass grafting were performed in 9, 4, and 1 patients in group I, II, and III, respectively. Postoperative pulmonary, renal, and hepatic function within 10 days were compared. Correlation between other perioperative variables and organ function was also investigated among all 95 patients.

RESULTS

Postoperative pulmonary, renal, and hepatic function in group III was not significantly inferior to those in groups I and II. The operation time, and amount of red blood cells and fresh frozen plasma used during operation, were significantly greater in group I, which showed an intimate correlation to significant elevation of hepatic enzymes.

CONCLUSIONS

Although lower functional reserve of vital organs in the elderly patients was predicted, they showed an acceptable functional recovery after operation with DHCA. Other perioperative variables such as operation time and blood transfusion showed a negative impact on postoperative hepatic function.

Biochemical and morphological changes in herniated human intervertebral disc

The molecular and morphologic features of herniated human intervertebral disc tissues are of particular importance to clarify the pathogenesis. The present study analyzed the biochemical and morphological features of herniated intervertebral disc tissues to determine the constituent factors responsible for intervertebral disc herniation. A total of 32 herniated disc specimens and 4 control disc samples were analyzed. Collagen subunit composition, collagenase activity, lipid peroxidation level, caspase-3 activity, metal levels, morphologic studies, and genetic analysis were performed on herniated disc tissues of chronic (group A) and acute (group B) group and compared with findings of control group. Nick translation analysis in situ revealed apoptotic-positive stained DNA fragments as black-brown spots in herniated disc tissues. The presence of type II collagen in control disc samples and its absence in herniated samples were confirmed immunohistochemically. The increased caspase-3 activity, the apoptotic-positive stained DNA fragments, and the electron microscopic findings suggest enhanced programmed cell death in herniated discs. The significant increase in lipid peroxidation levels and collagenase activity, and the low metal levels suggest the enhancement of cell death signals in herniated discs, caused by oxygen stress. Linkage analysis of herniated disc tissues in Japanese individuals may suggest ethnic variation. These findings may be helpful in understanding the pathogenesis of herniated disc disease.

Allosterically controlled single-chained maxizymes with extremely high and specific activity

For the treatment of chronic myelogenous leukemia (CML), attempts have been made to design various ribozyme motifs that can specifically recognize and cleave BCR-ABL fusion mRNAs. In the case of L6 BCR-ABL b2a2 mRNA, it is difficult to cleave the abnormal mRNA specifically because the mRNA includes no sequences that can be cleaved efficiently by conventional hammerhead ribozymes near the BCR-ABL junction. We recently succeeded in designing a novel maxizyme, which specifically cleaves BCR-ABL fusion mRNA, as a result of the formation of a dimeric structure [Kuwabara, T.; et al. Mol. Cell 1998, 2, 617-627; Tanabe, T.; et al. Nature 2000, 406, 473-474]. Specifically, we tailored the maxizyme with molecular switching function: the maxizyme splices a cleavable GUC site, but only when it appears within a strand of mRNA that possesses the abnormal splice junction. We demonstrated that this approach is generalizable [Tanabe, T.; et al. Biomacromolecules 2000, 1, 108-117]. All the maxizymes designed in the past functioned as a result of the formation of a dimeric structure. Questions have been asked whether a similar molecular switching might be possible within a single molecule when two monomer units of the maxizyme were connected via a linker sequence. We found that an analogous conformational change could not be induced within a single molecule when two maxizyme units were simply connected via a nonregulatable linker sequence. However, an active conformation was achieved by the introduction of an antisense modulator within the linker sequence that adjusted the overall structure to the correct form. Results of studies in cultured cells suggested that the desired conformational change could indeed be induced within the modified single-chained maxizyme and such a construct caused apoptosis only in leukemic cells with the Philadelphia chromosome.

Tyropeptins A and B, new proteasome inhibitors produced by Kitasatospora sp. MK993-dF2. I. Taxonomy, isolation, physico-chemical properties and biological activities

Tyropeptins A and B, new proteasome inhibitors, were isolated from the culture broth of Kitasatospora sp. MK993-dF2. They were purified using ethyl acetate extraction, silica gel column chromatography, Sephadex LH-20 column chromatography and HPLC. Tyropeptin A inhibited the chymotrypsin-like (ChT-L) and trypsin-like (T-L) activities of 20S proteasome with IC50 values of 0.1 microg/ml and 1.5 microg/ml respectively, but did not inhibit the peptidylglutamyl-peptide hydrolyzing (PGPH) activity of 20S proteasome at a concentration of 100 microg/ml. The inhibitory activities of tyropeptin A were about two times as strong as that of tyropeptin B. Taxonomy of the producing strain is also described.

Tripropeptins, novel antimicrobial agents produced by Lysobacter sp. I. Taxonomy, isolation and biological activities

Peptide antibiotics tripropeptins A, B, C, D and Z were isolated from cultured cells and broth of Lysobacter sp. The differences among these components are in the lengths of the alkyl side chain. Tripropeptins are active against Gram-positive bacteria including MRSA in vitro. Bactericidal activity of tripropeptin C disappeared in the simultaneous presence of chloramphenicol, a bacteriostatic agent.

Some biological and biochemical activities of resormycin, a novel herbicidal antibiotic

Biological and biochemical activities of resormycin were studied using unicellular green algae, Selenastrum capricornutum (abbreviated as Selena.), as a test organism. Resormycin inhibited the growth in vitro of Selena. more strongly in the dark than in the light. A weaker but more photo-stable derivative, (+/-)-2,3-dihydro-resormycin, showed more long-lasting activity against Selena. in the light. Resormycin started killing Selena. only after exposure for 2 days and longer, even at high concentrations. Resormycin at concentrations near IC50 rapidly inhibited incorporation of 3H-leu, but not 3H-UR or 3H-TdR, into the TCA insoluble fraction of Selena. Herbicidal activity of resormycin was confirmed using some crops and weeds.

Ischemic preconditioning and lipopolysaccharide attenuate nuclear factor-kappaB activation and gene expression of inflammatory cytokines in the ischemia-reperfused rat heart

Ischemic preconditioning (IP) and pretreatment with lipopolysaccharide (LPS) reduce myocardial infarct size, but the precise mechanisms remain unknown. Rats were divided into 3 groups: the Control (C) group was subjected to 30 min ischemia followed by 3 h reperfusion; the IP and LPS groups had the same ischemia-reperfusion (I-R) insult with either preconditioning stimuli or pretreatment with LPS, respectively. Infarct size was smaller in the IP (23.4+/-2.3% of risk zone size) and LPS groups (28.5+/-2.0% of risk zone size) than in the C group (52.3+/-3.4% of risk zone size). Nuclear factor kappa-B (NF-kappaB) binding activity increased at 30 min reperfusion and declined thereafter, then rose again at 3 h reperfusion in the C group. The values in the IP (362% of control) and LPS (324% of control) groups were higher before I-R, and then decreased from 30 min (46% and 64% of control, respectively) until 3 h reperfusion (22% and 36% of control, respectively). Nuclear staining of NF-kappaB after reperfusion was less in the IP and LPS groups than in the C group. Expressions of cytokine mRNAs (interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha) were detected 30 min after the onset of reperfusion and their levels remained high after 3 h of reperfusion. These expressions of cytokine mRNAs after I-R were substantially suppressed by IP and LPS, although IP and LPS alone induced modest expressions of these cytokine mRNAs. These data suggest that IP and LPS contribute to infarct size reduction via the downregulation of NF-kappaB and the attenuation of cytokine gene expression.

Isolation and structural determination of phepropeptins A, B, C, and D, new proteasome inhibitors, produced by Streptomyces sp

We have isolated four related compounds named phepropeptins A, B, C, and D, as inhibitors of proteasome proposed to regulate many cellular functions. From an NMR analysis, the phepropeptins appeared as cyclic hexapeptides, differing in the two residues of the constituent amino acids from one another, with four conserved amino acid moieties. Based on an amino acid analysis, we synthesized two possible cyclic peptides to phepropeptin B that differ in the configurations. A comparison of the properties between the natural and synthesized compounds revealed that the structure of phepropeptin B was cyclo(-L-Leu-D-Phe-L-Pro-L-Phe-D-Leu-L-Val-). The phepropeptins showed inhibition to the proteasomal chymotrypsin-like activity but not to alpha-chymotrypsin.

Human meniscus cell: characterization of the primary culture and use for tissue engineering

Human meniscus cells from 47 surgically excised menisci were grown in primary culture. Cell proliferation and morphologic features were evaluated in three different culture media. Human meniscus cells showed three distinguishable cell types in monolayer culture: elongated fibroblastlike cells, polygonal cells, and small round chondrocytelike cells. These cells proliferated in Dulbecco's modified Eagle's medium, but by Day 7, elongated fibroblastlike cells became predominant. Cells did not proliferate in Ham's nutrient mixture-F-12. In a mixture of Ham's nutrient mixture-F-12 and Dulbecco's modified Eagle's medium, cells proliferated, maintaining their morphologic features and their ability to express messenger ribonucleic acids for aggrecan and Types I, II, and III collagen. Hyaluronan enhanced cellular proliferation without altering morphologic features or chondroitin sulfate production. Cultured human meniscus cells attached to a porous collagen sponge after cell seeding. Gene transfer was successful and an introduced gene was expressed by the cells, indicating that human meniscus cells can undergo gene manipulation. The finding that cells collected from small surgical specimens of human meniscus could be cultured, propagated, and seeded onto a collagen scaffold holds promise for the development of a cell-based, tissue engineered collagen meniscus.

Neurally mediated syncope and cardiac beta-adrenergic receptor function

To evaluate the mechanism of neurally mediated syncope (NMS), we investigated basal autonomic nerve function using a conventional pharmacological method and [123I]-metaiodobenzyl-guanidine (MIBG) single photon emission computed tomography (SPECT). Nine patients with NMS, whose syncope was induced by head-up tilt test with or without isoproterenol, underwent [123I]-MIBG SPECT. Eight of nine NMS patients showed reduced myocardial uptake (two patients, diffuse; four patients, anteroseptal and inferior; one patient, anteroseptal; one patient, inferior). In the study of pharmacological autonomic nervous function test, atropine sulfate (atr.) (0.04 mg/kg), isoproterenol (isp.) (5 x 10(-3) microg/kg/min), propranolol (prop.) (0.2 mg/kg), phenylephrine (phenyl.) (0.4 microg/kg/min), and phentolamine (phent.) (0.2 mg/kg) were successively administered to patients with NMS (n = 5) and control subjects (n = 5). The heart rate (HR) after atr. and prop., and systolic blood pressure (SBP) after phent. were defined as intrinsic HR (IHR) and intrinsic SBP (ISBP). Parasympathetic activity (increase in HR by atr.), beta-sympathetic tone (HR after atr. minus IHR), beta-sensitivity (change in HR by 1 microg isp./kg/min), beta-secretion (beta-tone/beta-sensitivity), alpha-sympathetic tone (SBP before phenyl. minus ISBP), alpha-sensitivity (change in SBP by 1 microg phenyl./kg/min) and alpha-secretion (alpha-tone/alpha-sensitivity) were also calculated. The beta-secretion was decreased (0.0027+/-0.0008 versus 0.0060+/-0.0004 microg/kg/min/isp.; p < 0.05), while the beta-sensitivity was increased (5850+/-947 versus 3150+/-292 beats/microg/kg/min isp.; p < 0.05) in NMS compared with control subjects. In the other indexes, there were no significant differences between two groups. The results of the present study suggest that increased beta-sensitivity may contribute hypercontraction of left ventricles, which might partially explain the mechanism of NMS.

Widespread use of TATA elements in the core promoters for RNA polymerases III, II, and I in fission yeast

In addition to directing transcription initiation, core promoters integrate input from distal regulatory elements. Except for rare exceptions, it has been generally found that eukaryotic tRNA and rRNA genes do not contain TATA promoter elements and instead use protein-protein interactions to bring the TATA-binding protein (TBP), to the core promoter. Genomewide analysis revealed TATA elements in the core promoters of tRNA and 5S rRNA (Pol III), U1 to U5 snRNA (Pol II), and 37S rRNA (Pol I) genes in Schizosaccharomyces pombe. Using tRNA-dependent suppression and other in vivo assays, as well as in vitro transcription, we demonstrated an obligatory requirement for upstream TATA elements for tRNA and 5S rRNA expression in S. pombe. The Pol III initiation factor Brf is found in complexes with TFIIIC and Pol III in S. pombe, while TBP is not, consistent with independent recruitment of TBP by TATA. Template commitment assays are consistent with this and confirm that the mechanisms of transcription complex assembly and initiation by Pol III in S. pombe differ substantially from those in other model organisms. The results were extended to large-rRNA synthesis, as mutation of the TATA element in the Pol I promoter also abolishes rRNA expression in fission yeast. A survey of other organisms' genomes reveals that a substantial number of eukaryotes may use widespread TATAs for transcription. These results indicate the presence of TATA-unified transcription systems in contemporary eukaryotes and provide insight into the residual need for TBP by all three Pols in other eukaryotes despite a lack of TATA elements in their promoters.

Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with endoButton femoral fixation: A prospective study

PURPOSE

This prospective study was conducted to compare the single-socket and the bi-socket anterior cruciate ligament (ACL) reconstruction techniques in terms of outcome.

TYPE OF STUDY

Nonrandomized control trial.

METHODS

There were 160 consecutive patients with unilateral chronic ACL insufficiency who underwent endoscopic single- or bi-socket ACL reconstruction alternately using multiple-stranded medial hamstring tendon and EndoButton (Smith & Nephew, Andover, MD) femoral fixation. All patients underwent the same postoperative rehabilitation protocol. Of them, 106 patients (57 single, 49 bi) were available for 2-year follow-up.

RESULTS

According to the IKDC Knee Ligament Evaluation Form, 23 patients (40%) of the single-socket group were subjectively graded as normal, 30 (53%) as nearly normal, and 4 (7%) as abnormal. Twenty-six patients (53%) of the bi-socket group were graded as normal, 21 (43%) as nearly normal, and 2 (4%) as abnormal (P =.19). The mean side-to-side anterior laxity difference (KT-1000 manual maximum force) was 0.9 +/- 1.8 mm for the single-socket group and 0.7 +/- 1.2 mm for the bi-socket group (P =.44). Fifty-three of 57 patients (93%) in the single-socket group and all patients in the bi-socket group showed anterior laxity differences of +/-3 mm or less (P =.12). There were no differences in thigh muscle strength between the groups.

CONCLUSIONS

Both single- and bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton fixation provided satisfactory anterior stability, and there were no statistically significant differences in subjective results or measured restored stability between the 2 groups.