Touchdown of the Hayabusa Spacecraft at the Muses Sea on Itokawa

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

Detailed images of asteroid 25143 Itokawa from Hayabusa

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Cloning and sequence of the gene encoding a cefotaxime-hydrolyzing class A beta-lactamase isolated from Escherichia coli

Escherichia coli TUH12191, which is resistant to piperacillin, cefazolin, cefotiam, ceftizoxime, cefuzonam, and aztreonam but is susceptible to cefoxitin, latamoxef, flomoxef, and imipenem, was isolated from the urine of a patient treated with beta-lactam antibiotics. The beta-lactamase (Toho-1) purified from the bacteria had a pI of 7.8, had a molecular weight of about 29,000, and hydrolyzed beta-lactam antibiotics such as penicillin G, ampicillin, oxacillin, carbenicillin, piperacillin, cephalothin, cefoxitin, cefotaxime, ceftazidime, and aztreonam. Toho-1 was markedly inhibited by beta-lactamase inhibitors such as clavulanic acid and tazobactam. Resistance to beta-lactams, streptomycin, spectinomycin, sulfamethoxazole, and trimethoprim was transferred by conjugational transfer from E. coli TUH12191 to E. coli ML4903, and the transferred plasmid was about 58 kbp, belonging to incompatibility group M. The cefotaxime resistance gene for Toho-1 was subcloned from the 58-kbp plasmid by transformation of E. coli MV1184. The sequence of the gene for Toho-1 was determined, and the open reading frame of the gene consisted of 873 or 876 bases (initial sequence, ATGATG). The nucleotide sequence of the gene (DDBJ accession number D37830) was found to be about 73% homologous to the sequence of the gene encoding a class A beta-lactamase produced by Klebsiella oxytoca E23004. According to the amino acid sequence deduced from the DNA sequence, the precursor consisted of 290 or 291 amino acid residues, which contained amino acid motifs common to class A beta-lactamases (70SXXK, 130SDN, and 234KTG). Toho-1 was about 83% homologous to the beta-lactamase mediated by the chromosome of K. oxytoca D488 and the beta-lactamase mediated by the plasmid of E. coli MEN-1. Therefore, the newly isolated beta-lactamase Toho-1 produced by E. coli TUH12191 is similar to beta-lactamases produced by K. oxytoca D488, K. oxytoca E23004, and E. coli MEN-1 rather than to mutants of TEM or SHV enzymes. Toho-1 has shown the highest degree of similarity to K. oxytoca class A beta-lactamase. Detailed comparison of Toho-1 with other beta-lactamases implied that replacement of Asn-276 by Arg with the concomitant substitution of Thr for Arg-244 is an important mutation in the extension of the substrate specificity.

A four-disulphide-bridged toxin, with high affinity towards voltage-gated K+ channels, isolated from Heterometrus spinnifer (Scorpionidae) venom

A new toxin, named HsTX1, has been identified in the venom of Heterometrus spinnifer (Scorpionidae), on the basis of its ability to block the rat Kv1.3 channels expressed in Xenopus oocytes. HsTX1 has been purified and characterized as a 34-residue peptide reticulated by four disulphide bridges. HsTX1 shares 53% and 59% sequence identity with Pandinus imperator toxin1 (Pi1) and maurotoxin, two recently isolated four-disulphide-bridged toxins, whereas it is only 32-47% identical with the other scorpion K+ channel toxins, reticulated by three disulphide bridges. The amidated and carboxylated forms of HsTX1 were synthesized chemically, and identity between the natural and the synthetic amidated peptides was proved by mass spectrometry, co-elution on C18 HPLC and blocking activity on the rat Kv1.3 channels. The disulphide bridge pattern was studied by (1) limited reduction-alkylation at acidic pH and (2) enzymic cleavage on an immobilized trypsin cartridge, both followed by mass and sequence analyses. Three of the disulphide bonds are connected as in the three-disulphide-bridged scorpion toxins, and the two extra half-cystine residues of HsTX1 are cross-linked, as in Pi1. These results, together with those of CD analysis, suggest that HsTX1 probably adopts the same general folding as all scorpion K+ channel toxins. HsTX1 is a potent inhibitor of the rat Kv1.3 channels (IC50 approx. 12 pM). HsTX1 does not compete with 125I-apamin for binding to its receptor site on rat brain synaptosomal membranes, but competes efficiently with 125I-kaliotoxin for binding to the voltage-gated K+ channels on the same preparation (IC50 approx. 1 pM).

Amino-terminal region of secreted form of amyloid precursor protein stimulates proliferation of neural stem cells

Beta-amyloid precursor protein (APP) has been reported to be expressed in the CNS from the early stages of development. However, the functional role of APP during early development remains unclear. In the present study, we found that the secreted form of APP (sAPP) significantly enhanced proliferation of neural stem cells. Cells were prepared from 13-day embryonic rat neocortex, which was dissected with a Pasteur pipette to make cell clusters. After 12 h of cultivation in the medium without serum, cells around the centre of the cluster were still nestin-positive proliferative cells, i.e. neural stem cells. To determine whether the proliferation of cells was regulated by sAPP, cultures were treated with recombinant sAPP695, the secreted form of human APP695 produced by yeast. Both DNA synthesis and expression of proliferating cell nuclear antigen markedly increased after 5 h of sAPP695 addition. The enhancement of DNA synthesis by sAPP695 stimulation was blocked by the 22C11 monoclonal antibody specific for the amino-terminal region of sAPP. Then, we examined the effect of the amino-terminal fragment of sAPP and the epitope peptide of 22C11 antibody, and found that both of them also promoted DNA synthesis, suggesting that the amino-terminal region of sAPP is responsible for the biological activity. Our findings indicate the possibility that sAPP enhances proliferation of neural stem cells in vivo and plays an important role during the early CNS development.

Penetration of macrolides into human polymorphonuclear leucocytes

Five 14C-labelled macrolide antibiotics (erythromycin, josamycin, clarithromycin (TE-031), rokitamycin and roxithromycin) were studied for their transport into human polymorphonuclear leucocytes. Intracellular/extracellular concentration ratios (transport ratios) of these macrolides were quite high: erythromycin, 6.6; josamycin, 15.5; clarithromycin, 16.4; rokitamycin, 30.5; and roxithromycin, 21.9. When polymorphonuclear leucocytes were pre-treated with formaldehyde or incubated at 4 degrees C, or at low pH, transport ratios were reduced. When extracellular macrolide was removed, intracellular macrolide concentrations became as low as 30% of the pre-wash concentrations in 5 min. KF lowered the transport ratios of josamycin and rokitamycin in particular and NaCN reduced the transport ratios of erythromycin and josamycin strikingly. Ouabain slightly lowered transport ratios of all the antibiotics tested except roxithromycin, and 2, 4-dinitrophenol decreased the transport ratio of clarithromycin markedly. The addition of various amino acids or hexose did not inhibit the transfer. Adenosine, however, inhibited the transfer of these antibiotics except erythromycin and lowered transport ratios by 83 to 92%. Puromycin reduced transport ratios of the same antibiotics by 59 to 95%. With polymorphonuclear leucocytes that had phagocytosed Legionella pneumophila serogroup 1, transport ratios of all five drugs tended to decrease. However, when Staphylococcus aureus ATCC 25923 or opsonized zymosan was phagocytosed, transport ratios for macrolides, except for roxithromycin, increased.

Bootstrap approach for constructing confidence intervals for population pharmacokinetic parameters. I: A use of bootstrap standard error

In population pharmacokinetic studies, one of the main objectives is to estimate population pharmacokinetic parameters specifying the population distributions of pharmacokinetic parameters. Confidence intervals for population pharmacokinetic parameters are generally estimated by assuming the asymptotic normality, which is a large-sample property, that is, a property which holds for the cases where sample sizes are large enough. In actual clinical trials, however, sample sizes are limited and not so large in general. Likelihood functions in population pharmacokinetic modelling include a multiple integral and are quite complicated. We hence suspect that the sample sizes of actual trials are often not large enough for assuming the asymptotic normality and that the asymptotic confidence intervals underestimate the uncertainties of the estimates of population pharmacokinetic parameters. As an alternative to the asymptotic normality approach, we can employ a bootstrap approach. This paper proposes a bootstrap standard error approach for constructing confidence intervals for population pharmacokinetic parameters. Comparisons between the asymptotic and bootstrap confidence intervals are made through applications to a simulated data set and an actual phase I trial.

Molecular cloning and characterization of a new insulin/IGF-like peptide of the nematode Caenorhabditis elegans

Diapause, aging, and fat accumulation in Caenorhabditis elegans are regulated by DAF-2, a homolog of mammalian insulin/insulin-like growth factor-I (IGF-I) receptors. We have cloned and characterized a C. elegans gene encoding a new insulin/IGF-like peptide. The gene containing three exons encodes a precursor protein 95 residue long. Although the putative precursor contains a signal peptide, B chain, C peptide, and A chain like the preproinsulin, the mature peptide consists of one polypeptide-like IGF. The predicted tertiary structure seems similar to crystal structure of insulin. Therefore, the peptide may be a hybrid molecule of insulin and IGF. The peptide expression was detected at the embryonic and several larval stages. Disruption of the peptide production led to an extended life span like the daf-2 mutation, suggesting that the peptide should be one of the ligands of the DAF-2. This is the first description of the peptide that mediates animal longevity.

Pathogenesis of hyponatremia following subarachnoid hemorrhage due to ruptured cerebral aneurysm

BACKGROUND

Hyponatremia following subarachnoid hemorrhage (SAH) occurs due to the inappropriate secretion of antidiuretic hormone (SIADH). However, this condition is also sometimes associated with certain dehydration states.

METHODS

To clarify the pathogenesis, daily values of urine volume, water balance, and sodium balance (Na Bal) were correlated with plasma levels of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), and plasma renin activity (PRA) in 31 cases of SAH.

RESULTS

Na Bal was markedly negative on days 2 and 3. Cumulative Na Bal showed continuous negative values until day 10 following SAH. ANP values showed a consistent elevation, while ADH showed only an initial surge. PRA, as the gross indicator of circulatory volume, showed a lack of suppression, indicating no increase in the circulatory volume.

CONCLUSION

Hyponatremia following SAH therefore appears to be the result of increased natriuresis, due to the inappropriate elevation of ANP rather than SIADH. In this situation, water restriction should not be recommended, since the circulatory volume is decreased.

Purification, characterization, and synthesis of three novel toxins from the Chinese scorpion Buthus martensi, which act on K+ channels

Three novel toxins belonging to the scorpion K+ channel-inhibitor family were purified to homogeneity from the venom of the Chinese scorpion Buthus martensi. They have been identified according to their molecular mass (3800-4300 Da) and their neurotoxicity in mice and characterized as 37-amino acid peptides. One of them shows 81-87% sequence identity with members of the kaliotoxin group (named BmKTX), whereas the other two, named BmTX1 and BmTX2, show 65-70% identity with toxins of the charybdotoxin group. Their chemical synthesis by the Fmoc methodology allowed us to show that BmKTX, unlike BmTX1 and BmTX2, possesses an amidated C-terminal extremity. Toxicity assays in vivo established that they are lethal neurotoxic agents in mice (LD50s of 40-95 ng per mouse). Those toxins proved to be potent inhibitors of the voltage-gated K+ channels, as they were able to compete with [125I]kaliotoxin for its binding to rat brain synaptosomes (IC50s of 0.05-1 nM) and to block the cloned voltage-gated K+ channel Kv1.3 from rat brain, expressed in Xenopus oocytes (IC50s of 0.6-1.6 nM). BmTX1 and BmTX2 were also shown to compete with [125I]charybdotoxin for its binding to the high-conductance Ca2+-activated K+ channels present on bovine aorta sarcolemmal membranes (IC50s of 0.3-0.6 nM). These new sequences show multipoint mutations when compared to the other related scorpion K+ channel toxins and should prove to be useful probes for studying the diverse family of K+ channels.

S-1 as adjuvant chemotherapy for stage III colon cancer: a randomized phase III study (ACTS-CC trial)

BACKGROUND

S-1 is an oral fluoropyrimidine whose antitumor effects have been demonstrated in treating various gastrointestinal cancers, including metastatic colon cancer, when administered as monotherapy or in combination chemotherapy. We conducted a randomized phase III study investigating the efficacy of S-1 as adjuvant chemotherapy for colon cancer by evaluating its noninferiority to tegafur-uracil plus leucovorin (UFT/LV).

PATIENTS AND METHODS

Patients aged 20-80 years with curatively resected stage III colon cancer were randomly assigned to receive S-1 (80-120 mg/day on days 1-28 every 42 days; four courses) or UFT/LV (UFT: 300-600 mg/day and LV: 75 mg/day on days 1-28 every 35 days; five courses). The primary end point was disease-free survival (DFS) at 3 years.

RESULTS

A total of 1518 patients (758 and 760 in the S-1 and UFT/LV group, respectively) were included in the full analysis set. The 3-year DFS rate was 75.5% and 72.5% in the S-1 and UFT/LV group, respectively. The stratified hazard ratio for DFS in the S-1 group compared with the UFT/LV group was 0.85 (95% confidence interval: 0.70-1.03), demonstrating the noninferiority of S-1 (noninferiority stratified log-rank test, P < 0.001). In the subgroup analysis, no significant interactions were identified between the major baseline characteristics and the treatment groups.

CONCLUSION

Adjuvant chemotherapy using S-1 for stage III colon cancer was confirmed to be noninferior in DFS compared with UFT/LV. S-1 could be a new treatment option as adjuvant chemotherapy for colon cancer.

CLINICALTRIALSGOV

NCT00660894.

A new antibiotic CJ-17,665 from Aspergillus ochraceus

A new antibiotic, CJ-17,665 (I) was isolated from the fermentation broth of Aspergillus ochraceus, CL41582. It inhibits growth of multi-drug resistant Staphylococcus aureus, Streptococcus pyogenes, and Enterococcus faecalis, with MICs of 12.5, 12.5 and 25 microg/ml, respectively. The structure contains a diketopiperazine and an indole N-oxide moiety that is unusual in natural products.

Cloning and sequencing of the gene encoding Toho-2, a class A beta-lactamase preferentially inhibited by tazobactam

Escherichia coli TUM1083, which is resistant to ampicillin, carbenicillin, cephaloridine, cephalothin, piperacillin, cefuzonam, and aztreonam while being sensitive to cefoxitin, moxalactam, cefmetazole, ceftazidime, and imipenem, was isolated from the urine of a patient treated with beta-lactam antibiotics. The beta-lactamase (Toho-2) purified from the bacteria hydrolyzed beta-lactam antibiotics such as penicillin G, carbenicillin, cephaloridine, cefoxitin, cefotaxime, ceftazidime, and aztreonam and especially had increased relative hydrolysis rates for cephalothin, cephaloridine, cefotaxime, and ceftizoxime. Different from other extended-spectrum beta-lactamases, Toho-2 was inhibited 16-fold better by the beta-lactamase inhibitor tazobactam than by clavulanic acid. Resistance to beta-lactams was transferred by conjugation from E. coli TUM1083 to E. coli ML4909, and the transferred plasmid was about 54.4 kbp, belonging to the incompatibility group IncFII. The cefotaxime resistance gene for Toho-2 was subcloned from the 54.4-kbp plasmid. The sequence of the gene was determined, and the open reading frame of the gene was found to consist of 981 bases. The nucleotide sequence of the gene (DDBJ accession no. D89862) designated as bla(toho) was found to have 76.3% identity to class A beta-lactamase CTX-M-2 and 76.2% identity to Toho-1. It has 55.9% identity to SHV-1 beta-lactamase and 47.5% identity to TEM-1 beta-lactamase. Therefore, the newly isolated beta-lactamase designated as Toho-2 produced by E. coli TUM1083 is categorized as an enzyme similar to Toho-1 group beta-lactamases rather than to mutants of TEM or SHV enzymes. According to the amino acid sequence deduced from the DNA sequence, the precursor consisted of 327 amino acid residues. Comparison of Toho-2 with other beta-lactamase (non-Toho-1 group) suggests that the substitutions of threonine for Arg-244 and arginine for Asn-276 are important for the extension of the substrate specificity.

Crystal structure of the E166A mutant of extended-spectrum beta-lactamase Toho-1 at 1.8 A resolution

Bacterial resistance to beta-lactams is mainly due to the production of beta-lactamase. Especially through the production of extended-spectrum beta-lactamases (ESBLs), bacteria have acquired resistance not only to penicillins, but also to expanded-spectrum cephems. Here, we describe the crystal structure of the E166A mutant of class A beta-lactamase Toho-1 at 1.8 A resolution, the first reported tertiary structure of an ESBL. Instead of the wild-type enzyme, a mutant Toho-1, in which Glu166 was replaced with alanine, was used for this study, because of the strong tendency of the wild-type enzyme to form twinned crystals. The overall structure of Toho-1 is similar to the crystal structures of non-ESBLs, with no pronounced backbone rearrangement of the framework. However, there are some notable local changes. First, a difference in the disposition of an arginine residue, which is at position 244 in non-ESBLs but at position 276 in Toho-1 and other ESBLs, was revealed and the role of this arginine residue is discussed. Moreover, changes in the hydrogen-bonding pattern and in the formation of the hydrophobic core were also observed near the Omega loop. In particular, the lack of hydrogen bonds in the vicinity of the Omega loop could be a cause of the extended substrate specificity of Toho-1. Through the generation of a model for the enzyme-substrate complex, a conformational change of Toho-1 occurring on complex formation is discussed based on the active-site cleft structure and the substrate profile.

Involvement of amyloid precursor protein in functional synapse formation in cultured hippocampal neurons

Amyloid precursor protein (APP) is known to be widely expressed in neuronal cells, and enriched in the central and peripheral synaptic sites. Although it has been proposed that APP functions in synaptogenesis, no direct evidence has yet been reported. In this study we investigated the involvement of APP in functional synapse formation by monitoring spontaneous oscillations of intracellular Ca2+ concentration ([Ca2+]i) in cultured hippocampal neurons. As more and more neurons form synapses with each other during the culture period, increasing numbers of neuronal cells show synchronized spontaneous oscillations of [Ca2+]i. The number of neurons that showed synchronized spontaneous oscillations of [Ca2+]i was significantly lower when cultured in the presence of monoclonal antibody 22C11 against the N-terminal portion of APP. Moreover, incubation with excess amounts of the secretory form of APP or the N-terminal fragment of APP also inhibited the increase in number of neurons with synchronized spontaneous oscillations of [Ca2+]i. The addition of monoclonal antibody 22C11 or secretory form of APP did not, however, affect MAP-2-positive neurite outgrowth. These findings suggest that APP play a role in functional synapse formation during CNS development.

Synovial sarcoma of the prostate with t(X;18)(p11.2;q11.2)

A case of monophasic synovial sarcoma of the prostate in a 37-year-old man is reported. Histologically, the tumor was chiefly composed of uniform spindle and oval cells, which often formed interlacing fascicles resembling those of fibrosarcoma. In some areas, the compact fascicles of tumor cells alternated with hypocellular myxoid tissue bearing a superficial resemblance to peripheral nerve sheath tumors, whereas small portions of the tumor showed a pericytomatous pattern consisting of polygonal cells arranged around dilated, thin-walled blood vessels. By immunohistochemistry, vimentin was detected in most cells, and a focal reactivity for epithelial membrane antigen was also observed. The tumor cells, however, were negative for keratin, S-100 protein, neuron-specific enolase, CD34, desmin, muscle-specific actin, and alpha-smooth muscle actin. Cytogenetic analysis and fluorescence in situ hybridization (FISH) using the cultured tumor cells demonstrated a translocation t(X;18)(p11.2;q11.2), an aberration specific for synovial sarcoma. To the authors' knowledge, this is the first report of a primary prostatic synovial sarcoma confirmed by cytogenetic analysis.

A single amino acid substitution converts cytochrome P450(14DM) to an inactive form, cytochrome P450SG1: complete primary structures deduced from cloned DNAS

Genes for lanosterol 14-demethylase, cytochrome P450(14DM), and a mutated inactive cytochrome P450SG1 were cloned from S. cerevisiae strains D587 and SG1, respectively. A single nucleotide change resulting in substitution of Asp for Gly-310 of cytochrome P450(14DM) was found to have occurred in cytochrome P450SG1. In this protein the 6th ligand to heme iron is a histidine residue instead of a water molecule, which may be the ligand for the active cytochrome P450(14DM). Molecular models of the active sites of the cytochrome P450(14DM) and cytochrome P450SG1 were built by computer modeling on the basis of the known structure of that of cytochrome P450CAM whose crystallographic data are available. The mechanisms which may cause a histidine residue to gain access to the heme iron are discussed.

Characteristics of aneurysms arising from the horizontal portion of the anterior cerebral artery

BACKGROUND

Aneurysms arising from the proximal portion of the anterior cerebral artery (A1: horizontal portion) are quite rare and are considered to be unique, because they are usually connected with other vascular anomalies and are sometimes part of a multiple aneurysm occurrence. A1 aneurysm cases experienced over the past seven and a half years are summarized in this paper.

METHODS

A total of 413 patients were surgically treated including 142 patients with subarachnoid hemorrhage (SAH); the remaining 271 patients had unruptured aneurysms. Among them, nine cases were categorized as constituent A1 aneurysms, three with SAH and six with unruptured aneurysms.

RESULTS

The shape of the aneurysm was saccular in all nine cases. Three of the nine cases had associated vascular malformations. The average aneurysm diameter in the three cases with SAH was 4.0 mm, which is smaller than other common aneurysms presenting with SAH. Eight aneurysms developed at the takeoff point of perforating arteries-the medial lenticulostriate artery in five cases and the recurrent artery of Heubner in three cases. In the remaining case, the aneurysm originated from the proximal end of the associated A1 fenestration. All nine patients had an excellent outcome after surgery.

CONCLUSION

A1 aneurysms require surgical elimination even if they are small. We emphasize the importance of preserving the blood flow of these perforating arteries by avoiding compression with either the clip blade or the clip body itself.

A broad-spectrum matrix metalloproteinase inhibitor prevents hemorrhagic complications induced by tissue plasminogen activator in mice

Delayed activation of tissue plasminogen activator (tPA) can lead to the disruption of the blood-brain barrier (BBB), resulting in hemorrhagic complications. In the present study, we focused on tight junction proteins (TJPs), occludin, zona occludens (ZO)-1, and claudin-5, which are important structural components of the BBB, and investigated whether inhibition of matrix metalloproteinases (MMPs) provides a protective effect against hemorrhagic complications induced by tPA. We subjected mice to 6-h filamental middle cerebral artery occlusion (MCAO) with vehicle, delayed tPA alone, or combined tPA (10 mg/kg, i.v.) plus GM6001 (100 mg/kg, i.p.), a broad-spectrum MMP inhibitor. We evaluated brain hemoglobin and the expression of MMP-9 and TJPs by immunoblotting. GM6001 significantly reduced tPA-elevated brain hemoglobin, MMP-9, and inhibited the degradation of occludin and ZO-1 induced by tPA, but not claudin-5. Treatment with GM6001 also significantly prevented the decrease in the survival rate and the reduction in locomotor activity caused by tPA at 7 days after ischemia/reperfusion. Furthermore, GM6001 treatment also significantly prevented cell damage, determined by release of lactase dehydrogenase (LDH) activity, and the decrease in transendothelial electrical resistance (TEER) induced by tPA. These findings indicate that GM6001 prevented the hemorrhagic complications and improved the behavioral abnormalities induced by tPA, partly via protection of TJPs. This suggests that GM6001 may be a useful candidate for combination therapy against the hemorrhagic complications induced by tPA.

Cloning of cDNA encoding for a novel isozyme of fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase from human placenta

Two independent cDNA clones encoding fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase were isolated from a human placental cDNA library. The deduced amino acid sequences showed that one of the clones, 2K-1, was almost identical to the rat testis isozyme and the other, 2K-3, was different from any known isozymes expressed in mammalian tissues. The results of Southern blot analysis suggested that clones 2K-1 and 2K-3 were encoded as single copy genes and located in different parts of the genome. Since open reading frames of the cDNA clones were not complete, we obtained the 5'-end of the clone 2K-3 cDNA using the 5'-rapid amplification of cDNA end method. The entire cDNA (HP; 1,756 bp) had a coding capacity of 519 amino acids (M(r) = 59,410), and putative phosphorylation sites for protein kinases A and C on the C terminus. Northern blot analysis using a fragment of the HP as a probe showed that a major band of 5.4 kb, significantly different in size from known isozyme mRNAs such as liver (2.1 kb), muscle (1.9 kb), heart (4.0 kb), and testis (2.0 kb), was present in poly(A)+RNA preparations of human first trimester and term placentae. These results strongly suggested that this 5.4 kb mRNA codes a novel isozyme of fructose 6-phosphate,2-kinase/fructose 2,6-bisphosphatase.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

Two cell lines established from mixed müllerian tumors of the uterus. Morphologic, immunocytochemical, and cytogenetic analyses

To clarify the cellular origin and characteristics of malignant mixed müllerian tumor (MMMT), the authors investigated two cell lines (designated as FU-MMT-1 and FU-MMT-2) established from two patients with heterologous MMMT of the uterus. Both cell lines propagated continuously for 83 and 55 serial passages over 1.5 years, respectively. Morphologically, FU-MMT-2 was a mixture of carcinoma cells and sarcoma cells with predominance of carcinoma cells; FU-MMT-1 only had a sarcomatous element with distinct rhabdomyoblastic differentiation. Immunocytochemically, the sarcoma cells of each cell line expressed, not only myogenic and mesenchymal antigens (desmin, myoglobin, and vimentin), but also epithelial antigens, including epithelial membrane antigen and keratin. The carcinoma cells in FU-MMT-2 were positive for the epithelial antigens and vimentin and negative for desmin and myoglobin. Both lines had abnormal karyotypes; the modal chromosome numbers of FU-MMT-1 and FU-MMT-2 were 47 and 80, respectively. In addition, FU-MMT-1 had trisomy 8, and FU-MMT-2 had complex structural abnormalities. When transplanted into nude mice, FU-MMT-1 reproduced and maintained the characteristics of the original tumor. These cell lines and xenografts appear to provide a useful system for studying the biologic behavior, cytogenetic features, and histogenesis of MMMT. In conclusion, the presence of epithelial antigens in the sarcomatous and carcinomatous elements seemed to support the hypothesis that both elements are derived from a common stem cell.