Mechanism of hypergammaglobulinemia by HIV infection: circulating memory B-cell reduction with plasmacytosis

The mechanism of hypergammaglobulinemia in patients infected with HIV has remained unclear in spite of the identification of a reduction of CD4+ T cells. The amounts of CD27+ memory B cells were remarkably reduced in the peripheral blood and immunoglobulin (Ig) production was diminished in HIV-infected patients. Some of the freshly isolated patients' T cells expressed the CD70 (CD27 ligand) on the surface and the CD70 expression on both of the CD4+ and CD8+ T cells was greatly enhanced by various stimuli. It was also striking that plasmacytosis was observed in patients' bone marrow. Thus, our findings suggest that CD70 expressed spontaneously or by activation on T cells of HIV-infected patients stimulates memory B cells via CD27 and promotes their differentiation into plasma cells, resulting in the elevation of serum Ig levels and the elimination of circulating memory B cells in HIV-infected patients.

Crystal structure of a novel-type archaeal rubisco with pentagonal symmetry

BACKGROUND

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the key enzyme of the Calvin-Benson cycle and catalyzes the primary reaction of CO2 fixation in plants, algae, and bacteria. Rubiscos have been so far classified into two types. Type I is composed of eight large subunits (L subunits) and eight small subunits (S subunits) with tetragonal symmetry (L8S8), but type II is usually composed only of two L subunits (L2). Recently, some genuinely active Rubiscos of unknown physiological function have been reported from archaea.

RESULTS

The crystal structure of Rubisco from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 (Tk-Rubisco) was determined at 2.8 A resolution. The enzyme is composed only of L subunits and showed a novel (L2)5 decameric structure. Compared to previously known type I enzymes, each L2 dimer is inclined approximately 16 degrees to form a toroid-shaped decamer with its unique L2-L2 interfaces. Differential scanning calorimetry (DSC), circular dichroism (CD), and gel permeation chromatography (GPC) showed that Tk-Rubisco maintains its secondary structure and decameric assembly even at high temperatures.

CONCLUSIONS

The present study provides the first structure of an archaeal Rubisco, an unprecedented (L2)5 decamer. Biochemical studies indicate that Tk-Rubisco maintains its decameric structure at high temperatures. The structure is distinct from type I and type II Rubiscos and strongly supports that Tk-Rubisco should be classified as a novel type III Rubisco.

4'-Ethynyl nucleoside analogs: potent inhibitors of multidrug-resistant human immunodeficiency virus variants in vitro

A series of 4'-ethynyl (4'-E) nucleoside analogs were designed, synthesized, and identified as being active against a wide spectrum of human immunodeficiency viruses (HIV), including a variety of laboratory strains of HIV-1, HIV-2, and primary clinical HIV-1 isolates. Among such analogs examined, 4'-E-2'-deoxycytidine (4'-E-dC), 4'-E-2'-deoxyadenosine (4'-E-dA), 4'-E-2'-deoxyribofuranosyl-2,6-diaminopurine, and 4'-E-2'-deoxyguanosine were the most potent and blocked HIV-1 replication with 50% effective concentrations ranging from 0.0003 to 0.01 microM in vitro with favorable cellular toxicity profiles (selectivity indices ranging 458 to 2,600). These 4'-E analogs also suppressed replication of various drug-resistant HIV-1 clones, including HIV-1(M41L/T215Y), HIV-1(K65R), HIV-1(L74V), HIV-1(M41L/T69S-S-G/T215Y), and HIV-1(A62V/V75I/F77L/F116Y/Q151M). Moreover, these analogs inhibited the replication of multidrug-resistant clinical HIV-1 strains carrying a variety of drug resistance-related amino acid substitutions isolated from HIV-1-infected individuals for whom 10 or 11 different anti-HIV-1 agents had failed. The 4'-E analogs also blocked the replication of a non-nucleoside reverse transcriptase inhibitor-resistant clone, HIV-1(Y181C), and showed an HIV-1 inhibition profile similar to that of zidovudine in time-of-drug-addition assays. The antiviral activity of 4'-E-thymidine and 4'-E-dC was blocked by the addition of thymidine and 2'-deoxycytidine, respectively, while that of 4'-E-dA was not affected by 2'-deoxyadenosine, similar to the antiviral activity reversion feature of 2',3'-dideoxynucleosides, strongly suggesting that 4'-E analogs belong to the family of nucleoside reverse transcriptase inhibitors. Further development of 4'-E analogs as potential therapeutics for infection with multidrug-resistant HIV-1 is warranted.

A possible functional organization of the corticostriatal input within the weakly-correlated striatal activity: a modeling study

Recently, it was reported in an in vivo study that pairs of the striatal projection neurons (medium-sized spiny neurons) of the basal ganglia show asynchronous spiking within weakly-correlated subthreshold depolarized states. In this computational study, we investigate a possible functional organization of corticostriatal inputs that accounts for the experimental observations within known anatomical and physiological constraints. In a pair of medium-sized spiny neurons, a small fraction of corticostriatal fibers is common to both neurons. To explain the weak correlations in sub- and supra-threshold activities of the neuron pair, we postulate that the two input channels, common or specific to the individual neurons, have distinct functional roles. The common input channel delivers random spike trains and is primarily responsible for the initiation and maintenance of the depolarized states. In contrast, the input through the neuron-specific channels elicit postsynaptic spikes by delivering intermittently-synchronized spikes. The results of this model were compared with those derived from a newly-performed analysis of the previous double-intracellular recording data. We show that the behavior of this model agrees qualitatively and quantitatively with that of the medium-sized spiny neurons observed in the experiments in a certain range of the coincident time window.

[Pressure wire guide provisional coronary stent implantation]

OBJECTIVES

Whether coronary artery lesion successfully dilated by balloon angioplasty should be stented or not is unclear. The purpose of this study is to evaluate the provisional stent implantation method assessing residual ischemia by pressure wire.

METHODS

Thirty-one patients with de-novo lesions suitable for stenting were enrolled in a pressure wire guided provisional stent study. The pressure wire was used to assess the fractional flow reserve(FFR) before and after balloon angioplasty. When the FFR after angioplasty was less than 0.75, stent implantation was planned. Patients with lesions consisting of an intermediate stenosis proximal to the target lesion, chronic total occlusion, bypass graft and left main lesion were excluded from the study. Stent implantation was permitted even if the FFR was more than 0.75 when the operator thought stenting was necessary. Medical treatment was given with aspirin 162 mg/day, cilostazol 200 mg/day for 6 months and additional ticlopidine 200 mg/day for a month after stenting the lesion.

RESULTS

Target vessel was the left anterior descending coronary artery in 19 lesions, the right coronary artery in 3, and the circumflex coronary artery in 9. Stent implantation was performed in seven (23%) of 31 lesions and the other 24(77%) lesions were treated with only balloon angioplasty. The FFR before intervention was 0.58 +/- 0.16, and improved to 0.87 +/- 0.07 (p < 0.0001). Percentage diameter stenosis before intervention was 70.7 +/- 12.6% and improved to 20.1 +/- 13.3% (p < 0.0001) after intervention. There was no major cardiac event (death, coronary artery bypass grafting, myocardial infarction, stent thrombosis). Six months follow-up angiography was performed in 27 patients (87%). Angiographic restenosis (percentage diameter stenosis > or = 50%) was found in four patients (15%). A new lesion was found in two patients. Target vessel revascularization was performed in six patients (21%).

CONCLUSIONS

Lesions successfully dilated by balloon angioplasty with FFR > or = 0.75 do not require stenting.

An increase in circulating mast cell colony-forming cells in asthma

We compared a potential to generate mast cells among various sources of CD34(+) peripheral blood (PB) cells in the presence of stem cell factor (SCF) with or without thrombopoietin (TPO), using a serum-deprived liquid culture system. From the time course of relative numbers of tryptase-positive and chymase-positive cells in the cultured cells grown by CD34(+) PB cells of nonasthmatic healthy individuals treated with G-CSF, TPO appears to potentiate the SCF-dependent growth of mast cells without influencing the differentiation into mast cell lineage. CD34(+) PB cells from asthmatic patients in a stable condition generated significantly more mast cells under stimulation with SCF alone or SCF+TPO at 6 wk of culture than did steady-state CD34(+) PB cells of normal controls. Single-cell culture studies showed a substantial difference in the number of SCF-responsive or SCF+TPO-responsive mast cell progenitors in CD34(+) PB cells between the two groups. In the presence of TPO, CD34(+) PB cells from asthmatic children could respond to a suboptimal concentration of SCF to a greater extent, compared with the values obtained by those of normal controls. Six-week cultured mast cells of asthmatic subjects had maturation properties (intracellular histamine content and tryptase/chymase enzymatic activities) similar to those derived from mobilized CD34(+) PB cells of nonasthmatic subjects. An increase in a potential of circulating hemopoietic progenitors to differentiate into mast cell lineage may contribute to the recruitment of mast cells toward sites of asthmatic mucosal inflammation.

Induction of polyploidization by jaspamide in HL-60 cells

Jaspamide, a natural peptide isolated from the marine sponge Hemiastrella minor, was used in the study of polyploidy in HL-60 cells. Jaspamide at 5 x 10(-8) M concentration exhibited antiproliferative activity and an increased CD4 and CD14 surface expression. After 2 days of cultivation, 56.3% of the exposed cells became multinuclear compared with 2.4% in controls. Moreover, the size and the number of nuclei of the cells increased in a time-dependent manner. An increased number of metaphase chromosomes was observed by microscopical enumeration after colcemid treatment for 60 min. The analysis of the DNA content of these cells, measured by propidium iodide staining, revealed a significant increase in the cells percentage with increased DNA content. Taken together, these findings indicate that the jaspamide treatment induces polyploidization in the HL-60 cell line.

Distribution of bone mineral density in the proximal tibia in mid-teens

The distribution of bone mineral density (BMD) in the proximal tibia was studied in 94 knees from 47 mid-teens. The subjects were healthy high school freshmen (19 male; 28 female) who engaged in daily physical exercise. We measured BMD at six regions of interest (ROI) at the bilateral proximal tibia (three immediately above and three immediately be-low the physeal line) using dual-energy X-ray absorptiometry (QDR-2000; Hologic, Waltham, MA, USA). Subjects were supine during the measurements, with the knee extended and the foot fixed in a special holding device, ensuring correct rotational alignment of the knee. Measurements were performed using the forearm array scan mode. The precision of this method (coefficient of variation) was 1.1%-4.9% (mean 2.5%) for six ROIs. The BMD of the medial side was higher than that of the lateral side, and the BMD at the center of the metaphysis was higher than that of the epiphysis. The subjects in the present study did not show any misalignment of the knee joints. These findings indicate that the medial side of the proximal tibia already has higher BMD than the lateral side in teenagers with normal alignment of the knee joint, and that the increase in epiphyseal BMD may be slower than that of metaphyseal BMD. It is suggested that this phenomenon should be life-long and may play a role in the progression of osteoarthritis of the knee.

Fibrinogen Matsumoto V: a variant with Aalpha19 Arg-->Gly (AGG-->GGG). Comparison between fibrin polymerization stimulated by thrombin or reptilase and fibrin monomer polymerization

Fibrinogen Matsumoto V (M-V) is a dysfibrinogen identified in a 52-year-old woman with systemic lupus erythematous. The triplet AGG encoding the amino acid residue Aalpha19 was replaced by GGG, resulting in the substitution of Arg-->Gly. Residue Aalpha19 has been shown to be one of the most important amino acids in the so-called 'A' site or alpha-chain knob. The thrombin-catalyzed release of fibrinopeptide A from M-V fibrinogen was only slightly delayed yet release of fibrinopeptide B was significantly delayed. Both thrombin-catalyzed fibrin polymerization and fibrin monomer polymerization were markedly impaired compared to normal fibrinogen. In addition, reptilase-catalyzed fibrin polymerization of M-V was much more impaired than thrombin-catalyzed fibrin polymerization. These results indicate 'B' and/or 'b' site of M-V fibrinogen play a more important role in thrombin-catalyzed fibrin polymerization than that of normal control fibrinogen.

Duodenal somatostatinoma and erythrocytosis in a patient with von Hippel-Lindau disease type 2A

A female with von Hippel-Lindau (VHL) disease type 2A first presented with erythrocytosis at the age of 9 years. This patient revealed multiple paragangliomas at age 22. After the removal of tumors, a retinal hemangioblastoma developed. Our diagnosis of VHL disease type 2A was confirmed. Moreover, systemic examination showed a duodenal somatostatinoma. Frequent and long-term monitoring is important for patients with pheochromocytomas or paragangliomas, and a screening for VHL disease and other hereditary cancer syndromes is recommended. Recognition of neuroendocrine tumors as a manifestation of VHL disease permits earlier diagnosis and improves prognosis.

Genetic linkage of Kozak sequence polymorphism of the platelet glycoprotein Ib alpha with human platelet antigen-2 and variable number of tandem repeats polymorphism, and its relationship with coronary artery disease

The -5 C/T polymorphism of platelet glycoprotein (GP) Ib alpha is a major determinant of the level of GP Ib/V/IX complex surface expression. We investigated the frequency of this polymorphism among Asian populations. The gene frequencies of cytosine (C) in this polymorphism were 0.283 and 0.219 in Japanese and Korean populations respectively. The C allele is linked with human platelet antigen (HPA)-2a and smaller types of variable number of tandem repeats (VNTR). A novel allele, C-HPA-2a-D of VNTR, was found. No association was observed between these alleles and coronary artery disease in this case-control study. The clinical relevance of this polymorphism in the thrombotic status remains undetermined.

A 15-year longitudinal follow-up study of heart rate and heart rate variability in healthy elderly persons

BACKGROUND

Few researchers have conducted heart rate (HR) studies in healthy very elderly subjects aged 70 years or older, and there are no longitudinal follow-up studies in this population. The objective of this study was to evaluate long-term changes in HR and heart rate variability (HRV) with aging in healthy elderly persons by means of comparison between two Holter monitor recordings obtained at an interval of 15 years.

METHODS

The study population consisted of 15 healthy elderly persons (10 women and 5 men) aged 64 to 80 years (mean 70 +/- 4.1) at the first recording, and 79 to 95 years old (mean 85 +/- 4.1 years) at the second recording 15 years later. Nighttime (midnight to 5 AM) and daytime (noon to 5 PM) HR and HRV were obtained, and paired t tests were performed to assess the differences in each parameter of nighttime and daytime HR and HRV between the two (15-year interval) Holter monitor recordings.

RESULTS

The results of the t-test comparisons were as follows: there was a significant increase in minimal, maximal, and average HRs (nighttime, p < .01; daytime, p < .05, respectively). On the other hand, with regard to HRV, there was a significant nighttime decrease in the SDNN index (mean of standard deviations of normal RR intervals between adjacent QRS complexes resulting from sinus node depolarizations for all 5-minute segments) (p = .0086), and a significant daytime increase in the NN50 (number of adjacent normal RR intervals >50 milliseconds) per hour (p = .0425). Moreover, there was a significant decrease in the low-frequency (LF) component (nighttime, p = .0151; daytime, p = .0032), and a significant decrease in the LF/HF ratio (nighttime, p = .0270; daytime, p = .0371), but there was no significant change in the nighttime or daytime high-frequency (HF) component.

CONCLUSIONS

HR increased with age over the 15-year period in the healthy elderly persons. As for concurrent changes in HRV, however, the parameters of sympathetic modulation decreased, and the parameters of parasympathetic modulation were unchanged or slightly increased.

Syntheses of 4'-C-ethynyl-beta-D-arabino- and 4'-C-ethynyl-2'-deoxy-beta-D-ribo-pentofuranosylpyrimidines and -purines and evaluation of their anti-HIV activity

4'-C-Ethynyl-beta-D-arabino- and 4'-C-ethynyl-2'-deoxy-beta-D-ribo-pentofuranosylpyrimidine and -purine nucleosides were synthesized and evaluated for their in vitro anti-HIV activity. The key intermediate, 4-C-ethynyl- or 4-C-triethylsilylethynyl-D-ribo-pentofuranose, was prepared from D-glucose and glycosidated with various pyrimidine or purine bases. The arabinopyrimidine derivatives were prepared from the corresponding ribo derivatives via O(2),2'-anhydro nucleosides. The 2'-deoxy-ribo derivatives were synthesized by radical reduction of 2'-bromo or 2'- phenoxythiocarbonyloxy nucleosides. Among these 4'-C-ethynyl nucleosides, seven analogues proved to be potent against HIV-1 in vitro with EC(50) values ranging from 0.0003 to 0. 03 microM. These compounds also exerted activity against clinical and multi-dideoxy-nucleoside-resistant HIV-1 strains with comparable EC(50) values. Three such 4'-C-ethynyl-2'-deoxypurine analogues including 4'-C-ethynyl-2'-deoxyadenosine and 4'-C-ethynyl-2, 6-diamino-2'-deoxypurine were less cytotoxic [selectivity indices (SIs): 975-2733] than three 4'-C-ethynyl-2'-deoxycytidine analogues (SIs: 63-363). 4'-C-Ethynyl-5-fluoro-2'-deoxycytidine was least toxic (SI: >3333) and potent against all HIV strains tested.

Trisomy 10 in acute myeloid leukemia. Three additional cases from the database of the Japan Adult Leukemia Study Group (JALSG) AML-92 and AML-95

To clarify the clinical and hematologic features of a rare numerical chromosome abnormality, we searched for trisomy 10 in acute myelogenous leukemias (AMLs) using the database of the Japan Adult Leukemia Study Group (JALSG) AML 92 and 95. Among the sequentially registered patients of JALSG-AML 92 (655 patients) and JALSG-AML 95 (531 patients), chromosome results were obtained in 1,074 patients (90.6%), and we found 3 patients with trisomy 10 as a sole abnormality. The first patient had an AML-M1 morphology with CD7 antigen; the patient obtained complete remission (CR) with the first course of chemotherapy. The second patient had an AML-M1 morphology without expressing CD7 antigen; this patient obtained CR, but relapsed 3 months later, and underwent allogeneic bone marrow transplantation. He suffered from chronic graft-versus-host disease and expired 38 months after the AML diagnosis. The third patient had AML-M0 with CD7 positivity. He obtained CR; however, brain abscess and cerebral hemorrhage occurred. In the literature, the mean age of patients with trisomy 10 AML is 57.8 years, the gender ratio is M/F = 1.5, and the frequency of M0/M1/M2 is 85.7%. A high incidence (81. 8%) of CD7 expression of leukemia cells is notable. About 73% of patients survived for greater than 12 months.

Synthesis and biological activities of 2'-deoxy-2'-fluoro-4'-thioarabinofuranosylpyrimidine and -purine nucleosides

As part of our ongoing investigation of the synthesis of biologically interesting 2'-modified-4'-thionucleosides, we synthesized 2'-deoxy-2'-fluoro-4'-thioarabinofuranosylpyrimidine and -purine nucleosides, and evaluated their antiviral and antitumor activities. In the pyrimidine series, beta-anomers of 5-ethyluracil, 5-iodouracil, 5-chloroethyluracil, and 5-iodocytosine derivatives showed potent and selective anti-HSV-1 and HSV-2 activities in vitro. In the purine series, guanine and 2,6-diaminopurine derivatives showed prominent antiviral activities with slight cytotoxicity. On the other hand, the 5-fluorocytosine derivative (5F-4'-thioFAC) showed potent antitumor activity against both leukemia and solid tumor. Its antitumor spectrum against 14 human solid tumor and one leukemic cell lines was compared with that of 4'-thioFAC. The results showed that 5F-4'-thioFAC had an antitumor spectrum similar to that of 4'-thioFAC. However, 5F-4'-thioFAC was about 10 times less active than 4'-thioFAC.

Hypofibrinogenemia associated with a heterozygous missense mutation gamma153Cys to arg (Matsumoto IV): in vitro expression demonstrates defective secretion of the variant fibrinogen

We genetically analyzed a case of hypofibrinogenemia that showed no bleeding or thrombotic tendency. Direct sequencing of a polymerase chain reaction-amplified gamma-chain gene segment showed a novel nucleotide substitution. This heterozygous mutation encodes both Cys (TGT) and Arg (CGT) at residue 153. To examine the basis for the fibrinogen deficiency, we prepared expression vectors containing mutant gamma-chain DNAs encoding gamma153R and gamma153A for in vitro expression in Chinese hamster ovary (CHO) cells. Enzyme-linked immunosorbent assay and immunoblot analysis of the culture media and cell lysates showed that CHO cells transfected with gamma153R or gamma153A synthesized the variant gamma-chain, but did not secrete variant fibrinogen into the culture medium. Metabolic pulse-chase experiments showed that fibrinogen assembly was impaired when either variant gamma-chain was expressed. In cells expressing normal fibrinogen, assem- bly intermediates and intact fibrinogen were seen in cell lysates prepared after short (3 minutes) or long (1 hour) incubation with (35)S-methionine. Neither intermediates nor intact fibrinogen was seen with the variant gamma-chains. These data suggest that gamma-chains have an important early role in fibrinogen assembly. Thus, our results support the model for fibrinogen assembly proposed by Huang et al (J Biol Chem 268:8919, 1993), in which the first step in assembly is the formation of alphagamma or betagamma dimers, or both. This model implies that gammaCys153 has a critical role in the formation of these early assembly intermediates. We concluded that the gamma153Cys-->Arg substitution does not allow fibrinogen assembly and secretion, and this is manifest in vivo as a fibrinogen deficiency. We designated this variant as fibrinogen Matsumoto IV.

A lung metastasis from giant cell tumor of bone at eight years after primary resection

We report a case of extensive pulmonary metastasis from a histologically benign giant cell tumor. A 34-year-old woman had undergone tumor resection, curettage and artificial bone grafting for giant cell tumor in the left tibia. At eight years after surgery, a chest radiograph revealed an extensive tumor shadow in the right thoracic cavity. Tumor resection with right upper and middle bilobectomy was performed. Its histological features were consistent with those of the primary tumor of the tibia. Distant metastases from a giant cell tumor of bone are rare, with only 50 reported cases. Metastasis has occurred mainly within 3 years after the primary resection. However, in 20% of reported cases, metastasis occurred after 5 years or longer. Long-term follow-up and careful observation for distant metastasis are necessary for this histologically benign disease.

Ribulose bisphosphate carboxylase/oxygenase from the hyperthermophilic archaeon Pyrococcus kodakaraensis KOD1 is composed solely of large subunits and forms a pentagonal structure

We previously reported the presence of a highly active, carboxylase-specific ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in a hyperthermophilic archaeon, Pyrococcus kodakaraensis KOD1. In this study, structural analysis of Pk -Rubisco has been performed. Phylogenetic analysis of Rubiscos indicated that archaeal Rubiscos, including Pk -Rubisco, were distinct from previously reported type I and type II enzymes in terms of primary structure. In order to investigate the existence of small subunits in native Pk -Rubisco, immunoprecipitation and native-PAGE experiments were performed. No specific protein other than the expected large subunit of Pk -Rubisco was detected when the cell-free extracts of P. kodakaraensis KOD1 were immunoprecipitated with polyclonal antibodies against the recombinant enzyme. Furthermore, native and recombinant Pk -Rubiscos exhibited identical mobilities on native-PAGE. These results indicated that native Pk -Rubisco consisted solely of large subunits. Electron micrographs of purified recombinant Pk -Rubisco displayed pentagonal ring-like assemblies of the molecules. Crystals of Pk -Rubisco obtained from ammonium sulfate solutions diffracted X-rays beyond 2.8 A resolution. The self-rotation function of the diffraction data showed the existence of 5-fold and 2-fold axes, which are located perpendicularly to each other. These results, along with the molecular mass of Pk -Rubisco estimated from gel filtration, strongly suggest that Pk -Rubisco is a decamer composed only of large subunits, with pentagonal ring-like structure. This is the first report of a decameric assembly of Rubisco, which is thought to belong to neither type I nor type II Rubiscos.

Hairy cell leukemia with translocation (11;20)(q13;q11) and overexpression of cyclin D1

We report on a male Japanese patient with hairy cell leukemia (HCL). A cytogenetic study with lipopolysaccharide stimuli showed a novel translocation (11;20)(q13;q11) in 10% of the analyzed cells. Northern blot analysis and RT-PCR analysis for cyclin D1 revealed the overexpression of cyclin D1, although the southern blot analysis of PRAD1 gene showed no rearrangement. In this particular case, the t(11;20)(q13;q11) might play some role in the oncogenesis of HCL and the overexpression of cyclin D1.

7-Chloro-5-hydroxy-1-[2-methyl-4-(2-methylbenzoyl-amino)benzoyl ]-2,3,4,5-tetrahydro-1H-1-benzazepine (OPC-41061): a potent, orally active nonpeptide arginine vasopressin V2 receptor antagonist

We previously reported a series of benzazepine derivatives as orally active nonpeptide arginine vasopressin (AVP) V2 receptor antagonists. After the lead structure OPC-31260 was structurally evaluated and optimized, the introduction of the 7-Cl moiety on the benzazepine and 2-CH3 on the aminobenzoyl moiety enhanced its oral activity. The new AVP-V2 selective antagonist OPC-41061 was determined to be a potent and orally active agent.

Stimulation of peroxidase activity by decamerization related to ionic strength: AhpC protein from Amphibacillus xylanus

AhpC protein, purified from Amphibacillus xylanus with a molecular mass of 20.8 kDa, protects cells against oxidation damage. The enzyme catalyses the reduction of hydroperoxides in cooperation with the 55 kDa flavoprotein, A. xylanus NADH oxidase (NADH oxidase-AhpC system). A. xylanus AhpC has two disulfide linkages between monomers and can act in the homodimer form. Gel-filtration column chromatography and dynamic light scattering (DLS) suggest that A. xylanus AhpC also forms a large oligomeric assembly (10-12 mers). A. xylanus AhpC was crystallized and X-ray diffraction data were collected to 3.0 A. The self-rotation function revealed fivefold and twofold axes located perpendicularly to each other, suggesting that the molecular assembly of A. xylanus AhpC is composed of ten monomers. The oligomerization of A. xylanus AhpC is affected by ionic strength in the DLS measurements. The H(2)O(2) reductase activity of the A. xylanus NADH oxidase-AhpC system is also affected by ionic strength, and it was found that the decamerization of AhpC might be required for the activation of the NADH oxidase-AhpC system.

Liver cirrhosis with marked thrombocytopenia and highly elevated serum thrombopoietin levels

Three patients with liver cirrhosis (LC) and a bleeding tendency due to marked thrombocytopenia of less than 20 x 10(9)/l were admitted to our hospital for further examination. Bone marrow examination revealed megakaryocytic hypoplasia in all three patients. All patients exhibited amegakaryocytic thrombocytopenic purpura, myelodysplastic syndrome, or bone marrow hypoplasia. 111In-labeled platelet kinetic studies revealed decreased platelet production in all patients. Although serum thrombopoietin (sTPO) levels are usually within the normal level in patients with LC, the sTPO levels of our patients were about 10 times higher than the levels of normal subjects (1.22 +/- 0.37 fmol/ml): 13.34, 16.79, and 10.46 fmol/ml, respectively. These sTPO data supported our findings of decreased megakaryopoiesis. Our findings suggest that examination of sTPO levels is useful in determining the etiology of marked thrombocytopenia in LC patients.

Mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum with chromosomal translocation of the t(11;18)(q21;q21) and an additional aberration of trisomy 3

A rare case of primary mucosa-associated lymphoid tissue lymphoma (MALT) of the rectum is reported. A 56-yr-old man was referred to our hospital for further examination and treatment of rectal neoplasm. A physical examination and laboratory data showed no special abnormalities. However, endoscopic colorectal observation revealed multiple red and slightly elevated nodular lesions with erosive changes of the rectum. The lesions were composed of diffuse, small atypical lymphoid cells (i.e., centrocyte-like cells) and were stained with L26 and BCL-2 but not cyclin D1. Surface markers of cells obtained from biopsy specimens were CD5-, CD10-, CD19+, CD20+, kappa+, and lambda-. No BCL-2 gene rearrangement was observed. The clonal karyotype of t(11;18)(q21;q21) was observed in six of nine lymphoid cells. Trisomy was also identified two of 144 cells by fluorescence in situ hybridization. We report a rare case of the rectal MALT lymphoma bearing characteristic chromosomal aberrations; t(11;18)(q21;q21) and trisomy 3. We suggest that chromosomal analysis using biopsy specimens may be useful for the diagnosis of MALT lymphoma.

Polymorphisms of platelet membrane glycoprotein Ib alpha and plasma von Willebrand factor antigen in coronary artery disease

To examine the relationships of two polymorphisms of platelet glycoprotein (GP) Ib alpha and coronary artery diseases (CAD) in Japanese patients, we conducted a case-control study with 158 Japanese patients and 169 control subjects. The frequencies of HPA-2 polymorphism and the variable number of tandem repeat (VNTR) polymorphisms in the macroglycopeptide region did not significantly differ between CAD patients and control subjects. The polymorphisms of GPIb alpha were not associated with the number of affected vessels in CAD patients. When patients with acute coronary syndrome only were analyzed, the frequencies of the two polymorphisms of GPIb alpha showed no significant difference. Although plasma von Willebrand antigen (vWF:Ag) levels in patients were significantly higher than in controls, no association between vWF concentration and GPIb genotypes was observed. In patient groups with higher or lower vWF:Ag concentrations, no increase in the frequencies of Met145 or larger VNTR polymorphisms was seen in either group. Our findings indicate that no association exists between the frequencies of the two polymorphisms of GPIb alpha and CAD.