Function of the propeptide region in recombinant expression of active procathepsin L in Escherichia coli

In order to determine the functional role of the procathepsin L propeptide region for the preparation of active recombinant rat cathepsin L (CL), cDNAs encoding two short-length propeptides (C-terminal 2 and 27 residues) and the full-length (96 residues) one plus the entire CL were expressed as two soluble fusion proteins with a fragment of maltose-binding protein and an insoluble fusion protein with glutathione-S-transferase in Escherichia coli, respectively. After refolding of the insoluble fusion protein, each gene product was purified to homogeneity by amylose or glutathione-Sepharose-4B affinity column, and digestion with factor Xa and alpha-thrombin under alkaline conditions (pH approximately 8.0) led to the elution of two pure short-length procathepsin Ls (PCLs) and a full-length one, respectively. The enzymatic activity, estimated by hydrolytic assaying of benzoxycarbonyl-Phe-Arg-7-(4-methyl)coumarylamide under acidic conditions (pH 5.5), indicated that the two short-length PCLs exhibited in a great loss of the activity, as compared with the full-length PCL. The CD spectra of the short-length PCLs were different from that of the full-length one. The present results clearly show that the full-length propeptide is essential for construction of the active tertiary structure of CL at the stage of recombinant protein expression, although the expression of CL itself in E. coli does not require the propeptide. Based on the tertiary structure of PCL, the propeptide region necessary for the construction of the CL active structure has been discussed.

Two divergent signaling pathways for TGF-beta separated by a mutation of its type II receptor gene

Transforming growth factor beta (TGF-beta) can inhibit epithelial cell growth and induce extracellular matrix formation through signal transduction via its two receptors and its downstream intracellular Smad proteins. We recently reported a germline mutation, i.e., substitution of methionine for threonine at codon 315 in the kinase subdomain IV, of the TGF-beta type II receptor gene in a kindred of hereditary nonpolyposis colorectal cancer without microsatellite instability and found that the mutant receptor abolished the signal transduction for growth inhibition by TGF-beta. In this study, we performed further functional analysis of this mutant receptor. The results showed that, in contrast to its failure to mediate growth inhibition by TGF-beta, the mutant receptor still retained the ability to induce one of the extracellular matrix proteins, plasminogen activator inhibitor type 1, upon TGF-beta treatment. However, coincident with its failure to mediate growth inhibition by TGF-beta, the mutant receptor failed to transcriptionally upregulate one of the cyclin-dependent kinase inhibitors, p15(INK4B), in response to TGF-beta. These data suggest that threonine 315 of the TGF-beta type II receptor is dispensable for extracellular matrix protein production, but is essential for the growth inhibition by TGF-beta, and that the lack of growth inhibition due to the mutant receptor is possibly mediated through its failure to upregulate p15(INK4B).

PQBP-1, a novel polyglutamine tract-binding protein, inhibits transcription activation by Brn-2 and affects cell survival

A novel gene, designated PQBP-1, which encodes a 265 residue protein that binds to the polyglutamine tract of the brain-specific transcription factor Brn-2, was identified. PQBP-1, which also interacts with the polyglutamine tract of triplet repeat disease gene products, binds with a higher affinity to an expanded polyglutamine tract. PQBP-1 has several functional domains, including hepta- and di-amino acid repeat sequences rich in polar residues essential for its interaction with the polyglutamine tract, a WWP/WW domain which binds to proline-rich motifs in other proteins, a putative nuclear localization signal sequence and a C2domain implicated in Ca2+-dependent phospholipid signaling. PQBP-1 is located in the nucleus and inhibits transcriptional activation by Brn-2. Overexpression of PQBP-1 in P19 embryonic carcinoma cells suppresses their growth rate and enhances their susceptibility to various stresses including serum deprivation, retinoic acid treatment and UV irradiation. Northern blot and in situ hybridization analyses revealed that PQBP-1 is a ubiquitous protein and is expressed primarily in neurons throughout the brain, with abundant levels in hippocampus, cerebellar cortex and olfactory bulb. These results suggest that PQBP-1 mediates important cellular functions under physiological and pathological conditions via its interaction with polyglutamine tracts.

The response of the slow atrioventricular nodal pathway to temperature

The present study attempted to determine the lowest temperature at which the slow atrioventricular nodal pathway responds to heating and the temperature necessary for successful ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT). The study group comprised 23 consecutive patients (14 women, 9 men) with symptomatic AVNRT. Radiofrequency current was delivered at the slow pathway potential recording site using a HAT 200S catheter ablation system. Successful radiofrequency ablation of the slow pathway was achieved in all 23 patients. Junctional beats, suggesting the response of the slow pathway to temperature, were detected in 62 of the total 136 applications. The temperature measured at the first junctional beat was 45.4+/-4.2 degrees C. The maximum temperature required for the successful ablation of AVNRT ranged from 45 to 88 degrees C. There were no complications except for 1 patient with transient atrioventricular (AV) block. There were no recurrences of AVNRT during follow-up. The lowest temperature at which the slow pathway was responsive to heat was quite similar to that for accessory pathways or the AV junction. However, the temperature required for the successful ablation of AVNRT differed markedly among the patients.

Positive and negative modulation of vitamin D receptor function by transforming growth factor-beta signaling through smad proteins

Several lines of experiments demonstrated the interplay between the transforming growth factor-beta (TGF-beta) and vitamin D signaling pathways. Recently, we found that Smad3, a downstream component of the TGF-beta signaling pathway, potentiates ligand-induced transactivation of vitamin D receptor (VDR) as a coactivator of VDR (Yanagisawa, J., Yanagi, Y., Masuhiro, Y., Suzawa, M., Watanabe, M., Kashiwagi, K., Toriyabe, T., Kawabata, M., Miyazono, K., and Kato, S. (1999) Science 283, 1317-1321). Here, we investigated the roles of inhibitory Smads, Smad6 and Smad7, which are negative regulators of the TGF-beta/bone morphogenetic protein signaling pathway, on the Smad3-mediated potentiation of VDR function. We found that Smad7, but not Smad6, abrogates the Smad3-mediated VDR potentiation. Interaction studies in vivo and in vitro showed that Smad7 inhibited the formation of the VDR-Smad3 complex, whereas Smad6 had no effect. Taken together, our results strongly suggest that the interplay between the TGF-beta and vitamin D signaling pathways is, at least in part, mediated by the two classes of Smad proteins, which modulate VDR transactivation function both positively and negatively.

Successful treatment of refractory bronchorrhea by inhaled indomethacin in two patients with bronchioloalveolar carcinoma

Bronchorrhea in patients with bronchioloalveolar carcinoma is not uncommon. However, to our knowledge, an effective treatment for bronchorrhea in these patients has not been established. Recently, we have confirmed the efficacy of inhaled indomethacin in severe refractory bronchorrhea in comparison to that of other medications in two patients with bronchioloalveolar carcinoma. Despite the administration of a macrolide and corticosteroid, sputum volume increased to 700 mL/d in case 1 and to 200 mL/d in case 2 and hypoxemia and dyspnea deteriorated. Within a few days after the initiation of treatment with inhaled nebulized indomethacin (75 mg/d), sputum volume started to decrease and was controlled to < 100 mL/d, associated with alleviation of dyspnea and hypoxemia. To our knowledge, this is the first report of successfully treated refractory bronchorrhea associated with bronchioloalveolar carcinoma by inhaled indomethacin, resulting in markedly reduced sputum volume, improved quality of life, and prolonged survival.

Eosinophilic pneumonia with eosinophilic gastroenteritis

A 48-year-old man was admitted to our hospital with cough, fever and dysphagia. He had a past history of bronchial asthma and surgery for nasal polyp. Chest radiograph and computed tomography showed atelectasis in the right lower field and infiltrative shadow in the left lower field and overall thickening of the esophageal wall. Transbronchial lung biopsy (TBLB) specimens revealed infiltration of eosinophils and lymphocytes under the bronchial mucosa. Gastrointestinal tract biopsy specimens showed submucosal infiltration of eosinophils. These findings led to a definite diagnosis of eosinophilic pneumonia associated with eosinophilic gastroenteritis, a disease which has been rarely reported.

Evaluation of contrast agents for delineation of vessel wall boundary by intracoronary ultrasound after coronary angioplasty in human

We evaluated the potential for improving visualization at intervention sites using contrast-enhanced intracoronary ultrasound (ICUS) and the suitable contrast agents for this procedure in humans. In 37 patients, ICUS (30 MHz) was performed with intracoronary bolus injection (3 mL) of seven different contrast preparations and without the contrast agents (control) after coronary intervention. The contrast agents used were as follows: saline solution, standard iomeprol, standard ioxaglate, sonicated iomeprol, sonicated ioxaglate, 50% Albunex, and 100% Albunex. Homogeneous and complete opacification of the vessel lumen and false lumen was observed with sonicated ioxaglate, 50% and 100% Albunex. Shadowing was not observed at all with sonicated ioxaglate and was uncommon with 50% Albunex, whereas 100% Albunex caused shadowing in all cases. The coronary delineation rate with the other contrast agents was only 60%-70%, and the homogeneity and peak intensity were relatively low. Thus, sonicated ioxaglate and 50% Albunex both achieved good visualization, but the latter is more expensive, more difficult to handle, and takes longer to prepare. Of the agents we studied, sonicated ioxaglate appears to be best suited for contrast-enhanced ICUS. ICUS using suitable contrast agents could only visualize the large dissections and the strategy was changed according to the contrast-enhanced ICUS results in five cases. Thus, suitable contrast agents, e.g., sonicated ioxaglate, should be used during ICUS after intracoronary intervention.

Synergistic signaling in fetal brain by STAT3-Smad1 complex bridged by p300

The cytokines LIF (leukemia inhibitory factor) and BMP2 (bone morphogenetic protein-2) signal through different receptors and transcription factors, namely STATs (signal transducers and activators of transcription) and Smads. LIF and BMP2 were found to act in synergy on primary fetal neural progenitor cells to induce astrocytes. The transcriptional coactivator p300 interacts physically with STAT3 at its amino terminus in a cytokine stimulation-independent manner, and with Smad1 at its carboxyl terminus in a cytokine stimulation-dependent manner. The formation of a complex between STAT3 and Smad1, bridged by p300, is involved in the cooperative signaling of LIF and BMP2 and the subsequent induction of astrocytes from neural progenitors.

Multiple alternative transcripts of the human homologue of the mouse TRAD/R51H3/RAD51D gene, a member of the rec A/RAD51 gene family

Yeast RAD51, a homologue of Escherichia coli recA, plays a crucial role in mitotic and/or meiotic recombination and in the repair of double-strand DNA breaks. We have identified unique multiple alternative transcripts of a human TRAD/R51H3/RAD51D gene, a member of the recA/RAD51 gene family. One of the transcripts encoded a 328-amino-acid protein with 83.0% overall amino acid identity and 98. 2% similarity with the mouse TRAD gene and had two nucleotide binding consensus sequences, motif A and motif B, conserved among members of this family. Other transcripts encoded truncated proteins with a partial N-terminal region of the orthologue or short proteins lacking internal sequences which contain nucleotide binding motifs. Northern blot analysis revealed that multiple transcripts of the human TRAD gene were expressed in various tissues and their distribution was not ubiquitous.

Convergence of transforming growth factor-beta and vitamin D signaling pathways on SMAD transcriptional coactivators

Cell proliferation and differentiation are regulated by growth regulatory factors such as transforming growth factor-beta (TGF-beta) and the liphophilic hormone vitamin D. TGF-beta causes activation of SMAD proteins acting as coactivators or transcription factors in the nucleus. Vitamin D controls transcription of target genes through the vitamin D receptor (VDR). Smad3, one of the SMAD proteins downstream in the TGF-beta signaling pathway, was found in mammalian cells to act as a coactivator specific for ligand-induced transactivation of VDR by forming a complex with a member of the steroid receptor coactivator-1 protein family in the nucleus. Thus, Smad3 may mediate cross-talk between vitamin D and TGF-beta signaling pathways.

[Clinical investigation of 15 patients with pulmonary cryptococcosis--clinical comparison of HTLV-I carriers and non-carriers]

We investigated 15 pulmonary cryptococcosis patients. The group had a mean age of 51.7 years, and 6 (40%) of the patients were women. Cryptococcosis was primary in 13 patients and secondary in 2 (diabetes mellitus and smoldering adult T-cell leukemia). Eight patients were asymptomatic and 9 patients were detected by medical examinations. Dry cough was the most common symptoms. On chest radiographs, 5 patients showed solitary nodules, 4 patients showed infiltrative shadows, and 4 patients showed multiple nodules. The right lower lobe was the predominant location of solitary nodules, and the left upper and middle lung fields were the predominant locations of infiltrative shadows. Transbronchial lung biopsy was the method of diagnosis for 9 patients, and open lung biopsy for the others. Eleven patients were treated with fluconazole, and the mean treatment period was 7 months. Four patients underwent, resection procedures only, and experienced no recurrence. Five patients were positive for HTLV-I (one had smoldering ATL) and 5 were negative. Eighty percent of the HTLV-I positive patients had some symptoms and 80% of the HTLV-I negative patients were asymptomatic. HTLV-I positive patients showed various pulmonary shadows and 80% of the HTLV-I negative patients showed solitary nodules. The pulmonary lesions in HTLV-I positive patients were more extensive than those in HTLV-I negative patients (p < 0.05). We postulate the possible existence of subtle immunological abnormalities, including abnormalities of cellular immunity, in HTLV-I carriers.

Drosophila dSmad2 and Atr-I transmit activin/TGFbeta signals

BACKGROUND

Much is known about the three subfamilies of the TGFbeta superfamily in vertebrates-the TGFbetas, dpp/BMPs, and activins. Signalling in each subfamily is dependent on both shared and unique cell surface receptors and Smads. In invertebrates, mutants for BMP pathway components have been extensively characterized, but thus far, evidence for an activin- or TGFbeta-like pathway has been lacking, preventing the use of the extensive genetic tools available for studying several key issues of TGFbeta signalling.

RESULTS

Here we report the identification of dSmad2, a new Drosophila Smad which is most related to the activin/TGFbeta-pathway Smads, Smad2 and Smad3. We show that dSmad2 induces activin responsive genes in Xenopus animal cap assays. dSMAD2 is phosphorylated by ATR-I and PUNT, but not by activated THICK VEINS, and translocates to the nucleus upon activation. Furthermore, we show that dSMAD2 complexes with MEDEA only in the presence of ATR-I and PUNT. dSmad2 is expressed in the imaginal disks and in the outer proliferation centre of the larval brain, suggesting that it may have important proliferative and patterning roles during Drosophila development.

CONCLUSION

Our data provide evidence for the existence of an activin/TGFbeta pathway in Drosophila. We show that dSmad2 participates in this pathway, and that it functions with Atr-I and punt. We show that Medea also participates in this pathway, indicating the conservation of roles for Co-Smads in diverse phyla. Expression patterns of dSmad2 suggest that it functions in imaginal disks and in the brain, in tissues that undergo extensive patterning and proliferation.

Intermittent bundle branch blocks in a patient with uncommon-type atrioventricular nodal reentrant tachycardia and enhanced atrioventricular nodal conduction

We report on a patient with uncommon-type atrioventricular (AV) nodal reentrant tachycardia with a short tachycardia cycle length (235-270 ms), in whom transient wide QRS tachycardia with both left bundle branch block and right bundle branch block aberrancy were followed by narrow QRS complexes. In addition, His-ventricular (H-V) block and a sudden prolongation of the H-V interval occurred during the tachycardia. As the determinant of these unusual findings, the possibility that the anterograde limb of the reentry circuit has an enhanced AV nodal conduction property is discussed, as is the clinical significance of this type of tachycardia.

Signal transduction of the TGF-beta superfamily by Smad proteins

Members of the TGF-beta superfamily regulate the growth and differentiation of various types of cells. Smads are recently identified proteins that mediate intracellular signaling of the TGF-beta superfamily. Smads are grouped into three classes depending on their structure and functions. R-Smads are phosphorylated by type I serine-threonine kinase receptors for TGF-beta superfamily members. R-Smads then associate with Co-Smads. Smad4 is the only vertebrate Co-Smad identified thus far, and is required for the signaling pathways of different ligands. The heteromeric Smad complex translocates into the nucleus, where it activates target genes. Anti-Smads inhibit signaling by R-Smads and Co-Smads. Smads bind to DNA directly or indirectly via other DNA binding proteins. R-Smads interact with transcriptional coactivators, and have intrinsic transactivation activity. Elucidation of the functions of Smads will provide the framework for research on TGF-beta superfamily signaling.

Polar amino acid-rich sequences bind to polyglutamine tracts

Polyglutamine tracts are found in different proteins including transcription factors and cofactors as well as in triplet repeat disease gene products. To characterize the protein motif that binds to the polyglutamine tract, we screened a human embryonic brain cDNA library with the polyglutamine tract of Brn-2 as bait using the yeast two-hybrid method. All six isolated clones encoding polyglutamine tract binding proteins were rich in polar amino acids. Three of these clones could form polar helical structures. These observations suggest that polar amino acid-rich sequences are essential for binding to the polyglutamine tract.

Quantitative analysis of human multidrug resistance 1 (MDR1) gene expression by nonisotopic competitive reverse transcriptase polymerase chain reaction assay

We have established competitive reverse transcriptase polymerase chain reaction (RT-PCR) assay for the quantification of MDR1 mRNA encoding P-glycoprotein (P-gp) by analyzing leukemia sublines of MOLT-3 with various expression of MDR1. The expression was quantified by simultaneous RT-PCR of cellular RNA with decreasing amounts of heterologous competitor RNA, which shares the MDR1 primer sequences with the cellular MDR1 mRNA, but yields a different-sized PCR product. This allows resolution of the amplified cDNA fragments. The amounts of MDR1 mRNA measured by the assay were accurate and reproducible over wide range, and were determined as 31.6, 100, and 316 amol/microgram total RNA in MOLT-3/TMQ70, MOLT-3/ TMQ800, and MOLT-3/VCR1,000, respectively. The relative ratio of MDR1 mRNA measured by the competitive RT-PCR among three sublines was similar to that of MDR1 transcript determined by Northern analysis (1:4:12) and to that of P-gp measured by flow cytometry (FCM) analysis. In mononuclear cells from patients with leukemia, MDR1 mRNA could be sufficiently quantified by the competitive RT-PCR established, while FCM assay could scarcely detet P-gp. This study demonstrated that the competitive RT-PCR assay using heterologous competitor RNA is a rapid, reliable, and non-radioactive procedure and is acceptable for the evaluation of MDR1 expression in clinical samples.

New diagnostic finding to assess para-Hisian pacing observed in a patient with a permanent form of junctional reciprocating tachycardia

Para-Hisian pacing, a useful method to differentiate conduction over an accessory pathway from conduction over the AV node, is assessed essentially by comparing the timing of local atrial electrograms between His-bundle captured beats and His-bundle noncaptured beats. We describe the case of a patient with a permanent form of junctional reciprocating tachycardia, in whom an atrial double potential was recorded only during the tachycardia at the right posterior septum. During para-Hisian pacing, a morphologic change in the atrial electrogram at the posterior septum was also identified, as well as a change in the retrograde atrial sequence. Since the morphologic change of atrial electrograms during para-Hisian pacing cannot be demonstrated in a patient without an accessory pathway, this new finding could be considered a new additional diagnostic criterion suggesting the presence of an accessory pathway.

Pulmonary manifestations in cerebrotendinous xanthomatosis

We investigated five cases with cerebrotendinous xanthomatosis (CTX) with particular reference to biochemical and pathological pulmonary disorders. To date, few reports discuss the pathophysiology of pulmonary disorders of CTX patients. This study is the first investigation of such pulmonary disorders. All 5 patients had no pulmonary symptoms and no disturbances on radiological studies and pulmonary function tests. However, in bronchoalveolar lavage (BAL) fluids, many cells with cruciform reflexes, which is characteristic of intracellular sterol accumulation, were found under phase contrast microscopy. Biochemically, cholestanol was found to be increased in the BAL fluid as well as in serum. Pathological findings of transbronchial lung biopsy (TBLB) samples disclosed foamy macrophages and small granulomas in alveolar septa. In conclusion, the lung was apparently involved in CTX, and the lesions were characterized with the accumulation of foamy and giant cells with a high concentration of cholestanol, which likely results in the formation of foreign body granulomas.

Premature bifurcation of the apical dendritic trunk of vibrissa-responding pyramidal neurones of X-irradiated rat neocortex

1. Electrophysiological and morphological experiments were performed on the pyramidal neurones of the somatosensory neocortex of the adult rat that had been exposed in utero to 200 rad of X-irradiation. Under urethane anaesthesia, evoked gross potentials, extracellular and intracellular neuronal responses, and laminar field potentials were recorded. The evoked epicortical potential to deflection of a single whisker was a long-lasting positive wave which contrasted with a biphasic positive-negative complex in unirradiated controls. Neurones were initially tested during extracellular recording for responses to whisker deflections. This was followed by intracellular injection with horseradish peroxidase (HRP), and the HRP-stained neuronal elements were visualized using diaminobenzidine as a chromagen. 2. Fifty neurones were recorded and stained through the soma. The mean response latency was 15.1 ms. Of these, thirty-six showed premature bifurcation of the apical dendrite. The angle of bifurcation of the apical dendrite was measured in the coronal plane and was found to be a function of the depth at which the soma was located and the distance between the soma and bifurcation point. It was suggested that the apical dendrites of these neurones underwent premature bifurcation due to an imbalance between the growth of neurones and skull. 3. Fifteen neurones were recorded and stained through the presumed apical dendritic shaft. The mean response latency was 19.5 ms. The electrode track left in the histological specimen pointed to the stained apical dendrite. Dendritic elements distal to the entry point were preferentially filled with HRP. In no cases were somata stained. There was, in turn, no evidence of recording from dendritic elements distal to the bifurcation since no electrode track was found to point to these elements. That dendritic spike responses may not travel beyond the bifurcation was further substantiated by laminar analysis of field potentials.

Extracellular matrix production regulation by TGF-beta in corneal endothelial cells

PURPOSE

Production of extracellular matrix (ECM) by corneal endothelial cells is related to physiologic functions and pathologic conditions and is regulated by many cytokines, including transforming growth factor-beta (TGF-beta). In this study, the molecular mechanism of ECM production regulation by TGF-beta was investigated in cultured corneal endothelial cells.

METHODS

The production of ECM components (laminin and fibronectin) was detected in cultured corneal endothelial cells by western blot analysis. To determine the signal transduction pathways, mutant TGF-beta type I receptor (TbetaR-I) and/or Smad protein family members (intracellular signal transducers in TGF-beta signaling) were overexpressed by transfecting their cDNA into the cultured cells, and the effects on ECM production were observed.

RESULTS

The production of laminin and fibronectin was stimulated by treatment with TGF-beta1 or TGF-beta2. After transient transfection of cDNA of the constitutively active (CA) mutant of TbetaR-I, the production of laminin and fibronectin was stimulated even in the absence of TGF-beta. The transfection of the dominant negative mutant of TbetaR-I counteracted the effects of TGF-beta. These results confirm that TGF-beta directly stimulates ECM production from corneal endothelial cells through TbetaR-I. The ECM production stimulation by TGF-beta or CA TbetaR-I was accelerated by the overexpression of Smad2, Smad3, and/or Smad4 and inhibited by that of Smad7. These results show that TGF-beta signals connected to ECM production are regulated by Smad family members, located downstream of TbetaR-I.

CONCLUSIONS

The results of this study show that TGF-beta stimulates ECM production from corneal endothelial cells through TbetaR-I and Smad family transducers.

Two cases of idiopathic CD4+ T-lymphocytopenia in elderly patients

We present 2 cases of idiopathic CD4+ T-lymphocytopenia (ICL) in elderly patients. Case 1, a 73-year-old man, with pneumonia had received several antibiotics with unsuccessful results at another hospital. On admission, his CD4+ T-lymphocyte count was 109/microl and Pneumocystis carinii was detected by bronchoalveolar lavage fluid staining. No evidence of human immunodeficiency virus (HIV) infection was found. Despite therapy, the patient died of respiratory failure. Case 2, a 72-year-old man, contracted severe pneumonia, and Hemophillus influenzae was believed to be the pathogen. On admission, his CD4+ T-lymphocyte count was 238/microl. No evidence of HIV infection was found. He received antibiotics and improved successfully. We suggest that ICL may currently be incubating in a number of elderly pneumonia patients.

Mushroom worker's lung resulting from indoor cultivation of Pleurotus osteatus

Indoor cultivation of oyster mushroom Pleurotus osteatus lead to an outbreak of extrinsic allergic alveolitis in two workers. High titer of indirect fluorescent antibody and positive precipitins against basidiospores of P. osteatus were demonstrated in sera of the patients. Mushroom workers should protect themselves from the basidiospores, being aware of their pathogenicity.

Control of rat glomerular microcirculation by juxtaglomerular adenosine A1 receptors

The role of adenosine A1 receptors in the glomerular microcirculation and tubuloglomerular feedback (TGF) was studied in anesthetized Sprague-Dawley rats. TGF activity was assessed as the reduction in proximal tubular stop-flow pressure (SFP) on establishing orthograde perfusion of the loop of Henle with artificial tubular fluid at 40 nl/min. Administration of a selective A1 receptor antagonist, KW-3902 (0.5 microg/kg/min i.v.), increased fractional excretion of Na (FE(Na)) 4.3-fold without changing blood pressure, glomerular filtration rate, renal plasma flow, or filtration fraction. SFP in the absence of distal flow (SFP0) increased, and TGF-mediated SFP reduction was suppressed dose dependently [by 23 +/- 2% from an SFP0 of 34 +/- 1 mm Hg, by 15 +/- 4% from 36 +/- 2 mm Hg, and by 2 +/- 1% from 39 +/- 1 mm Hg during vehicle, low- and high-dose infusions (0.5 and 5.0 microg/kg/min), respectively]. Intratubular or peritubular capillary administration of 10(-4) M KW-3902 completely suppressed TGF without affecting SFP0. TGF suppression and elevation of SFP0 during systemic A1 blockade indicated vasodilation, both in the afferent arteriole and more proximal preglomerular vessels. Inhibition of tubular Na reabsorption combined with TGF suppression allowed the marked natriuresis. TGF suppression through systemic, luminal, and peritubular application of the drug suggest that juxtaglomerular apparatus A1 receptors are important in the control of glomerular microcirculation.

Role of p300, a transcriptional coactivator, in signalling of TGF-beta

BACKGROUND

Smad proteins are novel transcriptional regulators mediating the signalling of the transforming growth factor-beta (TGF-beta) superfamily. Coactivators such as p300/CBP promote transactivation by various transcription factors through a direct interaction with them. Adenoviral oncoprotein E1A, which binds p300, was shown to inhibit the signalling of TGF-beta. These findings raise the possibility that p300 may be involved in TGF-beta signalling.

RESULTS

We investigated whether p300 is involved in transactivation by Smads. p300 enhanced the Smad-induced transactivation of p3TP-Lux, a TGF-beta responsive reporter. E1A inhibited this enhancement, and the inhibition required its ability to bind p300/CBP. p300 and Smad3, as well as Smad2, interacted in vivo in a ligand-dependent manner. The binding region in Smad3 was its C-terminal half that was previously shown to possess an intrinsic transactivation activity. The binding region in p300 was mapped to its C-terminal 678 amino acids. The minimal Smad2/3-interacting region, as well as the rest of the p300, inhibited the transactivation of p3TP-Lux in a dominant-negative fashion.

CONCLUSION

p300 interacted with Smad2 and Smad3 in a ligand-dependent manner, and enhanced the transactivation by Smads. Our results present the molecular basis of the transactivation by Smad proteins.

Diffuse panbronchiolitis in rheumatoid arthritis

The association of progressive obliterative bronchiolitis (OB) with rheumatoid arthritis (RA) is uncommon but has been reported previously. Diffuse panbronchiolitis (DPB) is a unique inflammation principally affecting the respiratory bronchioli and has been reported mainly in Japanese adults. Recently, DPB has also been noted in patients with RA in Japan. Therefore, there might be considerable overlap in clinical features between DPB and OB associated with RA in Japan. The aim of this study was to evaluate the clinicopathological characteristics of bronchiolitis in patients with RA. Three RA patients clinically diagnosed as having DPB were evaluated. All patients underwent chest radiographs, pulmonary function tests (PFT) and post mortem examination. Clinical features in all patients were a history of productive cough, exertional dyspnoea, wheezing and/or coarse crackles. Chest radiographs showed small nodular shadows up to 2 mm in diameter with bronchiolectasis throughout both lungs in all patients. The PFT revealed marked obstructive impairment in all patients. All patients died of progressive respiratory failure. Pathologically, two out of the three cases were confirmed as DPB, while the remaining one case was confirmed as OB, because the primary obstructive lesions were in the respiratory bronchioli in the former and in the membranous bronchioli and the proximal small bronchi in the latter. Thus, the clinical features of DPB and OB were strikingly similar, but the histopathological features revealed distinct differences. This study demonstrated that there was considerable overlap in clinical features between diffuse panbronchiolitis and obliterative bronchiolitis associated with rheumatoid arthritis, suggesting that diffuse panbronchiolitis might be a new manifestation of rheumatoid arthritis. The differentiation of these two disease entities is significant in making decisions on their therapeutic modality and is possible by analysing the precise histopathological findings of the lung.

Interplay of signal mediators of decapentaplegic (Dpp): molecular characterization of mothers against dpp, Medea, and daughters against dpp

Decapentaplegic (Dpp) plays an essential role in Drosophila development, and analyses of the Dpp signaling pathway have contributed greatly to understanding of the actions of the TGF-beta superfamily. Intracellular signaling of the TGF-beta superfamily is mediated by Smad proteins, which are now grouped into three classes. Two Smads have been identified in Drosophila. Mothers against dpp (Mad) is a pathway-specific Smad, whereas Daughters against dpp (Dad) is an inhibitory Smad genetically shown to antagonize Dpp signaling. Here we report the identification of a common mediator Smad in Drosophila, which is closely related to human Smad4. Mad forms a heteromeric complex with Drosophila Smad4 (Medea) upon phosphorylation by Thick veins (Tkv), a type I receptor for Dpp. Dad stably associates with Tkv and thereby inhibits Tkv-induced Mad phosphorylation. Dad also blocks hetero-oligomerization and nuclear translocation of Mad. We also show that Mad exists as a monomer in the absence of Tkv stimulation. Tkv induces homo-oligomerization of Mad, and Dad inhibits this step. Finally, we propose a model for Dpp signaling by Drosophila Smad proteins.

Effects of lysophosphatidic acid on proliferation of stellate cells and hepatocytes in culture

Lysophosphatidic acid (LPA) is a growth factor-like mediator for fibroblasts or smooth muscle cells produced and released by activated platelets. Platelet activation occurs with hepatic necrosis and subsequent liver regeneration and fibrosis. In the fibrosis, hepatic stellate cells proliferate with phenotypic transformation to myofibroblasts. Thus, effects of LPA on proliferation of hepatocytes and stellate cells were investigated. In cultured rat stellate cells, LPA increased DNA synthesis with enhanced MAP kinase activity. Pertussis toxin (PTX) attenuated this mitogenic action. In contrast, LPA decreased DNA synthesis by cultured rat hepatocytes induced by hepatocyte growth factor (HGF) or epidermal growth factor (EGF) without affecting protein synthesis. Enhanced MAP kinase activity by HGF or EGF was not changed by LPA. This anti-mitogenic action was attenuated by PTX. TGFbeta level in the medium was less than the level effective for inhibiting the DNA synthesis in the presence of LPA. Our results suggest that LPA might affect proliferation of hepatocytes and stellate cells in liver diseases complicating platelet activation.

Smad proteins exist as monomers in vivo and undergo homo- and hetero-oligomerization upon activation by serine/threonine kinase receptors

Smad proteins are signal transducers for the members of the transforming growth factor-beta (TGF-beta) superfamily. Here we show that, in the absence TGF-beta stimulation, Smads exist as monomers in vivo. Smad2 and Smad3 form homo-oligomers upon phosphorylation by the constitutively active TGF-beta type I receptor, and this oligomerization does not require Smad4. Major portions of Smad4, Smad6 and Smad7 are also present as monomers in vivo. Analysis using a cross-linking reagent suggested that the Smad2 oligomer induced by receptor activation is a trimer. Studies by gel chromatography demonstrated that the Smad2-Smad4 heteromer is not larger than the Smad2 homomer. Moreover, overexpression of Smad4 prevented Smad2 from forming a homo-oligomer. These findings suggest that Smad2 may form a homotrimer, or heterotrimers with Smad4, which are probably composed of two and one, or one and two molecules of Smad2 and Smad4, respectively, depending on the amount of each protein. Gel-mobility shift assay revealed that the Smad3 homomer and Smad3-Smad4 heteromer constitute DNA-binding complexes. Transition of the Smad proteins from monomers to oligomers is thus a critical event in the signal transduction of the TGF-beta superfamily members.

Sequence analysis and expression of a novel mouse homolog of Escherichia coli recA gene

Escherichia coli recA and its yeast homologs RAD51 and DMC1 play crucial roles in mitotic and/or meiotic recombination and in repair of double-strand DNA breaks. We have identified a murine novel recA-like gene (MmTRAD). The predicted 329 amino acid protein showed significant homology to mouse Rec2, Rad51, Dmc1 (or Lim15) and E. coli RecA. Northern blot analysis revealed that MmTRAD was ubiquitously transcribed in various tissues.

A single missense mutant of Smad3 inhibits activation of both Smad2 and Smad3, and has a dominant negative effect on TGF-beta signals

A missense mutation of Smad2 identified in cancer cells was reconstructed on the corresponding residue of Smad3. This mutant, Smad3D407E, was not phosphorylated by the constitutively active form of type I receptor for transforming growth factor-beta (TGF-beta), and inhibited the phosphorylation of co-expressed wild-type Smad2 and Smad3. This mutant also had a dominant negative effect on the growth inhibition of HaCaT cells and on the expression of p3TP-lux reporter gene induced by TGF-beta. However, it did not alter the phosphorylation of Smad1 induced by the constitutively active form of the bone morphogenetic protein type IA receptor. These findings showed that a single missense mutation in Smad3 could specifically block TGF-beta signals by preventing activation of both Smad2 and Smad3.

Lyme disease Borrelia species in northeastern China resemble those isolated from far eastern Russia and Japan

Fifty-nine Borrelia burgdorferi sensu lato culture isolates collected from northeastern China were characterized by 5S-23S rRNA intergenic spacer restriction fragment length polymorphism (RFLP) analysis and reactivity with monoclonal antibodies (MAbs). Among 59 culture isolates, 30 (50.8%) were Borrelia garinii and 17 (28.8%) were Borrelia afzelii, 2 were mixtures composed of B. garinii with RFLP pattern B and B. garinii with pattern C, and 9 were mixtures composed of B. garinii and B. afzelii. One isolate, ChY13p, produced a unique pattern and was identified as B. garinii based on analyses of 16S rRNA gene sequence, flagellin PCR-RFLP typing, and MAb reactivities. No Borrelia burgdorferi sensu stricto or Borrelia japonica isolates were detected. The results indicate that Lyme disease Borrelia species in northeastern China resemble those of Borrelia isolates from far eastern Russia and Japan.

[Lyme disease]

Lyme disease is a tick-borne disease, and recognized as a complex, multisystem disorder. An outbreak [correction of outback] of Lyme disease was first described in the United States in the 1970s. The presence of Borrelia burgdorferi, its causative agent, in the skin results in the development of characteristic expanding red skin lesions, erythema migrans (EM). EM may be associated with cardiac abnormalities, meningitis, and cranial peripheral neuropathies. Arthritis, neurologic and skin manifestations may persist for several years and become chronic in a small percentage of patients. Studies on the classification of B. burgdorferi resulted in the identification of three closely related genospecies, and different clinical manifestation of Lyme disease have been correlated with the infecting genospecies. The diagnosis of Lyme disease should be based primarily on the clinical presentation, epidemiological information and serological tests. Antimicrobials are effective in the treatment of Lyme disease in most patients. Lyme disease is a zoonosis and endemic in areas where suitable mammalian reservoirs for B. burgdorferi and appropriate hosts for the tick vector are present. According to changes in the natural environment, the distribution of infected ticks and reservoirs is anticipated to expand.

Direct fractionation of proteins in particle-containing feedstocks by a filter paper pieces-based DEAE-cellulose column chromatography. Rapid, robust and low-cost capturing procedure for protein

Filter paper pieces-based (FPB) DEAE-celluloses was prepared for direct fractionation of proteins in particle-containing feedstocks. FPB DEAE-cellulose has a protein binding capacity equivalent to that of commercially available DEAE-cellulose. Crude extracts from porcine intestine and kiwi fruit pulp, which were unmanageable by commercially available chromatographic media due to rapid clothing, could be directly fractionated with FPB DEAE-cellulose column. In addition, effluents from an FPB DEAE-cellulose column were extensively clarified. The present approach can be used as a rapid, robust and low-cost capturing step for protein from particle-containing feedstocks.

[Pulmonary sclerosing hemangioma with specific CT findings]

A 44-year-old woman was admitted to our hospital for evaluation of an abnormal lung shadow. Chest computed tomography (CT) revealed a tumor surrounded by air-space and an infiltrative shadow in the right S2. Right upper lobectomy was performed and pulmonary sclerosing hemangioma was diagnosed. Usually, pulmonary sclerosing hemangioma shows a solitary round nodule on a chest CT scan. We report a case of pulmonary sclerosing hemangioma with an unusual shadow on a chest CT scan, and review the literature.

Identification of the granulocyte colony-stimulating factor (G-CSF) producing cell population in human decidua and its biological action on trophoblast cell

Granulocyte colony-stimulating factor (G-CSF) is a hematopoietic factor, which induces differentiation and proliferation of immature granulocytes. During pregnancy, decidual tissue produces G-CSF and the receptor for G-CSF is expressed on chorionic villous tissues. This study attempted to determine the cell population responsible for G-CSF production in decidual tissue and the influence of G-CSF on trophoblasts. Immunostaining and in situ hybridization showed that both the decidual cells and macrophages in the decidual tissue were sources of G-CSF. With 50 micrograms of G-CSF, the [3H] thymidine uptake was 11,100 +/- 2,200 DPM and the control uptake was 7,970 +/- 1,820 DPM. G-CSF induced proliferation of trophoblasts 1.4-fold higher than that of control. It is concluded that the decidual cells and macrophages were sources of G-CSF in the decidual tissue, and G-CSF promoted trophoblast cell proliferation.

Effects of lemildipine, a new calcium channel blocker, on renal microcirculation in SHR

The effects of lemildipine, a new dihydropyridine calcium channel blocker, on renal hemodynamics and the tubuloglomerular feedback (TGF) mechanism were examined in anesthetized 9- to 10-wk-old spontaneously hypertensive rats (SHR). Lemildipine, 3 micrograms.kg-1 i.v., did not reduce mean blood pressure (MBP) but tended to increase GFR and increased urinary excretion of sodium (UNaV). Filtration fraction (FF) and fractional excretion of sodium (FENa) remained unaltered. An additional dose of lemildipine, 9 micrograms.kg-1 i.v., reduced MBP and renal vascular resistance. Renal plasma flow tended to increase, and GFR was unchanged. FF significantly fell. UNaV and FENa remained at the control level. Micropuncture experiments revealed that the maximal reduction in proximal stop-flow pressure (SFP), an index of glomerular capillary hydrostatic pressure (Pgc), induced by perfusion of the loop of Henle was significantly reduced by high-dose treatment (8.8 +/- 1.3 vs. 13.7 +/- 1.9 mmHg in control). A high dose of lemildipine induced a rightward and slightly upward shift of the TGF curve; the steady-state tubular flow rate (V1/2) was increased, the maximal slope of the curve decreased, and SFP at V1/2 unaltered. A low dose of lemildipine did not affect TGF response. These results indicate that lemildipine attenuates the TGF response in SHR by dilating afferent arterioles and thereby corrects the left and downward shift of the TGF curve in SHR. In addition, the fall in FF indicates lemildipine-induced efferent arteriolar vasodilatation. Through balanced systemic and glomerular vasodilatation, lemildipine maintains the levels of Pgc and GFR in the face of reduced renal perfusion pressure.

Mammalian thioredoxin is a direct inhibitor of apoptosis signal-regulating kinase (ASK) 1

Apoptosis signal-regulating kinase (ASK) 1 was recently identified as a mitogen-activated protein (MAP) kinase kinase kinase which activates the c-Jun N-terminal kinase (JNK) and p38 MAP kinase pathways and is required for tumor necrosis factor (TNF)-alpha-induced apoptosis; however, the mechanism regulating ASK1 activity is unknown. Through genetic screening for ASK1-binding proteins, thioredoxin (Trx), a reduction/oxidation (redox)-regulatory protein thought to have anti-apoptotic effects, was identified as an interacting partner of ASK1. Trx associated with the N-terminal portion of ASK1 in vitro and in vivo. Expression of Trx inhibited ASK1 kinase activity and the subsequent ASK1-dependent apoptosis. Treatment of cells with N-acetyl-L-cysteine also inhibited serum withdrawal-, TNF-alpha- and hydrogen peroxide-induced activation of ASK1 as well as apoptosis. The interaction between Trx and ASK1 was found to be highly dependent on the redox status of Trx. Moreover, inhibition of Trx resulted in activation of endogenous ASK1 activity, suggesting that Trx is a physiological inhibitor of ASK1. The evidence that Trx is a negative regulator of ASK1 suggests possible mechanisms for redox regulation of the apoptosis signal transduction pathway as well as the effects of antioxidants against cytokine- and stress-induced apoptosis.

An example of variation and pattern in saltation and stasis growth dynamics

The serial data from two siblings, aged 6.6 and 7.5 years of age at the initiation of the study, measured each evening for total standing height during 365 days, are analysed by two methods to investigate the nature of the underlying growth pattern. The saltation and stasis model, designed to identify the presence of statistically significant pulses in sequential data, is compared for goodness-of-fit to first to sixth degree polynomial functions, used to investigate the presence of a slowly varying smooth continuous function in the data, and high order polynomials of the same degree of flexibility as the individual's saltation and stasis results. The saltation and stasis model is found to better-fit the experimental data than the slowly varying smooth continuous functions (p < 0.01 to 0.001). The timing characteristics of the saltation and stasis patterns are investigated and the temporal patterns are suggestive of a non-random, aperiodical deterministic system.

Interaction of Drosophila inhibitors of apoptosis with thick veins, a type I serine/threonine kinase receptor for decapentaplegic

Decapentaplegic (Dpp) is a Drosophila member of bone morphogenetic proteins, which belong to the transforming growth factor-beta superfamily. Members of this family regulate a variety of biological processes such as cell proliferation, morphogenesis, immune response, and apoptosis. Dpp plays a critical role in many aspects of Drosophila development. Members of the transforming growth factor-beta superfamily bind to two different types of serine/threonine kinase receptors, termed type I and type II. Type I receptors act as downstream components of type II receptors in the receptor complexes. Therefore, intracellular proteins that interact with the type I receptors are likely to play important roles in signaling. Several proteins have been identified through protein-protein interaction screenings. We identified Drosophila inhibitor of apoptosis (DIAP) 1 as an interacting protein of a Dpp type I receptor, Thick veins (Tkv). DIAP1 associates with Tkv in vivo. The binding region in DIAP1 is mapped to its C-terminal RING finger region. DIAP2, another Drosophila member of the inhibitor of apoptosis protein family, also interacts with Tkv in vivo. These data suggest that DIAP1 and DIAP2 may be involved, possibly as negative regulators, in the Dpp signaling pathway, which leads to cell apoptosis.