Identification of alpha-fodrin as a candidate autoantigen in primary Sjögren's syndrome

It is unclear whether organ-specific autoantigens are critical for the development of primary Sjögren's syndrome (SS). A 120-kilodalton organ-specific autoantigen was purified from salivary gland tissues of an NFS/sld mouse model of human SS. The amino-terminal residues were identical to those of the human cytoskeletal protein alpha-fodrin. The purified antigen induced proliferative T cell responses and production of interleukin-2 and interferon-gamma in vitro. Neonatal immunization with the 120-kilodalton antigen prevented the disease in mice. Sera from patients with SS reacted positively with purified antigen and recombinant human alpha-fodrin protein, whereas those from patients with systemic lupus erythematosus and rheumatoid arthritis did not. Thus, the immune response to 120-kilodalton alpha-fodrin could be important in the initial development of primary SS.

Assessment of regional sympathetic nerve activity in vasospastic angina: analysis of iodine 123-labeled metaiodobenzylguanidine scintigraphy

With the use of iodine 123-labeled metaiodobenzylguanidine (123I-MIBG) scintigraphy, this study evaluated regional sympathetic nerve activity in vasospastic angina. Twenty male patients with left anterior descending coronary artery spasm and 18 male patients with normal coronary arteries as a control group were studied. All patients underwent quantitative 123I-MIBG scintigraphy and atropine stress 123I-MIBG scintigraphy. Both groups showed a similar heterogeneous 123I-MIBG uptake in the left ventricle. However, the regional washout rate in patients with coronary artery spasm was significantly reduced in all three territories compared with that in the control group. In vasospastic angina, the regional washout rate in the left anterior descending coronary artery territory was significantly reduced as compared with the other two regions. After intravenous injection of 1 mg atropine, the regional washout rate in the three regions significantly increased in both groups, but the regional differences between the two groups disappeared. The current study demonstrated that cardiac sympathetic nerve activity in vasospastic angina was suppressed, especially in the territory of the spasm-induced coronary artery, probably because of the enhanced parasympathetic nerve activity.

Possible nicotinic receptor-mediated modulation of synaptic transmission in nucleus of the solitary tract

Signal transmission from afferent nerves to neurons in the nucleus of the solitary tract (NTS) may be mediated partially by nicotinic acetylcholine receptors (nAChRs). Here, we investigated nAChR-mediated signal transmission using rat NTS slices. First, we characterized nAChRs by obtaining patch-clamp recordings from NTS neuronal cell bodies. Under whole cell voltage-clamp conditions at -60 mV, application of nicotine induced an inward current, and this effect was blocked by hexamethonium. In outside-out patch recordings, nicotine was seen to induce a hexamethonium-sensitive single-channel current. Second, we investigated nAChR-mediated signal transmission. Fast synaptic transmission mediated by nAChRs was not detected. The action of diffusible acetylcholine (ACh) on nAChRs was then tested using the outside-out patches excised from NTS neurons as probes for ACh. When the patch was placed at a distance of 20-30 microm from the cell body, single-channel currents were recorded, and these were inhibited by hexamethonium. The frequency of channel opening was increased by high-extracellular potassium concentration solution suggesting the voltage-dependent release ofACh that acts on nAChRs. These results suggested that nAChR-mediated signal transmission from sensory afferents to NTS neurons is in part mediated by diffusible ACh.

Decrease in the expression of a novel TGF beta1-inducible and ras-recision gene, TSC-36, in human cancer cells

TSC-36, a TGF beta1-inducible gene, encodes a polypeptide that shows significant similarity to SPARC (secreted protein rich in cysteine), and follistatin, an activin-binding protein. The expression of the TSC-36 gene was reported to be extinguished in v-ras-transformed mouse fibroblastic cells, and also was found also to be abrogated in cells transformed with v-myc. The level of expression was, however, not affected in cells transformed with v-src, v-abl, or v-raf. The TSC-36 cDNA was first isolated from mouse cells, and recently its rat and human homologues have been reported which show striking similarity with each other. In various human tumor cells, TSC-36 mRNA was almost undetectable. TSC-36 mRNA was detected in various mouse organs, but its level was the highest in the lung. TSC-36 mRNA level was the highest in the lung among mouse organs, and on in situ hybridization, the TSC-36 transcript was detected in the alveolar epithelium but not in the bronchial epithelium. These features suggest possible usage of TSC-36 as one of the markers in human tumors.

Chromosomal deletions in Streptomyces griseus that remove the afsA locus

We have recently constructed a physical map of the Streptomyces griseus 2247 genome using the restriction enzymes AseI and DraI, which revealed that this strain carries a 7.8 Mb linear chromosome. Based on this map, precise macrorestriction fragment and cosmid maps were constructed for both ends of the chromosome, which localized the afsA gene 150 Kb from the left end. Two afsA- mutants were found to have suffered chromosomal deletions that removed the afsA locus. The sizes of the deletions were 20 and 130 Kb at the right end and 180 and 350 kb at the left end, respectively. Hybridization experiments using cosmids carrying a deletion endpoint indicated that the ends of the chromosome in the mutants were fused to form a circular chromosome.

Ectrodactyly, ectodermal dysplasia, and cleft lip syndrome. Case report

We describe five sporadic cases of the EEC syndrome (ectrodactyly, ectodermal dysplasia, and cleft lip). There are only a few reports of the syndrome being inherited in Japan. Two of the five patients had genitourinary anomalies and one mental retardation. Four of the five patients had clefts in the primary and secondary palate. All had deformities of the hands, polydactyly, syndactyly, and camptodactyly. Syndactyly could be a component of the syndrome.

cDNA cloning and expression of the Xenopus laevis vitellogenin receptor

A Xenopus laevis oocyte cDNA library was screened with a PCR-generated X. laevis vitellogenin (VTG) receptor probe and a 3.6 kb cDNA clone containing the entire open reading frame, and 5' and 3' noncoding regions were isolated. The deduced amino acid sequence was 72% homologous to the chicken VLDL/VTG receptor, and the characteristic domains were highly conserved. Ligand binding analysis confirmed that the cloned receptor was Xenopus VTG-specific. Although Northern blotting analysis revealed that this gene was expressed as a major transcript of 3.6 kb in Xenopus ovary, weak but significant expression was observed in other tissues by RT-PCR analysis. The fact that major expression of the gene occurs in the ovary suggests that it has an important function in this organ.

Truncated activin type II receptors inhibit bioactivity by the formation of heteromeric complexes with activin type I. receptors

Truncated activin type II receptors have been reported to inhibit activin receptor signaling in Xenopus embryos, although the mechanism of action for this effect has not been fully understood. In the present study we demonstrate that in P19 embryonal carcinoma cells both the induction of the activin responsive 3TP-lux reporter construct and the inhibition of retinoic acid-induced neuronal differentiation by activin are blocked by expression of a truncated activin receptor. To reveal the mechanism of action of truncated activin receptors, the interaction between different activin receptors has been investigated upon coexpression in COS cells followed by cross-linking of 125I-activin A and subsequent immunoprecipitation. Complexes between a truncated activin type IIA receptor and activin type IA and type IB receptors can be formed, as demonstrated by coimmunoprecipitation of these type I receptors with the truncated activin type IIA receptor. Other type I receptors known as ALK-1 and ALK-6 also coimmunoprecipitate with the truncated type IIA receptor, whereas ALK-3 and ALK-5 do not. Furthermore, the activin type IIB2 receptor does not coimmunoprecipitate with the truncated type IIA receptor, but decreases activin binding to the truncated type IIA receptor. In double immunoprecipitation experiments with cell lysates from COS cells, in which full-length activin type IIA and type IIB2 receptors were cotransfected, no interaction between these receptors was found. In contrast, homomeric complexes of full-length activin type IIA receptors were detected. These results implicate that truncated activin receptors can interfere with activin signaling by interacting with activin type I receptors. Additionally, truncated activin type IIB2 receptors might also interfere with type IIA receptor signaling by decreasing activin binding to the type IIA receptor and therefore might be more potent in inhibiting activin signal transduction. Furthermore, our data indicate that truncated type IIA receptors can interact with other type I receptors and as such might inhibit signal transduction by type I receptors other than activin type IA and type IB receptors.

Intravenous infusion of diltiazem causes uricosuria with concomitant hypouricemia in rats

The effects of the continuous intravenous infusion of diltiazem on plasma urate levels and the urinary excretion of urate were examined in urethane anesthetized oxonate-loaded rats. The intravenous infusion of diltiazem (4 or 10 mu g/rat/min) caused a gradual decrease in blood pressure, a gradual increase in renal blood flow and a transient increase in glomerular filtration rate. This infusion also caused diuresis, natriuresis, uricosuria and definite hypouricemia. Our results show that diltiazem infused i.v. has uricosuric and hypouricemic effects.

Follistatins neutralize activin bioactivity by inhibition of activin binding to its type II receptors

Follistatin is an activin-binding protein, which inhibits activin bioactivity in several biological systems. In the present study it is demonstrated that preincubation of iodinated activin A with follistatin, purified from porcine follicular fluid, completely abolished the binding of activin to activin type IIA, IIB2 and IIB4 receptors, and consequently to activin type IB receptor, transiently transfected in COS cells. Binding of activin A to membrane proteins on the activin-responsive P19 embryonal carcinoma cells was also prevented by this follistatin preparation. The same results were obtained with a carboxy-terminally truncated form of follistatin (FS-288), which is only present in minor amounts in the purified follistatin preparation. Since FS-288 has a high affinity for heparan sulfate proteoglycans on the cell surface, we tested whether membrane-bound FS-288 presents activin A to the different activin receptors, thereby facilitating activin binding. FS-288 did bind to the cell surface of transfected COS cells, but inhibited the binding of activin A to its receptors IIA, IIB2 and IIB4. Furthermore, after addition of FS-288 to K562 erythroleukemia cells, the total binding of activin via cell surface-bound FS-288 was increased, whereas the binding of activin A to activin type II and type I receptors present on these cells was inhibited. These findings reveal that different forms of follistatin can neutralize activin bioactivity by interference with binding of activin to all known activin type II receptors, rather than that they inhibit the binding of the type I receptor to the activin/activin type II receptor complex. In addition, our studies indicate that cell surface-associated follistatin cannot present ligand to signalling receptors.

Impaired fibrinolysis early after percutaneous transluminal coronary angioplasty is associated with restenosis

This study examined the role of fibrinolytic components in the process of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Seventy-two patients with single-vessel disease who underwent successful PTCA were prospectively selected. Tissue plasminogen activator (TPA), free plasminogen activator inhibitor-1 (free PAI-1), TPA/PAI-1 complex, and total PAI-1 antigen levels were measured before, at 1 week after, and at 3 months after PTCA. Six months after PTCA, the study patients were divided into two groups: 41 patients without restenosis and 31 patients with restenosis. There were no significant differences with regard to sex, age, coronary risk factors, or morphologic changes in the target lesions between the two groups. There were no significant differences in plasma TPA, TPA/PAI-1 complex, or total PAI-1 levels at each sampling period, or in the time courses between the two groups, except for total PAI-1 levels at 1 week after PTCA. Although no significant differences in free PAI-1 levels before PTCA were observed, free PAI-1 levels after PTCA in the patients with restenosis were significantly higher than those in the patients without restenosis. In addition, each group had a significant change in the time course of free PAI-1 levels. The results suggest that impaired fibrinolysis early after PTCA might affect the repair process of vascular injury, which leads to restenosis, and also that serial determination of free PAI-1 levels could help predict restenosis.

Juvenile hyaline fibromatosis. Case report with five years' follow-up

Juvenile hyaline fibromatosis (JHF) is a rare hereditary disorder named by Drescher et al. in 1969. As recently as 1985, only 30 cases had been reported worldwide. We report the case of a 9-year-old girl who was diagnosed with JHF at age 3 and has been closely followed since. She initially had slowly growing multiple soft tumors over her entire body as well as hypertrophic gingiva and mild bone deformities. She was originally misdiagnosed with infantile myofibromatosis at age 3. However, at age 6, because of the light and electron microscopic findings of the tumors, she was diagnosed as having JHF. Currently, at age 9, she has nodular lesions developing over her body as well as bone changes that are progressing with no evidence of regression.

A Klebsiella aerogenes moaEF operon is controlled by the positive MoaR regulator of the monoamine regulon

A 30-kDa protein accumulated upon induction by a high concentration of tyramine or dopamine in cells of Klebsiella aerogenes (Ka). These cells carried a plasmid (pAS123) that included the arylsulfatase operon (atsBA). Deletion analysis showed that the region essential for induction of the 30-kDa protein was located within a 2.0-kb cloned segment downstream of the atsBA operon. The nucleotide (nt) sequence of the 2.0-kb fragment revealed two open reading frames (ORFs), moaE and moaF. Transcription from a putative promoter of moaE was induced by the addition of tyramine, and the moaF gene was co-transcribed from this monoamine-inducible Ka promoter. The deduced Ka MoaE protein was homologous to insect-type alcohol dehydrogenase. The sequence of the 18 amino acids from the N-terminus of the purified 30-kDa protein agreed with that deduced from the nt sequence of moaF. Using a Ka strain with a mutant moaR gene, we found that MoaR, that acts as the positive regulator of the monoamine regulon, also acts as the positive regulator of the moaEF operon.

The uricosuric effect in rats of E5050, a new derivative of ethanolamine, involves inhibition of the tubular postsecretory reabsorption of urate

N-[3-[4'-(2",6"-Dimethylheptyl)phenyl]butanoyl]ethanolamine (E5050), a newly synthesized compound, was shown recently to induce uricosuria in humans via inhibition of the postsecretory reabsorption of urate. We examined the effects of this compound on urate excretion in rats loaded with oxonate and compared these effects with those of the uricosuric drugs trichlormethiazide and probenecid. When administered i.p., E5050 (0.3-15 mg/kg) increased the urinary excretion rate of urate and the ratio of urate clearance to inulin clearance in a dose-dependent manner, while the urine volume increased only slightly, and the glomerular filtration rate and plasma urate level were not changed. No paradoxical effect on urate excretion was observed. In contrast, trichlormethiazide and probenecid had a biphasic effect on urate excretion. In a pyrazinoic acid suppression test, the uricosuric effect of E5050 was completely inhibited by pretreatment with pyrazinoic acid. In a phenolsulfonphthalein (PSP) test, E5050 did not affect urinary PSP excretion, while probenecid strongly decreased such excretion. Thus, E5050 also appears to be uricosuric in rats.

Identification of activins and follistatin proteins in human follicular fluid and placenta

Follistatin, an activin-binding protein, is able to neutralize the various activities of activin by forming an inactive complex with it. The widespread tissue localization of follistatin is very similar to that of activin, which suggests that it plays a local modulatory role in the various paracrine/autocrine actions of activin. We detected significant activin-binding activities in human follicular fluid and placental homogenates, although they were much lower than those in porcine and bovine follicular fluids, which raised the possibility that follistatin is present in human follicular fluid and placenta. Therefore, we attempted to identify the protein molecules responsible for this activin-binding activity in human follicular fluid and placental homogenates. Human follicular fluid, collected from in vitro fertilization patients, was processed by affinity chromatography successive steps on sulfated gel matrices and reverse phase high performance liquid chromatography (HPLC). The final HPLC yielded abundant follistatin and almost equimolar amounts of activin-A, -AB, and -B. The follistatin protein showed characteristic multiple bands when analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The ability of each band to bind activin specifically was determined by activin binding assay and ligand blotting analysis. Several pieces of evidence, including the immunoblotting analysis and functional assay results, demonstrated the presence of three activin isoforms, A, AB, and B, in the follicular fluid. In contrast, human placental homogenates were found to contain follistatin and activin-A proteins only. Activin-AB and -B were not detected in any HPLC fraction, indicating that activin-A is the major form of activin in the human placenta. The present data indicate that the three activin isoforms and multiple forms of follistatin exist in human follicular fluid, and the activin-A isoform and follistatin exist in human placenta. They suggest that the physiological functions of the activin isoforms during embryonic development differ and that follistatin plays a functional role in the local control system(s) that regulates human reproduction.

Comparison of mesoderm-inducing activity with monomeric and dimeric inhibin alpha and beta-A subunits on Xenopus ectoderm

Activin possesses mesoderm-inducing activity, erythroid-differentiating activity, and follicle-stimulating hormone-releasing activity. The chemical structures of the activin molecule are formed by a combination of two beta-subunit peptides of inhibin. Inhibin is a dimer consisting of an alpha and beta subunit. To examine the mesoderm-inducing activity of these substances, we tested several configurations including: (1) two types of alpha-subunit peptide; (2) two types of inhibin A and B dimer; (3) beta A-subunit peptide monomer; (4) three types of activins A, AB and B, and (5) follistatin (activin-binding protein) by the animal cap assay using Xenopus laevis ectoderm, and by the erythroid-differentiating factor (EDF) test. Activins, which are composed of dimeric inhibin beta A- or beta B-subunit peptides, had the highest mesoderm-inducing and EDF activities. The monomeric beta A-subunit peptide exhibited mesoderm-inducing and EDF activities that were much lower than activin A. The inhibitory effect of follistatin on mesodermal induction by the beta A-subunit peptide was also lower than that of activin. Both inhibins A and B had very weak mesoderm-inducing activity and no EDF activity. The two types of inhibin alpha-subunit monomer had little mesoderm-inducing activity and no EDF activity. The mesoderm induction caused by activin A was not suppressed by the addition of the alpha-subunit monomer and inhibin. The mesoderm-inducing activity in relation to the chemical structures of the monomeric and/or dimeric inhibin alpha and beta A subunits is discussed.

Structural analysis of N-linked oligosaccharides of equine chorionic gonadotropin and lutropin beta-subunits

Equine chorionic gonadotropin (eCG) and lutropin (eLH) are composed of alpha- and beta-subunits with an identical amino acid sequence but show different biological activities. To elucidate the molecular difference between these gonadotropins, the structure of the N-linked oligosaccharides of each beta-subunit was determined. N-linked sugar chains, liberated as tritum-labeled oligosaccharides by hydrazinolysis followed by N-acetylation and reduction with NaB3H4, were neutralized by sialidase digestion and/or methanolytic desulfation. Neutralized oligosaccharides were fractionated by sequential chromatography on serial lectin affinity columns and on a Bio-Gel P-4 column. Each oligosaccharide structure was determined by sequential exoglycosidase digestion in conjunction with elution profiles on lectin columns and methylation analysis. Each beta-subunit contained a single N-glycosylation site, but a high degree of microheterogeneity was observed in the structure of its N-linked oligosaccharides. eCG beta contained mono-, bi-, tri-, and tetraantennary complex-type oligosaccharides in a ratio of 3:63:13:1. eCG beta oligosaccharides contained about 16% of the bisecting GlcNAc and about 20% of poly-N-acetyllactosamine structures. Elongation of N-acetyllactosamine units showed a preference to the Man alpha 1-->6 side rather than the Man alpha 1-->3 side. Triantennary chains had only a C-2, 4-branched structure. eLH beta contained only mono- and biantennary complex-type and hybrid-type oligosaccharides in a ratio of approximately 18:67:10. eLH beta also contained bisected structures in about 18%. Oligosaccharides derived from the sulfated fraction of eLH beta contained GalNAc residues at nonreducing termini. Oligosaccharides from the sialylated/sulfated fraction of eLH beta contained both Gal and GalNAc residues at nonreducing termini, and those GalNAc residues were preferentially distributed to the Man alpha 1-->3 side of the trimannosyl core. These results clearly indicate that eCG beta and eLH beta possess structurally distinct N-linked oligosaccharides in addition to different charge groups even though they have a protein moiety identical to each other. Our results suggest that the biological activity of these hormones might be modulated by its terminal charge groups and stem structures of carbohydrate moiety synthesized in different organs.

Characterization of activin A-, activin AB- and activin B-responding cells by their responses to hypothalamic releasing hormones

Activin A-, AB- and B-responding cells were characterized by their responsiveness in cytosolic free calcium ([Ca2+])i) to four hypothalamic releasing hormones, CRH, GHRH, TRH and GnRH. First, rat pituitary cells responding to activin A, AB and B in [Ca2+]i were determined in a mixed population of pituitary cells. The populations of the activin A-, AB-, and B-responding cells were 13.9%, 9.3% and 13.2%, respectively. Overlapping of response among each population of activin- responding cells was present in some of the cells. The cells responding to activin A, AB, and B were then characterized by their responses to CRH, GHRH, TRH and GnRH. Most of the cells responding to activin A, AB, and B also responded to GHRH or TRH. These results reveal that there are distinct differences among each population of activin A-, AB- and B-responding cells and that there is still functional overlapping of responsiveness among these populations. The characterization of activin-responding cells suggests involvement of somatotropes and lactotropes in activin-induced biological events in the pituitary.

Changes in the immunoreactivity of follistatin within preovulatory follicles after the primary gonadotrophin surge in rats

Cyclic changes in follistatin localization and the role of the primary gonadotrophin surge in regulating follistatin expression were studied in rat ovaries by immunohistochemistry. Two different polyclonal antisera were raised against synthetic peptides corresponding to amino acids 123-134 and 300-315 of human follistatin. Immunoreactive follistatin was detected in granulosa cells of secondary and mature follicles. Although immunoreactions with anti-follistatin (300-315) occurred in preovulatory follicles until immediately before ovulation (23:00 h on the day of pro-oestrus), follistatin was not immunodetected in newly formed corpora lutea (11:00 h on the day of oestrus). Granule-like immunoreactions with anti-follistatin (123-134) serum in preovulatory follicles markedly decreased in intensity on the evening of pro-oestrus, indicating the loss of follistatin production. Blocking the primary gonadotrophin surge by a pentobarbitone injection (40 mg kg-1) at 13:30 h on the day of pro-oestrus sustained the immunoreactivity with anti-follistatin (123-134) in preovulatory follicles up to 23:00 h on the day of pro-oestrus. Injection of pentobarbitone-treated animals with exogenous LH (100 micrograms kg-1) or FSH (50 micrograms kg-1) at 15:30 h on the day of pro-oestrus eliminated the immunoreactions. These results indicate that the expression of follistatin in preovulatory follicles is suppressed by the primary gonadotrophin surge during pro-oestrus. Hence, it is conceivable that the cessation of follistatin production in preovulatory follicles may occur before ovulation, and that it may be caused by the primary gonadotrophin surge.

Localization of activin and follistatin proteins in the Xenopus oocyte

We found a binding protein for activin and follistatin in serum from female Xenopus laevis and identified it as vitellogenin, which is synthesized in the liver and transported into yolk platelets. Then, we investigated the localization of activin and follistatin proteins in early Xenopus oocytes (stage 6) by electron microscopic immunolabeling with gold colloidal particles. The protein molecules were found to be localized uniformly in oocyte yolk platelets, but not in other cytoplasmic organelles. These findings suggest a novel role of yolk platelets as a reservoir for inductive signals transported by vitellogenin in the differentiation and patterning of cells in Xenopus embryos.

Chromosomal assignment of HepG2 3'-directed partial cDNA sequences by Southern blot hybridization using monochromosomal hybrid cell panels

Large-scale sequencing of a 3'-directed cDNA library from the human liver cell line HepG2 has generated several hundred species of cDNA gene signatures, about 85% of which identify novel genes. They are useful molecular landmarks for human genome mapping. We used 160 of these novel signatures as probes for Southern hybridization to human DNA. We then identified the copy number of the corresponding genes and assigned them to chromosomes, with reference to monochromosomal hybrid cell mapping panels. The distribution profile of the expressing genes among chromosomes suggested that the expressing gene density is not uniform.

Assessment of quantitative exercise thallium-201 emission computed tomography in patients with vasospastic angina--value of washout rate analysis

This study was performed to assess the value of washout rate analysis of quantitative exercise thallium-201 emission computed tomography in vasospastic angina patients without significant coronary stenosis. Quantitative analysis of both thallium-201 perfusion and washout rate before and after drug treatment was performed in 48 patients with vasospastic angina and no significant coronary artery stenosis. All of the patients attained more than 90% of their age-predicted heart rate during each exercise test. Before drug treatment, 26 patients exhibited exercise-induced ischemia (perfusion defects on stress polar map), 17 did not exhibit exercise-induced ischemia (normal stress and washout rate polar maps), and the remaining 5 patients showed no perfusion defects, but did show extensive abnormal washout rates. On coronary angiography, multivessel coronary spasm was documented in 12 of the 26 patients with exercise-induced ischemia, in 7 of the 17 patients without exercise-induced ischemia and in 4 patients with an extensive abnormal washout rate and a normal stress polar map. In the 17 patients without exercise-induced ischemia, the mean washout rate was significantly decreased (p < 0.05) in association with a significant decrease in the double product (p < 0.05) after drug treatment. Of the 26 patients with exercise-induced ischemia, 18 (group 1) showed an increase in the mean washout rate with improved perfusion defect after drug treatment. The remaining 8 patients (group 2) showed a decrease in the mean washout rate with improved perfusion defect after drug treatment, which increased significantly on repeat exercise test performed after additional increased doses of antianginal drugs were administered (p < 0.01). The number of patients with multivessel coronary spasm was significantly high in group 2 (p < 0.01). Thirteen patients showed an extensive abnormal washout rate before drug treatment, including 8 patients with exercise-induced ischemia and 5 patients with no perfusion defects, who showed an increased mean washout rate after drug treatment (p < 0.05). These findings indicate that washout rate analysis aids in the diagnosis in vasospastic angina patients with exercise-induced ischemia. Some patients with exercise-induced ischemia can not be detected by thallium-201 perfusion analysis alone, especially those with multivessel coronary spasm and when this procedure is performed after drug treatment. In addition, a high frequency of abnormal washout rate in vasospastic angina may result not only from exercise-induced ischemia due to main epicardial coronary artery spasm, but also from microspasm, or impairment of microcirculation or myocyte.

Identification of activins A, AB, and B and follistatin proteins in Xenopus embryos

There are several lines of evidence that activin is a crucial molecule for mesoderm induction in early Xenopus embryos. However, it is not known what kind and what amounts of activin proteins exist in cleavage stage embryos. Three isoforms of activins, A, AB, and B, were demonstrated to be present at least in part as a complex with abundant follistatin, an activin-binding protein, in early Xenopus embryos (stage 1-5). These results suggest that activin stored in eggs has an important role for mesoderm induction during early Xenopus embryogenesis and that follistatin can modulate the function of activin in signaling developmental changes.