Miniature endplate currents at the newly formed neuromuscular junction in Drosophila embryos and larvae

Miniature endplate currents (mepcs) were recorded in embryos and larvae of Drosophila melanogaster with the patch clamp technique in the whole cell configuration from abdominal ventral oblique muscles. Shortly after nerve-muscle contacts (16 h after egg laying) mepcs were small and infrequent. The mean amplitude of mepcs increased abruptly during late embryonic stages but did not change any further up to second instar larvae. The amplitude distribution of mepcs was skewed toward larger amplitudes and changed drastically to a more broader distribution at the time of hatching, but did not change any further. These muscle cells were found to be electrically coupled to those in the rostral neighbor segment. The synaptic current has a fast rising phase and decayed with a single exponential throughout the developmental period examined. The decay time constant increased with amplitude but the rise time did not. Neither the rise time nor the decay time constant changed with development. Many synaptic currents decayed in a stepwise manner revealing underlying single channel events. Two discrete steps were discerned, with amplitudes of about 7.6 and 16 pA at -60 mV. These two types of channels were observed throughout the stages examined.

Synthesis and angiotensin converting enzyme-inhibitory activity of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives

As part of a search for potent and long-lasting angiotensin converting enzyme (ACE) inhibitors, various types of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives (7a, 8-11) were prepared. The key synthetic intermediate, N-[(1S)-5-(1-benzyloxycarbonyl-4-piperidyl)-1- ethoxycarbonylpentyl]-L-alanine (17a), was synthesized by asymmetric reduction of the alpha-oxoester (13) with Lactobacillus paracasei subsp. paracasei followed by a substitution reaction with tert-butyl L-alaninate (15) and subsequent treatment with hydrogen chloride. Compounds 7a and 8-11 showed potent and long-lasting ACE-inhibitory activity in rats.

Synthesis and platelet-activating factor (PAF)-antagonistic activities of 1,4-disubstituted piperazine derivatives

During the screening of novel platelet-activating factor (PAF) antagonists, we found that 1-(6-methoxy-3,4-dihydro-2-naphthoyl)-4- (3,4,5-trimethoxybenzyl)piperazine and its 4-(3,4,5- trimethoxybenzoyl)piperazine derivatives (1b, 2b) exerted in vitro and in vivo PAF-antagonistic activities. Modifications of the 1-acyl group, the substituent at the 4-position and the piperazine ring of 1a and 2b were examined and from this series 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl++ +)-4- (3,4,5-trimethoxybenzoyl)piperazine (2g) was found to be one of the most potent PAF antagonists.

Synthesis and platelet-activating factor (PAF)-antagonistic activities of trisubstituted piperazine derivatives

2- or 3-Substituted 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8- ylcarbonyl)-4-(3,4,5-trimethoxybenzoyl)- and 4-(3,4,5-trimethoxybenzyl)piperazines (2a-s, 3a, b) were prepared and evaluated for antagonistic activities against platelet-activating factor (PAF)-induced platelet aggregation and blood pressure reduction. The 2-methoxymethyl derivative (2f) showed the most potent activities in this series. The enantiomers (R)-(+)-2f and (S)-(-)-2f were synthesized from carbobenzoxy-O-benzyl-L- and D-serine in several steps. In the binding experiment, (S)-(-)-2f showed thirty times greater affinity than the R isomer for the PAF receptor.

Differential expression of homeobox-containing genes Msx-1 and Msx-2 and homeoprotein Msx-2 expression during chick craniofacial development

The expression pattern of chick Msx-1 and Msx-2 homeobox genes in craniofacial primordia was examined by in situ hybridization using cRNA probes. Both genes were expressed in the distal region of the facial primordia, where the distribution of Msx-2 expression was restricted distally within the Msx-1 expression domain. On the contrary, Msx-2 expression in the lateral choroid plexus and cranial skull was broader and more intensive than Msx-1 expression. Our findings suggest that these two genes cooperate to play differential roles in craniofacial development. Msx-2 protein was detected immunohistochemically, and its localization essentially corresponded to the mRNA expression pattern, substantiating the involvement of Msx-2 protein as a transcriptional regulator in developing limb and face.

Effect of an angiotensin II receptor antagonist, CV-11974, and its prodrug, TCV-116, on production of aldosterone

In dispersed rabbit adrenocortical glomerulosa cells, a non-peptide angiotensin II (AT1) receptor antagonist, CV-11974 (10(-10)-10(-5) M), competitively inhibited angiotensin II- or angiotensin III-stimulated aldosterone production, whereas PD123177, an angiotensin AT2 receptor antagonist, did not. CV-11974 inhibited aldosterone production induced by 4 mM K+ but not by 12 mM K+. CV-11974 had no effect on adrenocorticotropic hormone-stimulated aldosterone or corticosterone production, but inhibited angiotensin II-stimulated corticosterone production. In the rat, TCV-116, the prodrug of CV-11974, (0.1 and 1 mg/kg, p.o.) markedly reduced the elevation of both plasma aldosterone concentration and blood pressure induced by i.v. infusion of angiotensin II. In spontaneously hypertensive rats, TCV-116 at daily p.o. doses of 0.1, 1 and 10 mg/kg for 2 weeks caused a dose-dependent reduction of blood pressure and plasma aldosterone concentration without affecting plasma corticosterone. Thus, TCV-116 inhibited the induction of aldosterone production by not only exogenous but also endogenous angiotensin II.

Mapping of antigenic sites involved in serotype-cross-reactive neutralization on group A rotavirus outercapsid glycoprotein VP7

Two neutralizing monoclonal antibodies (N-mAbs) were utilized to locate amino acid (aa) residues involved in the formation of serotype-cross-reactive epitopes on the VP7 of selected group A rotaviruses. N-mAb 954/159/13 neutralized G serotype 3 as well as porcine G serotype 4 rotaviruses, whereas N-mAb 57/8 neutralized G serotype 3, 4, 6, 9, and 10 strains. Neutralization-resistant variants of each serotype were selected in the presence of these two monoclonal antibodies. Sequence analysis of the gene encoding VP7 of such variants revealed: (i) variable regions VR-5 (aa 88-100), VR-8 (aa 209-223), and VR-9 (aa 235-242) are involved in cross-reactive neutralization; (ii) an aa substitution can occur at the same position on the VP7 of different serotypes selected by a given N-mAb; (iii) the location of an aa substitution on the variant VP7 selected by a given N-mAb can vary depending on the rotavirus serotype; (iv) a substituted single aa species at a specific position on the variant VP7 selected by a single N-mAb can vary, resulting in variants which exhibit antigenic differences; and (v) the VP7 of a porcine rotavirus Gottfried strain has a unique antigenic mosaic of serotype 3 and serotype 4.

Cell adhesion activity of a 30-kDa major secreted protein from human bladder carcinoma cells

Human bladder carcinoma cell line EJ-1 secreted a protein of 30 kDa as a major component. This protein was purified from the serum-free conditioned medium of EJ-1. Its N-terminal amino acid sequence was identical to that of fibroblast-derived endothelial cell growth factor (f-ECGF), but there were differences in their amino acid compositions and isoelectric points. The 30-kDa protein showed no effect on the growth of bovine capillary endothelial cells, but it promoted the attachment and spreading of rat liver cell line BRL and human umbilical vein endothelial cell line ECV-304. These results suggest that the 30-kDa protein, tentatively named "tumor-derived adhesion factor (TAF)", may be related with the aberrant cell adhesion of cancer cells.

Expression of nerve growth factor family neurotrophins in a mouse osteoblastic cell line

With cultured osteoblastic cells, clone MC3T3-E1 derived from newborn mouse calvaria, the mRNAs encoding three representative neurotrophins, namely, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), were proved in estimation by the polymerase chain reaction (PCR) method. The increase and then subsequent decrease of all three mRNAs within the proliferation phase were followed by their gradual increase in the differentiation phase, with a tendency of enhancement by exogenous TGF-beta as was particularly evident in the case of NGF. These findings were further substantiated by identification of NGF-like neutrophils in the conditioned medium of the osteoblastic cells by an immunoblotting and neurite extension assay.

Higher-order structure of bovine mitochondrial tRNA(Phe) lacking the 'conserved' GG and T psi CG sequences as inferred by enzymatic and chemical probing

Bovine mitochondrial (mt) phenylalanine tRNA (tRNA(Phe)), which lacks the 'conserved' GG and T psi YCG sequences, was efficiently purified by the selective hybridization method using a solid phase DNA probe. The entire nucleotide sequence of the tRNA, including modified nucleotides, was determined and its higher-order structure was investigated using RNaseT2 and chemical reagents as structural probes. The D and T loop regions as well as the anticodon loop region were accessible to RNaseT2, and the N-3 positions of cytidines present in the D and T loops were easily modified under the native conditions in the presence of 10mM Mg2+. On the other hand, the nucleotides present in the extra loop were protected from the chemical modification under the native conditions. From the results of these probing analyses and a comparison of the sequences of mitochondrial tRNA(Phe) genes from various organisms, it was inferred that bovine mt tRNA(Phe) lacks the D loop/T loop tertiary interactions, but does have the canonical extra loop/D stem interactions, which seem to be the main factor for bovine mt tRNA(Phe) to preserve its L-shaped higher-order structure.

Effects of intravenous lidocaine on cardiac sympathetic nerve activity and A-V conduction in halothane-anesthetized cats

To study neural contributions to the alterations in intracardiac conduction induced by i.v. lidocaine, we measured cardiac sympathetic nerve activity (CSNA) simultaneously with sinus cycle length (SCL) and A-V cats. Sixteen cats were anesthetized with halothane in oxygen and mid-sternotomized. The His-bundle electrogram and CSNA were recorded from an electrode placed in the interatrial septum and from the left ventrolateral or ventromedial nerve, respectively. Atrium-His (A-H), His-Purkinje (H-V), and total intraventricular (H-S) conduction times were measured during atrial pacing conducted at a cycle length of 300 ms. In eight cats, 1 MAC, 2 MAC, and 3 MAC halothane were given during i.v. lidocaine (Groups H-1, H-2 and H-3). In the other eight cats, anesthesia was switched from halothane to i.v. alpha-chloralose (30-50 mg.kg BW-1; Group C). A significant decrease in CSNA with i.v. lidocaine, 2 mg.kg BW-1 was recognized in Groups C and H-1, but not in Groups H-2 and H-3. Prolongations of SCL during the spontaneous cycle, A-H and H-V in the paced mode following i.v. lidocaine were significant in Groups C, H-1 and H-2, but not significant in Group H-3. We conclude that i.v. lidocaine induces a significant decrease in CSNA during alpha-chloralose or 1 MAC halothane anesthesia which partly contributes to the control of intracardiac conduction.

[A case of ruptured left ventricular aneurysm due to syphilitic myocarditis]

This case involved a 20-year-old male who on May, 14, 1992, lost consciousness while working and went into a state of shock. He was taken to a hospital, where cardiac tamponade was diagnosed. He was later transferred to this hospital. Based on the results of echocardiography, coronary arteriography and left ventriculography, a ruptured ventricular aneurysm was diagnosed. The patient underwent emergency surgery. Serologic tests for syphilis performed at admission were definitely positive. Histopathological examination of the wall of the ventricular aneurysm disclosed fibrous myocarditis and peripheral coronary endarteritis accompanied by infiltration of plasma cells and lymphocytes. Immunohistological study revealed treponeme in the histiocytes of the aneurysmal wall. The diagnosis was a ruptured ventricular aneurysm caused by syphilitic myocarditis. Since the advent of penicillin therapy, cardiovascular syphilis, particularly syphilitic myocarditis, has become a rare disease. The chief interest of this case is that treponeme was detected in the lesion of myocarditis.

Positive and negative selection for tumor necrosis factor responsiveness reveals an inhibitory role for EGF receptor in TNF-induced antiproliferation

Tumor necrosis factor (TNF) induces dose-dependent, but incomplete cytotoxicity in ME-180 cervical carcinoma cells resulting in a significant reduction in cell viability. In this cell line there exists a characteristic residual tumor cell population that appears to be resistant to TNF. In order to investigate tumor cell heterogeneity and characteristics that correlate with their escape from TNF-induced cytotoxicity, TNF-resistant ME-180 cell variants (ME-180R) were isolated from a population of ME-180 cervical carcinoma cells (ME-180 parental). Incubation of ME-180 parental cells with TNF resulted in measurable changes in tumor cell DNA structural integrity and dose-dependent cytotoxicity, whereas ME-180R cell growth and DNA integrity were not effected by incubation with TNF. Binding of 125I-labeled TNF to a TNF-specific cell-surface receptor was measurable and equivalent on both ME-180R and ME-180 parental cells and both cell lines predominantly expressed the p55 form of the TNF receptor based upon flow cytometric analysis. Although both cell lines shared similar doubling times, intrinsic EGF receptor tyrosine kinase activity in ME-180R cells was found to be > 3-fold higher than that isolated from ME-180 parental cells. These results suggest that TNF-responsiveness may be mediated at a point subsequent to TNF binding and may be regulated, in part, by the expression of tyrosine kinase activity. To further explore this hypothesis, A431 vulvular carcinoma cells that express resistance to TNF were cloned and variants were isolated that escaped EGF-induced growth inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Existence of nuclear-encoded 5S-rRNA in bovine mitochondria

A number of proteins functioning in mitochondria are synthesized in the cytoplasm and imported into the mitochondria via specific transport systems. In mammals, on the contrary, mitochondrial membranes have generally been considered to be impermeable to nucleic acids. However, here we show that an RNA with 120 nucleotides, the sequence of which is identical to that of the nuclear-encoded 5S RNA, exists in bovine mitochondria, although the mitochondrial genome encodes no 5S RNA gene. This RNA molecule was found to be retained in purified bovine mitochondria as well as in the mitoplasts, even after extensive treatment with an RNase, demonstrating that the 5S RNA is actually located inside the mitochondrial inner membrane. The 5S rRNA molecule was also shown to exist in mitochondria from rabbit and chicken.

Characterization of serine and leucine tRNAs in an asporogenic yeast Candida cylindracea and evolutionary implications of genes for tRNA(Ser)CAG responsible for translation of a non-universal genetic code

Five serine and three leucine isoaceptor tRNAs were purified from the asporogenic yeast Candida cylindracea, in which codon CUG is translated as serine instead of leucine, and their primary structures were determined. From the wobble hypothesis, it was assumed that one of the tRNA(Leu) species (Leu1), with the anticodon CmAA, corresponded to the UUG leucine codon, and that the remaining two leucine tRNAs (Leu2 and Leu3), with the same IAG anticodon sequence would decode the CUU, CUC and CUA codons as leucine, but not the CUG codon; this was clarified by an in vitro translation experiment with C.cylindracea using synthetic mRNAs containing the CUA or CUG codons. One of the serine tRNAs (Ser1) has already been demonstrated to have the anticodon CAG and to be responsible for translation of the codon CUG in C.cylindracea. Three of the other species of tRNA(Ser) (Ser2,3 and 4), with the anticodon sequences cm5UGA, IGA and CGA, can translate all four codons in the UCN codon box, while the remaining species (Ser5), with the anticodon GCU, corresponds to AGU and AGC serine codons. The gene sequences for these five serine and three leucine tRNAs were also determined, with the finding that only tRNA(Ser)CAG (Ser1) has an intron. At least five different types of tRNA(Ser)CAG genes exist in the genome of C.cylindracea. The nucleotide sequences of the flanking regions of these tRNA(Ser)CAG genes indicated that the tRNA(Ser)CAG gene has duplicated at least three times on the genome. The existence of multiple genes for tRNA(Ser)CAG on the genome may account for the observation that codon CUG is used very frequently in C.cylindracea. All of these tRNASerCAG genes contain the CCA sequence in their 3' termini, suggesting the possibility that during their multiplication process in the evolution of the C.cylindracea genome, the tRNA(Ser)CAG molecule was integrated into DNA via reverse transcription.

Unusual anticodon loop structure found in E.coli lysine tRNA

Although both tRNA(Lys) and tRNA(Glu) of E. coli possess similar anticodon loop sequences, with the same hypermodified nucleoside 5-methylaminomethyl-2-thiouridine (mnm5s2U) at the first position of their anticodons, the anticodon loop structures of these two tRNAs containing the modified nucleoside appear to be quite different as judged from the following observations. (1) The CD band derived from the mnm5s2U residue is negative for tRNA(Glu), but positive for tRNA(Lys). (2) The mnm5s2U monomer itself and the mnm5s2U-containing anticodon loop fragment of tRNA(Lys) show the same negative CD bands as that of tRNA(Glu). (3) The positive CD band of tRNA(Lys) changes to negative when the temperature is raised. (4) The reactivity of the mnm5s2U residue toward H2O2 is much lower for tRNA(Lys) than for tRNA(Glu). These features suggest that tRNA(Lys) has an unusual anticodon loop structure, in which the mnm5s2U residue takes a different conformation from that of tRNA(Glu); whereas the mnm5s2U base of tRNA(Glu) has no direct bonding with other bases and is accessible to a solvent, that of tRNA(Lys) exists as if in some way buried in its anticodon loop. The limited hydrolysis of both tRNAs by various RNases suggests that some differences exist in the higher order structures of tRNA(Lys) and tRNA(Glu). The influence of the unusual anticodon loop structure observed for tRNA(Lys) on its function in the translational process is also discussed.

Differences in plaque size and VP4 sequence found in SA11 virus clones having simian authentic VP4

We isolated five stable SA11 clones (TN-S1, TN-S2, TN-L1, TN-L2, and BN-S4) with different plaque sizes from two SA11 stocks. In polyacrylamide gel electrophoresis, the mobilities of the fourth, fifth, and seventh RNA segments of SA11 clones with large plaque size (TN-L1 and TN-L2) were faster than those of clones with small plaque size (TN-S1, TN-S2, and BN-S4). Nucleotide sequence determination of the fourth RNA segment identified a five-amino-acid difference in VP4s between the clones with large and small plaque sizes. The VP4 sequences of two clones with small plaque size (TN-S1 and BN-S4) were the same as the sequence of SA11-SEM reported by K. Nishikawa et al. (1988, J. Virol. 62, 4022-4026), while the VP4 sequences of the clones with large plaque size (TN-L1 and TN-L2) were similar, but not identical, to that reported by D. B. Mitchell and G. W. Both (1989, Nucleic Acids Res., 17, 2122). A single-gene reassortant, K8-L2.4, in which RNA segment 4 was derived from clone TN-L2 of SA11 virus and the other RNA segments were from strain K8, produced large plaques like TN-L2, suggesting that the five-amino-acid difference in VP4 between the clones with large and small plaque sizes might be associated with the difference in plaque size.

[Mandibular reconstruction using a vascularized osteocutaneous scapular flap]

Composite tissue defect of the mandible following the surgical resection of head and neck neoplasma or osteoradionecrosis causes functional and cosmetic disorders. Mandibular reconstruction is, therefore, necessary to obtain satisfactory results. The introduction of microvascular surgery has made it possible to transfer various types of vascularized bone grafts and this technique is considered one of the most reliable procedures for mandibular reconstruction. Recently it has been reported that an osteocutaneous scapular flap is useful for mandibular reconstruction. We have performed, over the last 2.5 years, 13 mandibular reconstructions using a vascularized osteocutaneous scapular free flap, and successful results have been achieved. The features of this flap are as follows: 1) it provides a consistent blood supply to the bone and the skin and has a constant vascular pedicle; 2) since the skin island and bone flap have separate pedicles, three-dimensional reconstructions are facilitated; 3) if needed, two skin flaps can be elevated; 4) the skin island is not so bulky; 5) the lateral border of the scapula provides highly vascularized bone of thick cortical density and osteotomies are safely performed; 6) using an angular branch based on thracodorsal artery, a bi-pedicled scapula bone can be raised and two completely vascularized bone segments can be transferred with a single pedicle. Thus, a vascularized osteocutaneous scapular flap has proven very useful for complex mandibular reconstructions.

Unique structure of new serine tRNAs responsible for decoding leucine codon CUG in various Candida species and their putative ancestral tRNA genes

In an asporogenic yeast, Candida cylindracea, codon CUG is not translated as leucine but as serine. On the basis of our recent work on the determination of the genetic code using in vitro translation systems coupled with isolation of the corresponding tRNA molecules, it appears that this non-universal genetic code is unitized not only in C cylindracea but also in various Hemiascomycetes. Here we show that in addition to the species already reported, three pathogenic yeasts, C guilliermondii, C lusitaniae and C tropicalis, have tRNA(Ser)CAG, indicating that this non-universal genetic code (CUG=Ser) also exists in these species. Determination of their primary structures revealed that the uridine conserved at position 33 in usual tRNAs, is replaced by guanosine or cytidine. This suggests that the three-dimensional structures of the anticodon loop of these tRNAs differ from the conventional structure comprising the U turn in this position. Moreover, we succeeded in isolating putative ancestral serine tRNA genes whose sequences are highly homologous to tRNA(Ser)CAG in each case. These tRNA genes all have the anticodon sequence CGA corresponding to the codon UCG, indicating that tRNA(Ser)CAG might have emerged from tRNA(Ser)CGA during evolutionary change of the assignment of codon CUG.

A development of symmetric extension method for subband image coding

Describes the development of a technique for subband image coding called the symmetric extension method which utilizes the nature of a symmetrically extended image to achieve high quality coding. There are, however, some restrictions on the usable subband coding system. The development is done based on the property of a symmetrically extended signal in the analysis process to remove the restriction. The behavior of the sequence after two processes, filtering and decimation, is examined and formulated. The development extends the application area of the technique.

[The histogenesis and malignant transformation of inverted papilloma on the sino-nasal cavity--in comparison with inverted papilloma on the urinary bladder]

Inverted papilloma on the sino-nasal cavity (IP on SN) is a rare benign tumor. However, local recurrence and distant metastasis do occasionally occur. The histogenesis and histological prospects for the biological behavior of this tumor are still unknown. To clarify these issues, we histologically studied 25 cases of IP on SN and 10 cases of IP on the urinary bladder (IP on UB), which were biopsied or resected in the National Shikoku Cancer Center Hospital. Since, with regard to aspects of histogenesis such as metaplasia, dysplasia and malignant transformation, there were some similarities and differences between these two benign tumors. Biopsied or resected specimens were microscopically examined with hematoxylin-eosin (HE), periodic acid-Shiff (PAS), and Azan stains. Sixteen of 25 IP on SN presented a typical inward growth Pattern and 9 cases were simultaneously associated with an exophilic proliferation pattern. In cases of IP on UB, a typical inverted growth Pattern was observed in 3 cases. Seven of 10 IP on UB showed a complex of inward and exophilic patterns. Subsequently, we focused on metaplasia of IP, probably caused by certain physiological, chemical and inflammatory stimuli. All IP on SN bore squamous metaplasia and 5 cases simultaneously showed features of transitional metaplasia. Often, these two types of metaplasia were observed in the submucosal glands. In IP on UB, 7 of 10 cases showed squamous metaplasia and 9 cases presented intestinal metaplasia. These metaplastic changes were also found in Brunn's nest. Furthermore, the metaplastic epithelium in 24 IP on SN demonstrated stratified proliferation, atypical nuclei and/or mitosis which were considered to be evidence of malignancy. In fact, 9 of 25 IP on SN partially contained a component of squamous cell carcinoma and 7 cases out of 10 IP on UB showed features of transitional carcinoma in a portion of the papilloma lesion. This evidence suggests that both IP on SN and IP on UB originate in submucosal glands, specifically exocrine glands in the sino-nasal region and Brunn's nest in the urinary bladder. Also, in these glands, metaplastic change was commonly seen, and occasionally revealed malignant features such as squamous cell carcinoma in the sino-nasal cavity and transitional carcinoma in the urinary bladder. We finally concluded that the process of growth and the mechanism of malignant transformation might be similar between IP on SN and IP on UB and metaplastic change might play an important role in the malignant transformation of IP on SN and IP on UB.

The effect of interleukin 2 and transforming growth factor-beta 2 (TGF-beta 2) on the proliferation and natural killer activity of decidual CD16- CD56bright natural killer cells

The present study, using flow cytometry, demonstrated that CD16- CD56bright natural killer (NK) cells, which are abundant in the decidua, have both interleukin-2 receptor alpha (IL-2R alpha) and interleukin-2 receptor beta (IL-2R beta). The NK activity and DNA synthesis of CD16- CD56bright NK cells were markedly elevated even by treatment with small amounts of IL-2. These results indicate that decidual CD16- CD56bright NK cells possess a high-affinity receptor for IL-2. Transforming growth factor-beta 2 (TGF-beta 2), which is contained in the decidua and is thought to serve as a major immunosuppressive factor, reduced the NK activity of decidual CD16- CD56bright NK cells, but it hardly affected the IL-2-induced augmentation of the NK activity or DNA synthesis of decidual CD16- CD56bright NK cells. The conclusion has therefore been reached that once IL-2 is produced in the decidua, the IL-2-induced potentiation of the NK activity of decidual CD16- CD56bright NK cells cannot be suppressed by TGF-beta 2.

Concealed Wolff-Parkinson-White syndrome detected during spinal anaesthesia

We report a case of concealed Wolff-Parkinson-White syndrome detected for the first time during spinal anaesthesia in an adult male. Episodes of tachyarrhythmia with a heart rate of approximately 115 beat.min-1, wide QRS complexes and negative T waves which lasted 30-60 s, but were unassociated with hypotension, occurred three times after spinal anaesthesia. Postoperative Holter ECG monitoring showed the frequent occurrence of supraventricular premature contractions and paroxysmal supraventricular tachycardias with the same electrophysiological characteristics as those noted during spinal anaesthesia. The patient was diagnosed as having concealed Wolff-Parkinson-White syndrome. Since this condition is asymptomatic and undetectable by routine pre-operative screening it is likely that other unsuspected cases will arise. When episodes of tachyarrhythmia occur unexpectedly during anaesthesia, as was the case in this patient, postoperative examination including Holter ECG monitoring will be necessary to determine the nature and severity of the tachyarrhythmia.

Expression, purification and binding to the receptor of human insulin-like growth factor II

Human insulin-like growth factor II (IGF-II) was expressed as a fused protein with 14 additive amino acids in Escherichia coli with a high yield by an expression system using T7 RNA polymerase. Purification of the expressed protein was simply performed using only differential ultrafiltrations, giving a homogeneous preparation upon polyacrylamide gel electrophoresis and high-performance liquid chromatography. The expressed peptide was reacted with a monoclonal antibody raised against native IGF-II on a blotted membrane. Furthermore, the peptide was bound to IGF-II receptor in solubilized rat fetus membrane, though the affinity was slightly inferior to that of native IGF-II. In addition, fusion IGF-II immobilized on a gel matrix was useful for one-step purification of the IGF-II receptor with a high yield from solubilized rat fetus membranes.