Reversible phase transitions in polymer gels induced by radiation forces

Many polymer gels undergo reversible, discontinuous volume changes in response to changes in the balance between repulsive intermolecular forces that act to expand the polymer network and attractive forces that act to shrink it. Repulsive forces are usually electrostatic or hydrophobic in nature, whereas attraction is mediated by hydrogen bonding or van der Waals interactions. The competition between these counteracting forces, and hence the gel volume, can thus be controlled by subtle changes in parameters such as pH (ref. 4), temperature, solvent composition or gel composition. Here we describe a more direct influence on this balance of forces, by showing that the radiation force generated by a focused laser beam induces reversible shrinkage in polymer gels. Control experiments confirm that the laser-induced volume phase transitions are due to radiation forces, rather than local heating, modifying the weak interactions in the gels, in agreement with previous observations of light-induced chain association in polymer solutions. We find that, owing to shear-relaxation processes, gel shrinkage occurs up to several tens of micrometres away from the irradiation spot, raising the prospect that the combination of stimuli-responsive polymer gels and laser light might lead to new gel-based systems for applications such as actuating or sensing.

Clinicoepidemiologic features of sudden deafness diagnosed and treated at university hospitals in Japan

Nationwide epidemiologic surveys were done 3 times by the Research Committee of the Ministry of Health and Welfare in Japan to investigate the number of patients and clinical manifestations of idiopathic sudden sensorineural hearing loss (sudden deafness). The first, second, and third surveys were carried out during the 1970s, 1980s, and 1990s, respectively. For each patient, we have compiled data regarding age, sex, onset day, presence or absence of vertigo, and hearing ability, including initial and final audiograms, in a computer in the Nagoya University Computer Center. Regarding patients who visited university hospitals, complete data were collected for 421 subjects (age: 40.2+/-15.4 years, female: 203, male: 218) between July 1973 and June 1974, for 813 subjects (age: 45.1+/-15.4 years, female: 407, male: 406) in 1987, and for 1112 subjects (age: 49.1+/-16.0 years, female: 591, male: 521) in 1993. The number of patients with sudden deafness treated in university hospitals in Japan has increased, especially in the elderly population. This increase is associated with population increase and age-adjusted incidence rates per 100,000 in the elderly population. The initial and final hearing levels in the first survey were worse than those in the second and third surveys; there was no significant difference in hearing between the second and third surveys. The hearing levels were worse in children and elderly patients than in the other age groups.

Role of endogenous regucalcin in protein tyrosine phosphatase regulation in the cloned rat hepatoma cells (H4-II-E)

Regucalcin, a regulatory protein of Ca2+ signaling, is mainly present in liver cells. The role of regucalcin in hepatoma cells, however, has not been clarified. The role of endogenous regucalcin in the regulation of protein tyrosine phosphatase activity in the cloned rat hepatoma cells (H4-II-E) was investigated. Hepatoma cells were cultured for 3 days in a medium containing serum (10% fetal bovine serum). After subconfluency, the cells were used for the assay of protein phosphatase activity toward phosphotyrosine. The expression of regucalcin in hepatoma cells was detected by Western blotting using anti-regucalcin antibody. Protein tyrosine phosphatase activity was exhibited in the cytosol of hepatoma cells. The enzyme activity in the cytosol of hepatoma cells was significantly elevated by the addition of calcium chloride (10(-6)-10(-4) M) in the reaction mixture. This elevation was completely blocked by the addition of trifluoperazine (TFP: 2.5 x 10(-6) M), an antagonist of calmodulin. The addition of regucalcin (10(-7) M) caused a complete inhibition of the calcium (10(-4) M)-increased enzyme activity. The presence of anti-regucalcin monoclonal antibody (25, 50, and 100 ng/ml) in the enzyme reaction mixture produced a significant increase in protein tyrosine phosphatase activity in the cytosols of hepatoma cells and normal liver cells. This increase was completely prevented by regucalcin addition. The effect of antibody (50 ng/ml) in elevating the enzyme activity was partly inhibited by vanadate (10(-4) M). Protein tyrosine phosphatase activity was significantly elevated by the culture with Bay K 8644, a Ca2+-channel agonist. This increase was blocked by TFP addition in the enzyme reaction mixture, and it was enhanced in the presence of anti-regucalcin antibody. The present study demonstrates that regucalcin is expressed in hepatoma cells (H4-II-E), and that the protein may have an inhibitory effect on Ca2+/calmodulin-dependent protein tyrosine phosphatase activity in the cells.

Aberrant splicing of human Cu/Zn superoxide dismutase (SOD1) RNA transcripts

Two abnormal SOD1 mRNAs, exon 2-skipping and exon 2 and 3-skipping species, were identified from occipital brain tissue of sporadic amyotrophic lateral sclerosis (ALS) patients carrying no mutations in the SOD1 gene. Both transcripts were ubiquitously expressed in non-neuronal as well as neuronal tissues from a subject without neurological diseases. The expression pattern did not show disease specificity or lesional selectivity associated with ALS. Transient expression studies revealed weak expression of the proteins derived from the exon 2-skipping SOD1 cDNA in a cell-free translation system but not in cells. The putative abnormal SOD1 protein may accumulate and exert toxic effects on motor neurons in ALS when the proteolytic system is disturbed by aging or some causal factors.

The gene of Ca2+-binding protein regucalcin is highly conserved in vertebrate species

Regucalcin is a Ca2+-binding protein, which plays a regulatory role in liver cell functions related to Ca2+. In this study we have cloned cDNA for regucalcin from rabbit, bovine, chicken and toad livers by using rapid amplification of cDNA ends (RACE) method. The nucleotide and amino acid sequences of them are compared with published human, rat and mouse sequences. Comparison analysis revealed that the nucleotide sequences of regucalcin from seven vertebrate species were highly conserved in their coding region. The overall regucalcin proteins in these species consisted of 299 amino acids, and they had 69.9-91.3% identity. Furthermore, phylogenetic analysis showed that regucalcin in seven species appears to form a single cluster. This study demonstrates a great conservation of the regucalcin genes throughout evolution.

Real three-dimensional microstructures fabricated by photopolymerization of resins through two-photon absorption

Effective energy windows for two-photon absorption (TPA) photopolymerization of resins were investigated and, with a properly selected laser pulse energy, exquisite three-dimensional (3D) microstructures with submicrometer spatial resolution were achieved. The results show the inherent utility of TPA in the fabrication of real 3D patterns. In particular, we propose and utilize a resin pre-exposure technique by which freely movable components affixed to an axle are built, demonstrating a new application of TPA in laser microfabrication.

Expression of Ca(2+)-binding protein regucalcin in rat brain neurons: inhibitory effect on protein phosphatase activity

The expression of Ca(2+)-binding protein regucalcin and its role in the regulation of protein phosphatase activity in rat brain neuronal cells obtained with primary culture was investigated. The expression of regucalcin mRNA was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) analysis in brain neuronal cells using rat regucalcin-specific primers. Moreover, regucalcin protein in brain neuronal cells was detected by Western blot analysis using a polyclonal rabbit anti-regucalcin antibody. The presence of anti-regucalcin monoclonal antibody (20 or 50 ng/ml) in the enzyme reaction mixture caused a significant increase in protein phosphatase activity toward phosphotyrosine, phosphoserine and phosphothreonine in the reaction mixture containing the cytosol of neuronal cell homogenates. This increase was completely prevented by the addition of regucalcin (10(-8) M). Protein phosphatase activity toward three phosphoaminoacids was significantly elevated by the addition of Ca(2+) (100 microM) and calmodulin (5 microg/ml). This elevation was completely blocked by the addition of regucalcin (10(-8) M). The present study demonstrates that regucalcin is expressed in rat brain neuronal cells, and that it has an inhibitory effect on protein phosphatase activity in the cells.

[Evaluation of population-based lung cancer screening in Niigata and analysis of interval cases based on comparison lung cancer registry with screening records]

Survival analysis has been used as one way to examine the efficacy of cancer screening. However, this type of study is susceptible to many sources of bias, especially to a length bias. In the city of Sukumo in Japan, a survival analysis considering screening history for the purpose of eliminating the length bias was conducted. The efficacy of lung cancer screening was assessed by comparing those who participated in the screening in the year preceding diagnosis, with those who did not. The 5-year survival rate was 44% in the former and 16% in the latter. We tried to evaluate population-based lung-cancer screening in Niigata using the method as that of Sukumo by comparing lung-cancer registry data with screening records, those who died of lung cancer from 1991 to 1994 in the study area and had the opportunity to be screened were categorized according to the screening history for the year preceding diagnosis. The 5-year survival rate was 41% in those who were screened and 19% in those not screened. In addition, the median survival time of the former was 37 months, significantly longer than the 12 months of the latter. Replication of study results in different populations may suggest the efficacy of lung-cancer screening on an annual basis. We also analyzed the clinical background of 47 interval cases in the search for a future direction for the improvement of the screening method.

Primary malignant melanoma arising from the base of the tongue

A rare case of malignant melanoma of the base of the tongue in a 65-year-old Japanese woman is described. The primary and metastatic tumors were treated by surgery, chemohormone and immunotherapy. There was no recurrence for 5 years after the initial diagnosis. Electron microscopy suggested that the melanosomes of the melanoma cells in the cervical lymph nodes were less mature than those in the primary melanoma cells; melanosome immaturity was consistent with a more aggressive quality.

Transthoracic ultrasonic visualisation of coronary aneurysm, stenosis, and occlusion in Kawasaki disease

OBJECTIVE

To determine the sensitivity and specificity of our transthoracic echocardiographic technique using high frequency (7.5 MHz) transducers for identification of the presence and type of coronary artery disease in patients with Kawasaki disease.

DESIGN

The results of the prospective echocardiographic study in each of seven segments of the four major coronary arteries were compared with the selective coronary angiograms.

SETTING

Kitasato University Hospital.

SUBJECTS

60 patients with Kawasaki disease, ranging in age from 8.0 months to 22 years (median, 6.0 years).

RESULTS

Adequate echocardiographic images were obtained in 397 (95%) of 420 coronary segments. Coronary angiography showed the presence of coronary aneurysms in 87 segments and stenosis or occlusion in 28. The overall sensitivity and specificity of cross sectional echocardiography for correctly identifying coronary aneurysms were 95% and 99%, respectively; for correctly identifying coronary stenosis or occlusion the values were 85% and 98% for the right coronary artery, and 80% and 97% for the left anterior descending coronary artery. Agreement on the presence or absence of coronary aneurysms and obstructive lesions on echocardiograms between the two observers was 1.0 and 0.98, respectively.

CONCLUSIONS

Echocardiography may provide a non-invasive means of identifying the presence and type of coronary artery disease in patients with Kawasaki disease.

Echocardiographic evaluation of the ductal morphology in patients with refractoriness to lipo-prostaglandin E1 therapy

BACKGROUND

Lipo-prostaglandin (PG)E1 is effective at lower doses and has fewer side effects than PGE1-cyclodextrin (CD). Previous studies, however, have suggested that some patients show refractoriness to lipo-PGE1 in the course of treatment. The present paper examines: (i) whether such cases can be predicted by examining the ductal morphology before and 24 h after the start of lipo-PGE1 infusion; and (ii) whether PGE1-CD dilates the ductus arteriosus in patients with refractoriness to lipo-PGE1.

METHODS

The ductal morphology was evaluated with two echo indices, such as minimal and minimal plus maximal intraluminal diameters of the ductus. Two-dimensional echocardiography was performed in 24 patients with ductus-dependent congenital heart disease. The two echo indices were measured before and 24 h after lipo-PGE1 infusion and also at least twice per week until surgery.

RESULTS

In 19 of 24 patients, ductal patency was maintained until surgical treatment (group A). The remaining five patients (21%) showed ductal closure during the course of the lipo-PGE1 therapy (group B). There were no significant differences between the two groups, in either the maximal or minimal diameters, which were examined before and 24 h after treatment. In the five patients of group B, lipo-PGE1 was replaced with a relatively high dosage of PGE1-CD (50-100 ng/kg per min), resulting in good ductal patency until surgery.

CONCLUSIONS

Patients with refractoriness to lipo-PGE1 therapy could not be predicted from initial intraluminal diameters of the ductus using echocardiography. Therefore, serial echocardiographic examinations are important to detect early findings of ductal closure. In addition, PGE1-CD is still useful as back-up therapy in such patients.

Involvement of hepatic nuclear factor I binding motif in transcriptional regulation of Ca(2+)-binding protein regucalcin gene

The characterization of the binding of nuclear protein on the 5'-flanking region of the rat regucalcin gene was investigated. Nuclear extracts from rat liver and H4-II-E hepatoma cells were used for oligonucleotide competition gel mobility shift assay. An oligonucleotide between position -523 and -506 in the 5'-flanking region of the rat regucalcin gene, which contains a nuclear factor I (NF1) consensus motif TTGGC(N)(6)CC, competed with the probe for the binding of the nuclear proteins from rat liver and H4-II-E cells. The mutation of TTGGC in the consensus sequence caused an inhibition of the binding of nuclear factors. The presence of Bay K 8644, insulin, and phorbol esters could stimulate the binding of the nuclear factors to the TTGGC region of the rat regucalcin gene in H4-II-E cells. The specific mutation introduced in this region, which was ligated to a luciferase reporter gene, reduced significantly the effects of Bay K 8644, insulin, and phorbol esters in stimulating the regucalcin gene transcriptional activity in H4-II-E cells. These results suggest that the specific nuclear factor binds to the NF1-like sequence, which can stimulate the transcriptional activity, in the promoter region of regucalcin gene in liver cells.

Transcript heterogeneity of the human gene for Ca2+-binding protein regucalcin

Regucalcin is a Ca2+-binding protein which plays a regulatory role in liver cell functions related to Ca2+. In this study we have cloned and characterized cDNA for regucalcin from human liver and human hepatoma cell line Hep G2 by screening and rapid amplification of cDNA ends (RACE). The nucleotide sequences of the clones revealed that they were identical in their coding region and differed only in their 5' untranslated regions (UTRs). Northern blot analysis showed that regucalcin mRNA in the Hep G2 was longer than that of the liver. The present study demonstrates the existence of transcript heterogeneity of the human gene for regucalcin.

Increase in O(2) delivery with hyperoxia does not increase O(2) uptake in tetanically contracting dog muscle

We investigated the influence of hyperoxia on O(2) uptake in tetanically contracting canine gastrocnemius. Hyperoxia showed neither increase in O(2) uptake nor decrease in lactate release, irrespective of increased O(2) supply, venous Po(2) and vascular resistance, as compared to normoxia, suggesting that hyperoxia decreases O(2) diffusion conductance and/or effective O(2) supply probably due to arteriovenous O(2) diffusion shunt.

New index for oxygen cost of contractility from curved end-systolic pressure-volume relations in cross-circulated rat hearts

We have already reported the linear oxygen consumption per beat (VO(2))-systolic pressure-volume area (PVA) relation from the curved left ventricular (LV) end-systolic pressure-volume relation (ESPVR) in the cross-circulated rat heart. The VO(2) intercept (PVA-independent VO(2)) is primarily composed of VO(2) for Ca(2+) handling in excitation-contraction (E-C) coupling and basal metabolism. The aim of the present study was to obtain the oxygen cost of LV contractility that indicates VO(2) for Ca(2+) handling in E-C coupling per unit LV contractility change in the rat heart. Oxygen cost of LV contractility is obtainable as a slope of a linear relation between PVA-independent VO(2) and LV contractility. We obtained a composite VO(2)-PVA relation line at a mid-range LV volume (mLVV) under gradually enhanced LV contractility by stepwise increased Ca(2+) infusion and thus the gradually increased PVA-independent VO(2) values. As a LV contractility index, we could not use E(max) (ESP-V ratio; ESP/ESV) for the linear ESPVR because of the curved ESPVR in the rat LV. A PVA at a mLVV (PVA(mLVV)) has been proposed as a good index for assessing rat LV mechanoenergetics. Since the experimentally obtained PVA(mLVV) was not triangular due to the curved ESPVR, we propose an equivalent ESP-V ratio at a mLVV, (eESP/ESV)(mLVV), as a LV contractility index. This index was calculated as an ESP-V ratio of the specific virtual triangular PVA(mLVV) that is energetically equivalent to the real PVA(mLVV). The present approach enabled us to obtain a linear relation between PVA-independent VO(2) and (eESP/ESV)(mLVV) and the oxygen cost of LV contractility as the slope of this relation.

Transfection analysis of functional roles of complexin I and II in the exocytosis of two different types of secretory vesicles

Classical neurotransmitters such as gamma-aminobutyric acid and glutamate are released from synaptic nerve terminals by exocytosis of synaptic vesicles. PC12 cells also have SSVs capable of storing acetylcholine (ACh). A novel method to examine the effect of transient transfection of any gene of interest on the exocytosis of SSVs was developed. The transfection of choline acetyltransferase (ChAT) into PC12 cells which have lost ACh synthesizing activity resulted in the accumulation of a substantial amount of ACh. Synthesized ACh was released in Ca(2+)-dependent manner. Release was thought to occur by an exocytosis of SSVs because: (1) release was abolished by treating the cells with vesamicol, a specific inhibitor of the vesicular ACh transporter (VAChT) localizing specifically in SSVs; and (2) the release was further increased by cotransfecting rat VAChT with the ChAT. By means of this method, we showed that overexpression of complexin I or II with ChAT markedly suppressed high-K(+)-dependent ACh release of SSVs.

Decrease in protein kinase and phosphatase activities in the liver nuclei of rats exposed to carbon tetrachloride

The alteration in protein kinase and phosphatase activities in the liver nuclei of rats administered carbon tetrachloride (CCl(4)) was investigated. Rats received a single oral administration of CCl(4) (1 ml/100 g body wt of 5, 10, and 25% CCl(4) in corn oil), and 5, 24, and 48 h later they were euthanized by bleeding. The administration of CCl(4) (10 and 25%) caused a significant decrease in protein kinase activity in the liver nuclei. The enzyme activity in the liver nuclei from normal and CCl(4)-administered rats was significantly increased by the addition of Ca(2+) (0.5 mM) and calmodulin (10 microg/ml) in the reaction mixture, suggesting that Ca(2+)/calmodulin-dependent protein kinase activation is not suppressed by CCl(4) treatment. Liver nuclear phosphatase activity toward phosphotyrosine, but not phosphoserine and phosphothreonine, was markedly decreased by CCl(4) (5, 10, and 25%) administration. This decrease was seen 5 h after CCl(4) administration. The presence of vanadate (10(-4) M) in the reaction mixture caused a significant decrease in phosphotyrosine phosphatase activity in the liver nuclei from normal and CCl(4)-administered rats, whereas the enzyme activity was not decreased by okadaic acid (10(-5) M) or sodium fluoride (10(-3) M). The effect of anti-regucalcin antibody (100 ng/ml) in increasing phosphotyrosine phosphatase activity was seen in the liver nuclei of CCl(4)-administered rats, suggesting that regucalcin-sensitive phosphatase activity is decreased by CCl(4) administration. The present study demonstrates that CCl(4) administration induces a decrease in protein kinase and tyrosine phosphatase activities, which are involved in signaling factors in the liver nuclei of rats.

Muscle venous PO2 and VO2 are linearly related in repetitive tetanic contractions of canine muscle during hypoxic hypoxia

1. It has previously been shown that perfusion with high O2-affinity-erythrocytes decreases venous PO2 (PVO2) and decreases O2 uptake (VO2) in contracting muscle at the same O2 delivery (arterial O2 concentration x flow). A linear VO2-PVO2 relationship has been obtained with a VO2-axis intercept, suggesting that, during this type of hypoxia, VO2 is composed of a PVO2-dependent and -independent VO2. However, the VO2-PVO2 relation during hypoxic hypoxia has not been examined. 2. To clarify this relation, PVO2 and VO2 have been measured in contracting gastrocnemius (1 Hz trains of 0.2 s isometric tetani) under both normoxic and hypoxic conditions during 5 min of stimulation. 3. Venous O2 changes proportionally with O2 delivery. Each VO2-PVO2 relation was linear, with the mean described by the equation VO2 = 5.06 + 0.41 x PVO2 (n = 6, r = 0.81, P < 0.05). The VO2-axis intercept was significantly different from zero (P < 0.05). 4. These results were similar to those obtained during hypoxia induced by high O2-affinity-erythrocytes. We conclude that there is a linear relationship between PVO2 and VO2 above the VO2-axis intercept, regardless of the type of hypoxia.

Energy expenditure by Ba(2+) contracture in rat ventricular slices derives from cross-bridge cycling

To clarify the energy-expenditure mechanism during Ba(2+) contracture of mechanically unloaded rat left ventricular (LV) slices, we measured myocardial O(2) consumption (VO(2)) of quiescent slices in Ca(2+)-free Tyrode solution and VO(2) during Ba(2+) contracture by substituting Ca(2+) with Ba(2+). We then investigated the effects of cyclopiazonic acid (CPA) and 2,3-butanedione monoxime (BDM) on the Ba(2+) contracture VO(2). The Ca(2+)-free VO(2) corresponds to that of basal metabolism (2.32 +/- 0.53 ml O(2). min(-1). 100 g LV(-1)). Ba(2+) increased the VO(2) in a dose-dependent manner (from 0.3 to 3.0 mmol/l) from 110 to 150% of basal metabolic VO(2). Blockade of the sarcoplasmic reticulum (SR) Ca(2+) pump by CPA (10 micromol/l) did not at all decrease the Ba(2+)-activated VO(2). BDM (5 mmol/l), which specifically inhibits cross-bridge cycling, reduced the Ba(2+)activated VO(2) almost to basal metabolic VO(2). These energetic results revealed that the Ba(2+)-activated VO(2) was used for the cross-bridge cycling but not for the Ca(2+) handling by the SR Ca(2+) pump.

The influence of lung cancer mass screening on surgical results

BACKGROUND

After the introduction of the mass screening program for lung cancer, the number of patients detected by mass screening increased as well as the number of early staged patients. Therefore, we examined the influence of lung cancer mass screening on surgical results.

METHODS

A total of 1177 primary lung cancer cases, who underwent surgery from 1963 to 1992, were retrospectively reviewed. They were grouped according to the changes in the mass screening system: the first period (1963-1977) before lung cancer screening started, the second period (1978-1986) when mass screening was conducted by the local government, and the third period (1987-1992) after the launching of the national screening program.

RESULTS

The rate of cases detected by mass screening increased over time and the 5-year survival rate improved significantly, from 33.7% in the first period, to 51.8% in the second period and finally, to 58.4% in the third period. The improvement is attributable to a relative increase of rate of stage I cases and better stage I survival rate. Specifically, in stage I cases, improvement resulted from a relative increase of stage IA in peripheral type and roentgenographically occult lung cancer cases and from better survival rate of these two groups.

CONCLUSION

As lung cancer screening has come into widespread use, detection of peripheral small-sized lung cancer and roentgenographically occult lung cancer have increased and consequently, surgical results have improved.

The JAK-binding protein JAB inhibits Janus tyrosine kinase activity through binding in the activation loop

The Janus family of protein tyrosine kinases (JAKs) regulate cellular processes involved in cell growth, differentiation and transformation through their association with cytokine receptors. However, compared with other kinases, little is known about cellular regulators of the JAKs. We have recently identified a JAK-binding protein (JAB) that inhibits JAK signaling in cells. In the studies presented here we demonstrate that JAB specifically binds to the tyrosine residue (Y1007) in the activation loop of JAK2, whose phosphorylation is required for activation of kinase activity. Binding to the phosphorylated activation loop requires the JAB SH2 domain and an additional N-terminal 12 amino acids (extended SH2 subdomain) containing two residues (Ile68 and Leu75) that are conserved in JAB-related proteins. An additional N-terminal 12-amino-acid region (kinase inhibitory region) of JAB also contributes to high-affinity binding to the JAK2 tyrosine kinase domain and is required for inhibition of JAK2 signaling and kinase activity. Our studies define a novel type of regulation of tyrosine kinases and might provide a basis for the design of specific tyrosine kinase inhibitors.

Constitutive expression of mRNA for the same choline acetyltransferase as that in the nervous system, an acetylcholine-synthesizing enzyme, in human leukemic T-cell lines

Both muscarinic and nicotinic acetylcholine (ACh) receptors are known to be present on the surface of lymphocytes. We have shown that variable amounts of ACh are detectable in the blood of various mammals including humans, and a major portion of blood ACh is localized in circulating mononuclear leukocytes in humans. In order to investigate which types of blood cell are the source of ACh in human blood, expression of mRNA for choline acetyltransferase (ChAT, EC 2.3.1.6), which catalyzes ACh synthesis, was analyzed using human leukemic cell lines as models of lymphocytes and the reverse transcription-polymerase chain reaction (RT-PCR) method. We observed that mRNA for the same ChAT as that in the nervous system is expressed constitutively in all the T-cell lines tested, but not in B-, pre-lymphoma or monocytic cell lines. Furthermore, only T-cell lines showed high ACh-synthesizing activities and intracellular ACh contents. These results suggest that the major portion of ACh in the circulating blood originates from T-lymphocytes.

Identification and transgenic analysis of a murine promoter that targets cholinergic neuron expression

Choline acetyltransferase (ChAT) is a specific phenotypic marker of cholinergic neurons. Previous reports showed that different upstream regions of the ChAT gene are necessary for cell type-specific expression of reporter genes in cholinergic cell lines. The identity of the mouse ChAT promoter region controlling the establishment, maintenance, and plasticity of the cholinergic phenotype in vivo is not known. We characterized a promoter region of the mouse ChAT gene in transgenic mice, using beta-galactosidase (LacZ) as a reporter gene. A 3,402-bp segment from the 5'-untranslated region of the mouse ChAT gene (from -3,356 to +46, +1 being the translation initiation site) was sufficient to direct the expression of LacZ to selected neurons of the nervous system; however, it did not provide complete cholinergic specificity. A larger fragment (6,417 bp, from -6,371 to +46) of this region contains the requisite regulatory elements that restrict expression of the LacZ reporter gene only in cholinergic neurons of transgenic mice. This 6.4-kb DNA fragment encompasses 633 bp of the 5'-flanking region of the mouse vesicular acetylcholine transporter (VAChT), the entire open reading frame of the VAChT gene, contained within the first intron of the ChAT gene, and sequences upstream of the start coding sequences of the ChAT gene. This promoter will allow targeting of specific gene products to cholinergic neurons to evaluate the mechanisms of diseases characterized by dysfunction of cholinergic neurons and will be valuable in design strategies to correct those disorders.

Prospective echocardiographic analysis of progressive obstruction of the proximal pulmonary artery in congenital heart disease and obstructed pulmonary flow

BACKGROUND

It is uncertain whether proximal pulmonary artery (PA) obstruction exists soon after birth and whether its progress relates directly to postnatal ductal constriction in congenital heart disease and obstructed pulmonary flow.

METHODS

Serial morphometric analyses of the PA branches by echocardiogram were performed in 28 patients (mean age at initial study 2.5 days) until severe constriction of the ductus occurred (mean age 47 days). These patients were divided into 2 groups by subsequent angiographic or postmortem confirmation; 10 with proximal PA obstruction (group 1) and 18 without obstruction (group 2).

RESULTS

At the time of initial examination, the mean indexed diameter of the proximal PA on the side of the ductus arteriosus in group 1 was significantly smaller than that on the contralateral side (5.2+/-0.7 versus 9.0+/-0.7 mm/BSA0.5, P < .001) or that in group 2 (8.0+/-0.4 mm/BSA0.5, P < .001). In group 1, 8 patients had a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5, which was less than those of any group 2 patients. After severe constriction of the ductus, the proximal PA index on the ductal side further decreased only in group 1 (P < .01).

CONCLUSIONS

These data indicate that unilateral obstructive lesion of branch PA is present shortly after birth and its progression relates directly to ductal constriction. Neonates with branch PA obstruction can be identified on their initial echocardiogram as having a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5.

Case report: a patient who developed an amoebic liver abscess during treatment with interferon

A 65-year-old female received recombinant interferon (IFN) alpha-2b daily for the treatment of chronic hepatitis C. Fever (39 degrees C or higher) developed 14 days after the start of administration. Abdominal computed tomography suggested multiple liver abscesses, which had not been detected before IFN administration. An autopsy revealed an amoebic liver abscess. A subclinical infection of Entamoeba histolytica in this case developed into amoebic liver abscess during IFN administration.

Acetylcholine synthesis and muscarinic receptor subtype mRNA expression in T-lymphocytes

We used a sensitive and specific radioimmunoassay for acetylcholine (ACh), and detected significant amounts of ACh in the blood of various mammals, including humans. About 60% of human blood ACh was localized in mononuclear leukocytes. Human leukemic T-cell lines, used as T-lymphocyte models, contained both ACh and choline acetyltransferase (ChAT) activity. Furthermore, ChAT mRNA and protein were detected in the T-cell line MOLT-3. Phytohemagglutinin, a T-cell activator, increased both synthesis and release of ACh by MOLT-3 cells. Muscarinic receptor subtype mRNA expression was confirmed in various T-cell lines. These findings indicate that ACh synthesized by ChAT in T-lymphocytes acts on the muscarinic receptors on lymphocytes in autocrine and/or paracrine pathways and suggest that ACh in blood functions as a modulator of T-cell-dependent immune responses.

Effect of suture closure of coronary artery fistula on aneurysmal coronary artery and myocardial ischemia

This study indicates the importance of coronary angiography and myocardial scintigraphy on long-term follow-up of patients after surgery for coronary arterial fistula in view of the progression to coronary artery obstruction and myocardial ischemia.

Physiology and function of the erythropoietin receptor

Interaction between erythropoietin (EPO) and its membrane receptor induces the proliferation and differentiation of erythroid progenitors. Targeted disruption of the EPO receptor (EPOR) gene have clearly demonstrated the importance of the EPO/EPOR system for definitive erythroid cell survival and proliferation; however, in vitro rescue experiments have revealed that it is not essential for differentiation. The three-dimensional structure of the EPOR has been determined, and a biologically active 20 amino acid peptide has been shown to cause dimerization of the extracellular domain of EPOR. EPO activates the JAK2-STAT5 pathway, and two tyrosine residues (Y343, Y401) in the cytoplasmic domain of EPOR are important for STAT5 activation. However, the physiologic role of STAT5 in erythroid cell proliferation and differentiation is still controversial. Mutations that result in C-terminal deletion of EPOR are frequently found in familial erythrocytosis. Hematopoietic cell phosphatase, which binds to the C-terminal region, could be involved in negative regulation of EPOR function.

Epidemiological study and genetic analysis of GB virus C infection in general population from an area endemic for hepatitis C

The aim of this work was to study the prevalence, potential risk factors, clinical and laboratory features of GB virus C (GBV-C) infection in general population from an area endemic for hepatitis C. A reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of GBV-C RNA was used to examine the prevalence of GBV-C RNA in both hepatitis C virus (HCV) endemic (R town) and nonendemic areas (M town) in Yamagata prefecture, Japan. In R town, GBV-C RNA was detected in 23 (2.9%) out of the 800 residents, whereas anti-HCV and HCV-RNA were found in 226 (28.3%) and 163 (20.4%), respectively. The prevalence of GBV-C RNA in R town (2.9%) was higher than that in M town (1.0%), although the difference was not statistically significant. The individuals with anti-HCV had significantly higher frequency of active GBV-C-infection than those without anti-HCV in both towns. No evidence indicating that GBV-C infection affected the severity of hepatitis C was obtained. The multivariate analysis revealed that the young anti-HCV positive individuals with a history of blood transfusion had higher incidence of active GBV-C infection. The phylogenetic analysis showed that the GBV-C isolates from both R and M towns were divided into two separate branch groups designated HG and Asia GB groups.

Loss of cholinergic synapses on the spinal motor neurons of amyotrophic lateral sclerosis

The expression of vesicular acetylcholine transporter (VAChT) was examined immunohistochemically in the cholinergic synapses on the spinal motor neuron of the patient with sporadic amyotrophic lateral sclerosis (SALS). VAChT immunoreactive synapses were depleted on surviving motor neurons in SALS, while synaptophysin immunoreactivity was undiminished on the same neurons. This discrepancy suggests that in SALS, loss of cholinergic input on lower motor neurons is an early event, and may be part of the cause of death of those motor neurons.

Cloning and characterization of a novel class II phosphoinositide 3-kinase containing C2 domain

Phosphoinositide 3-kinases (PI3Ks) have been shown to play critical roles in cell growth, differentiation, survival, and vesicular transport. Class II PI3Ks have been recently identified in mouse and human (PI3K-C2 alpha/m-p170/m-cpk and HsC2-PI3K) and in Drosophila (PI3K 68D/cpk) which contain C2 domain at the C-terminus. However, their physiological function is largely unknown. We report here cloning and characterization of murine PI3K-C2 gamma, a novel class II PI3K. The catalytic domain as well as C2 domain are highly conserved in the Class II PI3K family, while the N-terminal regions of these proteins share little similarity. Unlike other Class II PI3Ks, PI3K-C2 gamma exclusively expressed in the liver, and a N-terminal truncated form was found in lung and a certain hematopoietic cell line. Specific antiserum against PI3K-C2 gamma precipitated PI3K activity from the membrane fraction of mouse liver but not from heart. Recombinant PI3K-C2 gamma exhibited a restricted lipid substrate specificity; it phosphorylated phosphatidylinositol (PtdIns) and PtdIns4P but not PtdIns(4,5)P2. Deletion mutations revealed that both the N-terminal region and the C2 domain were critical for enzymatic activity. The murine PI3K-C2 gamma gene locus was mapped to the distal region of mouse chromosome 6 in a region of homology with human chromosome 12p, which is distinct from the position of HsC2-PI3K. Cloning and biochemical characterization of the third member of class II PI3Ks provide a new insight into the function of this subfamily of PI3Ks.

Molecular characterization of the mouse vesicular acetylcholine transporter gene

The organization of the mouse choline acetyltransferase (ChAT) gene has been previously analyzed. Here we show that the first intron of the mouse ChAT gene contains an uninterrupted open reading frame. It is in the same transcriptional orientation as ChAT and encodes the vesicular acetylcholine (ACh) transporter (VAChT), the protein responsible for the translocation of cytoplasmic ACh into synaptic vesicles. The sequence of this transporter is very similar to the VAChT from rat and human (99% and 95% identity, respectively). Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed expression of mouse VAChT mRNA in spinal cord, brain (excluding the cerebellum) and brain stem, but not in peripheral tissues such as liver and kidney. Transgenic mouse analysis revealed that the 5'-flanking region of the mouse ChAT gene encompasses regulatory elements that allowed elevated expression of VAChT in the cholinergic system of transgenic mice.

Changes of expression levels of choline acetyltransferase and vesicular acetylcholine transporter mRNAs after transection of the hypoglossal nerve in adult rats

Acetylcholine, synthesized in the cytoplasm of cholinergic neurons by choline acetyltransferase (ChAT), is packaged in synaptic vesicles by vesicular acetylcholine transporter (VAChT). The entire VAChT gene has been reported to be located within the first intron of the ChAT gene. In order to examine whether or not ChAT and VAChT transcription may be coordinately regulated, the levels of ChAT and VAChT mRNAs in hypoglossal neurons were analyzed by in situ hybridization following transection of the hypoglossal nerve in adult rats. After unilateral transection, the levels of expression of ChAT and VAChT mRNAs were dramatically reduced in the ipsilateral hypoglossal nucleus 1 week after the surgery. However the expression of both mRNAs gradually recovered thereafter. These results suggest that the transcription of the two cholinergic genes is tightly linked in motor neurons.

Cloning and characterization of novel CIS family genes

We have reported two JAK-signaling modulators, CIS (cytokine-inducible SH2 protein) and JAB (JAK2 binding protein), which are structurally related. Here we cloned three additional CIS family genes (CIS2, CIS3, and CIS4) on the basis of an expression sequence tag (EST) database search. We also found at least two additional candidates of this gene family in the database. These genes were induced by erythropoietin and granulocyte-macrophage colony stimulating factor in certain hematopoietic cell lines. The SH2 domain and a C-terminal 40 amino acid region, designated the CIS homology domain (CH domain), are highly conserved in this family, while the N-terminal regions of these proteins share little similarity. A yeast two-hybrid assay and in vitro and in vivo binding assays revealed that in addition to JAB, CIS3 bound to the JAK2 tyrosine kinase domain (JH1), although the interaction of CIS3 with the JAK2-JH1 domain was much weaker than that of JAB. Transient expression of JAB and CIS3, but not other CISs, strongly inhibited leukemia inhibitory factor (LIF)-induced STAT3-reporter gene activation in 293 cells. Furthermore, constitutive overexpression of JAB and CIS3 in M1 leukemia cells prevented LIF-induced differentiation and growth arrest. Although the physiological function remains to be investigated, CIS family genes could play a role in the negative regulation of cytokine signaling by interacting with specific targets.

Evidence for active acetylcholine metabolism in human amniotic epithelial cells: applicable to intracerebral allografting for neurologic disease

Human amniotic epithelial (HAE) cells have been used for allotransplantation in patients with lysosomal storage disease due to lack of expression of HLA antigens. Previously, we have reported the expression of differentiation markers for both neural stem cells, and neuron and glial cells. In the present study, we investigated the presence of choline acetyltransferase (ChAT) and acetylcholine (ACh) in HAE cells using different experimental approaches. Cultured HAE cells showed strong immunoreactivity against ChAT antibody. ChAT activity in primary cells was 24.9 +/- 8.5 pmol/mg protein/h. Using HPLC with electrochemical detection, ACh was detected in both cell incubation media and cell pellets indicating that these cells synthesize and release ACh in a time-dependent manner. Additional confirmation of this hypothesis was gained from the data obtained from RT-PCR and Western blot analyses which revealed the expression of ChAT mRNA and ChAT protein, respectively, in HAE cells. Results of the present study suggest that HAE cells can possibly be applied for intracerebral allografting to treat neurologic diseases in which cholinergic neurons are damaged.

Detection of hepatitis G virus RNA in patients with hepatitis B, hepatitis C, and non-A-E hepatitis by RT-PCR using multiple primer sets

Hepatitis G virus(HGV)/GB virus C(GBV-C) is a newly identified virus associated with human hepatitis. The preliminary prevalence studies of HGV infection in Japan were entirely based on the detection of HGV RNA by RT-PCR. However, the selection of the different primer sets in such assay may influence sensitivity of the test because of the extensive genetic heterogeneity of HGV, and influence the estimation of the prevalence of HGV. To address this potential problem, we designed two primer sets from well conserved domains in the 5'NC and NS5 regions of HGV genome, and tested them together with the NS3-derived primer set in RT-PCR for their ability to detect HGV RNA in serial dilution of synthetic viral RNA templates. Subsequently, we used these three primer sets to detect HGV RNA in the sera of 371 Japanese patients with hepatitis B, hepatitis C, and non-A-E hepatitis. The results indicated that the primer set derived from the 5'NC region appeared to be most effective in detecting HGV RNA. The results also showed that only two out of the 126 patients (1.6%) with non-A-E hepatitis were positive for HGV RNA although the RNA were detected more frequently in patients with hepatitis B (2/38; 5.3%) and hepatitis C (17/207; 8.2%), suggesting that HGV is not a common causative agent for non-A-E hepatitis in Japan.

Case report: interferon induced coma in Sheehan's syndrome

A 54-year-old woman who was being treated with 10 million units (mu) of natural interferon (IFN)-alpha per day for chronic active hepatitis C at a local clinic, developed coma on the fourth day of treatment. On admission to Yamagata University Hospital, she was still in a state of semicoma with severe hyponatraemia (122 mEq/L) and hypochloraemia (89 mEq/L). After the administration of electrolytes, her condition improved remarkably. Endocrinological loading tests showed a hypofunction of the anterior pituitary gland. In consideration of these results, and her past experiences of haemorrhage during childbirth and subsequent amenorrhoea, we diagnosed her illness as a coma as a result of Sheehan's syndrome which had become overt during IFN therapy. She recovered completely after treatment with hydrocortisone and l-thyroxine.

A new protein containing an SH2 domain that inhibits JAK kinases

The proliferation and differentiation of cells of many lineages are regulated by secreted proteins known as cytokines. Cytokines exert their biological effect through binding to cell-surface receptors that are associated with one or more members of the JAK family of cytoplasmic tyrosine kinases. Cytokine-induced receptor dimerization leads to the activation of JAKs, rapid tyrosine-phosphorylation of the cytoplasmic domains, and subsequent recruitment of various signalling proteins, including members of the STAT family of transcription factors, to the receptor complex. Using the yeast two-hybrid system, we have now isolated a new SH2-domain-containing protein, JAB, which is a JAK-binding protein that interacts with the Jak2 tyrosine-kinase JH1 domain. JAB is structurally related to CIS, a cytokine-inducible SH2 protein. Interaction of JAB with Jak1, Jak2 or Jak3 markedly reduces their tyrosine-kinase activity and suppresses the tyrosine-phosphorylation and activation of STATs. JAB and CIS appear to function as negative regulators in the JAK signalling pathway.

Localization of two cholinergic markers, choline acetyltransferase and vesicular acetylcholine transporter in the central nervous system of the rat: in situ hybridization histochemistry and immunohistochemistry

Choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) are proteins that are required for cholinergic neurotransmission. Present knowledge concerning the organization of cholinergic structures has been derived primarily from immunohistochemistry for ChAT. In the present study, we investigated the distribution of mRNAs and the corresponding proteins for ChAT and VAChT by in situ hybridization histochemistry and immunohistochemistry. The patterns of distribution of perikarya containing ChAT mRNA. ChAT protein, VAChT mRNA and VAChT protein were similar in most regions, and co-localization in the same neuron of mRNAs for ChAT and VAChT, that of ChAT mRNA and ChAT protein, and that of VAChT mRNA and VAChT protein were demonstrated. However, in the cerebral cortex and hypothalamus, ChAT-immunoreactive perikarya were present, but they did not contain mRNAs for ChAT and VAChT, and VAChT protein. On the other hand, in the cerebellum, Purkinje cell bodies contained VAChT mRNA and VAChT protein, but they did not contain either ChAT mRNA or ChAT protein. Axon bundles were clearly revealed by immunohistochemistry for ChAT, but they were not detected by that for VAChT. Both ChAT and VAChT antibodies revealed preterminal axons and terminal-like structures. In the forebrain, they were present in the olfactory bulb, nucleus of the lateral olfactory tract, olfactory tubercle, lateral septal nucleus, amygdala, hippocampus, neocortex, caudate-putamen, thalamus and median eminence of the hypothalamus. In the brainstem, they were localized in the superior colliculus, interpeduncular nucleus and some cranial nerve motor nuclei, and further in the ventral horn of the spinal cord. These results indicate strongly that ChAT and VAChT are expressed in most of the cholinergic neurons, and that immunohistochemistry for VAChT is as useful to detect cholinergic terminal fields as that for ChAT.

CIS, a cytokine inducible SH2 protein, is a target of the JAK-STAT5 pathway and modulates STAT5 activation

We searched for immediate early cytokine responsive genes and isolated a novel gene, CIS (Cytokine Inducible SH2 containing protein) that is induced in hematopoietic cells by a subset of cytokines including interleukin-2 (IL-2), IL-3, and erythropoietin (EPO). The mutant IL-2 receptor that fails to activate STAT5 could not induce CIS, suggesting that STAT5 is involved in the cytokine-inducible expression of CIS. We cloned the 5'-flanking region of the CIS gene and found that about 200 bases upstream of the transcription-initiation site contain four potential STAT5 binding sites (MGF boxes). Luciferase reporter assays showed that these MGF boxes were essential for EPO-dependent promoter activity. Expression of STAT5 and the EPO receptor in HEK293 cells conferred EPO-dependent activation of the CIS promoter. These data indicate that CIS is a target of the JAK-STAT5 pathway of cytokine receptors. CIS contains an SH2 domain and binds to tyrosine-phosphorylated EPO and IL-3 receptors. In HEK293 cells expressing STAT5 and the EPO receptor, EPO-dependent tyrosine phosphorylation of STAT5, as well as EPO-dependent CIS-promoter activation, was suppressed when CIS was coexpressed. Moreover, the induction of oncostatin M, another STAT5 target, as well as the tyrosine-phosphorylation of STAT5, were partially suppressed by CIS expression in Ba/F3 cells. Thus, CIS is a feedback modulator of STAT5; its expression is induced by STAT5 and it negatively modulates STAT5 activation.

STAT5 activation correlates with erythropoietin receptor-mediated erythroid differentiation of an erythroleukemia cell line

Interaction between erythropoietin (EPO) and its membrane receptor induces the proliferation and differentiation of erythroid progenitors. EPO has been shown to activate the JAK2-STAT5 pathway in various hematopoietic cell lines, although the physiological role of this pathway is unclear. We have previously shown that epidermal growth factor activates a chimeric receptor bearing the extracellular domain of the epidermal growth factor receptor linked to the cytoplasmic domain of the EPO receptor, resulting in proliferation of interleukin-3-dependent hematopoietic cells and erythroid differentiation (globin synthesis) of EPO-responsive erythroleukemia cells. In the present study, we introduced various deletion and tyrosine to phenylalanine substitution in the cytoplasmic domain of the chimeric receptor and expressed these mutant chimeras in an EPO-responsive erythroleukemia cell line, ELM-I-1. Mutant chimeric receptors retaining either Tyr343 or Tyr401 could activate STAT5, judged by tyrosine-phosphorylation of STAT5 and induction of CIS, a target gene of STAT5. These mutants were able to induce erythroid differentiation. However, a chimeric receptor containing both Y343F and Y401F mutations could not activate STAT5 nor induce erythroid differentiation. Thus, Tyr343 or Tyr401 of the EPO receptor are independently necessary for erythroid differentiation as well as STAT5 activation. Moreover, exogenous expression of dominant-negative STAT5 suppressed EPO-dependent erythroid differentiation. These findings suggest that STAT5 plays an important role in erythroid differentiation through the EPO receptor cytoplasmic domain.

Human choline acetyltransferase mRNAs with different 5'-region produce a 69-kDa major translation product

Choline acetyltransferase (ChAT, EC 2.3.1.6) is the biosynthetic enzyme for acetylcholine. We have previously shown that multiple ChAT mRNA species with different 5'-noncoding regions are expressed in the rat and mouse. However, the diversity of ChAT mRNA species in human has not completely been elucidated. In this work N1- and N2-type ChAT cDNAs were cloned from a human brain cDNA library and the N-exon located in the human ChAT gene. Polymerase chain reaction analysis indicates that four species of ChAT mRNAs (R-, N1-, N2- and M-types) are produced in human brain and spinal cord. In all human transcripts, the ATG initiation codon in the rat, mouse and pig was replaced by ACG, which does not serve as an initiation codon for translation. In vitro translation and mammalian expression analyses revealed that N1-, N2- and R-type mRNAs give rise to a single 69 kDa enzyme, while M-type mRNA produces both 82 and 69 kDa enzymes. The translation efficiency of M-type mRNA was lower than that of the other mRNA species. Moreover, the translation efficiency of human ChAT mRNAs was considerably lower than that of rat ChAT mRNA, suggesting that the ATG codons for human ChAT are unfavorable for translation initiation compared with the initiation codon for rat ChAT. These results provide rational explanations for the previous reports that human ChAT protein purified from the brain and placenta had 66-70 kDa molecular mass, and that ChAT activity in a single motor neuron of human was far lower than that of other vertebrates. Sequencing of monkey ChAT gene showed that the initiation ATG in rodent ChAT was also replaced by ACA in the monkey.

Cellular proliferation and differentiation in rat atrophic gastric mucosa induced by N'-methyl-N'-nitro-N-nitrosoguanidine

It has been demonstrated that mucosal cell proliferation in atrophic gastritis is significantly accelerated, although the dynamics of the cell proliferation and differentiation have not been well characterized. We sequentially analyzed the markers of proliferation and differentiation of rat atrophic gastritis induced by MNNG. Immunohistochemical staining by anti-BrdU, anti-PCNA, and anti-PDGF-BB antibodies demonstrated that cell proliferation in atrophic gastritis was accelerated not only in the parenchymal tissue but also in the mesenchymal tissue. Expression of a gap junction protein (connexin 32), which is a marker for differentiation of epithelial cells, was reduced during the progression of atrophy. Some apoptotic cells were observed in the lower to middle third of the atrophic mucosa, whereas apoptotic cells were rarely seen in normal mucosa, which suggests that apoptosis in these parts of the mucosa may be related to the occurrence of mucosal atrophy.