[Relationship of in- and outpatient medical expenditure for the elderly to socioeconomics, medical services, and health and welfare projects]

In order to clarify what factors are associated with per capita medical care expenditure for those aged 65 years and over, for inpatients and outpatients respectively, correlation analyses were performed using several indices of medical services, socioeconomics, medical supply, health and welfare projects for fiscal 1989 among 99 administrative areas in Gifu Prefecture. The expense for inpatients was correlated with the service-acceptance rate, while on the other hand the expense for outpatients was correlated with average cost of medical receipts. Two major factors were number of physicians per person aged 65 years and over and per capita income. For outpatients, population density and per capita amount of subsidy for "elderly welfare projects" were significantly correlated with medical expenditure, with the latter showing a negative correlation. Multiple regression analyses indicated that these factors were independently correlated with the expenses. These findings indicate that expenses for inpatients and outpatients have different construction, with each being associated with different factors.

Amplification of c-MYC oncogene and point mutation of N-RAS oncogene point mutation in acute myelocytic leukemias with double minute chromosomes

Two patients with acute myelocytic leukemia (AML) showing double minute (dmin) chromosomes were analysed to identify oncogene activation. Cytogenetic analysis showed 1-53 dmin chromosomes with the normal karyotype in the first patient and 1-84 dmin chromosomes with complex chromosome aberrations. Analysis of DNA from two patients revealed five- to tenfold amplification of c-MYC oncogene in the leukemic cells. The other sixteen oncogenes studied showed no increase in the gene content. Furthermore, a transforming gene, N-RAS was detected in the first patient by nude mouse tumorigenicity assay (in vivo selection assay). These results suggest that the amplification of c-MYC gene is common in dmin-positive AML patients and co-ordination of c-MYC and N-RAS oncogene might also play a significant role in the pathogenesis of some AML patients.

Sex-dependent expression of class pi glutathione S-transferase during chemical hepatocarcinogenesis in B6C3F1 mice

Expression of class pi glutathione S-transferase (GST-II) was investigated during chemical hepatocarcinogenesis in female and male mice. Diethylnitrosamine (DEN; 10 mg/kg body wt) was administered to B6C3F1 mice on day 15 after birth, and liver sections were immunohistochemically stained with GST-II antibody at 12 and 24 weeks thereafter. In the normal mouse liver, GST-II was strongly expressed in males but only weakly in females. At 24 weeks after DEN treatment, the majority of preneoplastic foci could be detected as GST-II-positive in the female mice, while those in males were observed as to have decreased GST-II relative to the background. Class alpha GST-I and class mu GST-III did not exhibit any remarkable changes in preneoplastic foci. This result indicates that GST-II is a useful positive and negative marker for preneoplastic lesions in female and male mouse livers. In addition, class pi GST-II may be useful for the rapid screening hepatocarcinogens in mice because GST-II-positive or -negative single cells and minifoci, considered as precursor initiated populations, were detectable in females and males at 12 weeks after the DEN injection.

Sequence-specific 1H and 15N resonance assignments and secondary structure of GDP-bound human c-Ha-Ras protein in solution

All the backbone 1H and 15N magnetic resonances (except for Pro residues) of the GDP-bound form of a truncated human c-Ha-ras proto-oncogene product (171 amino acid residues, the Ras protein) were assigned by 15N-edited two-dimensional NMR experiments on selectively 15N-labeled Ras proteins in combination with three-dimensional NMR experiments on the uniformly 15N-labeled protein. The sequence-specific assignments were made on the basis of the nuclear Overhauser effect (NOE) connectivities of amide protons with preceding amide and/or C alpha protons. In addition to sequential NOEs, vicinal spin coupling constants for amide protons and C alpha protons and deuterium exchange rates of amide protons were used to characterize the secondary structure of the GDP-bound Ras protein; six beta stands and five helices were identified and the topology of these elements was determined. The secondary structure of the Ras protein in solution was mainly consistent with that in crystal as determined by X-ray analyses. The deuterium exchange rates of amide protons were examined to elucidate the dynamic properties of the secondary structure elements of the Ras protein in solution. In solution, the beta-sheet structure in the Ras protein is rigid, while the second helix (A66-R73) is much more flexible, and the first and fifth helices (S17-124 and V152-L171) are more rigid than other helices. Secondary structure elements at or near the ends of the effector-region loop were found to be much more flexible in solution than in the crystalline state.

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Detection and serotyping of rotaviruses in stool specimens by using reverse transcription and polymerase chain reaction amplification

Direct rotavirus serotyping (VP7, G type) in stool specimens was carried out by reverse transcription and polymerase chain reaction amplification (RT-PCR) and compared to serotyping by enzyme immunoassay with monoclonal antibodies (EIA-MAb). The methods used for double-stranded (ds) RNA extraction, RT-PCR amplification, and the primers used were modified from previous reports [Gouvea et al.: Journal of Clinical Microbiology 29:519-523, 1990; Gentsch et al.: Journal of Clinical Microbiology, 1992]. For samples that were positive by both methods, the serotypes obtained were identical, however RT-PCR typing was found to be considerably more sensitive (70.4% samples serotyped) than EIA-MAb (35.6% of samples serotyped). The overall sensitivities for detection of rotavirus in stool samples by latex agglutination, enzyme immunoassay, electron microscopy, polyacrylamide gel electrophoresis, and RT-PCR were essentially the same. The results confirm that RT-PCR typing (genotyping) is extremely valuable for G typing of samples which cannot be typed by EIA-MAb. We also developed a PCR confirmation technique for serotypes 1, 2, and 4.

A nickel-binding serpin, pNiXa, induces maturation of Xenopus oocytes and shows synergism with oncogenic ras-p21 protein

A nickel-binding serine proteinase inhibitor, pNiXa (43 kDa), was isolated from Xenopus ovary and assayed for effects on oocyte maturation. Microinjection of pNiXa (0.12 pmol/50 nl) induced maturation in 60% of Xenopus oocytes, beginning at 4 hours and reaching completion by 9 hours. Microinjection of oncogenic ras-p21 protein (0.12 pmol/50 nl) induced maturation in 79% of oocytes, beginning at 6 hours and reaching completion by 12 hours. Microinjection of pNiXa in combination with ras-p21 protein had a synergistic effect on maturation, which occurred in 92% of oocytes, beginning at 4 hours and reaching completion by 9 hours. Oocyte maturation did not occur in control oocytes, which received a microinjection of bovine serum albumin. In oocytes exposed to a combination of pNiXa (0.12 pmol/50 nl, by microinjection) and progesterone (10 micrograms/ml, in the medium), maturation was intermediate (68% at 9 hours) between that induced by pNiXa (60%) or progesterone (85%) alone. This study shows (a) that pNiXa is a potent inducer of oocyte maturation, (b) that pNiXa's effect is synergistic with that of oncogenic ras-p21 protein, and (c) that pNiXa partially antagonizes progesterone induction of oocyte maturation.

[Seroepidemiological study of human rotavirus in northern part of Tokyo from 1990 to 1992 by using reverse transcription-polymerase chain reaction]

A seroepidemiological study of rotavirus was conducted in the northern part of Tokyo from 1990 to 1992 by using reverse transcription-polymerase chain reaction (RT-PCR). G1 and G3 types were detected in the winter between 1990 and 1991, however G1 type was appeared mainly in the winter between 1991 and 1992. G3 type was observed as the main type during the winter in the 10 year survey in the Tokyo area for the first time. RT-PCR was useful in the seroepidemiological studies of rotavirus infection.

Ph+ acute myelogenous leukemia with t(7;11)(p15;p15) and clonal evolution in relapse after bone marrow transplantation

A 20-year-old female with Ph+ acute myelogenous leukemia (M2) associated with t(7;11)(p15;p15) is reported. Bone marrow aspirates were hypercellular with leukemic cells including Auer rods. Chromosome analysis showed t(7;11) and the Ph chromosome. After complete remission, normal karyotype was restored. Normal male karyotypic cells replaced the bone marrow following allogeneic bone marrow transplantation from her brother. On day 358, cytogenetic study at relapse revealed 14q+ as an additional change and clearly showed that the abnormal clone was derived from the patient, because metaphases with XX were all of abnormal karyotype and those with XY were normal.

Guanine-nucleotide binding activity, interaction with GTPase-activating protein and solution conformation of the human c-Ha-Ras protein catalytic domain are retained upon deletion of C-terminal 18 amino acid residues

A truncated human c-Ha-Ras protein that lacks the C-terminal 18 amino acid residues and the truncated Ras protein with the amino acid substitution Gly-->Val in position 12 were prepared by an E. coli overexpression system. The truncated Ras protein showed the same guanine-nucleotide binding activity and GTPase activity as those of the full-length Ras protein. Further, the same extent of GTPase activity enhancement due to GTPase-activating protein was observed for the truncated and full-length Ras proteins. In fact, two-dimensional proton NMR analyses indicated that the tertiary structure of the truncated Ras protein (GDP-bound or GMPPNP-bound) was nearly the same as that of the corresponding catalytic domain of the full-length Ras protein. Moreover, a conformational change around the effector region upon GDP-->GMPPNP exchange occurred in the same manner for both proteins. These observations indicate that the C-terminal flanking region (18 amino acid residues) of the Ras protein does not appreciably interact with the catalytic domain. Therefore, the truncated Ras protein is suitable for studying the molecular mechanism involved in the GTPase activity and the interaction with the GTPase-activating protein. On the other hand, an active form of the truncated Ras protein, unlike that of the full-length Ras protein, did not induce neurite outgrowth of rat pheochromocytoma PC12 cells. Thus, membrane anchoring of the Ras protein through its C-terminal four residues is not required for the interaction of Ras and GAP, but may be essential for the following binding of the Ras-GAP complex with the putative downstream target.

Effects of acute, transient coronary occlusion on global and regional right ventricular function in humans

OBJECTIVES

The aim of this study was to investigate the changes in right ventricular function during acute coronary occlusion produced by inflating a coronary angioplasty balloon catheter.

BACKGROUND

Alterations in right ventricular function are well known to occur in patients with acute myocardial infarction or ischemic cardiomyopathy. However, the changes in right ventricular function resulting from acute, transient coronary occlusion of each of the major coronary arteries have been scantily studied, perhaps because of serious limitations of currently available technology.

METHODS

A newly designed, mobile, multiwire gamma camera, in combination with generator-produced tantalum-178, affords high count rate first-pass radionuclide angiography and is thus ideal for studying right ventricular function at the bedside. Accordingly, 46 patients underwent first-pass radionuclide angiography at baseline and during transient coronary occlusion induced by a coronary angioplasty balloon catheter.

RESULTS

A significant, albeit modest, decrease in global right ventricular ejection fraction occurred during occlusion of the left anterior descending (from 42.9 +/- 9.3% to 39 +/- 8.7%, p < 0.05) and left circumflex (from 44 +/- 9.1% to 38.8 +/- 7.9%, p = 0.03) coronary arteries, but diagonal artery occlusion caused no significant change in right ventricular ejection fraction. Occlusion of the right coronary artery proximal (but not distal) to the acute marginal branch caused a significant decrease in right ventricular ejection fraction (from 42.6 +/- 4.7% to 35.7 +/- 7.2%, p < 0.01). Although occlusion of the left anterior descending, left circumflex and proximal right coronary arteries all caused significant deterioration in regional right ventricular function, only proximal right coronary occlusion caused right ventricular dilation (p < 0.005).

CONCLUSIONS

Significant impairment of right ventricular function occurs during transient occlusion of the left anterior descending, left circumflex and proximal right coronary arteries, but only occlusion of the latter causes acute right ventricular dilation, probably as a result of ischemia.

A novel cDNA clone for acid invertase in tomato fruit

The sequence of a novel cDNA clone, Aiv-1, for tomato acid invertase was similar to that of TIV1 (Klann et al., 1992) for the enzyme except for a unique intron-like insertion. It is considered that Aiv-1 is derived from either an alternatively spliced mRNA for an isozyme or a pre-mRNA of TIV1.

Possible regulation of caffeine-induced intracellular Ca2+ mobilization by intracellular free Na+

To gain some understanding of the regulatory mechanism involved in caffeine-induced Ca2+ release in adrenal chromaffin cells, we took advantage of the paradoxical observation that removal of divalent cations potentiated the secretory response to caffeine. We measured the concentration of cytosolic free Ca2+ ([Ca]in) in isolated cat chromaffin cells, by fura-2 microfluorometry, to see whether there was any correlation between the secretory response and the rise in [Ca]in. The caffeine-induced [Ca]in rise and catecholamine secretion were increased by treatment of cells with a divalent cation-deficient solution. These potentiated responses were strongly inhibited either by pretreatment with ryanodine, by the reduction of the external Na+ concentration, or by the addition of Ca2+ channel blockers. Removal of divalent cations caused a large rise in the cytosolic free Na+ concentration ([Na]in), which was measured using SBFI microfluorometry. This rise in [Na]in was reduced either by adding Ca2+ channel blockers or by reducing the external Na+ concentration. These results show a good correlation between caffeine-induced Ca2+ release and [Na]in at the time of stimulation, suggesting that caffeine-induced Ca2+ release is regulated by [Na]in.

Modulation of C2 and C3 gene expression of human peripheral blood monocytes by interleukin 1 beta, interferon gamma, tumor necrosis factor alpha and lipopolysaccharide

The effect of interleukin 1 beta (IL-1 beta), interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF alpha) and lipopolysaccharide (LPS) on the expression of the C2 and C3 genes in human adherent monocytes was studied. Stimulation of monocytes with IFN-gamma increased both C2 and C3 mRNA. IL-1 beta also increased C2 mRNA level, whereas C3 gene expression was not enhanced. TNF alpha failed to increase either C2 or C3 mRNA. LPS increased C2 mRNA, but suppressed C3 gene expression. These results suggest that C2 and C3 production by monocytes is regulated by IL-1 beta and IFN-gamma in the local tissues.

[Reactive histiocytosis during initial remission induction therapy for acute myeloblastic leukemia]

Six of 14 patients with acute myeloblastic leukemia (AML) complicated reactive histiocytosis during initial remission induction therapy. All six patients had a high fever without signs of infection during initial chemotherapy, and periods of myelosuppression were prolonged. Histiocytes with a mature appearance, some of which phagocyted erythrocytes, thrombocytes or neutrophils, increased in the bone marrow. All of 3 patients tested showed high serum levels of ferritin. Two of 3 patients treated with 125 mg/day methylprednisolone achieved complete remission. In the remaining 3 patients, one patient achieved complete remission, but the others died of fungal pneumonia or sepsis. Thus, reactive histiocytosis is one of the severe complications in patients with AML undergoing chemotherapy.

Nasal T-cell lymphoma associated with hemophagocytic syndrome. Immunohistochemical and genotypic studies

A 53-year-old man with nasal T-cell lymphoma exhibited hemophagocytic syndrome as a terminal event. Immunohistochemical studies revealed that neoplastic cells were derived from T cells. Genotypic analysis of DNA samples that were obtained from the frozen tissue specimens demonstrated clonal rearrangements of the T-cell receptor beta-chain genes. No rearrangement was observed in the immunoglobulin heavy-chain gene. To our knowledge, only three cases of nasal T-cell lymphoma with hemophagocytic syndrome have been reported before the present case. All of these cases occurred in Oriental patients. The present report suggests the beneficial effect of high-dose glucocorticoid therapy on the prolongation of survival compared with that of the other three cases.

[A case of common carotid artery stenosis due to hanging]

We report a case of a 50-year-old woman with traumatic dissection of the right common carotid artery secondary to attempted suicidal hanging. Initial examination showed marks of strangulation on the neck, facial edema, and multiple conjunctival petechiae accompanied by difficulty in breathing and loss of consciousness. She gradually recovered except for her left upper limb weakness. Rehabilitation, with a diagnosis of left brachial plexus injury, was started. Two years later, she occasionally felt numbness of the left upper extremity. On her second admission, a bruit was heard on the right side of her neck. Neurological examination did not reveal any change. CT scan showed atrophic changes. Angiography demonstrated approximately 80% stenosis of the right common carotid artery which was thought to be responsible for the attacks of numbness. Right carotid endarterectomy was performed. Histological findings revealed dissection of the medial layer of the arterial wall. Complaints of numbness disappeared postoperatively, and angiography showed good patency at a follow-up examination. We conclude that the stenosis of the common carotid artery was not due to atherosclerosis but due to the dissection as a result of hanging.

Specific phosphorylation of the acidic central region of the N-myc protein by casein kinase II

The central region of the N-myc protein has a characteristic amino acid sequence EDTLSDSDDEDD, which is very similar to those of particular domains of adenovirus E1A, human papilloma virus E7, Simian virus 40 large T, c-myc and L-myc proteins. Domains of these three viral oncoproteins have recently been shown to be specific binding sites for the tumor-suppressor gene retinoblastoma protein. We have noted that the sequence of serine followed by a cluster of acidic amino acids is exactly the same as that of a typical substrate of casein kinase II (CKII). Therefore, we investigated whether these nuclear oncoproteins are phosphorylated by CKII. For this purpose, we fused the beta-galactosidase and N-myc genes including this domain and expressed it in Escherichia coli cells. Several mutant N-myc genes, containing single amino acid substitutions in this domain, were also used to produce fused proteins. Strong phosphorylation by CKII was detected with the fused protein of wild-type N-myc. However, no phosphorylation of beta-galactosidase itself was observed and the phosphorylations of fused mutant proteins were low. Another fused N-myc protein containing most of the C-terminal region downstream of this acidic region was not phosphorylated by CKII. Analysis of phosphorylation sites in synthetic peptides of this acidic region identified the major sites phosphorylated by CKII as Ser261 and Ser263. On two-dimensional tryptic mapping of phosphorylated N-myc proteins, major spots of in vitro-labeled and in-vivo-labeled N-myc proteins were detected in the same positions. These results suggest that two serine residues of the acidic central region of the N-myc protein are phosphorylated by CKII in vivo as well as in vitro. The functional significance of this acidic domain is discussed.

[A 52-week dermal toxicity study of prednisolone farnesylate (PNF) gel in rats with a recovery period of 8 weeks]

The toxicity of Prednisolone farnesylate (PNF) gel, a synthetic glucocorticoid, was investigated in the Sprague-Dawley rat. PNF gel was administered dermally to the rats at doses of 0.125, 0.5 and 2.0 mg/kg/day for 52 weeks, then the drug was withdrawn for 8 weeks to evaluate the reversibility. The results are summarized as follows: 1. In the PNF gel 2.0 mg/kg/day group, thinning of the skin at the application site, slightly retarded body weight gains, a tendency toward a decrease in the white blood cell count, an elevation of serum GOT and GPT activity, free fatty acid level, and a decrease in alpha 1-globulin fraction were observed. In the pathological examinations, decreased organ weights of the thymus, spleen and adrenal glands, and thinning of the skin were observed. Histopathological examination revealed atrophy of the thymus and zona fasciculata of the adrenal glands, thinning of the skin with atrophied skin appendages, and hepatocellular hypertrophy with hypertrophied uncleus in the perilobular zone. 2. In the PNF gel 0.5 mg/kg/day group, thinning of the skin at the application site and a decrease in alpha 1-globulin fraction were observed. Histopathologically, thinning of the skin atrophied skin appendages was observed. 3. In the PNF gel 0.125 mg/kg/day group, there were no toxic signs induced by the drug. 4. After the 8-week recovery period, the changes in the skin were observed in the 2.0 mg/kg/day group, but the severity was lowered. The other changes disappeared and so it was demonstrated that the changes were reversible. 5. Based on these results, it was concluded that the overt toxic dose of PNF gel was 0.5 mg/kg/day and the non-toxic dose was 0.125 mg/kg/day in the present study.

DNA strand cleavage at 8-hydroxyguanine residues by hot piperidine treatment

The two findings indicate that 8-hydroxyguanine(8-OH-Gua) is a hot piperidine-sensitive lesion in DNA. These are cleavages of DNA containing 8-OH-Gua at the site of this residue and decomposition of 8-hydroxydeoxyguanosine when the DNA and nucleoside were treated in 1 M piperidine for 30 min at 90 degrees C. However, no cleavage was observed in DNA containing 8-hydroxyadenine or O6-methylguanine. 8-OH-Gua was found to be different from apurinic sites that are also alkali-labile lesions since the former was more resistant to alkali treatment. This property of 8-OH-Gua can be used as a check for the incorporation of this base into DNA after the synthesis of DNA containing 8-OH-Gua at a specific position or possibly can be one of the markers for the identification of 8-OH-Gua formed in DNA exposed to reactive oxygen species.

Deficiency of 8-hydroxyguanine DNA endonuclease activity and accumulation of the 8-hydroxyguanine in mutator mutant (mutM) of Escherichia coli

In this report, we have characterized mutM mutant with respect to its ability to repair 8-hydroxyguanine (oh8Gua) in DNA. The oh8Gua DNA endonuclease activity in mutM strain was minimal as compared with that in the wild-type cells. The presence of oh8Gua in DNA of mutM was 6-fold that of the wild-type strain corresponding to a characteristically higher frequency of G.C-->T.A transversions in this mutant strain. These results suggest that mutator phenotype of mutM is at least partially due to a spontaneous accumulation of oh8Gua resulting from a greatly reduced oh8Gua DNA endonuclease activity.

Azatyrosine inhibits neurite outgrowth of PC12 cells induced by oncogenic Ras

An antibiotic, azatyrosine [L-beta-(5-hydroxy-2-pyridyl) alanine], specifically converts ras-, raf- or c-erbB2 (neu)-transformed NIH3T3 cells to apparently normal phenotype. The reversion induced by azatyrosine is permanent, and the phenotype of the revertant cells does not change even after prolonged culture in the absence of azatyrosine [N. Shindo-Okada, O. Manabe, H. Nagahara & S. Nishimura (1989). Mol. Carcinogen., 2, 159-167]. In the present study, we found that neurite outgrowth of PC12 cells induced by expression of either the ras or raf oncogenes was inhibited by addition of azatyrosine to the medium. Azatyrosine also inhibited neurite outgrowth induced by microinjection of oncogenic Ras protein into PC12 cells. The dose dependency was much the same for the two systems, inhibition of neurite outgrowth of PC12 cells and reversion of the transformed NIH3T3 cells. Microinjection of azatyrosine into the cells was as effective as addition to the medium, indicating that the target of azatyrosine is intracellular. In contrast, neurite outgrowth induced by nerve growth factor, which has been shown to be mediated by normal Ras [N. Hagag, S. Halegouna & M. Viola (1986). Nature, 319, 680-682], was found to be resistant to azatyrosine. Azatyrosine also showed no effect on neurite outgrowth induced by a membrane-permeant cyclic AMP analog through another pathway. These findings suggest that azatyrosine sensitivity is the result of abnormal signal transduction by oncogenic Ras. It was shown that azatyrosine also inhibited differentiation-associated growth arrest of PC12 cells induced by oncogenic Ras. In Ras-induced neurite outgrowth, the azatyrosine-sensitive process was found to be completed in the first 6-9 h, and is probably essential for the commitment of PC12 cells to differentiation rather than to growth.

Clinical application of an active electrode using an operational amplifier

An active electrode (d10 mm, t6 mm) is presented, that functions as an impedance transformer (an input impedance > 10 G omega, an output impedance < 1 omega) by means of which we can derive surface EMG without any skin preparation and paste. This electrode was compared with a conventional one, and it was ascertained that the electrode could be replaced with the conventional one, and, moreover, it was preferable because it required less preparation time, and was less affected by environmental noise.