YKL-40 level in gingival crevicular fluid from patients with periodontitis and type 2 diabetes.

OBJECTIVE: YKL-40 is a chitin-binding glycoprotein, the level of which increases in inflammatory diseases, diabetes mellitus (DM), cardiovascular diseases, and tumors. Gingival crevicular fluid (GCF) contains many proteins and markers of periodontitis. The purpose of this study was to investigate YKL-40 level in GCF from patients with periodontitis and DM and the association between YKL-40 level and chronic periodontitis (CP) or DM. SUBJECTS AND METHODS: The subjects were 121 patients with DM, CP, DM and periodontitis (DM-P), and healthy subjects (H). GCF was collected using paper strips after the sites for GCF collection were clinically evaluated for probing depth (PD), gingival index (GI), and bleeding on probing (BOP). YKL-40 in GCF was identified by Western blotting, and its level was determined by ELISA. RESULTS: YKL-40 was contained in GCF samples from H, DM, CP, and DM-P sites, and its levels (amount and concentration) in CP and DM-P were significantly higher than those in H and DM. GCF YKL-40 level significantly correlated with PD and GI, and its level in BOP-positive sites was significantly higher than that in BOP-negative ones. CONCLUSIONS: GCF YKL-40 level was elevated in periodontitis, but not DM. YKL-40 in GCF may be an inflammatory marker for periodontitis.

Persistent glomerular hematuria in living kidney donors confers a risk of progressive kidney disease in donors after heminephrectomy.

Although glomerular hematuria is likely a sign of chronic kidney disease that will develop into overt nephropathy after donation, it remains unclear whether prospective donors with hematuria should be excluded. We reviewed the medical records of 242 donors who donated at our institution from 2001 to 2007 and surveyed the prevalence of hematuria pre- and postdonation. We then investigated the association of hematuria with proteinuria postdonation and trends in glomerular filtration rate. Before donation, 8.3% of 242 donors presented with persistent hematuria, a finding that was significantly associated with dysmorphic hematuria before donation. Most cases of predonation persistent hematuria persisted after donation, and the overall prevalence increased to 15.3%. During a median follow-up period of 2.3 years after donation, 8.3% developed persistent proteinuria, with incidence being significantly higher in donors having persistent hematuria with dysmorphic red blood cells (d-RBC) both before and after donation. Postdonation persistent hematuria with d-RBC was also associated with a progressive decline in renal function. These results indicate that persistent glomerular hematuria is strongly associated with a higher incidence of postdonation progressive kidney disease. Potential donors with persistent glomerular hematuria should be excluded, while those with isolated hematuria need to be evaluated with heightened caution.

Laboratory and imaging features of kidney involvement in autoimmune pancreatitis: incidence, correlation, and steroid therapy response.

AIM: Autoimmune pancreatitis (AIP) is a rare subtype of chronic pancreatitis. AIP has been suggested to be complicated by tubulointerstitial nephritis or glomerulonephritis, implying that the kidney is involved as a phenotype of IgG4-positive multi-organ lymphoproliferative syndrome; however, the clinical significance of this novel entity is not well-defined. METHODS: We conducted a retrospective cohort analysis of 47 (male, 39; female, 8) AIP patients. RESULTS: The patients (mean age, 70.3 +/- 9.5 years) had a mean observation period of 4.1 years. Before treatment, renal dysfunction with an eGFR of 30 and 15 ml/min/1.73 m2 developed only in 10.6% (5/47) and 2.1% (1/47) of the patients, respectively. Nevertheless, urinary N-acetyl-beta-D-glucosaminidase and alpha1-microglobulin levels were elevated in 78.6% (11/14) and 30.8% (4/13) of the patients, respectively. Renal involvement in contrast-enhanced CT imaging was present in 18.2% (8/44) of the patients and was associated with proteinuria (p = 0.04) and a decrease in eGFR (p < 0.01). Furthermore, a follow-up CT study (mean, 545 days) revealed improved kidney lesions in 80.0% (4/5) of the patients after oral corticosteroid administration. In contrast, first-time kidney involvements appeared newly in 3.6% (1/28) of the patients after steroid therapy for nonrenal AIP symptoms, and in 14.3% (1/7) of the patients under no specific therapy (p = 0.02). CONCLUSION: Although severe renal failure develops rarely in AIP patients, renal abnormalities have been significantly detected by biochemical and radiological tests. Oral corticosteroid administration, even when not targeting symptomatic nephropathy, can treat and prevent kidney involvements in AIP.

How do living kidney donors develop end-stage renal disease?

The clinical course and risk factors for developing end-stage renal disease (ESRD) after heminephrectomy in living kidney donors have scarcely been investigated. We reviewed medical records and identified eight case donors who developed chronic kidney disease (CKD) stage 5 or ESRD, and subsequently investigated the association between postoperative clinical courses and changes in renal function. To conduct a case-control study, we also selected a control group comprising 24 donors who had maintained stable renal function and were matched for age, sex and follow-up time since donation. Except for one donor who developed ESRD caused by a traffic accident, none of the donors developed progressive renal dysfunction immediately after donation. Their renal functions remained stable for a long period of time, but started to decline after developing new comorbidities, especially risk factors known as progression factors (proteinuria or hypertension) or accelerating factors (cardiovascular [CV] event or infection) of CKD. As compared with the control donors, incidence of postoperative persistent proteinuria, acute CV event, severe infection and hospitalization due to accelerating factors of CKD were significantly higher in the case donors. These results suggest the importance of long-term (more than 10 years) follow-up of donors with special attention on the risk factors of CKD.

Co-purification of alanine-glyoxylate aminotransferase with 2-aminobutyrate aminotransferase in rat kidney.

Alanine-glyoxylate aminotransferase and 2-aminobutyrate aminotransferase were co-purified from rat kidney to a single protein (about 500-fold purified from the homogenate). The activity ratios of alanine-glyoxylate aminotransferase to 2-aminobutyrate aminotransferase were constant during co-purification steps suggesting the 2-aminobutyrate aminotransferase activity was catalysed by only alanine-glyoxylate aminotransferase. The molecular weight of the enzyme was estimated to be approx. 213 000, 220 000 and 236 000 by analytical ultracentrifugation, Sephadex G-150 gel filtration and sucrose density gradient centrifugation, respectively. From the polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, the enzyme consisted of four apparently similar subunits having a molecular weight of approx. 56 000. The enzyme was almost specific to L-alanine and L-2-aminobutyrate as amino donor and to glyoxylate, pyruvate and 2-oxobutyrate as amino acceptor. The enzyme was identified with rat liver alanine-glyoxylate aminotransferase isoenzyme 2 but not with rat liver alanine-glyoxylate aminotransferase isoenzyme 1 from Ouchterlony double diffusion analysis. Absorption spectra and some kinetic properties of the enzyme were clarified.

Electron spin resonance studies of erythrocytes from spontaneously hypertensive rats and humans with essential hypertension.

The purpose of the present study was to investigate erythrocyte membrane abnormalities in hypertension by means of an electron spin resonance and spin-label technique. The erythrocytes from spontaneously hypertensive rats (SHR) and humans with untreated essential hypertension were examined and compared with their normotensive counterparts, and electron spin resonance spectra were obtained for a fatty spin-label agent (5-nitroxy stearate) incorporated into the erythrocyte membranes. The value of outer hyperfine splitting (2T' parallel) was significantly higher in erythrocytes of SHR and humans with essential hypertension than in erythrocytes of normotensive controls (at 37 degrees C: SHR, 56.14 +/- 0.51 gauss [G], n = 8; Wistar-Kyoto rats, 52.22 +/- 0.86 G, n = 4, p less than 0.01; humans with essential hypertension, 56.94 +/- 0.27 G, n = 11; normotensive subjects, 55.44 +/- 0.36 G, n = 8, p less than 0.01). The order parameter (S) was also increased in the hypertensive rats and humans compared to their respective normotensive controls. When calcium was loaded to erythrocytes with calcium ionophore A23187 (0.9 microM) and CaCl2 (1.0 mM), the parameters of the spectra were increased. These changes were more prominent in the hypertensive groups than in the normotensive controls. These results revealed that the erythrocyte membranes of the hypertensive subjects tolerated different spin motions than those of the normotensive controls in the electron spin resonance study and that membrane fluidity might be decreased in hypertension. Additionally, calcium loading to erythrocytes caused the reduction of membrane fluidity. Therefore, it is suggested that an abnormality of calcium handling at the cellular level might affect physical properties of the biomembranes in hypertension.

Oxidation of 3-hydroxykynurenine catalyzed by methemoglobin with hydrogen peroxide.

Methemoglobin (metHb) with H2O2 catalyzed the oxidation of 3-hydroxykynurenine (3-HKY) in the reaction mixture of metHb, 3-HKY, and H2O2. The spectrophotometric experiments suggest the following mechanism for the 3-HKY oxidation by metHb with H2O2. MetHb first reacts with H2O2 to form the ferryl complex of Hb. This species then oxidizes 3-HKY, while it returns to metHb. 3-HKY was more reactive with the ferryl complex than glutathione but less reactive than ascorbic acid. Scavengers of the hydroxyl radical, dimethyl sulfoxide and ethanol, scarcely inhibited the 3-HKY oxidation by metHb with H2O2. Desferrioxamine, a metal chelator, hardly suppressed the 3-HKY oxidation. These results indicate that the hydroxyl radical is not involved in the 3-HKY oxidation by metHb with H2O2.

Cloning and recombinant expression of rat and human kynureninase.

Kynureninase [E.C.3.7.1.3.] is one of the enzymes involved in the biosynthesis of NAD cofactors from tryptophan through the kynurenine pathway. By tryptic and CNBr digestion of purified rat liver kynureninase, we obtained about 28% of the amino acid sequence of the enzyme. The rat kynureninase cDNA, isolated by means of reverse-transcribed polymerase chain reaction and hybridization screening, codes for a polypeptide of 464 amino acids. Northern blot analysis revealed the synthesis of a 2.0 kb rat kynureninase mRNA. A cDNA encoding human liver kynureninase was also isolated. The deduced amino acid sequence is 85% identical to that of the rat protein. COS-1 cells were transfected with both cDNAs. The Km values of the rat enzyme, for L-kynurenine and DL-3-hydroxykynurenine, were 440 +/- 20 microM and 32 +/- 5 microM and of the human enzyme 440 /- 20 microM and 49 +/- 6 microM, respectively. Interestingly, COS-1 cells transfected with the cDNA coding for rat kynureninase also display cysteine-conjugate beta-lyase activity.

Localization of kynurenine aminotransferase immunoreactivity in the rat hippocampus.

The localization and distribution of kynurenine aminotransferase (KAT), the biosynthetic enzyme of the excitatory amino acid receptor antagonist, kynurenic acid, was studied in the rat hippocampal formation with immunohistochemical methods. The enzyme was found mainly in glial cells that could be distinguished as 3 types on the basis of their shapes and locations. Typically, these cells shared the morphological features of astrocytes and exhibited glial fibrillary acidic protein immunoreactivity as demonstrated by a double-labeling technique. The distribution of KAT-containing glial cells was heterogeneous throughout the hippocampal formation. In the hippocampus, the stratum lacunosum-moleculare of Ammon's horn and the hilus contained a higher density of KAT-positive glial cells than other regions, whereas the lowest density of KAT glial cells was observed in the granule cell layer of the dentate gyrus and in the stratum radiatum of CA subfields. In the subicular complex, the density of KAT-containing glial cells was generally higher in the superficial than in the deep layer. Hippocampal neurons exhibiting KAT immunoreactivity, distinguished as nonpyramidal cells, were very few in number and mainly distributed in strata oriens and pyramidale of Ammon's horn. Substantially more KAT-positive neurons were observed in layers II and III of the subicular complex. The organization of cellular elements containing KAT may be of relevance for the function and possible dysfunction of kynurenic acid in the rat hippocampal formation.

Effects of calcium antagonists on membrane fluidity in hypertension--an electron spin resonance study.

We examined alterations in membrane fluidity of hypertension and the effects of calcium antagonists on these changes by means of an electron spin resonance (ESR) and spin-label technique. Washed erythrocytes from spontaneously hypertensive rats (SHRs; aged 4 and 10-13 weeks) and from patients with essential hypertension, or cultured vascular smooth muscle cells from SHRs were examined and compared with those from normotensive controls. Electron spin resonance spectra for a fatty acid spin label-agent (5-nitroxy stearate) in the membranes were obtained. The values of hyperfine splitting and other parameters of the spectra were significantly higher in erythrocytes from hypertensive rats than in normotensive controls. Similar results were obtained in cultured vascular smooth muscles. These findings indicate that the membrane fluidity might be decreased in hypertension. When calcium was loaded to erythrocytes with Ca-ionophore A23187, the fluidity was decreased. The alternative degrees were greater in hypertensive rats than in controls, and these hypertensive changes were antagonized by diltiazem or verapamil. The results revealed that abnormalities of membrane fluidity in hypertension might be more prominent in the presence of calcium. Further, it is suggested that calcium antagonists could correct these membrane abnormalities in hypertension.

Detection of nucleic acid-derived radicals formed by alloxan.

Pyrimidine base-derived radical spin adducts were detected in reaction mixtures containing pyrimidine bases, glutathione, and alloxan by the ESR spin trapping technique with a spin trap, alpha-phenyl-N-tert-butyl nitrone (PBN). Pyrimidine nucleoside- and nucleotide-, and ribose- and deoxyribose-derived radical spin adducts of PBN were also observed. However, purine base- and nucleoside-derived radical spin adducts of PBN were not detected. A cytosine-derived radical spin adduct of PBN was not generated under anaerobic conditions. Catalase and mannitol inhibited the formation of the cytosine-derived radical spin adduct of PBN but superoxide dismutase (SOD) did not. EDTA stimulated it and desferrioxamine suppressed it nearly completely. From these results it is presumed that the hydroxyl radical is involved in the formation of the cytosine-derived radical spin adduct of PBN generated by alloxan.

Detection of radical species in mixtures of some retinoids with hematin by using the ESR spin-trapping technique.

Radical species were detected in mixtures of some retinoids with hematin by using the ESR spin-trapping technique. The rates of radical formation were approximately proportional to the oxygen consumption during the incubation of the retinoids with hematin. HPLC analyses of the incubation mixtures of the retinoids with hematin showed that 5,6-epoxides of the retinoids were formed. The amounts of the epoxides formed were proportional to both oxygen consumption and the amounts of radicals formed. These results suggest that the 5,6-epoxidations proceed via radical intermediates.

Retinoic acid 5,6-epoxidation by hemoproteins.

Retinoic acid 5,6-epoxidase activity was found in several hemoproteins such as human oxy- and methemoglobin (HbO2 and MetHb), equine skeletal muscle oxy- and metmyoglobin (MbO2 and MetMb), bovine liver catalase, and horseradish peroxidase. Hematin also catalyzed retinoic acid 5,6-epoxidation. The results suggest that the heme moiety participates in the epoxidation. However, neither horse heart cytochrome c, nor free ferrous ion nor free ferric ion exhibited the epoxidase activity. Some hemoproteins (HbO2, MetHb, MbO2, MetMb, catalase, peroxidase, and hematin) exhibited characteristic individual pH dependences of the activity, suggesting that the epoxidase activities of the hemoproteins are influenced by the apoenzymes to some degree. This view is also supported by the finding that preincubation of an HbO2 preparation at various temperatures (37-70 degrees C) reduced its epoxidase activity with increasing temperature, whereas the activity of hematin was unaffected. Active oxygen scavengers such as mannitol, catalase, and superoxide dismutase exhibited no effect on the epoxidase activities of HbO2, MetHb, MbO2, and MetMb. A ligand of heme, CN- (100 mM), inhibited the epoxidase activities but N3- (100 mM) did not. The epoxidase activities were completely inhibited by NADPH, NADH, and/or 2-mercaptoethanol but not by NADP+ and/or NAD+. An intermediate in the epoxidation may be reduced by NADPH, NADH and/or 2-mercaptoethanol. Radical species can be considered as plausible candidates for the intermediate.

Purification and amino- and carboxyl-terminal amino acid sequences of alanine-glyoxylate transaminase 1 from human liver.

In order to confirm the amino acid sequence predicted from the nucleotide sequence of cDNA and also to elucidate the intracellular localization and molecular evolution, human liver alanine-glyoxylate transaminase 1 (AGT1) was purified and subjected to partial amino acid sequence determination, with special attention to posttranslational modification. The enzyme was purified to homogeneity from the 10,000 x g supernatant of human liver homogenate. The purified enzyme showed only a single protein band at about 43 kDa on SDS-PAGE, indicating that it is a homodimer of two identical subunits, because the native enzyme has a molecular mass of about 80 kDa. Both the amino- and carboxyl-terminal peptides of the enzyme were isolated from a cyanogen bromide digest of the S-carboxyl-methylated protein and subjected to amino acid sequence determination. The alpha-amino group of the amino-terminal peptide was shown to be blocked by an acetyl group. The carboxyl-terminal sequence contained a putative N-glycosylation sequence (-Asn-Ala-Thr-), the only one present in the whole molecule, but this sequence was normally determined, indicating that the enzyme is not N-glycosylated. Purdue et al. [J. Cell Biol. 111, 2341-2351 (1990)] have reported that Pro-11, Gly-170, and Ile-340 in normal human AGT1 were replaced by Leu, Arg, and Met, respectively, in a patient with primary hyperoxaluria type 1. We confirmed that residue-11 was Pro. Both the amino- and carboxyl-terminal sequences of the enzyme showed extensive similarity with those of rat liver mitochondrial serine-pyruvate aminotransferase and the small chain of hydrogenase from a thermophilic unicellular cyanobacterium, Synechococcus PCC 6716.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement by catechols of hydroxyl-radical formation in the presence of ferric ions and hydrogen peroxide.

The effect of caffeic acid, a kind of catechol, on the Fenton reaction was examined by using the ESR spin trapping technique. Caffeic acid enhanced the formation of hydroxyl radicals in the reaction mixture, which contained caffeic acid, hydrogen peroxide, ferric chloride, EDTA, and potassium phosphate buffer. Chlorogenic acid, which is an ester of caffeic acid with quinic acid, also stimulated the formation of the hydroxyl radicals. Quinic acid did not stimulate the reaction, suggesting that the catechol moiety in chlorogenic acid is essential to the enhancement of the hydroxyl-radical formation. Indeed, other catechols and related compounds such as pyrocatechol, gallic acid, dopamine, and noradrenaline effectively stimulated the formation of the hydroxyl radicals. The above results confirm the idea that the catechol moiety is essential to the enhancement. Ferulic acid, 4-hydroxy-3-methoxybenzoic acid, and salicylic acid had no effect on the formation of the hydroxyl radicals. The results indicate that the enhancement by the catechols of the formation of hydroxyl radicals is diminished if a methyl ester is formed at the position of the hydroxyl group of the catechol. In the absence of iron chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP, formation of hydroxyl radicals was not detected, suggesting that chelators are essential to the reaction. The enhancement of the formation of hydroxyl radicals is presumably due to the reduction of ferric ions by the catechols. Thus, the catechols may exert deleterious effects on biological systems if chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP are present.

Fluorometric measurement of urinary alpha-L-iduronidase activity.

A fluorogenic substrate for alpha-L-iduronidase, 4-methylumbelliferyl alpha-L-iduronide, has been newly synthesized and the enzyme activity has been measured in urine samples obtained from normal persons and patients suffering from mucopolysaccharidosis. Urine samples derived from a patient with Scheie syndrome showed greatly reduced activity compared with a normal adult at a similar age. This patient exhibited a high level of urinary excretion of dermatan sulfate and heparan sulfate, which could be interpreted in terms of her low alpha-L-iduronidase activity. The use of the fluorogenic substrate has some advantages over existing methods because of the high sensitivity and the relative ease of handling, and it should be useful not only for diagnosis but also for following the purification process of the enzyme.

Molecular cloning and sequencing of a cDNA encoding alanine-glyoxylate aminotransferase 2 from rat kidney.

Alanine-glyoxylate aminotransferase (AGT) 2 is a pyridoxal 5'-phosphate dependent, mitochondrial enzyme which, in the rat, is expressed at a high level in the kidney. The amino acid sequences of nine tryptic and seven CNBr peptides of the rat kidney AGT2 were determined. Three overlapping cDNAs encoding the AGT2 were cloned on the basis of its partial amino acid sequences by means of a polymerase chain reaction-based approach involving rat kidney poly(A)+ RNA. The complete cDNA sequence comprised 1,919 bases, and contained a 1,536-base open reading frame which encodes a polypeptide of 512 amino acid residues with a putative presequence consisting of 39 amino acid residues at the amino terminus, giving a precursor protein with a molecular mass of 57,150 Da. The sequence of AGT2 exhibits significant homology with neither peroxisomal AGT1 from human liver nor mitochondrial AGT1 from rat liver. However, the sequence of AGT2 exhibited 30.8, 29.2, and 27.1% identity with those of Escherichia coli 4-aminobutyrate aminotransferase, rat ornithine aminotransferase, and Pseudomonas cepacia 2,2-dialkylglycine decarboxylase, respectively. The active site sequences were also well conserved among these aminotransferases. AGT2, thus, is more similar to the other aminotransferases than to AGT1. The results suggest that the rat kidney AGT2 may play a biological role in amino acid metabolism distinct from that of AGT1.

Immuno-localization of kynurenine aminotransferase (KAT) in the rat medulla and spinal cord.

In the mammalian brain, kynurenine aminotransferase (KAT) is pivotal to the synthesis of kynurenic acid, a preferential antagonist at the strychnine-insensitive NMDA-glycine site. As NMDA receptors are involved in autonomic function, we have examined the immunohistochemical localization of KAT in the medulla and spinal cord of the rat. KAT immunoreactivity (KAT-li) was found throughout these areas, in both glia and neurons. Unlike the mainly astrocytic localization in forebrain structures, KAT-li was predominantly neuronal, notably in areas important for blood pressure and heart rate regulation: ventral medulla, nucleus ambiguus, nucleus of the solitary tract and intramediolateral cell column of the spinal cord. The presence of KAT in these nuclei supports a neuromodulatory role for kynurenic acid in NMDA-mediated autonomic function.

Purification and characterization of kynurenine-pyruvate aminotransferase from rat kidney and brain.

Kynurenine-pyruvate aminotransferase (KPT), the enzyme responsible for the biosynthesis of the endogenous excitatory amino acid receptor antagonist kynurenic acid, was purified to homogeneity from rat kidney, as judged by polyacrylamide and sodium dodecyl sulfate electrophoresis. The protein appeared to consist of 2 identical subunits of approximately 48 kDa. Kinetic analysis showed Km values of 2.8 mM (kynurenine) and 3.8 mM (pyruvate), respectively. KPT was also partially purified from rat brain. Kidney and brain KPT were found to be identical when analyzed by a spectrum of biochemical, physico-chemical and, after production of anti-kidney KPT antibodies, immunological methods. Partially purified anti-KPT antiserum was used for first immunohistochemical studies, which revealed the presence of the enzyme in astrocyte-like cells throughout the brain. Less frequently, KPT was also found in discretely arranged neurons. The availability of pure KPT and specific anti-KPT antibodies can be expected to be of value for the further examination of the neurobiology of kynurenic acid.

Peroxisome localized human hepatic alanine-glyoxylate aminotransferase and its application to clinical diagnosis.

The subcellular localization of alanine-glyoxylate aminotransferase (EC 2.6.1.44 L-Alanine: glyoxylate aminotransferase) of adult human liver was examined by sucrose density gradient centrifugation. The enzyme sedimented at the same density as catalase, indicating that it was localized in the peroxisomes. Alanine-glyoxylate aminotransferase activity in the liver of patients with cirrhosis was about 65% of that of normal liver or 71% of that from patients with chronic hepatitis, but its activity in the serum of patients with cirrhosis was higher than that from patients with chronic hepatitis. Patterns of activity of alanine-glyoxylate aminotransferase in liver and serum differed from those of aspartate-2-oxoglutarate aminotransferase and ornithine carbamoyltransferase that have a different intracellular location. Serum immunoreactive alanine-glyoxylate aminotransferase (Im-AGT) was measured by enzyme-linked immunoadsorbent assay (ELISA). The Im-AGT levels (mean +/- SEM) in acute (80 +/- 13 micrograms/L) and chronic (72 +/- 4 micrograms/L) hepatitis were higher than those of normal controls (44 +/- 1 micrograms/L). However, the difference between acute and chronic hepatitis was not statistically significant. The level in liver cirrhosis (54 +/- 3 micrograms/L) was lower than those of the hepatitides but higher than that of normal controls. The apparent half-life of serum Im-AGT of patients who underwent liver lobectomy by a microwave tissue coagulation method was approximately 3-4 days.