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Biomedical subjects

N Hamato

Publications and source records attributed to N Hamato.

18 recordsLinked to original sources
PubMed1995

Evaluation of protective effects of prostaglandin E1 on ischemic liver damage with in vivo 31P-MR spectroscopy.

The cytoprotective effect of prostaglandins (PG) was evaluated by in vivo 31P MR spectroscopy. Twenty rabbits were divided into two groups; the control group given physiological saline, and the PG group given prostaglandin E1 (0.5 microgram/kg/min). Each solution was infused for 8 min, after which complete hepatic ischemia was induced for 20 min, followed by reperfusion for 40 min. During ischemia, beta-ATP decreased to 23.6% and 42.3%, phosphomonoester increased to 260% and 200% of their initial values in the control and the PG groups, respectively. Inorganic phosphate also increased. After reperfusion, beta-ATP recovered to 65.2% and 96.5%, phosphomonoester to 130% and 110%, inorganic phosphate to 140% and 120% in the control and PG groups, respectively. The changes during ischemia were significantly smaller and the recoveries during reperfusion were more complete in the PG group. These results may confirm the cytoprotective effect of prostaglandins by in vivo 31P-MR spectroscopy.

Adenosine Triphosphate↗
PubMed1995

Vascular complications in living related liver transplantation detected with intraoperative and postoperative Doppler US.

BACKGROUND/AIMS: The purpose of this study was to clarify changes in the graft hemodynamics induced by vascular complications in living related liver transplantation. METHODS: This study included 46 pediatric recipients who underwent partial liver transplantation from living related donors. The blood flow was evaluated in the portal system, the hepatic artery and the hepatic vein with serial intra- and post-operative Doppler ultrasound (US). RESULTS: In 12 patients, intraoperative Doppler US showed a decrease in portal venous inflow (< 9 ml.min-1.kg-1) toward the liver graft and could act as a guide for ligation of collaterals in seven patients, portal re-construction in two, thrombectomy in one and relief of hepatic venous outflow obstruction in two for increasing the portal venous inflow. In five patients, intraoperative Doppler US showed poor arterial inflow, i.e. dampened arterial waveforms which involved both low pulsatility index (< 0.90) and low peak-systolic velocity (< 31 cm/s). In three of them, the waveform was more pulsatile after re-anastomosis or relief from stretching of the hepatic artery. The remaining two patients developed hepatic artery thrombosis. Most of the hepatic venous outflow obstruction (four of five patients) had flat waveforms, low flow velocity (< 10 cm/s) of the hepatic vein, and poor portal inflow (flow velocity < 14 cm/s). Postoperative Doppler US showed hepatic venous outflow obstruction in three patients, hepatic artery thrombosis in three (twice in one patient), portal vein stenosis in two and portal vein thrombosis in one. These complications were successfully managed with surgical procedures in three patients, transhepatic angioplasty in three and conservative treatments in four. Six patients died of non-vascular complications. CONCLUSIONS: Serial intra- and post-operative Doppler US was a useful technique for making an early diagnosis of abnormal hemodynamics of the graft circulation. Furthermore, intraoperative Doppler US could assess reconstructed vessels objectively and would reduce the incidence of vascular complications following transplantation.

Adolescent↗
PubMed1995

Trypsin and elastase inhibitors from bitter gourd (Momordica charantia LINN.) seeds: purification, amino acid sequences, and inhibitory activities of four new inhibitors.

Serine proteinase inhibitors of the squash family were isolated from bitter gourd (Momordica charantia LINN.) seeds by the conventional purification method. Heat treatment of the extract of the seeds allowed removal of large amounts of protein without loss of trypsin and elastase inhibitory activities. From the supernatants thus obtained, the inhibitors were isolated to homogeneity by ion-exchange chromatography, gel filtration, and reversed phase chromatography. One trypsin inhibitor (Momordica charantia trypsin inhibitor-III; MCTI-III) and three elastase inhibitors (Momordica charantia elastase inhibitor-II, -III, and -IV; MCEI-II, -III, and -IV) were newly isolated in addition to trypsin inhibitors MCTI-I and -II and elastase inhibitor MCEI-I previously reported [Hara, S. et. al. (1989). J. Biochem. 105, 88-92]. The primary structures of the four new inhibitors were determined as follows. [sequence: see text] The dissociation constants, Ki, of MCTI-III complex with bovine beta-trypsin, and of MCEI-II, -III, -IV with porcine elastase were determined to be 1.9 x 10(-7) M, 9.4 x 10(-9) M, 4.0 x 10(-9) M, and 4.7 x 10(-9) M, respectively. Although MCTI-III differed from MCTI-I in only two amino acids, having Gly(3) and Gln(13) in place of Arg(3) and Arg(13), the Ki value of MCTI-III was 20-fold larger than that of MCTI-I. Addition of an amino terminal Glu residue, a dipeptide (Glu-Glu-), and a tripeptide (Glu-Glu-Glu-) to MCEI-I strengthened its elastase inhibitory activity by 200-fold.

Amino Acid Sequence↗
PubMed1995

Azygos venous blood flow: measurement with direct bolus imaging.

PURPOSE: To evaluate a magnetic resonance (MR) imaging technique for measurement of azygos blood flow volume, which is an important indicator of superior collateral circulation in patients with portal hypertension. MATERIALS AND METHODS: Azygos blood flow was measured by means of direct bolus (DB) imaging, an MR flow measurement technique. A presaturation pulse was applied in combination with electrocardiographic gating. RESULTS: The measured flow volume was 320 mL/min +/- 30 (mean +/- standard error of mean) in the control subjects, 550 mL/min +/- 130 in patients with cirrhosis of the liver and without varices, and 660 mL/min +/- 60 in patients with cirrhosis of the liver and with varices. The flow volume was significantly higher in each of the groups with cirrhosis of the liver than in the control group (P < .01). Furthermore, a significant correlation was shown between DB imaging and continuous thermodilution measurements (r = .707, P < .01). CONCLUSION: DB imaging, which is noninvasive, was useful in the monitoring of the effect of treatment and in determination of the prognosis in patients with portal hypertension.

Aged↗
PubMed1992

Use of proton nuclear magnetic resonance spectroscopy of plasma in screening for malignant disease.

In 1986, narrow plasma proton nuclear magnetic resonance (NMR) methyl and methylene line widths were reported to be associated with malignant disease, but more recent studies have not confirmed this relationship. The authors analyzed 106 plasma samples from healthy control subjects and patients with cirrhosis, hepatocellular carcinoma, metastatic liver tumors, other untreated cancers, and hyperlipidemia. NMR spectroscopy was performed using a proton NMR spectrometer operating at 399.65 MHz. A significant difference was found between the mean line widths of the plasma methyl resonances in control subjects and those in patients with cancer or hyperlipidemia. However, no significant difference was found between the mean plasma methylene line widths in control subjects and patients with cancer. Plasma samples from patients with liver disease or hyperlipidemia showed a characteristic methylene spectral pattern. The methylene pattern could be separated into three types: type A had a small peak on the right shoulder of the main peak; type B was a sharp single peak; and type C was a broad single peak. All control subjects had type A pattern; patients with liver disease had type C pattern; and patients who had hyperlipidemia had type B pattern, and hyperlipidemia may affect methyl and methylene line widths in NMR spectra. Because the methyl and methylene levels and their average line widths correlated inversely with triglyceride levels, considering the spectral patterns that indicate hyperlipidemia should decrease false-positive results and make the methyl line width useful for cancer screening.

Adult↗
PubMed1992

Trypsin inhibitors from bottle gourd (Lagenaria leucantha Rusby var. Depressa Makino) seeds. Purification and amino acid sequences.

Two almost identical trypsin isoinhibitors, LLDTI-I and LLDTI-II, from bottle gourd (Lagenaria leucantha Rusby var. Depressa Makino) seeds were purified by acetone precipitation, gel filtration and reversed phase chromatography. LLDTI-I and LLDTI-II consist of 30 and 29 amino acid residues, respectively, and have identical sequences, except that LLDTI-I has one additional pyroglutamic acid residue at N-terminus. Both proteins are strong inhibitors of bovine trypsin, with Ki values of 2.4.10(-10) M (LLDTI-I) and 9.6.10(-11) M (LLDTI-II). Amino acid sequences are as follows: [sequence: see text]

Amino Acid Sequence↗
PubMed1992

Purification and characterization of serine proteinase inhibitors form gourd (Lagenaria leucantha Rusby var. Gourda Makino) seeds.

Gourd seed inhibitors were purified in the following manner: gourd seeds were ground and extracted with 10 mM ammonium carbonate, pH 7.8. The extract was precipitated with 65-90% acetone and the acetone precipitates were gel filtered in a Cellulofine GCL-90-m column. Fractions of 3000 Da showing trypsin inhibitory activity were combined and purified further by ion exchange and reversed phase chromatographies. Three inhibitors, LLTI-I, II, and III were thus purified to homogeneity and the amino acid sequences of these inhibitors were: [sequence: see text] The exact sequences are unique but very similar to proteinase inhibitors belonging to the squash family. Based on the sequence, it is assumed that the peptide bond (Arg-Ile) found in the three inhibitors is the reactive site for trypsin. The Ki values estimated for complexes of LLTI-I, II, and III with bovine trypsin were 3.6 x 10(-10) M, 6.5 x 10(-11) M, and 3.0 x 10(-11) M, respectively.

Amino Acid Sequence↗
PubMed1991

Mucin-histochemical and immunohistochemical profiles of epithelial cells of several types of hepatic cysts.

Epithelial cells of several types of hepatic cysts were examined by mucin histochemistry and immunohistochemically. There were some differences in mucus and antigenic expression among the hepatic cysts examined. Epithelial cells of non-parasitic simple cysts and adult-type polycystic liver showed similar mucin-histochemical and immunohistochemical features, and were characterized by little mucin and weak immunoreactivities to several antibodies examined. Epithelial cells of hepatic hilar cysts were characterized by much mucin and moderate immunoreactivities to carbohydrate antigen 19-9 (CA 19-9), carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). Epithelial cells of ciliated hepatic foregut cysts were characterized by much mucin and immunoreactivities to actin and tubulin which were positive in cilia. Epithelial cells of biliary cystadenoma were characterized by much mucin and moderate to strong immunoreactivities to cytokeratins CAM5.2 and AE1 and 3 as well as to CA 19-9, CEA, EMA and DU-PAN-2. Epithelial cells of biliary cyst-adenocarcinoma were characterized by much mucin and moderate to strong immunoreactivities to cytokeratins CAM5.2 and AE1 and 3 as well as to CA 19-9, CEA, EMA and DU-PAN-2. These differences in epithelial mucus and antigenic expression among several types of hepatic cysts may reflect differences in their origin and biological characteristics. These differences may be helpful in the differential diagnosis of hepatic cysts in small biopsy specimens.

Antigens↗
PubMed1991

Photodynamic therapy using pheophorbide-a and Q-switched Nd:YAG laser on implanted human hepatocellular carcinoma.

To evaluate whether administration of pheophorbide-a, a new photosensitizer, followed by use of Q-switched Nd:YAG laser produces a photodynamic reaction, we administered pheophorbide-a to female nude mice (BALB/c-nu) that had been implanted with human hepatocellular carcinoma. Intra-tumoral concentrations of pheophorbide-a were measured by high-performance liquid chromatography. 3 hours after peroral administration of 1 mg/kg body weight, the intra-tumoral concentration was too low to reveal photodynamic effects. Peroral administration of 250 mg/kg body weight, intra-peritoneal administration of 5 mg/kg body weight, and intra-tumoral injection of 200 micrograms yielded 0.24 micrograms/g, 0.83 micrograms/g and 3.68-108 micrograms/g tumor concentrations, respectively. All tumors were irradiated interstitially using a Q-switched Nd:YAG laser at 1064 nm. Only tumors that had been intra-tumorally injected had areas of necrosis larger than those in control tumors. The results suggest that the injection of pheophorbide-a followed by interstitial irradiation using a Q-switched Nd:YAG laser does not induce sufficient photodynamic reaction if the intra-tumoral pheophorbide-a concentration is less than 0.83 micrograms/g tumor tissue, and that photodynamic therapy may be useful if the pheophorbide-a tumor concentration is within the range of 0.83-108 micrograms/g.

Animals↗
PubMed1990

[Evaluation of photodynamic therapy using pheophorbide-a as a photosensitizer].

Intra-tumoral concentrations of pheophorbide-a, a new photosensitizer, were measured by high-performance liquid chromatography after administration of pheophorbide-a to nude mice (BALB/c-nu) that had been implanted with human hepatocellular carcinoma. The results were as follows: 1) 0.009 +/- 0.007 microgram/g tissue in 1 mg/kg body p.o. administration group, 2) 0.22 +/- 0.06 microgram/g tissue in 250 mg/kg body p.o. administration group, 3) 0.85 +/- 0.14 microgram/g tissue in 5 mg/kg body intra-peritoneal administration group, 4) 3.42 +/- 2.84 microgram/g tissue in not-injected side, and 116 +/- 24 microgram/g tissue in injected side of 200 micrograms intra-tumoral administration group. Tumors in each group were irradiated using an Nd:YAG laser (Q-switch; mean power 0.5 W, duration 10 min.). Areas of tumor necrosis were larger than in the control group only in the intra-tumoral administration group. These results suggest that no photodynamic reaction occurs if the intra-tumoral pheophorbide-a concentration is less than 0.85 microgram/g tissue.

Animals↗
PubMed1990

[Evaluation of the efficacy of photodynamic therapy on experimental hepatocellular carcinoma--using local injection of photosensitizer].

The effect on photodynamic therapy (PDT) of using pheophorbide-a as a photosensitizer and Nd: YAG laser (Q-switch) was evaluated. Two hundred micrograms (0.1 ml) of pheophorbide-a was injected into tumors that had been subcutaneously implanted into the backs of nude mice (BALB/c-nu). Interstitial Nd: YAG laser irradiation (Q-switch; mean power 0.5 W, duration 10 min.) was performed 72 hours after pheophorbide-a injection. Forty-eight hours after laser irradiation, the areas of tumor necrosis were measured; these were larger in the group with the injection of pheophorbide-a than in those without. The areas of tumor necrosis after Nd: YAG laser irradiation at a higher mean power (Q-switch; mean power 2 W, control temperature 43-43.5 degrees C, duration 10 min.) were also measured. Again, the areas were larger in the group injected with pheophorbide-a. These results show that the injection of pheophorbide-a and interstitial irradiation using Nd: YAG laser induce a photodynamic reaction, and that this combination is useful in the treatment of deep-seated tumors.

Animals↗
PubMed1990

Aleukemic leukemia cutis.

A 39-year-old man had multiple nodules on the skin. The appearance of atypical monocytes in a skin biopsy specimen preceded the onset of overt acute monocytic leukemia by 14 months.

Adolescent↗
PubMed1990

[1H-NMR studies of plasma from patients with liver diseases].

We examined the 1H-NMR spectra of the lipid region of human plasma according to the method of Fossel et al. as the specific blood test for cancer. The study group included 20 patients with hepatocellular carcinoma (HCC), 10 patients with liver cirrhosis (LC) and 10 normal controls (NC). We measured the linewidths of methyl and methylene resonances of lipoprotein lipids at a proton resonance frequency of 400 MHz using a JNM GX400 FT NMR spectrometer. The mean linewidth values and the standard deviation of methyl were as follows: 41.3 +/- 7.2 Hz (NC), 34.8 +/- 6.9 Hz (LC), 29.6 +/- 5.7 Hz (HCC). There was thus a significant difference between NC and HCC. On the other hand, there was no significant difference between the three groups in the case of methylene. Although the spectrum in the HCC and LC groups had a blunt head but narrow body, that of the NC group had a pointed head but wide body, and the linewidth values thus showed wide dispersion. This difference in spectral patterns between the two groups was characteristic. Linewidth values, however, did not correlate well with the laboratory data.

Adult↗
PubMed1990

[Portal hemodynamic changes from partial hepatectomy--quantitative analysis of portal flow before, during and after hepatectomy, using an Doppler ultrasound system].

We investigated portal hemodynamic changes in 86 patients with hepatic tumors who underwent partial hepatectomy. Portal blood flow was measured using a sector type Doppler ultrasound system before, during and after operation. In the intraoperative studies, the portal flow in patients who underwent massive liver resection decreased significantly. On the other hand, the portal flow in patients with minor liver resection tended to increase, but not significantly. Overall, portal flow per unit of cardiac out put decreased significantly; it also decreased significantly in patients who underwent massive or major liver resection, in patients with liver cirrhosis, and in patients whose post operative clinical course was satisfactory. In the post-operative studies (10-12 days after surgery), the portal blood flow decreased significantly in patients who manifested a severe post-operative clinical course; it showed no significant change in other patients. It is thus essential to monitor the portal hemodynamics of partial-hepatectomy patients. This is most readily realized using Doppler ultrasound.

Hepatectomy↗
PubMed1990

Hepatic function and portal hemodynamics in patients with liver cirrhosis.

We investigated the distribution of portal blood flow per kilogram of body weight (PBF/BW) in 112 healthy volunteers and 90 patients with liver cirrhosis using an ultrasonic Doppler duplex system. The PBF/BW in healthy volunteers showed a log-normal distribution, while the distribution was irregular and showed two peaks in patients with cirrhosis. This irregular distribution was thought to reflect their complex physiopathological state. We next analyzed the relationship between PBF/BW and the data from hepatic function tests (serum albumin, total bilirubin, indocyanine green 15-min retention rate, and indocyanine green plasma disappearance rate) in 48 patients with liver cirrhosis. The patients were divided into four groups according to their portal blood flow: group A with a hepatofugal or stagnant portal blood flow, group B with a hepatopetal PBF/BW of less than 12 ml/min/kg, group C with a hepatopetal PBF/BW of 12 or more but less than 20 ml/min/kg, and group D with a hepatopetal PBF/BW of 20 ml/min/kg or more. Among patients with cirrhosis, group A showed the worst results in hepatic function tests, group D the second worst, and group C the best. The effective hepatic blood flow was thought to have decreased because of the development of extrahepatic portosystemic shunts in the patients in groups A and B, whereas it decreased because of the development of intrahepatic shunts in patients in group D. The results of hepatic function tests deteriorated as a consequence of the decrease in the effective hepatic blood flow.

Adult↗
PubMed1990

[The changes in hepatic hemodynamics and hepatic energy charge (blood ketone body ratio) induced by vasopressin infusion in chronic liver disease].

We evaluated the changes in the hepatic hemodynamics and blood ketone body ratio (KBR) induced by vasopressin in 40 patients with chronic liver diseases to clarify the effect of hepatic blood flow on hepatic energy charge expressed by KBR. Following infusion of vasopressin, the rate of decrease in portal blood flow in liver cirrhosis (LC) was significantly lower than that in chronic hepatitis (CH). Moreover, the blood flow in the hepatic artery after vasopressin infusion was greater in LC than in CH. As a result, the total hepatic blood flow, which was the sum of the flow in the above two vessels, after vasopressin infusion was greater in LC than in CH but the decrease in the blood KBR was not significant in LC. Thus, vasopressin appears to be hemodynamically safe in patients with LC, but caution is needed since it may decrease blood pressure, total hepatic blood flow and KBR in some LC patients.

Adult↗