Chirality-transfer control using a heterotopic zinc(II) porphyrin dimer.
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Journal Article↗
Biomedical subjects
J Yamanaka
Publications and source records attributed to J Yamanaka.
"Ordered" structure in ionic dilute solutions: dendrimers with univalent and bivalent counterions.
As an intermediate sample of ionic solutes between colloidal particles (macroions) and simple electrolyte ions, we made small-angle x-ray scattering (SAXS) measurements for aqueous solutions of poly(amido amine) dendrimers of three generations (G4, G7, and G10). The SAXS curves of univalent acid solutions showed a single scattering peak, as observed for synthetic macroions. The peak position was dependent on the dendrimer concentration but independent not only of the acid concentration (degree of protonation) but also of the counterion species. The effective charge density of the dendrimer determined by conductivity measurements was found to be insensitive to the acid concentration and the counterion species. The nearest neighbor interparticle distance 2D(exp) calculated from the peak position of the structure factor of G7 and G10 was obviously smaller, though slightly, than the average interparticle distance 2D(0) calculated from molecular weights and concentrations of dendrimers, implying that acid solutions of dendrimers formed the two-state structures by the attractive force. The ultra-small-angle x-ray scattering curve for the hydrochloric acid solution did not show an upturn, which indicates the existence of large scale structural inhomogeneities such as localized ordered structures, probably due to the weak attraction and hence less clear distinction of the ordered and disordered regions. For sulfuric acid solutions, clear scattering peaks were not observed. The bivalent counterions were more strongly associated with the dendrimer ions than the univalent ones. The resulting low charge number of the dendrimers with the bivalent counterion was confirmed directly by the conductivity measurements. These observations confirm that the counterion-mediated attraction does exist even with the univalent counterions and point out that the frequently advanced claim that the effective potential is essentially repulsive with univalent counterions while attraction appears with bivalent counterions is not necessarily correct. It is noted that the intensity of the counterion-mediated attraction in dendrimer solutions is dictated by both the effective charge density and the effective charge number, in contrast with macroionic solutions or colloidal dispersions in which only the effective charge density appeared to be important.
Journal Article↗
Recyclable characteristics of hyaluronate-polyhydroxyethyl acrylate blend hydrogel for controlled releases.
Hyaluronate-hydroxyethyl acrylate blend hydrogels which have a wide range of composition and characteristics were investigated. Glycidyl methacrylate derivatized hyaluronate (GMA-HA) were synthesized by coupling GMA to hyaluronate (HA) in the presence of a photoinduced initiator for polymerization. By copolymerizing radically GMA-HA and hydroxyethyl acrylate (HEA) under various compositions (weight ratios of HEA and GMA-HA: 1-20), GMA-HA hydrogels could be prepared in wide ranges of characteristics. These HA-PHEA gels possessed the feature that the dried ones recovered completely to the original swelling states on repeated runs, i.e. recyclable gels. The water contents of these hydrogels in equilibrium swellings in water (W(w)) were 0.99-0.86, and their viscoelastic properties were measured by a creep. The spontaneous elastic moduli were 1.05x10(5)-1.94x10(5) N m(-2), and they were mechanically tough. Their effective charge densities were estimated from the partition coefficients of sodium benzoate (NaBA) and decreased from -0.033 to -0.044 mol dm(-3) with increasing contents of HEA. Release of NaBA was studied, and the diffusion coefficients were found to be from 6.95x10(-10) to 0.12x10(-10) m(2) s(-1) with increasing the ratio of HEA. Their diffusion coefficients were found to be much less than the values estimated from the lattice model.
Acrylates↗
Left hemihepatectomy with microsurgical reconstruction of the right-sided hepatic vasculature. A strategy for preserving hepatic function in patients with proximal bile duct cancer.
BACKGROUND: Right hemihepatectomy (RH) for proximal bile duct cancer occasionally results in liver failure. We report the feasibility of left hemihepatectomy (LH) with vascular reconstruction (VR) of the right-sided hilar vessels to preserve hepatic reserve. METHODS: Among 110 patients with proximal bile duct cancer (PBC) treated between January 1980 and December 1998, 11 patients underwent LH with VR of eight portal veins and nine hepatic arteries, and 14 underwent RH with VR of four portal veins and one hepatic artery. Microsurgical techniques were used in 80% (8/10) of the hepatic arterial reconstructions. RESULTS: Although operation time was significantly longer in the LH group, hospital mortality, blood loss and incidence of histologically cancer positive margin at the bilioenteric anastomotic site were similar in the two groups. Peak serum liver enzyme concentration was significantly higher in the LH group with longer inflow occlusion time, whereas peak serum total bilirubin concentration was significantly higher in the RH group, which had smaller liver remnant. No liver abscess occurred in any patients who underwent microvascular reconstructions. The cumulative survival of the LH group was worse than that of the RH group, in which the proportion of vascular invasion was lower, but not significantly. CONCLUSION: LH with right-sided microvascular reconstruction is technically possible and a feasible option when RH is likely to result in postoperative liver failure.
Bile Duct Neoplasms↗
Preparation of a novel aggregate like sugar-ball micelle composed of poly(methylglutamate) and poly(ethyleneglycol) modified by lactose and its molecular recognition by lectin.
We report the preparation and characteristics of a novel micellar aggregate of an amphiphilic diblock copolymer, poly(methylglutamate) (PMG)-poly(ethyleneglycol) (PEG), whose terminus was modified by lactose lactone (LA). Due to the terminal LA moiety, this aggregate could be specifically recognized by RCA120 lectin. PMG-PEG-LA was synthesized by polymerizing the N-carboxy anhydride of L-glutamic acid gamma-methyl ester with H2N-PEG-LA as a polymerization initiator. By applying a fluorescence method using pyrene as a probe molecule, we found that PMG-PEG-LA could form the aggregate in aqueous solution. Fluorescence measurements showed that the critical aggregation concentration (C.A.C.) was 1.1 x 10(-5) M. The average diameter of the aggregate was 220 nm at 25 degrees C, as determined by the dynamic light scattering method. Circular dichroism measurements for the aggregate solution showed that the PMG residue took an alpha-helical structure, and that they associated to constitute the hydrophobic core of the aggregate. By adding RCA120 lectin to the aggregate solution, the turbidity of the solution increased rapidly, due to association of the aggregates. This implies that the aggregate could be recognized by lectin, and also suggests that sugar residues locate at the surface of the aggregates. From these findings, we concluded that the PMG-PEG-LA molecules form an aggregate like a "sugar ball" micelle, whose surface is covered by the sugar moieties. Application of the present aggregate system as a drug carrier is briefly discussed.
Lactose↗
[Direct laryngoscopic extirpation and wound suture for hypopharyngeal lipoma: a case report].
We report a case of hypopharyngeal lipoma. An 82-year-old woman referred to our clinic for 10 years of wheezing and intermittent breathlessness developing 1 month before admission was found on laryngoscopic examination to have a mobile mass arising from the hypopharyngeal region intermittently obstructing the laryngeal airway. After emergency tracheotomy, the tumor was removed under direct laryngoscopy, given the patients age and general status. Under general anesthesia, the tumor was extirpated using a laser and electric scalpel under microlaryngoscopy. The operative wound was sutured under direct laryngoscopy using a specially designed probe with a U-shaped tip. The tumor was histologically diagnosed as lipoma. The surgical procedure enabled the operative wound to heal rapidly and oral feeding to start early.
Aged↗
[A new surgical technique combining autologous intracordal transplantation of fat and fascia for sulcus vocalis].
We developed a new surgical technique combining autologous intracordal transplantation of fat and fascia for sulcus vocalis. Fat tissue from the abdominal wall and fascia from the postauricular region were obtained and an incision was made on the lateral portion of the vocal cord and a small pocket prepared in the lamina propria using an elevator. After inserting fat tissue into the pocket, fascia was inserted to cover the fat graft to prevent its escape from the pocket. The surgical wound was then sutured using absorbable sutures. No evidence of postoperative absorption of transplanted fat tissue was seen, and vocal function improved postoperatively. This method proved useful as surgical treatment for sulcus vocalis.
Adipose Tissue↗
Optimal route of administration of mixed endothelin receptor antagonist (TAK-044) in liver transplantation.
It is well known that endothelin-1(ET-1) is a factor involved in the pathogenesis of ischemia-reperfusion injury. This study was undertaken to investigate the optimal route (intravenous vs intraportal) for administering mixed endothelin receptor antagonist (TAK-044) in a liver transplantation. First, in a rat isolated liver cold-perfusion model, the pharmacodynamics of TAK-044 and endothelin-1 (ET) in the liver tissue and the systemic circulation after cold perfusion were compared in the different administration routes. Next, in a rat orthotopic transplantation model, we compared the hepatoprotective effect of TAK-044 among different administration routes. In each model, there were three groups: IV group, intravenous injection of TAK-044 (10mg/kg) immediately before cold perfusion or anhepatic phase; IP group, intraportal administration with cold perfusion solution or with reflush solution for the graft; control group, no treatment. In the cold perfusion model, liver tissue ET level increased to a similar extent after reperfusion in the three groups, and the plasma and liver tissue TAK-044 concentrations after reperfusion were highest in the IV group. However, the increase in plasma ET was also greatest, and therefore, the ratio of liver tissue to plasma TAK-044 was lower in the IV group compared with the IP group. In the transplantation model, elevation of plasma ET was significantly higher in the IV group. Leakage of serum alanine aminotransferase (ALT), sinusoidal narrowing, and cell swelling after grafting were significantly suppressed in the IP group. We conclude that intraportal administration before reperfusion offers more efficient accumulation of TAK-044 in the liver tissue, without harmful systemic elevation of ET, and achieves a hepatoprotective effect on the graft compared with intravenous administration.
Alanine Transaminase↗
Viral serostatus and coexisting inflammatory activity affect metachronous carcinogenesis after hepatectomy for hepatocellular carcinoma. A further report.
Little data are available regarding the effects of hepatitis virus serostatus and the severity of coexisting chronic inflammation on intrahepatic recurrence after hepatectomy for hepatocellular carcinoma (HCC). We investigated the extent to which these factors modified the prognosis of hepatectomized patients. A total of 274 patients treated in the period January 1981 to December 1996 were divided into three groups: antihepatitis C-positive (HCV; n = 144), hepatitis B surface antigen-positive and HCV antibody (Ab)-negative (HBsAg; n = 106), and HBsAg-negative and HCV Ab-negative (NBNC; n = 20). Positivity for HBV-related antibody in the HCV group was 76%. Histologic grading of inflammatory activity from coexisting hepatitis was determined according to Knodel's histological activity index (HAI) scoring system. Post-hepatectomy crude survival rates and disease-free survival (DFS) rates were compared, according to tumor characteristics, between the three groups. In the patients overall and also in the patients with a single nodular HCC, the HCV group had significantly higher HAI scores and preoperative serum aspartate aminotransaminase (AST) levels than the other two groups. When the patients were limited to those with a single nodular HCC, the crude survival was similar in the three groups with comparable tumor characteristics; however, the DFS was different (NBNC > HBsAg > HCV). When the patients were further limited to those with a single nodular HCC without microscopic extracapsular spread, in whom removal of the tumor was expected to be microscopically complete, the difference in the DFS became more marked. Irrespective of the viral serostatus, better crude and disease-free survivals were observed in the patients with lower AST levels (< or =50 IU/ 1) than in those with higher AST levels (>50IU/l). In contrast, there were no differences in survivals and HAI scores according to the presence or absence of HBV-related antibody in the HCV group. From our univariate analysis, we can conclude that the severity of virally induced inflammation, which was well correlated with viral serostatus, may be a factor that affects intrahepatic recurrence, which is more likely to originate from metachronous carcinogenesis. Prior co-infection of HBV in HCV patients may not be an adverse risk factor for intrahepatic recurrence.
Carcinoma, Hepatocellular↗
Evolution of and obstacles in surgical treatment for hepatocellular carcinoma over the last 25 years: differences over four treatment eras.
This study was designed to clarify what differences the last 25 years have made in surgical results for patients with hepatocellular carcinoma (HCC). We examined results for 716 hepatectomized patients in four treatment eras: first era (1973-1980; n = 58), second era (1981-1985; n = 155), third era (1986-1990; n = 243), and fourth era (1991-1997; n = 260). Patient background, tumor characteristics, type of hepatectomy, treatment for intrahepatic recurrences, and surgical results in the four eras were compared by univariate analysis to clarify the factors that have contributed to or impeded progress in the surgical treatment of HCC. Although there were no significant chronological differences in liver pathology and surgical resectability, operative mortality was reduced to 2% in the fourth era, from 29% in the first era. With an increasing proportion of early-stage HCCs (TNM, stages I and II), the cumulative survival rate at 5 years improved in the course of the eras in our overall population of patients (12%, 31%, 38%, and 51%, respectively, for the first, second, third, and fourth eras) and in a subset of the population divided according to tumor stage. Also, we found a chronological improvement in the survival rate at 3 years after intrahepatic recurrence (10%, 28%, 36%, and 44%, respectively in the first second, third, and fourth eras). This improvement was associated with the establishment of an early detection program for intrahepatic recurrences. However, the recurrence rate was similar in any subset of the population through the four eras. Although this univariate study could not determine independent factors that contributed to the chronological progress in results for HCC surgery in the four eras, it is conceivable that the establishment of indication criteria for hepatectomy, an early detection program for primary and recurrent lesions, and the introduction of multimodal treatment for recurrence were contributory factors in this improvement. A strategy for alleviating the frequent recurrences originating from posthepatectomy metachronous carcinogenesis remains to be established.
Analysis of Variance↗
Recycled use of reopened umbilical vein for venous reconstruction in hepatopancreatobiliary surgery.
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Aged↗
Clinicopathologic analysis of stage II-III hepatocellular carcinoma showing early massive recurrence after liver resection.
BACKGROUND AND AIMS: Prognosis after hepatectomy for hepatocellular carcinoma (HCC) has been improved by progress in the evaluation of hepatic functional reserve, surgical techniques and perioperative management. However, even when curative resection is performed at a relatively early stage, a considerable number of patients develop early intrahepatic and/or extrahepatic recurrence postoperatively. This study analyzed the clinicopathologic features of HCC with early recurrence. METHODS: We reviewed records of 513 consecutive patients who had undergone liver resection for HCC. There were 48 deaths within a year after surgery from recurrence, including 21 patients with stage II or III HCC (group I). Clinicopathologic parameters of group I patients were compared with those of 188 patients (group II) who developed recurrence following resection of stage II or III HCC and died more than 1 year after surgery. RESULTS: On univariate analysis, age, tumor diameter (phi), alpha-fetoprotein (AFP):phi and protein induced by vitamin K absence or antagonist II (PIVKA-II):phi were significantly greater in group I than in group II. Macroscopic portal vein invasion, microscopic vascular invasion, intrahepatic metastasis, poor differentiation, pleomorphism, sarcomatous change, vascular lake, and angiographic condensed pooling were more frequently observed in group I than group II. Five independent determinants were selected by multivariate analysis: AFP:phi, histologic pleomorphism, sarcomatous change, vascular lake and angiographic condensed pooling. CONCLUSIONS: Highly malignant HCC with extremely poor prognosis exhibits peculiar clinicopathologic characteristics, particularly histologic immaturity, and can be predicted by preoperative indicators such as markedly elevated tumor marker concentrations and condensed pooling on angiography.
Aged↗
What patients can survive disease free after complete resection for hepatocellular carcinoma?: A multivariate analysis.
BACKGROUND: Although there have been extensive studies to determine risk factors affecting survival after resection for hepatocellular carcinoma (HCC), we still do not know which patients can survive disease free after curative resection. This study was undertaken to determine independent risk factors affecting the length of disease-free survival. METHODS: 171 patients, who survived disease free more than 1 year after curative resection, were divided into four groups according to the disease-free period: Group I (n = 96) for the patients with intrahepatic recurrence between 1 and 3 postoperative years, Group II(n = 27) for those between 3 and 5 years, Group III (n = 40) for those between 5 and 10 years and Group IV (n = 8) for those without recurrence within 10 years. The 37 variables (host factors, tumor factors, non-tumor liver factors, surgical factors) were compared among the four groups. Activity of hepatitis and hepatic fibrosis was scored by the Histological Activity Index (HAI). In a multivariate study, possible prognostic variables with a statistical difference in the disease-free survival rate among each category were preliminarily selected from the 37 variables and the independent variables were finally selected using a proportional hazard analysis. RESULTS: The patients' age, indocyanine green retention rate, microscopic tumor capsular invasion and portal invasion, cell differentiation, extent of hepatectomy, aggressiveness of chronic hepatitis and inflammatory activity assessed by HAI score were significantly different among the four groups. In the multivariate analysis, the following variables were selected as the independent determinants favorable for achieving a longer disease-free period: younger age, lower indocyanine green retention rate, solitary HCC with expansive growth, no microscopic portal invasion and lower activity of co-existing hepatitis. CONCLUSIONS: The importance of inflammatory activity in addition to aging, hepatic reserve and tumor characteristics was confirmed as a risk factor for recurrence by multivariate analysis. To achieve better disease-free survival, not only early detection but also suppression of co-existing hepatitis is necessary.
Aged↗
Characterization of lattice defects in strontium titanate single crystals by X-ray topography and transmission electron microscopy
Lattice defects in SrTiO3 single crystals were characterized by X-ray topography and transmission electron microscopy. We examined two groups of crystals whose lapped faces were (001) and (011), respectively. After taking X-ray topographs, crystals which included relatively many defects were chosen for detailed investigation by transmission electron microscopy, which gave the following results: (i) some subgrain boundaries observed by X-ray topography were small-angle tilt boundaries; and (ii) many dislocations were found in the region where thick line contrast was observed in X-ray topographs. Most of them had <100> type Burgers vectors.
Journal Article↗
Characteristics of complexes composed of sodium hyaluronate and bovine serum albumin.
Complexes composed of sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied to elucidate the exact composition of the complex, the phase separation, the electrophoretic mobility and the size using dynamic light scattering (DLS) and electrophoretic light scattering (ELS), etc. The phase diagram of the mixed solutions was determined. The complexes were soluble in neutral or weakly acidic pH regions and showed phase separation in the more acidic pH region. From the concentration of Na+ released from NaHA when it binds to BSA, the ratios of BSA to NaHA of the complexes were determined. In the region of soluble complexes, one BSA molecule was determined to bind with 15 carboxylic groups of NaHA and in the region of insoluble complexes to bind with 6 carboxylic groups. At the phase separation point, 117 BSA molecules bound with one NaHA molecule and 17% of the carboxylic groups of NaHA did not contribute to the binding of BSA. The sizes of the complexes decreased from several microm to several hundred nm as the binding ratio of BSA increases. Decreases in the viscosities of the mixed solutions were consistent with the decreases of the sizes. From these results, a model of complex formation is proposed.
Animals↗
[Autotransplantation of ectopic lingual thyroid--a case report].
A 22 year-old female came to our clinic complaining of a swallowing disturbance and dyspnea. ENT examination revealed a spherical mass at the base of the tongue partially obstructing the airway. Scintigraphy with an iodine isotope confirmed that the mass was an ectopic thyroid. Under general anesthesia, and the mass was carefully dissected together with its the feeding vessels and transplanted into the right submandibular gland was removed the space that had been created. The postoperative course was uneventful. Thyroid function one month after surgery was at the same level as before surgery, and scintigraphy two months after the operation revealed normal uptake in the area of the transplanted thyroid.
Adult↗
[Usefulness of electroglottogram (EGG) and photoglottogram (PGG) for the analysis or vocal fold vibration--a high speed digital imaging study].
Simultaneous recordings of EGG, PGG and high-speed digital imaging (HSDI) of vocal fold vibration were made in 3 normal male subjects and the results were compared to evaluate the usefulness of EGG and PGG for the analysis of the vibratory pattern. Each subject was required to produce sounds of 3 different pitches at 3 different intensity levels in the recording sessions and the 27 sets of data samples were collected. For each data set, the glottal area waveform (GAW), glottal width waveform (GWW), EGG, differentiated EGG, PGG, differentiated PGG, and voice waveform were displayed in a graphic form on the same time axis and their patterns were compared. Based on the analysis of GAW and GWW, it was found that there were variations in the pattern of closing and opening of the vocal fold margin corresponding to the differences in the type of phonation. The EGG waveform appeared to correspond well to that of the movement of the vocal fold margin in the closing phase, while the correspondency was less apparent in the opening phase. It is considered that the EGG waveform is dependent on the mode of contact between the two vocal folds and that a careful observation of the EGG is useful and practical for predicting the pattern of vocal fold vibration. On the other hand, it was difficult to determine the onset of the closing and opening phases only from PGG waveform and there was a timing difference between the PGG and GAW. Although PGG seemed to be useful for judging the presence or absence of the opening phase and for the pitch measurement, it is considered to be unsuitable for a precise cycle-by-cycle analysis of the pattern of vocal fold vibration.
Adult↗
[The management of infectious mediastinitis after the open heart surgery].
Between October of 1992 and September of 1998, we performed 604 open heart operations. Among them, 12 cases (1.9%) were complicated with postoperative infectious mediastinitis. Five patients (Group A) were treated by conservative therapy which consists of open drainage and intermittent closed irrigation with dilute povidone iodine solution. Seven patients (Group B) were treated surgically in addition to the above-mentioned conservative treatment. Among those patients, one patient developed fatal complication. We have realized that mental care of the patients was also very important when long term hospitalization was necessitated. The hyperbaric oxygen therapy seemed to be also effective for postoperative mediastinitis caused by MRSA.
Aged↗