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M Hamano

Publications and source records attributed to M Hamano.

At least 37 records · Page 2Linked to original sources
PubMed1998

Increasing frequency of occurrence of tuft cells in the main excretory duct during postnatal development of the rat submandibular gland.

Tuft cells, a widespread cell type that is present in the mucosal epithelia of hollow organs, including the main excretory duct (MED) epithelia of the rat salivary gland, are well documented morphologically. However, studies of their development are few. The purpose of the present study was to examine the perinatal and postnatal development of tuft cells in the main excretory duct of the rat submandibular gland. Main excretory ducts of the submandibular gland were obtained from five male Wistar rats at the ages of 0, 1, 7, 14, 17, 21, 23, 28, and 56 postnatal days and were prepared for scanning and transmission electron microscopy. The tuft cells, which are distinguished easily by their long microvilli protruding into the lumen, were recognizable first at 17 postnatal days. They showed a remarkable increase in number between 3 and 4 postnatal weeks. The percentages of tuft cells were 0.4% at 17 postnatal days and 0.8% at 3 postnatal weeks. The number of tuft cells represented approximately 5% of the total epithelial cells by 4 postnatal weeks. There was a significant difference between 3 and 4 postnatal weeks (P < 0.01). The microvilli of the tuft cells at the time of weaning had almost the same width as in the adult, but they were shorter. Microfilaments extending from the tips of the microvilli and microtubules and many electron-lucent vesicles in the supranuclear cytoplasm also were observed. These results indicate that tuft cells appeared in the MED of the submandibular gland during weaning and had abundant vesicles in their apical cytoplasm.

Animals↗
PubMed1998

Survey of human group C rotaviruses in Japan during the winter of 1992 to 1993.

Fecal specimens from patients with acute diarrhea were collected from 10 prefectures in Japan over a 6-month period (November 1992 to April 1993), and the specimens that were negative for human group A rotaviruses were screened for the presence of human group C rotaviruses (CHRVs) by the reverse passive hemagglutination test. Of 784 specimens examined, 53 samples (6.8%) that were collected in 7 of 10 prefectures were positive for CHRV, indicating that CHRVs are widely distributed across Japan. Most of the CHRV isolates were detected in March and April, and CHRVs mainly prevailed in children ages 3 to 8 years. The genome electropherotypes of eight strains isolated in five individual prefectures were surprisingly similar to each other and were different from those of CHRV strains isolated to date. The outer capsid glycoprotein (VP7) gene homologies of the isolates retrieved in 1993 were subsequently analyzed by the dot blot hybridization method. As a result, the VP7 genes of the isolates revealed very high levels of homology not only with each other but also with the VP7 gene of the OK118 strain isolated in 1988. These results suggest that a large-scale outbreak of CHRV occurred during the winter of 1992 and 1993 in Japan.

Adolescent↗
PubMed1998

Role of estrogen and estrogen-related growth factor in the mechanism of hormone dependency of endometrial carcinoma cells.

The role of estrogen and estrogen-related growth factors in the mechanism of hormone dependency of endometrial adenocarcinoma cells was investigated. The proliferation of hormone-responsive human endometrial adenocarcinoma cells (Ishikawa cells), which possess both estrogen and progesterone receptors, was optimally stimulated by 10 nM estradiol. Both transforming growth factor (TGF)-alpha and epidermal growth factor (EGF), added to the culture media, stimulated the proliferation of Ishikawa cells in a dose-dependent manner. Anti-TGF-alpha antibody completely eliminated the stimulatory effects of TGF-alpha. Anti-EGF receptor antibody inhibited the proliferation of these cells. The production of TGF-alpha into culture media was 5-40 pg/10 cells/24 h in 9 human endometrial adenocarcinoma cells. Ten nanomoles of estradiol increased the TGF-alpha production of Ishikawa cells by approximately 2.5-fold of the control level. In contrast, the production of TGF-alpha in hormone-unresponsive HEC-50 cels was not influenced by estradiol. C-erbB-2 oncoprotein expression of human endometrial adenocarcinoma cells, detected by both immunocytochemical staining and Western blot analysis, was associated with the tumor grade of the original tumor tissues. Ten nanomoles of estradiol clearly increased the c-erbB-2 oncoprotein levels at an optimal incubation period of 72 h, whereas estradiol did not affect the expression in HEC-50 cells.

Adenocarcinoma↗
PubMed1998

Presence of anti-ovalbumin IgE antibody in the sera of laboratory-reared squirrel monkeys (Saimiri sciureus) fed quail eggs.

In this study, we examined serum anti-ovalbumin (OVA) IgE and IgG antibodies in laboratory-reared squirrel monkeys (Saimiri sciureus), that were fed a boiled quail egg everyday. We found that 36 of 95 monkeys (38%) possessed specific IgE and 44% (42/95) had specific IgG against OVA. These antibody titers seemed to increase with age. There was, however, no apparent correlation between the anti-OVA IgE and IgG antibody titers.

Animals↗
PubMed1998

External hydrocephalus after aneurysm surgery: paradoxical response to ventricular shunting.

OBJECT: The authors sought to investigate the mechanisms and pathophysiological effects of subdural fluid collection after surgery for aneurysmal subarachnoid hemorrhage (SAH). METHODS: The authors retrospectively analyzed the medical records of 76 patients who had undergone craniotomy. The patients included 55 with aneurysmal SAH (SAH group) and 21 with unruptured aneurysms (non-SAH group) who were used as controls. Subdural fluid collection was more common in the SAH than in the non-SAH group (38% compared with 14%, p < 0.05). Although older patients appeared to be at greater risk for subdural fluid collection in both groups (p < 0.05), this condition developed even in relatively young patients with SAH. In the SAH group most subdural fluid collection was associated with ventricular dilation (81%), and a significant correlation was seen between fluid collection and the need for subsequent shunt placement (48% compared with 21%, p < 0.05). These results point to an association between hydrodynamic dysfunction and subdural fluid collection. The course of patients with subdural fluid collection varied from spontaneous resolution to normal-pressure hydrocephalus. Seven patients with persistent subdural collections underwent shunt placement (ventriculoperitoneal [VP] shunt in six and lumboperitoneal in one), which resulted in resolution of fluid collection in all seven. CONCLUSIONS: The results indicate that for most patients in the SAH group, subdural fluid collection represented "external hydrocephalus" rather than simple "subdural hygroma." Decreased absorption of cerebrospinal fluid because of SAH and surgically created tears in the arachnoid membrane communicating with the subdural space were factors in the development of external hydrocephalus. The authors believe that differentiating external hydrocephalus from subdural hygroma is extremely important, because VP shunt placement can be used to treat the former but could worsen the latter.

Absorption↗
PubMed1997

Recovery of pancreatic tissue perfusion and ATP tissue level after reperfusion in canine pancreas grafts preserved by the two-layer method.

We examined whether pancreas grafts preserved by the two-layer method maintained adenine nucleotides pool as substrates for ATP synthesis before reperfusion and had the ability to recover pancreatic tissue perfusion and synthesize ATP promptly after reperfusion. After preservation by the two-layer cold storage method using EC for 48 h (group 1) or simple cold storage in EC for 48 h (group 2), canine pancreas grafts were autotransplanted. In controls (group 3), canine pancreas grafts were autotransplanted without preservation. Tissue adenine nucleotide concentrations were measured using high-performance liquid chromatography, and pancreatic tissue perfusions were measured using the hydrogen gas clearance method. Graft survival rates were five of five, zero of five, and five of five in groups 1, 2, and 3, respectively. Total adenine nucleotide levels before reperfusion in group 1 were almost the same as in group 2. Furthermore, ATP tissue levels in group 1 before reperfusion were also the same as in group 2. However, tissue ATP levels in group 1 after 2 h of reperfusion (6.71 +/- 1.19 mumol/g dry weight) were significantly higher than group 2 (4.51 +/- 0.51 mumol/g dry weight; p < 0.05). On the other hand, pancreatic tissue perfusions in grafts preserved by the two-layer method (group 1) after 2 h of reperfusion were significantly higher than in group 2. We conclude that oxygenation of pancreas grafts during preservation by the two-layer method allows for ATP synthesis and leads to maintenance of the grafts' ability to recover ATP levels and tissue perfusions after reperfusion.

Adenine Nucleotides↗
PubMed1997

[Work intensity during working hours and different types of care done by special nursing home workers].

This study was done to estimated work intensity during working hours and different types of care to obtain basic data for making a care program. The subjects were care workers in good health (n = 8, 24-45 years) who worked in a special nursing home. The estimated maximal oxygen intake level, which is the maximal aerobic capacity, of each subject was assessed as normal to very good. The energy expenditure was 1787 +/- 534kcal during working hours. The work intensity was 0.061 +/- 0.011kcal/kg/min, 2.7 +/- 0.7RMR, 98 +/- 6beats/min, and 30.3 +/- 2.0% VO2max. Among the duties assessed for work intensity, bathing had the highest intensity, followed by transferring, changing diapers, feeding, and dressing. The work intensity of bathing was 0.081 +/- 0.31kcal/kg/min, 3.9 +/- 1.0RMR, and 40.0 +/- 6.1 VO2 max, which was significantly higher than feeding, dressing, and transferring(p < 0.05). Care giving at the time of bathing was significantly longer than the other care types (p < 0.05). Feeding and transferring by inexperienced care workers were significantly low intensity (p < 0.05). Work intensity of care was at high levels within the maximal permissible level in which fatigue doesn't make an appearance during working hours and in five types of care. Furthermore, care work intensity increased according to a decrease in the ADL level among the elderly. It is concluded that when making a care program, it is important to consider the ADL level of the elderly, work intensity and the amount of care-giving time, not only to maintain the health of care workers, but, also, to give superior quality care to the elderly.

Activities of Daily Living↗
PubMed1996

Direct evidence of pancreatic tissue oxygenation during preservation by the two-layer method.

The purpose of this study was to measure directly tissue oxygen tension (PO2) of the ischemically damaged pancreas graft during preservation by the two-layer (University of Wisconsin solution/perfluoro-chemical) method at 20 degrees C using Clark-type polarographic oxygen electrodes and to make clear the relationship of tissue PO2 and ATP levels during preservation and graft survival after transplantation in a canine model. During warm ischemia, tissue PO2 and ATP were dramatically decreased. Tissue PO2 continued to decrease, and tissue ATP levels were not elevated during simple storage in oxygenated University of Wisconsin solution at 20 degrees C. On the contrary, during preservation by the two-layer method at 20 degrees C, tissue PO2 promptly increased and reached about 50% of the preprocurement level at 30 min of preservation. Then, tissue PO2 was maintained this level throughout the preservation period. Tissue ATP levels were still low in the first 1 hr, but after that tissue ATP increased in a time-dependent manner. Consequently, the two-layer method at 20 degrees C could restore the viability of pancreas damaged by warm ischemia during 3- and 5-hr preservation. We conclude that the ischemically damaged pancreas grafts were oxygenated, and tissue ATP was increased during preservation by the two-layer (University of Wisconsin solution/pefluorochemical) method at 20 degrees C. Consequently, the graft was resuscitated and survived after transplantation.

Adenosine↗
PubMed1996

Extending the margin of safety of preservation period for resuscitation of ischemically damaged pancreas during preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C with thromboxane A2 synthesis inhibitor OKY046.

We have shown that 5-hr preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C allows ATP synthesis and makes it possible to resuscitate a canine pancreas subjected to 90 min of warm ischemia. However, 8 hr of preservation using this method caused a disturbance of vascular microcirculation and did not resuscitate the grafts. The aim of this study was to examine the effect of thromboxane A2 synthesis inhibitor OKY046 on vascular endothelial cells and ATP tissue levels of canine pancreas during preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C, and vascular microcirculation and pancreas viability after transplantation. Graft viability was judged by graft survival following autotransplantation. ATP tissue levels were measured by high-performance liquid chromatography at the end of preservation. Viability of the vascular endothelial cells was judged using nuclear trypan blue uptake of the graft after preservation. Pancreatic tissue perfusion was measured using an H2 clearance technique after reperfusion. Pancreas grafts subjected to 90 min of warm ischemia were not viable (0/5). However, 5-hr preservation made it possible to recover the pancreas (5/5); 8-hr preservation was not successful (0/3). ATP tissue levels after 5-hr and 8-hr preservation were 9.40+/-2.09 and 7.37+/-1.06 micromol/g dry weight, respectively, and OKY046 did not affect ATP synthesis during 8-hr preservation (8.44+/-0.92 micromol/g dry weight). The percentage of nuclear trypan blue uptake of endothelial cells in 8-hr-preserved grafts was 37.6+/-11.6% and was significantly higher than the value in 5-hr-preserved grafts (5.0+/-3.0%; P<0.01). However, OKY046 significantly reduced trypan blue uptake in 8-hr-preserved grafts (8.2+/-3.6%; P<0.01). Pancreatic tissue perfusion in 8-hr-preserved grafts after 2 hr of reperfusion was 28.5+/-7.5 ml/min/100 g, and was significantly lower than the value in 5-hr-preserved grafts (57.1+/-4.4 ml/ min/100 g; P<0.01), but OKY046 dramatically improved pancreatic tissue perfusion (97.1+/-14.6 ml/min/100 g; P<0.01). As a consequence, 8-hr-preserved grafts were resuscitated (4/5). We conclude that OKY046 protects the vascular endothelium during preservation by the two-layer method at 20 degrees C and consequently improves vascular microcirculation on reperfusion. Together with ATP synthesis, which is essential for repairing damaged cells, the canine pancreas graft subjected to 90 min of warm ischemia is resuscitated during 8-hr preservation by the two-layer method at 20 degrees C. This method holds promise for pancreas-kidney transplantation from cardiac arrest donors.

Adenosine↗
PubMed1996

Small bowel preservation using a cavitary two-layer (University of Wisconsin solution/perfluorochemical) cold storage method.

Preservation of the small bowel by a cavitary two-layer (University of Wisconsin solution [UW]/perfluorochemical) cold storage method was evaluated in the heterotopic rat segmental small bowel transplant model. Simple cold storage UW was effective only for 24-hr preservation. However, the cavitary two-layer method using UW made it possible to prolong preservation time up to 48 hr. Furthermore, without oxygen bubbling, the cavitary two-layer method was not effective for 48-hr preservation. Histologic studies of grafts preserved by the cavitary two-layer method for 48 hr at 7 days after transplantation showed normal architecture of the intestinal mucosa. This study demonstrates that the oxygenation of the small bowel during preservation by the cavitary two-layer method using UW makes it possible to extend preservation time up to 48 hr in the heterotopic rat segmental small bowel transplant model.

Adenosine↗
PubMed1996

Resuscitation of ischemically damaged pancreas during short-term preservation at 20 degrees C by the two-layer (University of Wisconsin solution/perfluorochemical) method.

We have shown that 24-hr preservation by a two-layer (University of Wisconsin solution [UW]/perfluorochemical [PFC]) cold storage method allows tissue ATP synthesis and makes it possible to resuscitate a canine pancreas subjected to 90 min of warm ischemia. The purpose of this study was to examine whether increasing preservation temperature to 20 degrees C makes it possible to shorten a preservation period for recovery of ischemically damaged pancreas grafts. After 90 min of warm ischemia, canine pancreas grafts were preserved using the two-layer (UW/PFC) method for 1 to 8 hr at 20 degrees C, and then autotransplanted. A K-value of intravenous glucose tolerance test more than 1.0 at 2 weeks after transplantation was considered graft survival. ATP tissue levels were measured by high performance liquid chromatography at the end of preservation. Pancreatic tissue perfusions were measured using an H2 clearance technique after 30 min to 4 hr of reperfusion. Pancreas grafts subjected to 90 min of warm ischemia were not viable (0/5, control group). However, 3- and 5-hr preservations made it possible to recover the ischemically damaged pancreas (3/5 and 5/5, respectively), although 1- and 8-hr preservations were not successful (0/3 and 0/3, respectively). ATP tissue levels in 1-hr-preserved grafts were 2.55 +/- 0.38 mumol/g dry weight and were significantly lower compared with the levels in 5- and 8-hr-preserved grafts, 9.40 +/- 2.09 (P < 0.01) and 7.37 +/- 1.06 (P < 0.01), respectively. On the other hand, pancreatic tissue perfusions in 8-hr-preserved grafts after 2 hr of reperfusion were 28.50 +/- 7.52 ml/100 g/min and were significantly lower than the values in 1- and 5-hr-preserved grafts, 66.0 +/- 11.22 (P < 0.01) and 57.10 +/- 4.40 (P < 0.01), respectively. It was suggested that 1-hr-preservation was not enough to synthesize ATP, which was essential to repair damaged cells, although vascular microcirculation at reperfusion was maintained and 8-hr preservation incurred microcirculatory disturbances, although ATP for repairing damaged cells was synthesized. We conclude that 3- to 5-hr preservation at 20 degrees C by the two-layer (UW/PFC) method accelerates ATP synthesis, which is essential for repairing damaged cells and protects vascular microcirculation. This makes it possible to resuscitate ischemically damaged pancreases faster. This method holds promise for pancreas-kidney transplantation from cardiac arrest donors.

Adenosine↗
PubMed1996

Resuscitation of ischemically damaged pancreas by the two-layer (University of Wisconsin solution/perfluorochemical) mild hypothermic storage method.

We have shown that 24-hour preservation by a two-layer [University of Wisconsin solution (UW)/perfluorochemical (PFC)] cold storage method at 4 degrees C allowed tissue ATP synthesis and resuscitated canine pancreases subjected to 90 minutes of warm ischemia. The purpose of this study was to examine whether the two-layer (UW/PFC) mild hypothermic storage method at 20 degrees C could shorten a preservation period for recovery of ischemically damaged pancreas and clarify changes of tissue adenine nucleotide metabolism and tissue perfusions. After 90 minutes of warm ischemia, canine pancreas grafts were preserved by the two-layer method and then autotransplanted. Tissue adenine nucleotide levels at the end of preservation and tissue perfusions after reperfusion were measured. Pancreas grafts subjected to 90 minutes of warm ischemia did not survive (0 of 5), without preservation. During a 5-hour preservation by the two-layer cold storage method the grafts did not synthesize enough ATP to repair damaged cell, although tissue perfusions were maintained after reperfusion. Consequently, ischemically damaged pancreases were not resuscitated (0 of 3). However, during 5-hour preservation by the two-layer mild hypothermic storage method, the grafts supplied enough ATP for processes that repair damaged cells, and tissue perfusions were maintained after reperfusion. As a result, ischemically damaged grafts were resuscitated (5 of 5). We conclude that 5-hour preservation by the two-layer mild hypothermic storage method accelerates ATP synthesis, which is essential for repairing damaged cells and protects the vascular microcirculation. This method can resuscitate ischemically damaged pancreas faster and holds promise for pancreas-kidney transplantation from cardiac arrest donors.

Adenine Nucleotides↗
PubMed1996

Recovery of adenosine triphosphate tissue levels of grafts preserved by the two-layer method after reperfusion.

Recovery of tissue adenosine triphosphate (ATP) levels after transplantation is very important for graft survival. We examined whether the pancreas grafts preserved by the two-layer method have the ability to synthesize ATP after reperfusion, and this is one of the mechanisms of action for the two-layer method in successful pancreas preservation. After preservation by the two-layer method using Euro-Collins' solution (EC) for 48 h (Group 1, n = 5) or simple cold storage in EC for 48 h (Group 2, n = 5), canine pancreas grafts were autotransplanted. In controls (Group 3, n = 5), canine pancreas grafts were autotransplanted without preservation. Graft viability was judged from graft survival after transplantation. Tissue adenine nucleotide concentrations were measured using high performance liquid chromatography after preservation, before reperfusion, and after 1 and 2 h of reperfusion. Graft survival rates were 5 of 5, 0 of 5, and 5 of 5, in Groups 1, 2, and 3, respectively. However ATP tissue levels in Group 1 were significantly higher compared with those in Group 2 after preservation and before reperfusion, respectively (10.95 +/- 1.52 vs. 2.75 +/- 0.33 and 2.90 +/- 0.51 vs. 2.03 +/- 0.68 mumol/g dry weight, p < 0.01 and p < 0.05, respectively). Total tissue adenine nucleotide levels in Group 1 before reperfusion were 7.41 +/- 1.47 mumol/g dry weight, and there was no significant difference compared with Group 2, 6.64 +/- 2.23 mumol/g dry weight. After reperfusion, there was no significant difference of ATP tissue levels between Groups 1 and 2 (4.07 +/- 1.18 vs. 4.48 +/- 1.32, not significant [NS]) after 1 h of reperfusion. However, after 2 h of reperfusion, tissue ATP levels in Group 1 (6.71 +/- 1.19 mumol/g dry weight) were significantly higher than were those in Group 2 (4.51 +/- 0.51 mumol/g dry weight, p < 0.01) and almost at the same levels as control (6.32 +/- 1.62 mumol/g dry weight). It was clear that recovery of ATP after reperfusion did not depend on the residual nucleotides pool but on the ability of the pancreas graft to synthesize ATP after reperfusion. We conclude that oxygenation of the pancreas graft during preservation by the two-layer method allows for ATP synthesis, which is essential in maintaining cellular integrity and leads to maintaining the graft's ability to synthesize ATP promptly after reperfusion. This is one of the mechanisms of action of the two-layer method in successful pancreas preservation.

Adenosine Triphosphate↗
PubMed1996

Molecular analysis of outer capsid glycoprotein (VP7) genes from two isolates of human group C rotavirus with different genome electropherotypes.

Nucleotide sequences for the VP7 gene of human group C rotavirus were determined for two strains isolated in Okayama, Japan, during a 1988-1990 epidemic. These isolates, OK118 and OK450, were selected as prototypes of two different electropherotypes, patterns I and II, respectively. The genes were identical in size (1,063 bp), and both contained singled open reading frames encoding 332 amino acids. The alignment of two sequences revealed 46 nucleotide substitutions, 11 of which were predicted to give amino acid changes. The deduced amino acid sequence of VP7 from OK118 was similar to published sequences of a Japanese isolate and three foreign isolates (more than 98.4% identity), whereas the VP7 sequence of OK450 revealed around 96% identity with these isolates and had nine unique amino acid substitutions. The VP7 genes of nine Okayama isolated were than analyzed by dot blot hybridization with the VP7 probes of OK118 and OK450. Under highly stringent conditions, the OK118 probe produced strong hybridization signals with the genes of five pattern I strains and one pattern II strain, while the OK450 probe strongly reacted only with those of three pattern II strains. Our results concluded that relative sequence diversity in the VP7 gene was observed between two different electropherotypes prevalent in a limited area.

Amino Acid Sequence↗
PubMed1996

Pancreas transplantation using non-suture cuff technique in the neck.

To get a successful pancreas transplantation in a rat model, we performed heterotopic pancreas transplantation with non-suture cuff technique to neck vessels. As the graft was placed in the neck, we could avoid the clamping of systemic circulation which is essential but detriment to the rat during vascular anastomosis in intraabdominal grafting. The diameter of the portal vein was enlarged to prevent outflow block after transplantation. The cuff was fixed by fat clay during anastomosis to perform vascular anastomosis easily. As a result the success rates was 16/20, 80%. 16 rats survived more than 30 days and maintained serum glucose level within 200 mg/dl throughout the experiment. The heterotopic pancreas transplantation using non-suture cuff technique to the neck vessels is safe, reliable and recommended as the experimental model using the rat.

Animals↗