Biomedical subjects

N Kitamura

Publications and source records attributed to N Kitamura.

At least 181 records · Page 10Linked to original sources

PubMed1998

Three-dimensional development of bovine reticular cell (Cellula reticuli).

This paper describes the three-dimensional construction of the reticular cell, cellula reticuli, in bovine reticulum and its ontogenetic development. Reticular cells of fetal suckling calf and adult tissues were investigated both at the surface of intact mucosa and macerated samples using scanning electron microscopy. At the third month of gestation, the formation of the reticular cells on the mucosal surface started from the center of the cell and just above the reticular crest. The reticular crests were observed on the surface of the macerated sample at an earlier period of gestation (third month). In the eighth month of gestation, primary, secondary and tertiary reticular crests and papillae could be observed from the mucosal surface. Macerated samples showed that those structures were already formed completely under the epithelium by the first half of the seventh month of gestation. It is suggested that the development of the reticular papillae starts from the lower to the upper parts of the reticular cell.

Age Factors↗

PubMed1998

Efficacy of preconditioning with N-acetylcysteine against reperfusion injury after prolonged cold ischaemia in rats liver in which glutathione had been reduced by buthionine sulphoximine.

OBJECTIVE: To investigate the ability of N-acetylcysteine (NAC) to prevent cold ischaemic-reperfusion injury and improve hepatic integrity in a glutathione-depleted condition. DESIGN: Open laboratory study. SETTING: University hospitals, Japan and France. MATERIALS: 40 male Wistar rats. INTERVENTIONS: To produce a glutathione-depleted liver, buthionine sulphoximine (BSO) was injected intraperitoneally 2 hours before either NAC or 5% dextrose was infused 15 minutes before the liver was harvested. We used an isolated perfused rat liver model that had undergone prolonged hypothermic ischaemia, cold-storage for 48 hours and reperfusion for 120 minutes. MAIN OUTCOME MEASURES: Concentrations of hepatic enzymes released into samples of perfusate, concentration of adenosine triphosphate in liver tissue, concentrations of reduced and oxidized glutathione in perfusate, and bile production. RESULTS: The concentrations of the hepatocellular enzymes and oxidised glutathione in the perfusate samples were significantly reduced in the NAC group compared with the 5% dextrose group. Bile production improved significantly in the NAC group compared with the 5% dextrose group. The concentration of reduced glutathione in liver tissue was not increased by NAC. CONCLUSION: In a glutathione-depleted liver NAC prevented hepatic injury and improved liver integrity after a cold ischaemic-reperfusion injury, by acting not as a substrate for glutathione synthesis but as a direct free radical scavenger.

Acetylcysteine↗

PubMed1998

Immunohistochemical colocalization of serotonin, substance P and Met-enkephalin-Arg6-Gly7-Leu8 in the endocrine cells of the ruminant duodenum.

The duodenum of various ruminants was examined by immunohistochemical staining for serotonin, substance P and Metenkephalin-Arg6-Gly7-Leu8 (MENK8). Serotonin- and substance P-immunoreactive endocrine cells were detected in samples from cow, calf, sheep, goat, and barbary sheep, MENK8-immunoreactive endocrine cells were detected exclusively in samples from cow and calf. Substance P and MENK8 immunoreactivity was found in serotonin-immunoreactive endocrine cells of cattle. Substance P- and MENK8-immunoreactive nervous elements were detected in all ruminants examined. The present results suggest that the expression and/or the mechanism that controls the expression of each peptide might differ between endocrine cells and nerve cells and might also depend on animal species.

Aging↗

PubMed1998

Immunohistochemical study of endocrine cells in the gastrointestinal tract of the Philippine carabao (Bubalus bubalis).

The distribution and frequency of occurrence of endocrine cells in the gastrointestinal tract of the Philippine carabao (Bubalus bubalis) were studied by immunohistochemistry. Fourteen types of immunoreactive (IR) endocrine cells were revealed. Among the cell types, only chromogranin, serotonin, and bovine pancreatic polypeptide (BPP) were present in the entire gut, while the others showed restricted distribution: somatostatin, gastrin, and cholecystokinin in the abomasum and small intestine; methionine-enkephalin-Arg6-Gly7-Leu8, motilin, neurotensin, secretin, gastric inhibitory peptide, and substance P in the small intestine; peptide tyrosine tyrosine (PYY) in the large intestine; and glucagon in the whole intestinal tract. Most of the cell types showed peak density in the pyloric, duodenal, or rectal region. The highest cell type heterogeneity was observed in the duodenum. The distribution profile of the gut endocrine cells in the carabao is closely related to that in the Holstein cattle. Important findings include the occurrence of BPP-IR cells in the entire gut and the high frequency of PYY-IR cells in the large intestine.

Abomasum↗

PubMed1998

Inhibitory effects of tacrine and physostigmine on catecholamine secretion and membrane currents in guinea-pig adrenal chromaffin cells.

The effects of tacrine and physostigmine on catecholamine secretion induced by veratridine and high K+, and on voltage-dependent Na+ and Ca2+ currents, were investigated in guinea-pig adrenal chromaffin cells. In perfused adrenal glands, tacrine (100 microM) caused an inhibition of veratridine-induced catecholamine secretion, but physostigmine (100 microM) did not. In dispersed cells, both tacrine (1 microM-1 mM) and physostigmine (1 microM-1 mM) decreased catecholamine secretion induced by veratridine in a dose-dependent manner. The inhibitory effect of tacrine was much greater than that of physostigmine. Tacrine alone at a high concentration (such as 1 mM) caused a substantial increase in catecholamine secretion by itself and completely abolished the veratridine-induced secretory response in dispersed cells. High-concentration physostigmine showed a similar effect, but to a much lesser extent. The high K+ (46.2 mM)-evoked catecholamine secretion from dispersed cells was not affected by tacrine (1-100 microM) or physostigmine (1 microM-1 mM). In fura-2 loaded cells, tacrine (100 microM) almost abolished [Ca2+]i rise induced by veratridine, but only slightly reduced that evoked by high K+. In voltage-clamped cells, tacrine (300 microM) depressed the voltage-dependent Na+ and Ca2+ current by about 93% and 69%, and physostigmine (300 microM) depressed them by about 30% and 17%, respectively. These results suggest that tacrine decreases the veratridine-induced catecholamine secretion primarily by inhibiting the voltage-dependent Na+ channels rather than the Ca2+ channels. Physostigmine acts in a manner similar to tacrine, but its potency is much lower than that of tacrine.

Adrenal Glands↗

PubMed1998

Augmentation of mitochondrial reduced glutathione by S-adenosyl-L-methionine administration in ischemia-reperfusion injury of the rat steatotic liver induced by choline-methionine-deficient diet.

We examined whether warm ischemia-reperfusion (I/R) damage of the rat steatotic liver can be reduced by administration of S-adenosyl-L-methionine (SAMe). We examined the effect of SAMe on the mitochondrial reduced-glutathione (GSH) pool. Sixty minutes of partial left lobar vascular clamping followed by 2 h of reperfusion were employed for a model of hepatic warm ischemia. Either 5% dextrose or SAMe was injected intraperitoneally 2 h before I/R in steatotic rats (S-D5% or S-SAMe group). Serum liver enzyme concentrations 2 h after reperfusion were significantly lower in the S-SAMe group than in the S-D5% group. The cytosolic and mitochondrial GSH concentrations after I/R were significantly higher in the S-SAMe group than in the S-D5% group (p < 0.05). The cytosolic and mitochondrial oxidized-glutathione/GSH ratios after I/R were significantly greater in the S-D5% group than in the S-SAMe group (p < 0.01). The adenosine triphosphate concentration was higher in the S-SAMe group than in the S-D5% group (p = 0.0515). These results show that hepatocellular and mitochondrial oxidative stress after I/R in the steatotic liver can be reduced by administration of SAMe. The results also show that mitochondrial function and hepatocellular integrity can be restored by administration of SAMe in steatotic rats.

Animals↗

PubMed1998

An osteometrical study of the cranium and mandible of the lesser mouse deer (Chevrotain), Tragulus javanicus.

The lesser mouse deer (Tragulus javanicus) is one of the most primitive ruminants. Skulls of lesser mouse deer were measured to evaluate their growth. The age was estimated from the eruption and attrition of molars on the mandible. A total of 95 specimens was divided into five age groups, and the growth pattern in each sex was established for some measurements. The relative growth coefficients were calculated for the head and body length and several parts of the cranium and mandible against the profile length. Sexual dimorphism could not be found on the skull in any age group except for measurements related to the upper canine. However, females showed a higher value in head and body length in the oldest group. This feature was consistent with an interpretation of mouse deer society as monogamous. Growth was more rapid in length than in width. Various statistical analyses showed that the visceral cranium related to masticatory facility was much better developed than the neurocranium. However, observations on the shape of the mandible ramus and of the premolars implied that the masticatory function was not suitable for taking roughage. This speculation agreed with previous reports on the feeding habits and digestive organs of the mouse deer.

Age Determination by Teeth↗

PubMed1998

Expression of inhibin alpha-subunit in horse testis.

Inhibin is believed to play roles in the pituitary secretion of FSH and in the paracrine regulation of testicular function. Although it has been generally accepted that inhibin is produced in Sertoli cells, there was a recent evidence for the localization of inhibin in Leydig cells of primates, rat and sheep. However, there is no report on the expression of inhibin in the adult horse testis. Therefore, using immunohistochemistry, western blotting and in situ hybridization techniques, the present study examined inhibin alpha-subunit (Ih-alpha) expression in the adult horse testis. For the detection of Ih-alpha protein, we used anti-porcine Ih-alpha antibody in immunohistochemistry and western blotting. Furthermore, digoxigenin-labeled complementary RNA probes were prepared to detect intracellular messenger RNA (mRNA) of Ih-alpha. Immunostainings for Ih-alpha were found not only in Leydig cells but also in Sertoli cells. The intensity in Leydig cells was stronger than in Sertoli cells. Immunoreactivities for Ih-alpha were found at approximately 46 kDa, 56 kDa and 90 kDa in the homogenates from testicular interstitial tissues. The bands at 56 kDa and 90 kDa agree with previous report, but not at 46 kDa. Signals for mRNA of Ih-alpha by in situ hybridization were detected in Leydig cells and in the basal region of seminiferous epithelium including Sertoli cells. These results suggest that Ih-alpha is expressed in Leydig cells and Sertoli cells of horse testis, and the expression level should be higher in Leydig cells than Sertoli cells.

Animals↗

PubMed1998

[Interferon-alpha treatment for chemotherapy-resistant primary macroglobulinemia with stomach and lung invasion].

We reported a case of primary macroglobulinemia with stomach and pulmonary invasion. The patient was 71 years-old who had cervical lymphadenopathy and abdominal pain. Biopsy material of cervical lymph node showed non-Hodgkin's lymphoma, and he was diagnosed primary macroglobulinemia by IgM immunological histo-chemical staining of materials of stomach biopsies. Combination chemotherapies were not effective for the reduction of IgM-lambda protein, and organ invasion seemed to be progressive, so we tried interferon-alpha (IFN-alpha) to control M component. Daily injection of 6 megaunits of IFN-alpha induced significant reduction of M component and pulmonary invasion. This favorable changes were observed for 1 year. However, his pulmonary invasion on X-ray films relapsed and he died of respiratory failure by reason of severe pneumonia. IFN-alpha is currently available for myeloproliferative disease, especially chronic myelogenous leukemia and multiple myeloma. This case report showed that IFN-alpha was also available for primary macroglobulinemia.

Aged↗

PubMed1998

[Successful chemotherapy based on in vitro chemosensitivity testing in a case of recurrent thymic carcinoma].

A 71-year-old woman underwent radical resection in May 1994 for a mediastinal mass invading the anterior chest wall. Histopathological examination revealed adenosquamous cell carcinoma. She was treated with postoperative chemotherapy including 5-fluorouracil (5-FU) and 4'-D-tetrahydropyrayl-doxorubicin (THP), based on in vitro chemosensitivity testing (CST), by MTT assay, using a surgical specimen. In December 1994, a recurrent tumor was detected on the left anterior chest wall and the patient received two courses of 5-FU, THP and methotrexate (MTX). The size of the chest-wall tumor decreased 25%. In July 1995, the patient had involvement of the left axillary lymph node and brain metastases in addition to the mass on the chest wall. Therefore, cisplatin, 5-FU and MTX were selected as treatment agents, based on CST using a metastatic axillary lymph node. After two courses of these agents, chest computed tomography showed a 91% reduction in the size of the chest wall tumor. Radiation was administered for the brain metastasis. In March 1997, the patient died of thymic carcinoma.

Aged↗

PubMed1998

Role of macrophage scavenger receptors in diet-induced atherosclerosis in mice.

To clarify the role of type I and type II macrophage scavenger receptors (MSR-A) in the progression of diet-induced atherosclerosis, we generated mice lacking both MSR-A and low-density lipoprotein receptor (LDLR). After 4 or 12 weeks of a high-fat diet, the sizes of atherosclerotic lesions in MSR-A/LDLR double knockout mice were significantly reduced (p < 0.05) compared with those in LDLR single knockout mice. However, atherosclerotic lesions mainly composed of foamy macrophages were still observed in double knockout mice. Formation of atherosclerotic lesions in double knockout mice was partially explained by the participation of scavenger receptors other than MSR-A such as MARCO, CD36, and macrosialin/CD68. These receptors were clearly demonstrated in the atherosclerotic lesions in double knockout mice as well as LDLR single knockout mice by immunohistochemistry or by reverse transcriptase-polymerase chain reaction. Because the very low density lipoprotein (VLDL) fraction was elevated in the double and single knockout mice, we further examined the possibility that VLDL may participate in foam cell formation in atherosclerotic lesions. When incubated with VLDL isolated from LDLR-deficient mice, cholesterol ester accumulation and foamy transformation occurred in MSR-A-deficient macrophages as well as in normal macrophages. These data indicate that MSR-A plays an essential role in the development of diet-induced atherosclerosis. It also appears that other scavenger receptors, such as MARCO, CD36, and macrosialin/CD68, as well as uptake of VLDL are involved in foam cell formation during atherogenesis in MSR-A/LDLR double knockout mice.

Animals↗

PubMed1998

A monocyte chemotactic factor, S19 ribosomal protein dimer, in phagocytic clearance of apoptotic cells.

HL-60 cells derived from a human promyelocytic leukemia underwent apoptosis by heat treatment. When the heat-treated HL-60 cells were injected into guinea pig skin, monocyte/macrophage infiltration was observed 24 or 36 hours later, and the apoptotic cells were phagocytically cleared by 48 hours after their injection. The infiltration and clearance patterns were quite different from those observed in injection of necrotic or boil-fixed HL-60 cells. The apoptotic cells released a monocyte chemotactic factor in vitro 24 hours after the heat treatment. The chemotactic factor generated was identified as the cross-linked homodimer of S19 ribosomal protein by its immunologic and physicochemical properties. A serine protease that inactivates the monocyte chemotactic factor was also released from the apoptotic cells 30 hours after the heat treatment. A super infusion of this protease into the skin where the apoptotic cells had been injected diminished the number of infiltrated monocytes. The present results indicate an important role of the S19 ribosomal protein dimer in the phagocytic clearance of apoptotic cells.

Animals↗

PubMed1998

Dilatation of sealed Dacron vascular prostheses: a comparison of Gelseal and Hemashield.

OBJECTIVE: Early postoperative dilation of a gelatin-impregnated knitted dacron prosthesis (Gelseal, Vascutek) and a collagen-impregnated woven Dacron prosthesis (Hemashield, Meadox Medicals) was studied. EXPERIMENTAL DESIGN: Prospective study. SETTING: Institutional clinical research. MATERIALS AND METHODS: A total of 30 patients who underwent aortic repair for abdominal aortic aneurysm with a Gelseal (n=15) or Hemashield (n=15) were studied. Prior to and immediately following implantation, the diameter of each graft was measured with slide calipers. The external diameter was examined by CT scan 4 weeks after surgery. Early dilation of Gelseal and Hemashield was estimated and compared. RESULTS: Prior to implantation, the external diameter of the Gelseal and Hemashield was 120% and 113% of the package size (PS), respectively, while the internal diameter was 103% and 102% of the PS, respectively. Following implantation, the external diameter of the Gelseal and Hemashield was 122% and 113% (immediately after) and 129% and 118% (4 weeks later) of the PS, respectively. CONCLUSIONS: The actual dilation rate for the first 4 weeks after implantation was estimated as 8% with the Gelseal and 4% with the Hemashield.

Aged↗

PubMed1998

Routine coronary angiography prior to abdominal aortic aneurysm repair: incidence of silent coronary artery disease.

OBJECTIVE: Routine coronary angiogram (CAG) was performed in patients prior to elective repair of abdominal aortic aneurysm (AAA) to estimate the incidence of coronary artery disease (CAD) and to compare with risk factors for CAD and resting electrocardiogram (ECG). METHODS: History of CAD, risk factors for CAD, resting ECG, and standard CAG were assessed in 50 consecutive AAA patients. RESULTS: Nine patients had a history of CAD. Risk factors included: smoking in 82%, hypertension in 58%, hypercholesterolemia in 42%, and diabetes in 18%. CAG revealed that 46% of the patients had severe CAD with greater than a 75% stenosis of one or more coronary arteries. There was no relationship between the number of risk factors and prevalence of CAD. Eleven patients who had severe CAD as detected by CAG had no history of CAD and displayed no ischemic findings on ECG. No perioperative myocardial infarctions or angial attacks were noted despite the absence of prophylactic coronary interventions or revascularizations. CONCLUSIONS: The prevalence of severe CAD was 46% and incidence of silent CAD was 22% in this AAA population. The numbers of coronary risk factors and resting ECG were not worthwhile for predicting silent CAD.

Aged↗

PubMed1998

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (1996)].

The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. Ikemoto et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed. In 16 institutions around the entire Japan, 557 strains of presumably etiological bacteria were isolated mainly from the sputa of 449 patients with lower respiratory tract infections during the period from October 1996 to September 1997. MICs of various antibacterial agents and antibiotics were determined against 98 strains of Staphylococcus aureus, 93 strains of Streptococcus pneumoniae, 84 strains of Haemophilus influenzae, 84 strains of Pseudomonas aeruginosa (non-mucoid strains), 17 strains of Pseudomonas aeruginosa (mucoid strains), 31 strains of Moraxella subgenus Branhamella catarrhalis, 21 strains of Klebsiella pneumoniae etc., and the drug susceptibilities of these strains were assessed except for those strains that died during transportation. 1) S. aureus S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 micrograms/ml (methicillin-resistant S. aureus) accounted for 67.3%. The frequency of the drug resistant bacteria increased comparing to the previous year's 52.7%. Arbekacin (ABK) and vancomycin (VCM) showed the highest activities against both S. aureus and MRSA with MIC80s of 1 microgram/ml. 2) S. pneumoniae Imipenem (IPM) and panipenem (PAPM) of carbapenems showed the most potent activities with MIC80s of 0.063 microgram/ml. Faropenem (FRPM) showed the next potent activity with MIC80 of 0.125 microgram/ml. The other drugs except erythromycin (EM), clindamycin (CLDM) and tetracycline (TC) were active against S. pneumoniae tested with MIC80s of 8 micrograms/ml or below. 3) H. influenzae The activities of all drugs were potent against H. influenzae tested with MIC80s of 4 micrograms/ml or below. Cefotiam (CTM), cefmenoxime (CMX), cefditoren (CDTR) and ofloxacin (OFLX) showed the most potent activities with MIC80s of 0.063 microgram/ml. 4) P. aeruginosa (mucoid strains) Tobramycin (TOB) showed the most potent activity against P. aeruginosa (mucoid strains) with MIC80 of 1 microgram/ml. Ceftazidime (CAZ), cefsulodin (CFS), IPM, gentamicin (GM), ABK and ciprofloxacin (CPFX) showed the next potent activities, with MIC80s of 2 micrograms/ml. The MIC80s of the other drugs ranged from 4 micrograms/ml to 16 micrograms/ml. 5) P. aeruginosa (non-mucoid strains) TOB and CPFX showed the most potent activities against P. aeruginosa (non-mucoid strains) with MIC80s of 1 microgram/ml. The MIC80s of piperacillin (PIPC) and cefoperazone (CPZ) were 16 micrograms/ml in 1995, and they were 64 micrograms/ml in 1996. 6) K. pneumoniae All drugs except ampicillin (ABPC) were active against K. pneumoniae. CMX, cefpirome (CPR), cefozopran (CZOP) and carumonam (CRMN) showed the most potent activities against K. pneumoniae with MIC80s of 0.125 microgram/ml. The MIC80s of the other drugs ranged from 0.25 microgram/ml to 2 micrograms/ml. 7) M.(B) catarrhalis Against M.(B.) catarrhalis, all drugs showed good activities with MICs of 4 micrograms/ml or below. IPM and minocycline (MINO) showed the most potent activities with MICs of 0.063 microgram/ml. Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. Patients' backgrounds were examined for 557 isolates from 449 cases. The examination of age distribution indicated that the proportion of patients with ages over 60 years was 71.0% of all the patients showing a slight increase over that in 1994. Proportions of diagnosed diseases were as follows: Bacterial pneumonia and chronic bronchitis were the most frequent with 35.9% and 30.3% respectively. They were followed by bronchiectasis with a proportion of 10.

Adult↗

PubMed1998

[Stress ulceration related bleeding (SURB) in intensive care unit].

Today in critically ill patients the frequency of major stress ulceration related bleeding (SURB) has decreased. However this syndrome has not totally disappeared and its mortality remains very high once it develops. It's high mortality seems to be due to the facts that pathogenesis of SURB is mucosal ischemia resulting from splanchnic hypoperfusion in the setting of various insults in the ICU and that SURB reflects gut failure as a part of multiple organ failure (MOF). Therefore in the prevention of SURB, the optimization of tissue oxygen metabolism in splanchnic area must be considered in addition to the common prophylactic measures such as decreasing or neutralizing gastric acid and protecting gut mucosa.

Histamine H2 Antagonists↗

PubMed1998

[Analysis of adenovirus type 7 hexon hypervariable region].

The isolation of adenovirus type 7 (Ad7) has been rare in Japan in the past. However since April, 1995, many isolates of Ad 7 have been reported. In order to find the cause of Ad 7 re-emergence in Japan, we investigated the genome sequences of Ad 7 by analyzing the hexon hypervariable regions (HVRs). HVRs of genomes isolated before and after this prevalence showed little change and were closely related with each other. It was concluded that adenovirus hexon which contains HVRs is conserved in the same serotype of any genome type. At present, virus genome typing seems more suitable for comparing the differences of genomes than sequencing.

Adenoviruses, Human↗

PubMed1998

Life-threatening reperfusion injury in skeletal muscle: a simple technique to control critical hyperkalemia.

A 55-year-old male suffering from acute abdominal aortic occlusion due to iatrogenic aortic dissection was urgently admitted to hospital. An axillo-bifemoral bypass was constructed 6 hours from the onset of dissection. Before and after revascularization, blood samples were repeatedly obtained from a systemic artery and femoral vein. The arterial potassium concentration gradually increased, reaching 7.3 mM/L. Oliguria and arrhythmias occurred, and the left lower limb became rigid 3 hours after reperfusion. The femoral artery and vein were clamped and within 30 minutes, the arterial potassium concentration fell to 4.8 mM/L. The urine output increased. The left lower limb was amputated, and the patient survived. Immediately following revascularization, hyperkalemia may occur. Clamping of the afferent and efferent vessels is recommended as a simple and practical technique to quickly control life-threatening hyperkalemia.

Amputation, Surgical↗