Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 199 records · Page 11Linked to original sources

PubMed1999

Association between bacterial colonization on the tumor, bacterial translocation to the cervical lymph nodes and subsequent postoperative infection in patients with oral cancer.

OBJECTIVE: To investigate the association between postoperative infection, bacterial translocation to the cervical lymph nodes and bacterial colonization on the tumor in oral cancer patients. METHODS: Twenty-one oral mucosal cancer patients (11 male and 10 females: mean age 68.6 years) were studied. They underwent tumor surgery and neck dissection with free flap reconstruction. Ampicillin 1 g was parenterally administered from the start of the surgery as prophylaxis. Isolates from cervical lymph nodes, tumor and postoperative infected wound were studied microbiologically and pathologically. RESULTS: Bacterial translocation was found in 52 lymph nodes (52/107: 48.6%). Viable bacteria were isolated from 20 tumors (95.2%). Oral microflora and enteric bacteria were isolated. Postoperative infection was found in four cases. In three cases, enteric bacteria (Klebsiella, Enterobacter, Enterococcus) isolated from postoperative infections were also found in the tumor or the lymph nodes. CONCLUSIONS: The operative field in oral cancer surgery was colonized by the indigenous flora and enteric bacteria. These were recovered not only from the tumor surface but also from the cervical lymph nodes. Preoperative surveillance culture or tumor culture have value in predicting the bacteriology of postoperative infection, and in selecting the appropriate antibiotic treatment.

Journal Article↗

PubMed1999

Experimental His-bundle pacing: histopathological and electrophysiological examination.

His-bundle pacing gives a more physiological ventricular contraction in comparison to right ventricular apical pacing. However the problems of lead fixation and stability of long-term His-bundle pacing are yet unsolved. We used six adult beagles, in which a screw-in lead was anchored in the His-bundle region for observation of the pacing conditions and histopathologic changes of the conduction system over the course of 2 months. In the results, a satisfactory fixation was obtained using a conventional screw-in lead and no histological influence on the conduction system was observed. The pacing threshold at the time of implantation was 1.15 +/- 0.69 V (3.23 +/- 3.08 mA) in the pulse width of 0.5 ms. R wave amplitude, the impedance and slew rate were 7.28 +/- 2.04 mV, 409 +/- 102 Ohm, and 0.65 +/- 0.41 V/s, respectively. Two months later, these parameters changed to 2.83 +/- 1.06 V (10.4 +/- 5.71 mA), 5.63 +/- 1.62 mV, 310 +/- 71.3 Ohm, and 0.49 +/- 0.22 V/s, respectively. These results suggest the feasibility of clinical application of permanent His-bundle pacing.

Animals↗

PubMed1999

Immunochemical analysis of UMP kinase from Escherichia coli.

Mono- and polyclonal antibodies directed against UMP kinase from Escherichia coli were tested with the intact protein or with fragments obtained by deletion mutagenesis. As detected in enzyme-linked immunosorbent assay tests, the carboxy-terminal quarter of UMP kinase is immunodominant. Polyclonal antibodies inhibited the enzyme activity with partial or total loss of allosteric effects exerted by UTP and GTP, respectively. These data indicate that the UTP and GTP binding sites in UMP kinase are only partially overlapping. One monoclonal antibody (44-2) recognized a linear epitope in UMP kinase between residues 171 and 180. A single substitution (D174N) in this segment of the enzyme abolished its interaction with the monoclonal antibody (44-2). Polyclonal antisera were used to identify UMP kinase in the bacterial proteome. The enzyme appears as a single spot on two-dimensional electrophoresis at a pI of 7.24 and an apparent molecular mass of 26 kDa. Immunogold labeling of UMP kinase in whole E. coli cells shows a localization of the protein near the bacterial membranes. Because the protein does not contain sequences usually required for compartmentalization, the aggregation properties of UMP kinase observed in vitro might play a role in this phenomenon. The specific localization of UMP kinase might also be related to its putative role in cell division.

Animals↗

PubMed1999

Identification of an acid-activated Cl(-) channel from human skeletal muscles.

ClC-4 gene was isolated as a putative Cl(-) channel. Due to a lack of functional expression of ClC-4, its physiological role remains unknown. We isolated a human ClC-4 clone (hClC-4sk) from human skeletal muscles and stably transfected it to Chinese hamster ovary cells. Whole cell patch-clamp studies showed that the hClC-4sk channel was activated by external acidic pH and inhibited by DIDS. It passed a strong outward Cl(-) current with a permeability sequence of I(-) > Cl(-) > F(-). The hClC-4sk has consensus sites for phosphorylation by protein kinase A (PKA); however, stimulation of PKA had no effect on the currents. hClC-4sk mRNA was expressed in excitable tissues, such as heart, brain, and skeletal muscle. These functional characteristics of hClC-4sk provide a clue to its physiological role in excitable cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1999

Cellular and subcellular immunolocalization of ClC-5 channel in mouse kidney: colocalization with H+-ATPase.

To determine the immunolocalization of ClC-5 in the mouse kidney, we developed a ClC-5-specific rat monoclonal antibody. Immunoblotting demonstrated an 85-kDa band of ClC-5 in the kidney and ClC-5 transfected cells. Immunocytochemistry revealed significant labeling of ClC-5 in brush-border membrane and subapical intracellular vesicles of the proximal tubule. In addition, apical and cytoplasmic staining was observed in the type A intercalated cells in the cortical collecting duct. In contrast, the staining was minimal in the outer and inner medullary collecting ducts and the thick ascending limb. Western blotting of vesicles immunoisolated by the ClC-5 antibody showed the presence of H+-ATPase, strongly indicating that these two proteins were present in the same membranes. Double labeling with antibodies against ClC-5 and H+-ATPase and analysis by confocal images showed that ClC-5 and H+-ATPase colocalized in these ClC-5-positive cells. These findings suggest that ClC-5 might be involved in the endocytosis and/or the H+ secretion in the proximal tubule cells and the cortical collecting duct type A intercalated cells in mouse kidney.

Amino Acid Sequence↗

PubMed1999

Posthatching development of spinal motoneurons in the angelfish Pterophyllum scalare.

We investigated the posthatching developmental sequence of spinal motoneurons innervating the axial muscles in the teleost angelfish, Pterophyllum scalare, by means of retrograde labeling with horseradish peroxidase. Two discrete types of spinal motoneurons, primary-type motoneurons and secondary motoneurons were labeled in a temporally different sequence during the course of larval development. These two types of motoneurons were morphologically distinguishable from one other. Primary-type motoneurons are generated by day 1 posthatching and do not increase in number over the observed period (to day 12 posthatching). In contrast, the secondary motoneurons increase in number through posthatching day 3. Differentiation of the spinal motoneurons appears to be nearly complete a few days before the onset of free swimming. In addition, the data suggest that the differentiation of secondary motoneurons precedes the development of the red muscle that is to be innervated by the motoneurons.

Animals↗

PubMed1999

Gene expression in primary, metastatic and recurrent lesions of endometrial cancer.

Seventeen patients with endometrial cancer were studied. Tissues of primary (P) and metastatic (M) lesions were obtained from 8 patients and complete sets of P, M and Recurrent (R) lesions were obtained from 9 patients during a follow-up period of 1-10 years. Expressions of estrogen receptors, progesterone receptors, multidrug resistance protein-1, multidrug resistance-related protein, c-erbB-2, membrane-type metalloproteinase, human telomerase RNA, human telomerase reverse transcriptase RNA, E-cadherin and autocrine motility factor receptor were studied by RT-PCR. Also, telomeric restriction fragment length (TRFL) and microsatellite instability were determined between P, M and R. The results indicate that there are significant differences in the gene expression frequency during tumor progression. The mismatch rate ranged from 0 to 47.1% between P and M and from 14.3% to 66.7% between P and R, respectively. The TRFL analysis showed a marked reduction in P and M (P vs. M: 8.2 +/- 0.9 vs. 5.6 +/- 0.4 kb, mean +/-SEM, n = 9, p = 0.002 by paired Student's t test). The length further decreased in R (P vs. R: 8.2 +/- 0.9 vs. 3.2 +/- 0.7, p = 0.01, M vs. R: 5.6 +/- 0.4 vs. 3.2 +/- 0.7, p = 0.005). The genomic instability/replication error was tested by AluI arbitrary primed polymerase chain reaction (AP-PCR). Five out of 17 patients showed an altered replication error pattern (29.4%). The mean number of abnormal AluI AP-PCR patterns in M and R compared to the P was 1.5 (M) and 4 (R). The difference between the P and R was statistically significant (p < 0.04). The present data indicate that biological behavior of cancer cells in P, M and R may differ significantly.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Evaluation of left atrial wall elasticity using acoustic microscopy.

Left atrial wall elasticity is one of the important factors regulating left atrial stiffness and functions. The authors evaluated left atrial wall elasticity by measuring the sound speed through the left atrial wall, based on the hypothesis that high elasticity tissues will yield larger sound speed values through the tissue, and examined age-associated changes in left atrial wall elasticity. Left atrium specimens were obtained from 30 normal subjects (age, 15-95 years) at autopsy. An acoustic microscope, operating at 450 MHz, was used to measure the sound speed in the endocardium and the myocardium of the left atrium. The sound speeds in endocardium and myocardium demonstrated significant correlation with age (r = 0.74, p<0.0001 and r = 0.47, p<0.01, respectively). These findings indicate that left atrial wall elasticity increased with advancing age. These changes may lead to deterioration of left atrial compliance and eventual left atrial failure in older subjects.

Adolescent↗

PubMed1999

Sudden death with malignant hemangioendothelioma originating in the pericardium--a case report.

The authors report a rare case of a malignant hemangioendothelioma (MH) originating in the pericardium. In this case, a metastatic skin lesion was found first, and subsequently the existence of a primary cardiac lesion was confirmed. Generally, primary cardiac tumors grow slowly, and the prognosis of MH is relatively good. In this case, however, the patient died suddenly during the creation of a pericardial window for drainage. An autopsy showed that the MH originated from a pericardial lesion in the right atrium.

Death, Sudden↗

PubMed1999

Loculated pericardial effusion due to congestive heart failure: an unusual case of vanishing tumor--a case report.

Loculation of a pleural effusion within an interlobar fissure as a result of congestive heart failure is a well-known entity. It has been termed "vanishing" or "phantom" tumor because its roentgenographic appearance simulates a pulmonary tumor and resolves with treatment of the congestive heart failure. The authors describe an 89-year-old man with a loculated pericardial effusion on the left cardiac border on chest roentgenogram. This was initially thought to represent an occult metastatic malignancy; however, its etiology became obvious when it disappeared with therapy of heart failure. Loculated pericardial effusion should be included in the differential diagnosis of roentgenographic densities in the chest when seen on the left cardiac border.

Aged↗

PubMed1999

Cyclic variation of thickness in an age-related thick mitral valve observed by transthoracic echocardiography.

The cyclic variation of thickness during the cardiac cycle in age-related degenerative mitral valve (MV) has not been reported. Transthoracic echocardiography was used to evaluate the cyclic alteration in MV thickness in 40 patients with age-related MV thickening (diastolic MV thickness > or = 4 mm, age 70 +/- 14 years), 10 with mitral valve prolapse (MVP, age 49 +/- 11 years), 10 with rheumatic mitral stenosis (MS, age 66 +/- 9 years), and 31 control subjects (diastolic MV thickness < or = 3.6 mm, 53 +/- 17 years). After determination of the site of maximal thickness during diastole, the maximal and minimal thickness during systole of the anterior MV were measured. The percent change in MV thickness from diastole to systole (%deltaT) was calculated. The mitral regurgitation (MR) area was measured on color Doppler echocardiogram. The %deltaT (mean +/- sd) in age-related thickened MV and MVP groups were similar and significantly greater than that in control (60 +/- 8%, 61 +/- 6% vs 32 +/- 9%, p < 0.001). MR area was significantly greater in the age-related thickened MV group than that in controls (160 +/- 205 mm2 vs 14 +/- 40 mm2, p < 0.05). The %deltaT in MS (10 +/- 6%) was smallest (p < 0.001). A large cyclic alteration in valvular thickness was observed in the age-related degeneration of the MV and may be the cause of large MR despite no leaflet prolapse. The echocardiographic assessment of cyclic variation of MV thickness is feasible for estimating the histologic damage in thick MV.

Adolescent↗

PubMed1999

Tissue characterization of myocardial cells by use of high-frequency acoustic microscopy: differential myocyte sound speed and its transmural variation in normal, pressure-overload hypertrophic, and amyloid myocardium.

The purpose of the present study was to evaluate the acoustic properties of myocytes in normal, pressure-overload hypertrophic, and amyloid myocardium. Myocardial tissue specimens at autopsy were obtained from 10 subjects without cardiovascular disease, six patients with left ventricular (LV) hypertrophy, and six patients with cardiac amyloidosis. Sound speed of myocytes was measured at subendocardial and subepicardial regions in myocardium by use of a high-frequency (450 MHz) acoustic microscope. In normal myocardium, the sound speed of myocytes was significantly higher in subendocardial region (1,728+/-19 m/sec) than in subepicardial region (1,645+/-22 m/sec) (p<0.0001). A significantly higher sound speed of myocytes was observed in the subendocardial region in LV hypertrophic myocardium (1,779+/-19 m/sec) than that in normal myocardium (p<0.001). In amyloid myocardium, a significantly lower sound speed of myocytes was observed in subendocardial (1,560+/-8 m/sec) and subepicardial (1,594+/-48 m/sec) regions than that in respective regions of the normal myocardium (p<0.0001 and p<0.05, respectively). Transmural variation in sound speed of myocytes measured by high-frequency acoustic microscopy existed in normal left ventricle. The differential myocyte sound speed and its transmural variation was observed in LV hypertrophic and amyloid myocardium as compared with normal myocardium. High-frequency acoustic microscopy can be a promising technique for myocardial tissue characterization at the myocyte level.

Acoustics↗

PubMed1999

Skeletal features and growth patterns in 14 patients with haploinsufficiency of SHOX: implications for the development of Turner syndrome.

We report on clinical features in 14 Japanese patients (4 males and 10 females) with partial monosomy of the short arm pseudoautosomal region involving SHOX (n = 11) or total monosomy of the pseudoautosomal region with no involvement of disease genes on the sex-differential regions (n = 3). Skeletal assessment showed that three patients had no discernible skeletal abnormalities, one patient exhibited short 4th metacarpals and borderline cubitus valgus, and the remaining 10 patients had Madelung deformity and/or mesomelia characteristic of Léri-Weill dyschondrosteosis (LWD), together with short 4th metacarpals and/or cubitus valgus. Skeletal lesions were more severe in females and became obvious with age. Growth evaluation revealed that patients without LWD grew along by the -2 SD growth curve before puberty and showed a normal or exaggerated pubertal growth spurt, whereas those with LWD grew along by the standard growth curves before puberty but exhibited an attenuated pubertal growth spurt and resultant short stature. Maturational assessment indicated a tendency of relatively early maturation in patients with LWD. There was no correlation between the clinical phenotype and the deletion size. These findings suggest that haploinsufficiency of SHOX causes not only short stature but also Turner skeletal anomalies (such as short 4th metacarpals, cubitus valgus, and LWD) and that growth pattern is primarily dependent on the presence or absence of LWD. Because skeletal lesions have occurred in a female-dominant and age-influenced fashion, it is inferred that estrogens exert a maturational effect on skeletal tissues that are susceptible to premature fusion of growth plates because of haploinsufficiency of SHOX, facilitating the development of skeletal lesions.

Adolescent↗

PubMed1999

Regional blood flow distribution from the proximal arterial cannula during veno-arterial extracorporeal membrane oxygenation in neonatal dog.

Extracorporeal membrane oxygenation (ECMO) is frequently used for treatment of patients with severe hypoxemia due to life-threatening respiratory failure. Due to this hypoxemia, the myocardium of these patients is insufficiently provided with oxygen, and consequently their cardiac function commonly deteriorates. But veno-arterial (V-A) ECMO provides oxygenated blood to the coronary arteries from ECMO circuit insufficiently. To increase the coronary blood flow distributed from ECMO, we placed the arterial cannula 1 cm above the aortic valve and evaluated the regional blood from the proximal arterial cannula in comparison with the distal cannula. Eight neonatal dogs weighting 1.8-2.5 kg were supported by V-A ECMO. The regional blood flow from the arterial cannula was measured by injection of colored microspheres into ECMO circuit. The site of the arterial cannula was changed under fluoroscopy. The bypass flow was maintained at either 50 or 100 ml/min/kg. We found that the coronary blood flow distributed from the proximal arterial cannula was significantly higher than that from the distal cannula. The proximal arterial cannula appears necessary to provide sufficient oxygenated blood to the coronary circulation during V-A ECMO. Therefore, it is expected that the increased cardiac function may improved, and that the survival rate of the patients with retarded cardiac function due to severe hypoxemia may increase by proximal placement of the arterial cannula during V-A ECMO.

Animals↗

PubMed1999

The increase of parathyroid hormone-related peptide and cytokine levels in synovial fluid of elderly rheumatoid arthritis and osteoarthritis.

We simultaneously measured the concentrations of parathyroid hormone related peptide (PTHrP) and cytokines in synovial fluid (SF) to clarify the relationship between PTHrP and cytokine network in the SF of elderly patients with arthritis. SF was collected from knee joints of five RA patients aged 66+/-11 years old and nine osteoarthritis (OA) patients aged 80+/-9 years old. PTHrP in SF was measured by enzyme-linked immunosorbent assay (ELISA), whereas tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8) in SF were all measured by ELISA. The PTHrP levels in the SF of RA patients (2.56+/-0.89 pmol/l) were significantly (p<0.05) higher than those of OA patients (1.66+/-0.17 pmol/l). TNF-alpha, IL-1beta, IL-2 and IL-6 concentrations in SF of RA were also significantly higher than those in SF of OA (TNF-alpha 22.5+/-14.8 vs 4.8+/-3.0 pg/ml, p<0.01; IL-1beta 11.8+/-11.4 vs 1.4+/-1.3, p<0.05; IL-2 59.9+/-46.6 vs 12.5+/-8.0 pg/ml, p<0.05; IL-6 18424+/-8901 vs 3547+/-2948 pg/ml, p<0.01). The concentrations of IL-4 and IL-8 in SF of RA were similar to those of OA. Immunohistochemical studies revealed the presence of immunoreactive PTHrP in synovial fibroblasts from RA and OA. Among cytokines, only IL-6 was positively correlated with PTHrP levels in SF (r=0.685, p<0.01). In the culture of synovial cells from RA and OA, PTHrP was produced in RA more than OA after phorbol 12-mysistate 13-acetate (TPA) stimulation. These results indicate that PTHrP and cytokines, especially IL-6, might be involved in the inflammatory processes of elderly RA and OA. This is the first study in which PTHrP and cytokine levels were simultaneously examined in synovial fluid of elderly RA and OA.

Aged↗

PubMed1999

Development of atherosclerotic lesions in cholesterol-loaded rabbits.

To examine both of the target vessels and the optimal time of their endothelial denudation to study vascular restenosis after balloon injury in cholesterol-loaded rabbits, we made 36 atherosclerotic rabbits by feeding a hypercholesterol diet, and histologically examined the onset time and the development of atherosclerosis. Atheromatous changes were observed first after the 5th week in the thoracic aorta from the start of the diet, and then extended to the abdominal aorta, coronary artery with time. The atherosclerotic lesions in the thoracic aorta and the proximal portion of the coronary artery showed high-grade concentric intimal thickening with luminal stenosis. The abdominal aortic lesion mildly progressed. In the renal, carotid and femoral arteries, in contrast, slight atheroscleromatous changes developed during the diet period. These results suggest that the thoracic and abdominal aortas and the coronary artery would be suitable as target vessels to study vascular restenosis after balloon injury, and the endothelial denudation of these vessels should be performed between the 8th and 15th week in this diet protocol for an accurate analysis.

Animals↗

PubMed1999

Salt water promotes hypertension in Dahl-S rats.

Hypertension was induced in Dahl-salt-sensitive (Dahl-S) rats by administering salt in drinking water. Control rats receiving tap water did not show a significant change in blood pressure or abnormalities in the kidney. Rats receiving 0.5% NaCl solution developed moderate hypertension and renal lesions. Rats receiving 1.0% NaCl solution showed prominent and increasing hypertension and severe renal damage. This method of salt administration should be simpler than administration in the diet as a means of promoting renal hypertension. The lower concentration salt water caused chronic mild hypertension in Dahl-S rats, and may serve as a useful model for progressive hypertension.

Animals↗

PubMed1999

High incidence of persistent primitive arteries in moyamoya and quasi-moyamoya diseases.

This study investigated the incidences of persistent primitive arteries in patients with moyamoya disease, unilateral moyamoya disease, and quasi-moyamoya disease. Cerebral angiograms of 50 patients (39 moyamoya disease patients, 6 unilateral moyamoya disease patients, and 5 quasi-moyamoya disease patients) were retrospectively reviewed. There were 35 females and 15 males, aged from 3 to 63 years (mean 27.4 years). Persistent primitive carotid-basilar artery anastomoses were observed in three patients: primitive hypoglossal artery in one moyamoya disease patient, primitive trigeminal artery variant in one unilateral moyamoya disease patient, and an anastomosis between the accessory meningeal artery and the anterosuperior cerebellar artery in one quasi-moyamoya disease patient. The ophthalmic artery originated from the middle meningeal artery in three moyamoya and two quasi-moyamoya disease patients. The incidence of the persistent primitive arteries is significantly higher in patients with moyamoya disease (10.7%) and quasi-moyamoya disease (60%) than in patients with other disease (0.67%) (p < 0.001), so congenital factors may be important in the pathogenesis of moyamoya disease.

Adolescent↗