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Biomedical subjects

T Murakami

Publications and source records attributed to T Murakami.

At least 775 records · Page 43Linked to original sources
PubMed1996

Reduced coronary flow reserve in familial hypercholesterolemia.

UNLABELLED: Familial hypercholesterolemia (FH) presents the highest risk for coronary artery disease (CAD) among patients with hyperlipidemia. Therefore, early detection of coronary arterial atherosclerosis is important for the treatment of FH patients. The aim of this study was to detect early coronary arterial abnormalities that may relate to future atherosclerosis in asymptomatic FH patients by measuring coronary flow reserve (CFR) using PET and 13N-ammonia. METHODS: Twenty-five patients with FH (14 men, 11 women) without a history of myocardial ischemia and 14 control subjects (9 men, 5 women) were studied. Total serum cholesterol (mmole/liter) was 5.33 +/- 0.66 in control subjects and 7.90 +/- 0.77 in FH patients (p < 0.01 versus control subjects). RESULTS: Myocardial blood flow (MBF) at rest and during dipyridamole loading was measured using PET, and CFR was calculated. MBF (ml/min/100 g weight heart) at rest in the FH group (79.0 +/- 20.0) was comparable to that in control subjects (70.0 +/- 17.0). However, MBF during dipyridamole loading was significantly lower in FH patients (163.0 +/- 67.0) than in control subjects (286.0 +/- 120.0, p < 0.01). CFR in FH patients (2.09 +/- 0.62) was also significantly lower than that in control subjects (4.13 +/- 1.38, p < 0.01). CFR showed a gender-specific variance in FH patients (1.85 +/- 0.40 in men versus 2.55 +/- 0.74 in women p < 0.05) but not in control subjects. Significant inverse correlations between CFR and the total plasma cholesterol level as well as plasma LDL cholesterol were observed. CONCLUSION: The CFR was reduced in patients with FH. This abnormality was more prominent in men than in women patients. Noninvasive assessment of CFR by 13N-ammonia PET was useful to detect early abnormalities of the coronary arteries in asymptomatic patients with FH.

Ammonia↗
PubMed1996

[Trial of home infusion therapy for near-terminal stage patients with lung cancer].

To improve the quality of life in patients with malignant diseases at the near-terminal stage, we established a system for home infusion therapy (HIT) in Osaka Prefectural Habikino Hospital in 1994. Thirty-three patients were taken care of at home using the HIT system from January, 1995 to May, 1996. Their average age was 70 years old. The duration of HIT varied from 1 to 105 days (mean:25.5 days). Twenty-four cases received parenteral nutrition. The others received agents for brain edema (4 cases), morphine hydrochloride (2 cases), and anti-fungal agents (3 case). Additionally, 63% of these patients required home oxygen therapy (HOT) with HIT. Questionnaires to their families revealed that they were afraid of the progress of the disease in patients and their physical burden became heavier after the start of HIT. However, they were quite satisfied with the results of HIT.

Adolescent↗
PubMed1996

[Traumatic injuries of the thoracic aorta--report of five cases].

Five cases of traumatic aneurysm of the thoracic aorta associated with blunt chest trauma are described. Although we lost one case, four cases were successfully treated. Case 1, This was a 22-year-old female who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation two days after injury. Case 2, This was a 17-year-old male who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation 24 hours after injury. Case 3, This was a 56-year-old female who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation 24 hours after injury. Case 4, This was a 69-year-old male who underwent surgery for graft replacement with three branches for an aortic arch aneurysm under extracorporeal circulation one month after injury. Despite an emergency operation, we lost case 5 (a 21-year-old male) because of a complete discontinuity of the aortic isthmus. The postoperative course of the other four cases was uneventful. Vessel injury may be more widespread than preoperative radiographic findings demonstrates. Blunt chest trauma is usually accompanied by multisystem injury. Therefore, it is imperative to determine the first priority of treatment based on further preoperative examination in cases having associated injuries.

Adolescent↗
PubMed1996

[A case of swallowed fish bone-induced esophageal perforation and mediastinitis treated with pedicled omental graft].

We experienced a case of 47-year-old man who suffered swallowed fish bone-induced esophageal perforation with purulent mediastinitis and underwent direct suture closure of the perforation and reinforcement with a pedicled parietal pleura four days after the onset. Postoperative esophageal suture insufficiency was occured and reoperation was performed two months after the first operation. The esophageal fistula was plugged with a pedicled omental graft successfully. The postoperative course of the patient was uneventful and he discharged 45 days after the second operation. A reinforcement by pedicled omental graft for esophageal rupture accompanied with mediastinitis was considered to be a useful procedure.

Animals↗
PubMed1996

[Blood flow measurement of portal vein with fast cine phase contrast MR imaging under breath-holding].

Flow measurements of the right portal vein were performed in seven healthy volunteers with the segmented k-space fast gradient-echo phase-contrast (fcard-PC) sequence under breath-holding. The mean velocity and the flow rate of the right portal vein at maximal expiration, 14.3 +/- 4.4cm/sec and 457 +/- 218 ml/min, were significantly greater (p < 0.01) than those at maximal inspiration: 11.8 +/- 3.8cm/sec (mean +/- SD) and 364 +/- 191ml/min, respectively. Fcard-PC enabled flow measurements to be obtained under breath-holding. Using this technique, we demonstrated portal venous flow changes according to respiratory phase.

Adult↗
PubMed1996

A view of death and dying among the Chinese and Japanese.

The practices of medicine around the world have been fused into that of faith and religion. In serving our patients' need to accept death, physicians must also be sensitive to this underlying basic human concern as they prepare for this final journey. The Chinese and Japanese, reflecting their belief in Buddhism, perceive death as a natural part and an extension of life itself.

Attitude to Death↗
PubMed1996

[Primary right atrial hemangiosarcoma manifesting as cardiac tamponade: a case report with transesophageal echocardiography].

A 39-year-old woman presented with a right atrial hemangiosarcoma manifesting as cardiac tamponade with complaints of chest discomfort and dyspnea. Transthoracic echocardiography revealed remarkable pericardial effusion and a right atrial mass. Transesophageal echocardiography disclosed the tumor extending into the right atrial cavity. Surgery found the tumor was poorly demarcated, immobile and adhered to the adjacent right atrial wall and septum. The echocardiographic findings correlated well with the surgical and autopsy findings.

Adult↗
PubMed1996

Correlated confocal and intermediate voltage electron microscopy imaging of the same cells using sequential fluorescence labeling, fixation, and critical point dehydration.

Confocal laser scanning microscopy (CLSM) and intermediate voltage transmission electron microscopy (IVEM) each has its own particular advantages. CLSM can examine living cells, but is particularly useful when applied to cells that have been lightly fixed, permeabilized, and stained with fluorescent-labeled antibodies for localization of specific molecular species at the resolution of the light microscope while still in the hydrated state. IVEM provides much higher resolution images, but requires more drastic preparation procedures, including dehydration. This paper presents methods for combining these complementary approaches to examine exactly the same cells sequentially by CLSM and IVEM. Cells are grown in culture on sterile formvar films spread over gold index grids on cover glasses, which are mounted on larger cover glasses or microscope slides with spacers to prevent compression of the cells. Light and epifluorescence microscopy, and CLSM are performed concentrating on cells in grid openings. Then the grids are fixed with aldehydes followed by OsO4, dehydrated and critical point dried (CPD) from liquid CO2. Immediately following CPD, the grids are ready for examination in the IVEM. Low magnification (300-600x) survey images allow correlation of the IVEM images with the light microscopic images. In higher power images, structures that are fluorescent labeled can be related to corresponding regions in the IVEM images.

Animals↗
PubMed1995

A novel serpin-like protein, B-43, exists in both neurons and astrocytes: an immunohistochemical study in the parietal region of the bovine brain.

The presence of a novel member of serine proteinase inhibitor, B-43, was immunohistochemically indicated in both neurons and astrocytes in the parietal region of the bovine brain. B-43-like immunoreactivity was detected in pyramidal cells in the cortex and GFAP-positive astroglial cells in the white matter. The processes of B-43 may play a cooperative role with glia-derived nexin/protease nexin-1 and alpha 1-antichymotrypsin in the brain.

Animals↗
PubMed1995

Blood vascular bed and pericapillary space in rat parathyroid glands.

The blood vascular bed and pericapillary space of the rat parathyroid gland were studied by scanning electron microscopy of vascular casts, freeze-cracked tissue blocks, and NaOH-treated tissue specimens. The findings were supplemented by transmission light and electron microscopy of sectioned tissue samples. The rat parathyroid gland contained a rich network of freely anastomosing capillaries. These capillaries were surrounded by marked pericapillary spaces that were demarcated by basal lamina of both capillaries and parenchymal cells. The pericapillary spaces contained many collagen fibrils and frequently issued some projections running deep into the sheets of parathyroid cells. The latter projections may be useful to supply the parenchymal cells located far from the capillaries. The collagen fibrils may regulate the flow of tissue fluid in the pericapillary space and convey parathyroid hormone, which is released at the apicolateral domain, into the capillaries.

Animals↗
PubMed1995

Dexamethasone regulates obese expression in isolated rat adipocytes.

An obese (ob) gene product, expressed specifically in adipose tissues, regulates energy balance. Here we report adipocytes in adipose tissue actually express ob mRNA and that a synthetic glucocorticoid (dexamethasone) regulates expression of the ob gene. Addition of 100 nM dexamethasone to isolated rat adipocytes rapidly induced a 4-8 fold increase in ob mRNA. This increase in ob mRNA level was apparent within 1 h, and reached a maximum at about 7 h after stimulation. The dexamethasone-stimulated increase of ob mRNA was only partially blocked by protein synthesis inhibitors cycloheximide (20 micrograms/ml) or anisomycin (200 microM). This suggests that new protein synthesis is not necessarily required for the observed dexamethasone-stimulated increase in ob mRNA.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Induction of apoptosis by 5-azacytidine: drug concentration-dependent differences in cell cycle specificity.

There are conflicting data in the literature as to whether cytotoxicity of the cytidine antimetabolite 5'-azacytidine (AZC) is a consequence of its incorporation into RNA, DNA, or both. Because apoptosis appears to be the predominant mode of tumor cell death after treatment with most antitumor drugs, and in the case of some drugs, the proclivity of the cell to undergo apoptosis varies depending on the cell cycle position, this study was aimed toward elucidating whether induction of apoptosis by AZC is cell cycle phase specific. Human promyelocytic leukemic HL-60 cells were treated with varying concentrations of AZC, and flow cytometric methods that identify apoptotic cels and provide information about the cell cycle distribution of the apoptotic and nonapoptotic cell populations were used. At 2-6 microM concentrations of AZC, the cells in the G1 phase preferentially underwent apoptosis, whereas the cells in G2-M were particularly resistant. Although incorporation of bromouridine into RNA was suppressed at that low AZC concentration, the rate of 5'-bromo-2-deoxyuridine incorporation into DNA was not significantly affected. At an AZC concentration of 8-40 microM, no cell cycle phase specificity in induction of apoptosis was apparent, but both the rate of 5'-bromo-2-deoxyuridine incorporation into DNA and bromouridine into RNA were reduced in proportion to drug concentration. The data suggest that the mechanism of cell killing by AZC may be different, depending on its concentration. Namely, whereas incorporation of AZC into RNA may play a predominant role in the induction of cytotoxicity of G1 cells at low drug concentrations, the perturbation of both RNA and DNA metabolism may be responsible for triggering cell death in the G1 and S phases, as is seen at higher concentrations of this antimetabolite.

Apoptosis↗
PubMed1995

Cloning of rat obese cDNA and its expression in obese rats.

The mouse obese gene product, expressed specifically in adipose tissue, regulates energy balance in mice. Mutation of the obese gene results in marked obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. Here we report the cloning and sequencing of rat obese cDNA. Neither alterations of nucleotide sequence in the coding region nor changes of the gene structure were found in two rat strains with obesity, Zucker (fa/fa) and Otsuka Long Evans Tokushima Fatty. The expression level of obese mRNA in adipose tissue of Zucker (fa/fa) rat was found to be about 4 times that in lean littermates, suggesting some mutation or abnormal expression of the receptor for the obese product in obese rats of this strain.

Animals↗
PubMed1995

Identification of a discrete region of the G protein gamma subunit conferring selectivity in beta gamma complex formation.

The identification of multiple G protein beta and gamma subunit subtypes suggests a potential diversity of beta gamma heterodimers, which may contribute to the specificity of signal transduction between receptors and effectors. The assembly of beta and gamma subtypes is selective. For example, gamma 1 can assemble with beta 1 but not with beta 2, whereas gamma 2 assembles with both beta isoforms. To identify the structural features of the beta and gamma subunits governing selectivity in heterodimer assembly, a series of nonisoprenylated chimeras of gamma 1 and gamma 2 was constructed, and their interaction with beta 1 and beta 2 was assessed by their ability to direct beta expression to the cytosol in cotransfected COS cells. All of the gamma 1/gamma 2 chimeras were capable of interacting with beta 1 as judged by the cotransfection assay. Chimeras containing gamma 2 sequence near the middle of the molecule between two conserved sequence motifs were capable of interacting as well with beta 2. Among 12 divergent residues in this region, it was found that replacement of three consecutive amino acids in gamma 1, Glu-Glu-Phe (residues 38-40), with the three corresponding amino acids of gamma 2, Ala-Asp-Leu (residues 35-37), conferred the ability to assemble with beta 2. The reciprocal chimera containing Glu-Glu-Phe in the context of gamma 2 failed to assemble with beta 2. The last residue of this triplet is occupied by a leucine in all known mammalian gamma subunits except gamma 1 and appears to be a key determinant of the ability of a gamma subunit to assemble with beta 2. This locus maps to a region of predicted alpha-helical structure in the gamma subunit, likely to represent a point of physical contact with the beta subunit.

Amino Acid Sequence↗
PubMed1995

Isolation of the porcine heparin tetrasaccharides with glucuronate 2-O-sulfate. Heparinase cleaves glucuronate 2-O-sulfate-containing disaccharides in highly sulfated blocks in heparin.

Eleven tetrasaccharides were isolated from the repeating disaccharide region of porcine intestinal heparin after strong digestion with Flavobacterium heparinase. Their structures were determined by composition analysis, enzymatic analysis, and 1H NMR spectroscopy. Nine of them have the common tetrasaccharide backbone, delta HexA alpha 1-4GlcN alpha 1-4IdoA alpha 1-4GlcN, where delta HexA and IdoA represent 4,5-unsaturated hexuronic acid and L-iduronic acid, respectively, and their structural variations are based upon the positions of sulfate groups. The nine compounds include one hexasulfated, three pentasulfated and five tetrasulfated compounds, and four of them have not been isolated previously as discrete structures. The other two of the 11 tetrasaccharides have the following hitherto unreported structures with novel glucuronate 2-O-sulfate at the internal position: delta HexA(2-sulfate) alpha 1- 4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N-sulfate) and delta HexA(2-sulfate) alpha 1-4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N,6-disulfate). Thus, 2-O-sulfated glucuronate in the highly sulfated tetrasaccharide structures typical of heparin has been demonstrated. The former and the latter tetrasaccharides account for 0.31 and 0.32% (w/w) of the starting heparin, respectively. Their yield, however, is an underestimation, since these tetrasaccharide structures in longer sequences will be degraded by heparinase. Although the latter tetrasaccharide described above was unexpectedly cleaved by heparinase into two disaccharide units, the former was not degraded by the enzyme most likely due to the lack of the 6-O-sulfate group on the GlcN residue at the reducing terminus. The results indicate its capability of catalyzing both anti and syn elimination, a property shared by heparitinases I and II and chondroitinase ABC. Both tetrasaccharides were degraded into disaccharides by heparitinase II. Therefore, it is necessary to reevaluate the disaccharide composition of heparin/heparan sulfate or oligosaccharide structures, which were previously determined after heparinase or heparitinase II digestion. It is no longer possible to conclude that the 2-O-sulfated unsaturated uronic acid residues obtained from heparin/heparan sulfate by lyase digestions are always derived from iduronate 2-O-sulfate residues in the original polymer. It is quite possible that the novel glucuronate 2-O-sulfate structure in the highly sulfated region of heparin is involved in some of the biological activities of heparin.

Animals↗