Biomedical subjects

T Imamura

Publications and source records attributed to T Imamura.

At least 433 records · Page 24Linked to original sources

PubMed1992

Role of thrombin and plasmin in development of delayed hypersensitivity reaction in guinea pig skin.

Induration is a prominent feature of delayed hypersensitivity reaction (DHR), and fibrin deposition is the central mechanism. We studied the effects of two inhibitors of DHR on the activities of thrombin and plasmin in the extract of the skin site of DHR and compared the two activities in the site of DHR with those in the site of the Arthus reaction (AR) that lacks induration. Warfarin, an anticoagulant, inhibited thrombin activity and induration, but not plasmin activity. Ferritin, a blocker of a macrophage-dependent reaction, inhibited the two activities and induration. The lesion of DHR had three to four times the thrombin activity of the lesion of AR, and the activity paralleled the development of induration. In contrast, plasmin activity of the site of DHR was lower than that of the site of AR and was associated with the reduction of induration. The two protease activities in the site of AR did not correlate with the development of the AR lesion. These results suggest that thrombin and plasmin mediate the development of induration and that induration is produced by a synergistic effect of high thrombin activity and low plasmin activity in the site of DHR.

Amino Acid Sequence↗

PubMed1992

Microenvironment of tryptophan residues in beta-lactoglobulin derivative polypeptide-sodium dodecyl sulfate complexes.

The changes of microenvironment of tryptophan residues in beta-lactoglobulin A and its cyanogen bromide (CNBr) fragments with the binding of sodium dodecyl sulfate (SDS) were studied with measurements of the rates of N-bromosuccinimide (NBS) modification reactions by stopped-flow photometry. Two tryptophan residues of carboxyamidomethylated (RCM) beta-lactoglobulin A in the states of their complexes with SDS were clearly distinguishable by their differences in NBS modification rates. We confirmed by experiments with CNBr fragments containing trytophan residue. The modification rates of Trp 19 in RCM beta-lactoglobulin A-SDS complexes were about 10-fold smaller than those expected for tryptophan residues exposed entirely to the aqueous solvent. The Trp 61 was hardly changed. The change of rate constants for Trp 19 was virtually consistent with those observed when N-acetyl-L-trytophan ethylester was dissolved in SDS micelles. For various species of polypeptide-SDS complexes, all tryptophan residues were reactive to NBS and also, for some of them, the differences in NBS modification rates were observed between tryptophan residues on a common polypeptide chain. These results suggest micellar and heterogeneous bindings of SDS to polypeptides.

Cyanogen Bromide↗

PubMed1992

Coronary artery-cardiac chamber shunt: cineangiographic analysis.

Coronary artery-cardiac chamber shunts (CA-CC shunts) were observed in 101 out of 2267 consecutive patients (4.5%) receiving selective coronary angiography. In these patients, contrast medium injected into the coronary artery escaped directly into the cardiac chamber. CA-CC shunts were angiographically classified into the following two types. Type I: The endocardial layer was diffusely opacified, and contrast medium escaped into the cardiac chamber on systole (n = 83). Type II: Contrast medium escaped directly into the cardiac chamber via an undilated branch (n = 11). Type I and type II shunts were observed simultaneously in 7 patients. It is speculated that type I is a shunt via a persistent arterio-sinusoidal vessel, while type II is a shunt via a persistent arterio-luminal vessel. Both types were observed frequently (24.9%) in hypertrophic cardiomyopathy. The degree of CA-CC shunts in hypertrophic cardiomyopathy was not influenced by the presence or absence of myocardial squeezing. CA-CC shunts are considered to be due to an abnormality in the coronary microcirculation of the myocardium. We describe the angiographic features of the two types of CA-CC shunt and discuss their pathophysiological significance.

Adolescent↗

PubMed1992

Substance P as a potent stimulator of sneeze responses in experimental allergic rhinitis of guinea pigs.

Substance P was examined for sneeze-inducing activity and its involvement of sneeze responses in experimental allergic rhinitis. Substance P, dripped into a nostril of guinea pigs, at concentrations of 100 pM and above induced sneezing in a dose-dependent fashion. The activity of substance P was not affected by the previous subcutaneous injections of capsaicin that depleted substance P in nerve fibers. Histamine induced sneezing at concentrations of 30 mM and above and the activity was reduced by capsaicin treatment. The frequency of antigen-induced sneezing was proportional to the substance P content in nasal mucosa of sensitized guinea pigs treated with increasing doses of capsaicin; correlation coefficient 0.91. These results suggest that substance P plays an important role as a stimulator of sneeze responses in experimental allergic rhinitis in guinea pigs.

Animals↗

PubMed1992

Suppressive effect of LD78 on the proliferation of human hemopoietic progenitors.

LD78 is a cDNA newly isolated from human stimulated tonsillar lymphocytes. The expression of LD78 is related to inflammatory responses and its structure has a homology with macrophage inflammatory protein 1-alpha, which is known to have an inhibitory effect on murine CFU-S. Using a colony assay technique, we examined the effects of LD78 on human hemopoietic progenitors. The addition of doses of 100 ng/ml or more of LD78 suppressed the colony formation of KMT-2, a factor-dependent myelomonocytic cell line established from cord blood cells; this suppressive activity was neutralized by the addition of antibody against LD78. The same doses of LD78 suppressed the formation of neutrophil, macrophage, and megakaryocytic colonies which were supported by human interleukin-3 and erythropoietin; however, LD78 did not affect colony formation by either non-phagocytic mononuclear cells or sorted CD34+ cells. The conditioned medium of KMT-2 cells or peripheral blood mononuclear cells cultured with LD78 suppressed colony formation by CD34+ cells. From these findings, it is suggested that LD78 affects phagocytic cells and induces factors that are inhibitory for hemopoiesis. We consider LD78 to be a new cytokine that plays an inhibitory role in hemopoiesis.

Bone Marrow↗

PubMed1992

Hypergraphia associated with a brain tumour of the right cerebral hemisphere.

Two different neurobehavioural abnormalities have been reported under the term hypergraphia. One has been described in temporal lobe epilepsies and the other in the acute stage of strokes of the right cerebral hemisphere. The latter type of hypergraphia in a patient with a metastatic brain tumour confined to the right hemisphere is reported. Such hypergraphia is a general right hemisphere sign that is not peculiar to strokes in the acute stage and the writing behaviour is inattentive.

Adenocarcinoma↗

PubMed1992

Effect of capsaicin as a neuropeptide-releasing substance on sneezing reflex in a type I allergic animal model.

To elucidate the effect of capsaicin-sensitive nerve fibers, which are known to contain substance P (SP) and other sensory neuropeptides, on the sneezing reflex, we have investigated the effect of capsaicin on this reflex provoked in guinea pigs passively sensitized with anaphylactic antibody followed by specific antigen challenge. It has already been established that histamine released from mast cells is a reliable inducer of the sneezing reflex in type I allergy. Our experimental results indicated that the frequency of sneezing provoked by antigen challenge as well as histamine application was significantly reduced by pretreatment with capsaicin in a dose-dependent fashion. SP is considered to be one of the main neurotransmitters in sensory nerves. When the amount of SP in animal nasal mucosa was measured 12 h after capsaicin treatment, a marked reduction was noted. However, the histamine content in the nasal mucosa was not changed by capsaicin treatment. These data suggest that neuropeptides, especially SP, which are released or depleted from sensory nerves by capsaicin treatment, probably play an important role as neurotransmitters of the stimulant histamine in the development of sneezing in type I allergy.

Animals↗

PubMed1992

Endogenous calcitonin gene-related peptide mediates nonadrenergic noncholinergic depressor response to spinal cord stimulation in the pithed rat.

The role of endogenous calcitonin gene-related peptide (CGRP) in the nonadrenergic noncholinergic depressor response to spinal cord stimulation was studied in the pithed rat in vivo. Pithed rats were given hexamethonium (2 mg/kg per minute i.v.) to block autonomic outflow, and mean blood pressure was artificially maintained at approximately 100 mm Hg with methoxamine (10-15 micrograms/kg per minute i.v.). Electrical stimulation of the spinal cord at the level of the lower thoracic vertebra (T9-12) caused a fall in blood pressure in a frequency-dependent (0.5-10 Hz), voltage-dependent (2.5-50 V), and pulse duration-dependent (0.25-8 msec) manner. The heart rate did not change during the depressor response. The depressor response was long lasting, and the maximum response was elicited by stimulation at 4-6 Hz. The neurotoxin tetrodotoxin (100 micrograms/kg i.v.) abolished the depressor response to spinal cord stimulation, whereas treatment with propranolol (0.5 mg/kg per minute i.v.), atropine (0.05 mg/kg per minute i.v.), or a combination of pyrilamine (0.5 mg/kg per minute i.v.) and cimetidine (0.5 mg/kg per minute i.v.) did not affect the response. In pithed rats treated with capsaicin (total dose of 500 mg/kg s.c.), spinal cord stimulation caused a slight depressor response. Exogenous CGRP, but not acetylcholine, isoproterenol, histamine, or substance P, caused a sustained fall in blood pressure that mimicked the spinal cord stimulation-induced depressor response. Continuous infusion of CGRP[8-37] (60 nmol/kg per minute i.v.), a CGRP receptor antagonist, markedly inhibited the depressor responses not only to spinal cord stimulation but also to exogenous CGRP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Guinea pig plasma trypsin inhibitors. Purification and characterization of two functionally distinct proteinase inhibitors.

Two trypsin inhibitors (TI-1, TI-2) were isolated from guinea pig plasma and purified to homogeneity. In amino-acid composition as well as molecular masses, TI-1 (Mr 58,000) and TI-2 (Mr 57,000) are similar to each other and to human and mouse alpha 1-proteinase inhibitors, and mouse con-trapsin. The two inhibitors form equimolar complexes with proteinases. The effectiveness of the inhibitors was characterized by association rate constants under second-order rate conditions. The inhibitory action of TI-1 was rapid for bovine trypsin, porcine pancreatic elastase and guinea pig plasma kallikrein, but slow for bovine thrombin and guinea pig plasmin and not detectable for bovine chymotrypsin and porcine pancreatic kallikrein. The inhibitory action of TI-2 was rapid for trypsin and chymotrypsin, but slow for guinea pig plasma kallikrein and not detectable for other proteinases. These results show that TI-1 and TI-2 are physicochemically similar but functionally distinct from each other and from human alpha 1-proteinase inhibitor that inhibits trypsin, chymotrypsin and elastase.

Amino Acid Sequence↗

PubMed1992

Effect of intraperitoneally administered nucleoside-nucleotide on the recovery from methicillin-resistant Staphylococcus aureus strain 8985N infection in mice.

The effect of intraperitoneally administered nucleoside-nucleotide on the recovery from methicillin-resistant Staphylococcus aureus (MRSA) strain 8985N infection was studied in mice. Mice fed nucleic acid-free 20% casein diet were administered intraperitoneally with a nucleoside-nucleotide mixture or with saline (control group) daily for 30 days. On the tenth day on this treatment, mice were challenged with the bacteria. The survival rates were 25% and 72% for the control and nucleoside-nucleotide groups, respectively. The recovery of the survived mice from the infection was confirmed by the increment of body weight and the reduction of the bacteria in the organs. The results show the effectiveness of the intraperitoneal administration of the nucleoside-nucleotide mixture for the recovery from the MRSA strain 8985N infection in mice.

Animals↗

PubMed1992

[A case of pulmonary fibrosis in which inhibition of pulmonary vasoconstriction was detected using DSA pulmonary wedge angiography].

A 65-year-old man was admitted to our hospital complaining of productive cough and dyspnea on exertion. X-ray films and CT scan of the chest disclosed diffuse reticular shadows, especially in the bilateral lower lung fields. Blood gas analysis showed severe hypoxemia. Pulmonary function test disclosed severe restrictive pattern. From these findings, the patient was thought to have pulmonary fibrosis. Right heart catheterization showed pulmonary hypertension. To evaluate the pulmonary vascular bed, we performed DSA pulmonary wedge angiography. The pulmonary capillary phase stained homogeneously in normal subjects. However, in the present case, filling of the right pulmonary A9 was incomplete and capillary bed staining was decreased under room air condition. After breathing 5 L/min oxygen for 20 min., the A9 was filled well and capillary bed staining was increased. We consider that this change was induced by inhibition of hypoxic pulmonary vasoconstriction (HPV) by oxygen. DSA pulmonary wedge angiography was useful for visual evaluation of HPV.

Aged↗

PubMed1992

Postmortem changes of triazolam concentrations in body tissues.

Postmortem changes of triazolam concentrations in body tissues were examined using rats, in order to find the most suitable tissue samples for toxicological analysis. Triazolam was orally given to rats (5 mg/kg), and then the rats were sacrificed 1 hour after administration. Tissue samples were collected 0, 1 and 2 days after storage at 22-24 degrees C, and the triazolam concentration in each sample was measured using gas chromatography with a nitrogen phosphorus detector. Triazolam concentrations were markedly increased in the spleen, the abdominal muscle, the liver and the kidney, and were slightly increased in the blood and the lung. On the other hand, no changes were observed in the thigh muscle or the brain, and the value in the thigh muscle was similar to those in the blood samples collected immediately after death. The results indicate that triazolam diffuses into the surrounding tissues through the stomach wall after death, so that the thigh muscle and the brain have to be analyzed as well as the blood for a correct diagnosis of triazolam ingestion.

Administration, Oral↗

PubMed1992

A fatal case of a single stab wound penetrating the small, narrow atlantoaxial interspace.

A 73-year-old woman was found dead with a small wound on the nape of her neck. The wound was oval in shape, measuring about 0.6 cm in length along the major axis, with a slightly irregular margin. The wound injured the medulla oblongata through the atlantoaxial interspace, and reached the left vertebral artery. This wound was found to be the cause of death. The wound depth was 5 cm in length, with the direction of the wound canal from posterior-lower right to anterior-upper left. The size and appearance of the wound corresponded to those of the horizontal section of a skewer used by the assailant. Such a fatal case due to a single stabbing of the medullar oblongata by the chance gliding of a skewer through the small, narrow atlantoaxial interspace is considered to be exceptional.

Aged↗

PubMed1992

[Evaluation of cerebral intravascular blood flow by time density curve study of intravenous digital subtraction angiography].

Time density curve (TDC) can be reconstructed from the data of intravenous digital subtraction angiography (IVDSA). We evaluated peak time (PT) and modal transit time (MOTT) of the TDC as the probable indicator of cerebral intravascular blood flow. Cerebral IVDSA and single photon emission CT (SPECT) were performed on 12 patients of ischemic cerebrovascular disease, which consisted of 3 internal carotid artery (ICA) occlusions, one middle cerebral artery (MCA) occlusion, one anterior cerebral artery (ACA) branch occlusion and 7 lacunar infarctions. We classified former 4 patients as occlusion group and latter 8 as reference group. In 3 patients (2 ICA and one MCA occlusions), SPECT study revealed definite hypoaccumulation in the MCA territory of occlusive side. Two regions of interest (ROI) were placed on the territories of right and left middle cerebral arteries in the frontal view of cerebral IVDSA. Digital data processor fitted gamma curve to the TDC of each ROI, and calculated PT and MOTT. The absolute lateralities of PT and MOTT of MCA territory was significantly (p less than 0.05) larger in occlusion group than reference group. Patients with hypoaccumulation in SPECT had significantly (p less than 0.02) larger laterality of MOTT than patients with isoaccumulation. One ICA occluded patient without hypoaccumulation in corresponding MCA territory had relatively small laterality of MOTT similar to the patients of ACA branch occlusion and lacunar infarction. These results suggest that PT and MOTT are possible to detect the laterality of the intravascular blood flow in MCA territories caused by major artery occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography, Digital Subtraction↗

PubMed1992

[Cerebellar atrophy and persistent cerebellar ataxia after acute intoxication of phenytoin].

Chronic intoxication of phenytoin (PHT) is a well known cause of cerebellar atrophy or irreversible cerebellar ataxia. Little attention, on the other hand, is paid for acute PHT intoxication because its clinical signs are believed to be reversible. We here report a patient with acute PHT intoxication, which resulted in irreversible cerebellar ataxia with radiologically definite cerebellar atrophy. A 39-year-old man admitted to our hospital because of cerebellar ataxia and confusional state. He had been treated with PHT for convulsive seizures after receiving craniotomy for left parietal brain abscess 9 years before. The concentration of his serum PHT had been 4 to 7 micrograms/ml because he had frequently omitted taking drug, and the dose of PHT had been increased to 600 mg/day one year before. He had admitted to another hospital 2 months before for left Bell's palsy and had been obliged to take drug regularly. Cerebellar signs and confusion had gradually developed for 7 weeks. On admission to our hospital, he was awake but in severe confusional state with slurred speech and nystagmus. His serum PHT was 86 micrograms/ml, which returned to therapeutic range 2 weeks after the discontinuation of PHT. His consciousness normalized and nystagmus disappeared. However, slurred speech continued and neurological examination revealed postural tremor and severe limb ataxia. During the subsequent 10 months, his cerebellar signs showed minimal improvement. Computed tomographies of his brain on 3rd and 5th month after the onset of his cerebellar dysfunction showed the definite cerebellar atrophy which had not been noted on the CTs 7 months before and 7 weeks after the onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Differential expression in Escherichia coli of the alpha and beta forms of heparin-binding acidic fibroblast growth factor-1: potential role of RNA secondary structure.

Synthetic DNA fragments encoding the entire open-reading frame of human heparin-binding growth factor-1 (HBGF-1 beta) and its NH2-terminal truncated form (HBGF-1 alpha) were constructed. When both constructs were expressed in Escherichia coli under control of the trp-lac promoter, biologically active HBGF-1 alpha, but not HBGF-1 beta was produced in high yield. However, high level expression of HBGF-1 beta was obtained using the T7 polymerase expression vector. Computer analysis of HBGF-1 beta predicts the potential for the formation of exaggerated RNA secondary structure near the translation initiation codon and this could be implicated in contributing to the poor translation of HBGF-1 beta under the trp-lac promoter.

Base Sequence↗

PubMed1991

Intrapericardial OK-432 instillation for the management of malignant pericardial effusion.

Ten patients with malignant pericardial effusion were treated with intrapericardial injection of OK-432 (penicillin-treated and heat-treated lyophilized powder of the substrain of Streptococcus pyogenes A3). After intrapericardial insertion of a catheter, a maximal volume of pericardial fluid was withdrawn with cytologic confirmation of malignancy. Five or 10 Klinische Einheit (KE) (KE is a unit used to express the strength of a preparation) of OK-432 diluted in 20 ml of saline was injected into the pericardial space in seven and three patients, respectively. It was repeated in case of reaccumulation. Seven patients were treated only once and the remaining three required a second treatment. Complete control of pericardial effusion was achieved in all patients for an average of 329 days (range, 54 to 790 days). Fever and chest pain were experienced in six and five patients, respectively, but were controlled with antipyretics. Two of three patients who received 10 KE of OK-432 experienced hypotension that was successfully controlled with vasopressor drugs with or without reaspiration of pericardial fluid. Rapid reactive reaccumulation of the pericardial fluid was thought to be a cause of hypotension. A follow-up computed tomography (CT) scan was performed in seven patients and a thickened pericardium was noticed in five; no patients had constrictive pericarditis. These results suggest that intrapericardial administration of 5 KE of OK-432 is an effective and safe treatment for malignant pericardial effusion.

Adult↗

PubMed1991

Allelotype study of primary hepatocellular carcinoma.

Accumulation of mutations in oncogenes and tumor suppressor genes transforms a normal cell to a malignant cell by allowing it to escape from normal control of growth. In order to learn (a) how many tumor suppressor genes are involved in the tumor progression of hepatocellular carcinoma, (b) whether there is any association among allelic losses of chromosomes, or (c) whether integration of hepatitis B virus into host DNA influences any particular chromosomal losses, we have examined loss of heterozygosity with 44 restriction fragment length polymorphism markers in 46 cases of hepatocellular carcinoma. The markers represented all chromosomal arms except 5p, 8p, 9p, 18p, and acrocentric chromosomes. Allelic losses in tumors indicated that five tumor suppressor genes, located on chromosomes 5q, 10q, 11p, 16q, and 17p, may be involved in this cancer. However, no significant associations were observed among the various allelic losses or between the integration of hepatitis B virus and chromosomal losses. Furthermore, a deletion map for chromosome 16q indicated the localization of a tumor suppressor gene between q22 and q24 and that for chromosome 17p suggested the existence of a second tumor suppressor gene in addition to the p53 gene.

Alleles↗