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Biomedical subjects

T Honma

Publications and source records attributed to T Honma.

At least 145 records · Page 8Linked to original sources
PubMed1991

[Influence of respiratory frequency in measurement of specific airway conductance during non-panting breathing].

In order to investigate the influence of respiratory frequency in the measurement of specific airway conductance (sGaw) during non-panting breathing, we examined specific airway conductance using a body plethysmograph (BX-82, Minato) in 20 stable pulmonary emphysema patients and 19 normal control subjects. Our body plethysmograph device can measure sGaw automatically without panting by making various corrections using a 16-bit microcomputer. We measured sGaw first at a flow of 0.5 L/sec during both inspiratory and expiratory ventilatory phases, then the respiratory frequency was changed from 0.5 to 1.0, 1.5 and 2.0 Hz. In normal control subjects sGaw, tidal volume and mouth flow significantly changed by increasing respiratory frequency, and there was a significant correlation between sGaw and mouth flow. In pulmonary emphysema patients, tidal volume decreased significantly by increasing respiratory frequency, and there was a significant correlation between sGaw and tidal volume, but sGaw and mouth flow did not change significantly by increasing respiratory frequency. These results suggest that specific airway conductance is influenced by respiratory frequency, possibly due to the change in tidal volume and mouth flow. It is necessary to standardize respiratory frequencies and mouth flows in the measurement of specific airway conductance during non-panting breathing.

Aged↗
PubMed1991

[Etiology of left ventricular rupture following mitral valve replacement].

Two uncommon cases of left ventricular rupture that occurred during cardiac surgery were treated successfully. These cases may be useful in understanding the etiology of common left ventricular rupture following mitral valve replacement. One case occurred during coronary bypass surgery. The myocardium which is already abnormal seems to be weak to trauma such as bending, traction and torsion. In the other case, who underwent mitral valve replacement with preservation of the posterior leaflet with its attached chordae, the disruption was localized in the epicardial side of the left ventricular posterior wall, though direct injury by some instrument was excluded as a possibility, with a depth of half the thickness of the wall. In experiments using dogs, shape and movement of the mitral annulus were examined. The length of the annulus attached to the posterior leaflet in end-systole was shortened to 89.0 +/- 4.6% of that in late diastole. Furthermore, the annulus was distorted by the elevation of the heart. We approve of Cobbs' "untethered ventricle theory" and consider moreover as follows: In general, whether with or without preservation of the mitral loop, the mitral annulus and the left ventricular posterior wall after mitral valve replacement are severely constricted by the rigid prosthetic ring and become tense, which limits movement in both circular and longitudinal directions. Then even slight stress may cause a primary tear on the posterior wall of the left ventricle, resulting in rupture. In order to treat the rift, the prosthesis must be removed before the apex of the heart is lifted, to avoid excessive ventricular wall tension.

Aged↗
PubMed1990

Growth dynamics of the heart from perinatal period to childhood.

In order to obtain information useful for the diagnosis of fetus and newborn heart disease, we established a theoretical model of perinatal cardiac growth. We measured with the use of ultrasonic cross-section imaging system the mitral valve ring dimension, tricuspid valve ring dimension, and total cardiac dimension as morphological parameters of the heart in 45 cases composed of fetuses and children. The obtained data were entered into a computer. With the use of these data, simulation was made on the basis of the general theory of biological development. The present simulation showed that from the fetal stage to childhood the growth rates of the foregoing three morphological parameters mutually differ, but during the period of growth to the age of 12 years of the present study, they all demonstrated continuous growth up to 3 1/2 years after birth when they reached a growth saturation level.

Aging↗
PubMed1990

Effects of trichloroethylene, 1,1,1-trichloroethane and carbon tetrachloride on plasma lipoproteins of rats.

Effects of single intraperitoneal administration of trichloroethylene, 1,1,1-trichloroethane, and carbon tetrachloride (positive control) on the plasma contents of lipoproteins were investigated in rats. Plasma was fractionated to VLDL, LDL, and HDL by sequential ultracentrifugation. On the administration of carbon tetrachloride at 30 to 1000 mg/kg, VLDL and HDL were reduced dose-dependently, but the reduction in LDL was not dose-dependent. With trichloroethylene at 30 to 300 mg/kg, the lipid contents of VLDL and LDL fractions were decreased. At 1000 mg/kg, VLDL and LDL was increased by the trichloroethylene. The HDL was decreased with increasing doses of trichloroethylene at 30 to 1000 mg/kg. With 1,1,1-trichloroethane at 100 to 300 mg/kg, VLDL and LDL were increased. The HDL levels rose at 100 mg/kg but fell at 1000 mg/kg. Thus trichloroethylene impairs VLDL formation at low doses. 1,1,1-Trichloroethane stimulates the VLDL synthesis at low doses and inhibits it at high doses. The decreases in HDL at high doses of trichloroethylene and 1,1,1-trichloroethane resulted from the inhibition of HDL synthesis. Liver-to-body weight ratios were raised with increasing doses of carbon tetrachloride, trichloroethylene, and 1,1,1-trichloroethane. Plasma GOT and GPT activities rose at much higher doses of solvents than dose levels which produce the changes in lipoproteins and the increases in liver weights. The liver enlargement appeared to be a sensitive marker of hepatotoxicity related to the changes in lipoproteins, the profile of which was different in three solvents.

Alanine Transaminase↗
PubMed1990

[A case of retroperitoneal mucinous cystadenocarcinoma].

We reported is the histogenesis of a case of a primary retroperitoneal cystadenocarcinoma that was resected surgically in a 42-year-old woman who was admitted to hospital for SLE. On echographic examination, she was found to have a right abdominal tumor and underwent an operation for the complete removal of an abdominal tumor located in the right retroperitoneal cavity. A histological examination of the tumor revealed it to be compatible with a mucinous cystadenocarcinoma of the ovary. Only four cases of a primary retroperitoneal mucinous cystadenocarcinoma have been reported in the literature. This rare lesion was studied histopathologically and its histogenesis is discussed.

Adult↗
PubMed1989

Phase conjugation model for information transfer in the nervous system.

In the nervous system, dispersion in propagation time sometimes brings delay distortion or phase distortion on the information transmission. Also in the memory retrieval processes in the brain, some parts of images may be retrieved more slowly than others. For smooth control of fast movements as well as for keeping exact thinking, these distortions have to be taken out. To understand the distortion cancelling mechanism, new neural network models for compensating the phase distortion are proposed. The models stand on the concept of "phase conjugate mirror" which is used in optical image processing. Simulation studies based on the model resulted in successful cancellation of the delay dispersion involved in the information transmission in the nervous system.

Computer Simulation↗
PubMed1989

Analysis of cervical instability resulting from laminectomies for removal of spinal cord tumor.

Thirty-four patients with cervical cord tumor were followed in order to investigate the incidence of postoperative deformity or instability after laminectomies. Seven cases (20%) presented cervical instability, including three cases that required spinal fusion. Analysis of these cases revealed the identification of some risk factors that are involved in the pathogenetic mechanism of cervical instability, which are: age at operation, preoperative curvature in neutral position, number of removed laminas, C2 laminectomy, and destruction of facet joints. The number of these risk factors present in each case was shown to be directly related to the incidence of cervical instability. Patients who had not developed instability demonstrated 1.2 factors on average, while patients who had developed instability showed a mean of 2.5 factors. Patients who had additionally required spinal fusion presented 3 risk factors, including C2 laminectomy and destruction of facet joints.

Adult↗
PubMed1989

Assessment of apoptosis of infiltrating lymphocytes in erythema nodosum-like lesions of corticosteroid-treated patients with Behçet's syndrome.

Biopsy specimens of recurrent erythema nodosum-like lesions from corticosteroid-treated and non-treated patients with Behçet's syndrome were examined with the electron microscope to determine the incidence of apoptotic cell death of infiltrating lymphocytes in connective tissue. Apoptosis of infiltrating lymphocytes was detected in all corticosteroid-treated patients, but not in non-treated patients. While part of this phenomenon is undoubtedly due to a direct action of corticosteroids on the lymphocytes themselves, it seems likely that indirect action of the corticosteroids such as inhibition of lymphokine or interleukin production may deprive lymphocytes of proliferative and other stimuli and therefore also play some part in the overall response.

Adrenal Cortex Hormones↗
PubMed1988

Appearance of membranocystic lesion (Nasu)-like changes in Behçet's syndrome. An electron microscopic study of erythema nodosum-like lesions.

Membranocystic lesion (Nasu)-like changes were seen in the subcutaneous fat tissues of erythema nodosum-like lesions in three of 18 patients with Behçet's syndrome. The membranocystic structures, which were derived from degenerative fat cells with a loss of the cell membrane, were observed in the edematous connective tissues accompanied by fibrin deposition and diapedesis of erythrocytes. Electron microscopic evaluation revealed two different patterns of peculiar membranous structures in the cytoplasm of the degenerative fat cells. One was proliferating membrane structures such as well developed Golgi-endoplasmic reticulum, and the other was minute tubular structures such as intracytoplasmic microvesicles. These degenerative fat cells are considered to be derived from abnormal fat cells which lack a cell membrane, but whose cellular and nuclear configurations appear to be normal morphologically, because the cytoplasm of these abnormal cells showed the same tubular structures as those seen in the characteristic architecture of membranocystic lesion-like change. The relation between the appearance of such abnormal cells and the pathologic conditions of erythema nodosum-like lesions in Behçet's syndrome was discussed.

Adipose Tissue↗
PubMed1988

Ultrastructure of vascular changes in cutaneous manifestations of Behçet's disease.

We observed small dermal blood vessels embolized by thrombus at the sites of needle-prick reaction as well as erythema nodosum-like lesions in 4 patients with Behçet's disease, by means of electron microscopy. The ultrastructural finding associated with overproductive proliferation of the endothelial cells leading to obliteration of the vascular lumen was the sporadical appearance of degenerated cells among proliferating endothelial cells in both cutaneous manifestations. These degenerated cells showed contraction changes and may be involved in thrombogenesis.

Behcet Syndrome↗