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Biomedical subjects

Y Hosoda

Publications and source records attributed to Y Hosoda.

At least 109 records · Page 6Linked to original sources
PubMed1996

Rheumatoid arthritis complicated by pachy- and leptomeningeal rheumatoid nodule-like granulomas and systemic vasculitis.

Rheumatoid nodule is a frequent and characteristic extra-articular manifestation of rheumatoid arthritis (RA). Its involvement of central nervous system is a rare occurrence with only a few reported cases. A 78-year-old man with severe arthritis showing the formation of rheumatoid nodule-like granulomas in the dura and subarachnoid space along with the spleen is presented. The characteristic morphological finding of the granulomas was the presence of neutrophils and the absence of definite fibrinoid necrosis, which differed from the typical features of rheumatoid nodules previously described. The diagnosis should be based on the exclusion of diseases that may cause similar granulomatous reactions including infectious diseases. Additionally, there was systemic necrotizing vasculitis in the dura and multiple cerebral infarcts, although the association between vasculitis and cerebral infarcts was not clear.

Aged↗
PubMed1996

Radiologic and pathologic characteristics of mixed dust pneumoconiosis.

Modern radiologic technology has to led to increased diagnostic efficacy and accuracy in demonstrating pulmonary changes secondary to occupational dust exposure. This article presents three cases of typical and two cases of atypical silicosis with rounded atelectasis as seen in computed radiographic (CR), computed tomographic (CT), and scintigraphic images and autopsied lung specimens. Chest radiographs revealed both small rounded and small irregular opacities. Small irregular opacities on chest radiographs often proved to be reticular or honeycomb patterns on CT scans. Irregular opacities seen on CR and CT images represented interstitial fibrotic or mixed dust fibrotic changes associated with the accumulation of birefringent particles and emphysematous change, as noted at histologic analysis. CT scans and scintigrams were useful for visualizing parenchymal abnormalities, especially fibrotic change, emphysematous change, and pleural abnormalities.

Aged↗
PubMed1996

Angiographic assessment of the stretch-recoil-gain relation after balloon coarctation angioplasty and its relation to late restenosis.

The effects of stretch and immediate recoil after balloon angioplasty were evaluated in 21 patients with coarctation of the aorta who underwent balloon coarctation angioplasty. A total of 28 procedures were performed in these patients, who ranged in age from 1 month to 17 years with a mean of 4.3 years. The systolic pressure gradient and coarcted diameter changed significantly from 42 +/- 22 to 14 +/- 9 mmHg (P < 0.0001) and from 4.0 +/- 1.7 to 6.1 +/- 2.0 mm (P < 0.001), respectively. Immediate recoil was responsible for the loss of 33% of the potentially achievable coarcted dimension. Recoil was determined mainly by the degree of arterial stretch. Gain increased exponentially with an increase in stretch. There was a narrow range of % stretch (60-80%) within which an effective diameter gain could be obtained. Both gain and stretch were the best predictors for late restenosis: patients with a larger immediate gain and stretch developed more restenosis. These results suggest that the stretch-recoil-gain relationship may be clinically important for evaluating the best predictor of late restenosis after balloon coarctation angioplasty.

Adolescent↗
PubMed1996

Hemifacial dismasking flap for anterior skull base tumor--technical note.

A new approach to malignant tumor in the anterior skull base using a hemifacial dismasking flap is described. A bicoronal incision is extended unilaterally down to the neck, degloving the craniofacial tissue to widely expose the skeleton underneath, allowing easy resection of an extensive tumor without postoperative scarring of the face. This method has been used successfully on five patients.

Adenocarcinoma↗
PubMed1996

Angiogenesis from the eighth cranial nerve to vestibular schwannomas.

Vascularization between vestibular schwannomas and the adjacent eighth cranial nerve was examined in order to elucidate the angiogenic effect of these tumours. Specimens from 12 patients were examined by light microscopy and immunohistochemistry (series 1), while specimens from another 17 patients were examined by light and transmission electron microscopy (series 2). Slight to marked angiogenesis was found in 5 patients from series 1 and 7 patients from series 2. Ultrastructural examination indicated that these blood vessels were more fragile than those in the normal eighth cranial nerve. These findings suggested that sudden hearing loss in vestibular schwannoma patients may be related to the disruption of such blood vessels. In addition, surgical injury to these blood vessels may cause postoperative hearing loss despite preservation of the cochlear nerve.

Adult↗
PubMed1996

Direct measurement of eustachian tube compliance.

We developed a method by which tubal compliance can be directly measured, and using this method we examined tubal compliance in 18 adults with a disease-free ear and 8 adults with chronic otitis media. This method is advantageous in that one can directly measure tubal compliance in the cartilaginous part of the eustachian tube. It is our view that each eustachian tube has its own compliance which is not influenced by mucosal swelling or muscle tension around the tube.

Adult↗
PubMed1996

[Indication of CABG as reflected in the late results--10 year follow-up 1344 cases].

Because of the recent advancement and wide spread application of interventional cardiology, the indication and results of CABG have been more closely scrutinized. 10 year survival rate and cardiac event free rate of our 1344 cases pf CABG for the past 10 years was 79.3% and 69.8% respectively. Multivariate analysis revealed left ventricular dysfunction, old age, diabetes mellitus, severe symptom of angina, and no-use of ITA as variables influencing the late survival. These results are comparable to the published data from USA or European countries. The proper selection of patients in consultation with cardiologists may yield better surgical results.

Aged↗
PubMed1996

Time limitation of postural retrograde cerebral perfusion during cerebral hypothermic circulatory arrest. A report of an unsuccessful case.

We report an unsuccessful case with ruptured aortic arch aneurysm using deep hypothermia with postural retrograde cerebral perfusion by simply elevating central venous pressure in the Trendelenburg position. Ninety-three minutes of cerebral circulatory arrest by this method caused irreversible global cerebral damage. Ninety minutes may be over the time limit of this method.

Aged↗
PubMed1996

[Cancer epidemiology of radiation workers].

Ionizing radiation-induced cancer risk has been estimated mainly from the Radiation Effects Research Foundation study of atomic bomb survivors who were exposed to a high instant radiation dose. With the development of nuclear industries, the cancer risk has recently been estimated directly from epidemiological studies of radiation workers who were exposed to low-level protracted doses, though the results still remain controversial due to the lack of statistical power. The present article is to review, summarize and comment on epidemiological papers on radiation workers in various job types published up to 1994.

Female↗
PubMed1996

[A case report of aortic root replacement with fresh aortic homograft for valve detachment due infective endocarditis].

A 28-year-old male received a redo aortic valve replacement (AVR) with a 19 mm St. Jude Medical mechanical valve 3 months after the initial AVR because of recurrent valve detachment. We re-operated on this patient by aortic root replacement using a fresh aortic homograft. The donor of the homograft was a 59-year-old female who died of a traffic accident. The aortic root and valve was harvested aseptically and stored in a nutrient medium including antibiotics at 4 degrees C for 4 days. At the 3rd operation, aortico-ventricular discontinuity and an annular-abcess-like cavity were found. After debridement, the cavity was closed with a homograft aortic wall and then aortic root replacement was performed using a fresh aortic homograft. At first, prosthetic valve detachment seemed to be caused by infective endocarditis on the basis of his clinical history. However, causative organisms had never been recovered from the blood or the specimens obtained at the time of operation and reoperation. Post-operative HLA examination revealed No. 51 on HLA-B locus and thus we suspected that valve detachment might have been due to inflammation of the aortic wall caused by a subtype of Behçet disease. The early post-operative course was uneventful with a low dose of predonine. Post-operative aortography showed no aortic regurgitation and normal coronary anastomosis. Unfortunately however, he died suddenly 8 months after the operation. Autopsy demonstrated the presence of aortic wall necrosis with massive infiltration of macrophages and leucocytes resulting in dehiscence of the coronary anastomotic site. The cause of homograft detachment could not be determined for sure but might be recurrent infective endocarditis, although causative organisms were never identified, or infective endocarditis in combination with Behçet vasculopathy.

Adult↗
PubMed1996

[Pathology of arteriosclerosis obliterans].

Pathomorphological aspects of arteriosclerosis obliterans were reviewed. While the morphology is basically atherosclerosis, complete occlusions by fresh or old thrombi are often observed. Obstruction with lipid-poor fibrous tissue is also recognized. Calcification of intima or media is often present, but it does not correspond with grade of atherosclerosis. Occlusion of major arteries of the lower limbs are frequently discovered in asymptomatic aged persons. The occlusive lesions usually far-advanced before initial clinical manifestation of ischemic processes becomes apparent. Before clinical manifestations, various compensatory mechanisms including arterial anastomosis and decrease of the peripheral vascular resistance react to correct the abnormal arterial circulation. Clinical initiation first appears after the failure of these compensatory mechanisms. As in other atherosclerotic diseases, etiology of arteriosclerosis obliterans must be diverse, but upright gait of man may have some influence to develop the disease. Among many aggravating factors, diabetes mellitus is the most serious and it shows several features different from ordinary arteriosclerosis oblilerans.

Arteriosclerosis Obliterans↗
PubMed1996

What is the safe time limit for retrograde cerebral perfusion with hypothermic circulatory arrest in aortic surgery?

Retrograde cerebral perfusion technique has been used recently for the protection of the brain during circulatory arrest in aortic surgery. However, the safe time limit for retrograde cerebral perfusion has not been known. From July 1993 to April 1995, 20 patients underwent thoracic aortic operations using retrograde cerebral perfusion technique with hypothermic circulatory arrest. Retrograde cerebral perfusion was used to repair the aortic dissection in seventeen patients, aortic arch aneurysm in two patients and annuloaortic ectasia with severely calcified ascending aorta in one patient. The mean duration of retrograde cerebral perfusion was 74 minutes (19-135 min). There were six patients in whom retrograde cerebral perfusion exceeded 90 minutes, however no patients except one who had preoperative cerebral infarction showed any neurological deficits. There were two operative deaths and three hospital deaths, neither of which was related to postoperative neurological complications. Retrograde cerebral perfusion safely may provide a longer period of circulatory arrest at least up to 90 minutes.

Adult↗
PubMed1996

[Pathology of aortic dissection].

Aortic dissection is not a popular disease but it should be listed in the disease to be excluded especially in acute emergent cases, because of its serious and protean clinical manifestations. While DeBakey classification was used over 30 years. Stanford classification is now widely accepted for its clinical availabilities. The features of the aortic dissection are 1) presence of the intimal tear at the proximal end in almost all cases, 2) its frequent location in the ascending aorta and aortic segment just distal to the left subclavian artery, and 3) the dissected plane at the outer media or medial-adventitial border. Systemic hypertension is frequently noticed in cases with aortic dissection. These features suggest hemodynamic effect as a pathogenic factor in addition to mural fragility of the aorta. Aortic dissection is frequently encountered in Marfan syndrome and other heritable diseases of connective tissue. Concerning Marfan syndrome, mutation of fibrillin gene was confirmed. Fibrillin is a microfibril consisting of glycoprotein closely bound to elastin. Therefore, traditional "cystic medial necrosis" which was referred as a principal morphological change corresponding to aortic dissection is now thought to be a secondary change to the aortic injuries occurred in the aortic wall.

Aortic Dissection↗
PubMed1996

[Surgical pathology of infective endocarditis].

Underlying pathologic disorders of infected valves were analyzed in 36 consecutive patients with infective endocarditis (from April 1987 to May 1995) of 18 aortic, 11 mitral and 8 prosthetic valves. Among 29 cases of native valve endocarditis, 27 had known organic changes [aortic valve prolapse 8, bicuspid aortic valve 4, annuloaortic ectasia 1, mitral valve prolapse 9 (including 2 cases associated with hypertrophic cardiomyopathy), looping chordae 1, rheumatic heart disease 4]. However, the remaining two cases had unknown etiology. Histological examination of these two aortic valves revealed proliferation of small vessels and remnants of vascular smooth muscle cells, suggesting postinflammatory valve prolapse. Five cases with definite pathology had no clinical signs of infection. The preponderance of surgically resected valves with infective endocarditis in Japan is non-rheumatic in origin.

Adult↗
PubMed1995

CAM--a novel immunosuppressive agent.

This is an initial study of the immunosuppressive efficacy of CAM, a derivative of mycophenolic acid, in a rat heart allograft model when the major histocompatibility complex was fully incompatible, and its effect in improving heart allograft survival compared with mycophenolate mofetil (MMF, RS-61443). CAM or MMF was administered orally from day 1 following the allografting for 40 days. The median survival times (MST) were 6 days in rats with no immunosuppressive drug (control group; n = 6), 83 days with CAM 10 mg/kg (n = 6), and > 100 days with both 20 mg/kg (n = 7), and 30 mg/kg (n = 10). With MMF, in contrast, MST was 9, 17, 35, days with 10, 20, 30 mg/kg/day, respectively. All grafts in the CAM 30 mg/kg-treated group survived for more than 100 days after grafting, and, furthermore, CAM was also more effective than MMF in prolongation of the heart graft survival in rats at each dose. Rats with long-surviving cardiac allografts (30 mg/kg; CAM) accepted skin grafts from the donor-strain but rejected them from the third-party strain, suggesting that donor-specific tolerance was induced by CAM. In the tolerant rats, proliferative response against donor-type alloantigen was not impaired as compared with naive WKAH rats. In contrast, CML assay showed that T cells obtained from the rats bearing permanently accepted F344 heart grafts had less cytotoxic activity to the donor-type target, and the frequency of CTL precursor against donor-type alloantigen was also reduced.

Animals↗
PubMed1995

Ultrastructural evidence of cell communication between epithelial dark cells and melanocytes in vestibular organs of the human inner ear.

BACKGROUND: The possibility of interaction between epithelial dark cells and melanocytes in the mammalian inner ear has been pointed out because of their morphological and biochemical characteristics, although very few studies have dealt directly with communication between these two types of cells. We investigated the dark cell area of human vestibular organs in order to clarify the ultrastructural evidence for cell interaction between epithelial dark cells and melanocytes. METHODS: All of the material was obtained from vestibular schwannoma operations. Paraffin sections were stained with hematoxylin and eosin (H&E) and by the Fontana-Masson technique. Other paraffin sections were also stained immunohistochemically for S-100 protein. Glutaraldehyde fixed specimens were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: Light microscopy revealed melanin pigment granules in the cytoplasm of epithelial dark cells. Melanocytes in the subepithelial layer stained positively for S-100 protein. The presence of intraepithelial melanocytes was confirmed by the presence of cell profiles with a large number of melanin pigment granules and S-100 protein in the cytoplasm. SEM showed that the dark cells had a pentagonal surface with microvilli on the apical surface edge. They had complicated structures at the basal portion of their cytoplasm. Melanocytes extending cytoplasmic processes to adjacent areas were observed under the dark cells. TEM showed that the dark cells were tightly linked by junctional complexes in the upper lateral portion of their cytoplasmic membrane and interdigitated by lateral infoldings. Compound melanosomes (phagosomes or secondary lysosomes) found in the cytoplasm of the dark cells contained poorly pigmented melanosomes with a periodic internal structure. Gap junctions were clearly showed between adjacent melanocytes in the subepithelial layer. CONCLUSIONS: The characteristic substructures of dark cells and melanocytes suggested the presence of intimate cell interaction between these two types of cells in the vestibular organs of the human inner ear, although it is not clear at this stage whether such cell interaction is specific only for patients with vestibular schwannoma. Dark cells and melanocytes form a cell community that serves to maintain homeostasis in vestibular organs through communication in which cell information obtained by both dark cells and melanocytes serves to facilitate the system.

Adult↗