Biomedical subjects
Publications and source records attributed to Y Naka.
Benign mesenchymoma is a mixed tumor that has at least two mesenchymal components in addition to fibrous tissue. A case of benign mesenchymoma of the sole in a 7-year-old boy is presented. The literature is reviewed and discussed.
The density and distribution pattern of aminergic nerve fibers in intracranial and extracranial veins were compared by means of catecholamine histofluorescence studies. Extracranial veins (internal jugular, inferior caval, portal, renal, internal iliac, and femoral veins) showed quite a uniform distribution pattern. Large veins (jugular, caval, renal, and iliac veins) revealed a spiral pattern, and small veins presented as a meshwork (femoral vein) or in a longitudinal pattern (a branch of the femoral vein). In contrast, intracranial veins displayed more complex patterns: the dural sinus showed a longitudinal pattern and the internal cerebral vein and the superficial vein of Labbé revealed a meshwork of nerve fibers. The aminergic fibers were denser in cerebral veins (dural sinus and internal cerebral vein) than in extracranial veins. The complex distribution and the density of aminergic fibers in cerebral veins suggest that the aminergic innervation of the circulatory system may be more important in the brain than in the extracranial organs.
The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, had only aminergic nerve fibers. Intraparenchymal small blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers. This was quite a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers widely varied with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers throughout the spinal cord. This fact may give a clue to explain why the thoracic spinal cord is most susceptible to ischemic change.
By an immunohistochemical technique, vasoactive polypeptide (VIP)-and substance P-containing nerve fibers are observed in the cerebral blood vessels. VIP-containing nerve fibers distribute in a spiral pattern, similar to the muscle cell distribution pattern. Under an electron microscopic observation, VIP-immunoreactive terminals lie just near to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers show a meshwork pattern in the outer layer of the adventitia. In combination of acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers reveal almost same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role of smooth muscle control of the blood vessels, while substance P-containing nerve fibers may not take part in muscle control.
The distribution of nerve fibers in the cerebral blood vessels was studied by a catecholamine histofluorescence method, acetylcholinesterase (AChE) staining and immunohistochemistry. The ultrastructure of the terminal boutons in the vessel wall was also studied. In the adventitia of the cerebral artery, green fluorescence aminergic fibers and brownish AChE-positive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. The highest density of aminergic fibers were found in the dural sinus and the second highest in the internal cerebral vein. Serotonin immunoreactive nerve fibers were found along small intraparenchymal blood vessels such as perforating arteries in the brain stem, and arterioles and venules in the cerebral cortex. Under ultrastructural observation, a serotonin immunoreactive terminal was demonstrated in conjunction with the basement membrane of the capillary.
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The distribution of nerve fibers in the cerebral veins was studied by catecholamine fluorescence simultaneously with acetylcholinesterase (AChE) histochemistry. A comparison of nerve fibers in the cerebral arteries was made. The ultrastructure of terminal boutons in the veins fixed with potassium permanganate was also studied. In the adventitia of the cerebral artery, green fluorescent aminergic fibers and brownish AChE-reactive (probably cholinergic) fibers were observed. In contrast, the cerebral venous system showed no AChE-positive fibers. Catecholamine fluorescent varicose fibers were detected in the dural sinus, the internal cerebral vein, and the superficial vein of Labbé. The highest density of aminergic fibers was found in the dural sinus and the second highest in the internal cerebral vein. Most of the terminal boutons in the adventitia of the cerebral veins were found adjacent to a muscle-like cell and showed only cored vesicles under electron microscopy. Results of our study suggest that the cerebral venous system has a neurogenic innervation, mainly from aminergic fibers, which is different from the neurogenic supply to the cerebral arterial system.
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A case of a thymic carcinoid tumor is presented. The tumor was a mass measuring 7 by 6 by 5 cm in size. Microscopically, the tumor was composed of a mixture of round, cytoplasm-rich cells in addition to the predominantly spindle-shaped cells. The ultrastructural observation showed many secretory granules, about 120 mmu in size, in almost every cell of the tumor. In the cytoplasm many microfilaments were seen, in places forming large nodules and bundles. Centrioles were often observed in the tumor cells. Sometimes three or even more centrioles were seen in a single cell.
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FK506 and dexamethasone were used to investigate whether or not immunosuppression affects H. pylori colonization and gastric mucosal damage induced by Helicobacter pylori in Mongolian gerbils. Two weeks after H. pylori infection, FK506 and dexamethasone or vehicle alone were subcutaneously administered once daily for the following 2 weeks. FK506 or vehicle alone was administered subcutaneously once daily for 5 weeks (1 week before and 4 weeks after infection). In H. pylori-infected animals for 4 weeks, hemorrhagic erosions and inflammatory responses (neutrophil infiltration and lymphoid follicle formation) were induced in gastric mucosa at an incidence of 100%. Both FK506 and dexamethasone administered for 2 weeks markedly reduced such mucosal changes. In these animals, H. pylori viability in the stomach was significantly elevated. FK506 administered for 5 weeks also significantly inhibited the hemorrhagic erosions, edema and neutrophil infiltration in the stomach. H. pylori viability was slightly elevated as compared with the control. It was concluded that the host immune responses might play dual roles both by deteriorating gastritis induced by H. pylori and by protecting against H. pylori infection in its early stage.
Heart transplantation remains the treatment of choice for end-stage heart failure despite limited donor availability and allograft durability. Artificial heart technology was initially developed as a replacement for transplantation but the initial experience with these technologies was disappointing. The quest for a total artificial heart has largely been abandoned in favor of ventricular assist devices (VADs). VADs have gained widespread acceptance as bridge to transplant and bridge to recovery therapy. After more than a decade of clinical use, several FDA approved device designs have proved effective in treating patients with various causes of heart failure. This review describes the current, clinically available ventricular replacement and assist devices and defines the adult patient populations in which they are useful. The next generation of these devices will soon become available and their clinical utility will likely shape the future direction of heart failure therapy. Ultimately the concept of a long-term total artificial heart may be revisited.
Canine hearts immersed in modified Collins solution were transplanted heterotopically (n = 23) and orthotopically (n = 15) to evaluate the effect of terminal warm-blood cardioplegia with or without leukocyte depletion. As the index for graft function, preload recruitable stroke work was measured in both series before harvesting (control) and after transplantation (percentage). The heterotopic hearts were divided into four groups (group 1 to 4) according to the preservation method; hearts were preserved for 3 hours in group 1 and for 24 hours in groups 2, 3, and 4. Simple terminal warm-blood cardioplegia was applied in group 3, and terminal warm-blood cardioplegia with leukocyte depletion was used in group 4. In the orthotopic series, five hearts were transplanted soon after harvesting (group 5) to simulate on-site transplantation, and the remaining ten hearts were transplanted after 24 hours of hypothermic preservation without and with terminal warm-blood cardioplegia with leukocyte depletion (groups 6 and 7, respectively). Among the heterotopic transplants, the percentage of preload recruitable stroke work was highest in group 4 (91% +/- 6%, 51% +/- 4%, 83% +/- 10%, 140% +/- 11% in groups 1, 2, 3 and 4, respectively). All orthotopic transplants in groups 5 and 7 were weaned from cardiopulmonary bypass without inotropic support and without significant differences in cardiac function between groups 5 and 7 (percentage of preload recruitable stroke work, 99% +/- 10% versus 102% +/- 2%; cardiac output, 122 +/- 10 versus 140 +/- 22 ml/kg/min). No orthotopic transplants in group 6 could be weaned from cardiopulmonary bypass, even with inotropic support.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty four-hour heart-lung preservation with Belzer-UW solution was studied in the canine heterotopic heart-lung transplant model. Four pairs of mongrel dogs were used. The donor heart was arrested with cardioplegic solution. The heart and the lung were flushed with UW solution, then excised en bloc and immersed in 4 degrees C UW solution for 24 hours. The graft was transplanted heterotopically into the left pneumonectomized recipient. The transplant procedure consisted of end-to-end anastomosis of two left main bronchi, end-to-side anastomosis of the descending aortas, and end-to-end anastomosis of the donor's superior vena cava to the recipient's left pulmonary artery. The recipient's right pulmonary artery was ligated after an observation period, and cardiopulmonary functions were measured during room air ventilation. In all four transplanted dogs the grafts were able to sustain the recipient's circulation. The prepreservation and posttransplant cardiac output was 71.2 +/- 21.6 ml/min/kg and 96.4 +/- 44.4 ml/min/kg; the arterial PO2 was 80.8 +/- 12.9 mm Hg and 74.1 +/- 2.7 mm Hg; and the arterial PCO2 was 25.6 +/- 5.5 mm Hg and 35.9 +/- 13.3 mm Hg, respectively. There were no significant differences between the prepreservation and posttransplant values. Posttransplant myocardial water content was within the normal range. Pulmonary vascular resistance increased significantly, to 13.8 +/- 3.7 from 8.8 +/- 5.2. Wood units, and the wet/dry ratio of the lung increased significantly, to 8.3 +/- 1.6 from 4.4 +/- 0.6. In conclusion, heart-lung grafts preserved in UW solution for 24 hours were able to sustain the recipient's circulation. Significant pulmonary edema, however, could not be prevented.