Biomedical subjects

K Yada

Publications and source records attributed to K Yada.

At least 19 recordsLinked to original sources

PubMed1996

Effect of recombinant human macrophage-colony stimulating factor on marrow, splenic, and peripheral hematopoietic progenitor cells in mice.

The effects of human macrophage colony-stimulating factor (M-CSF) on marrow, splenic, and peripheral progenitor cells (CFU-M, CFU-GM, and CFU-G) were investigated in mice administered recombinant human M-CSF (8-4,000 micrograms/kg). Single injection of 4,000 micrograms/kg of M-CSF resulted in a decrease in the number of marrow progenitor cells (CFU-M, CFU-GM, and CFU-G) on day 2 followed by a gradual increase, returning to the original level on day 4 or 5. In contrast, each type of splenic progenitors tested for started to increase markedly on day 2, reaching a level 4- to 15-fold higher than that of the basal value on day 3 or 4. Peripheral CFU-M, CFU-GM, and CFU-G also increased on day 2. In addition, administration of 800 micrograms/kg of M-CSF in mice caused a decrease in marrow CFU-G, as well as an increase in splenic CFU-G. The present results indicate that treatments of mice with pharmacological concentrations of human M-CSF affect the number of progenitor cells not only of monocyte/macrophage lineage but also of granulocyte lineage. Also, the coincidence between decrease of marrow progenitor cells and increase of splenic and peripheral progenitor cells suggests that the progenitor cells are released from bone marrow to peripheral blood and reseeded to the spleen by the action of M-CSF.

Animals↗

PubMed1996

Pituitary choristoma composed of corticotrophs and adrenocortical cells in the sella turcica.

A pituitary tumour composed of well-differentiated corticotrophs and adrenocortical cells is reported. Sections of the tumour revealed a mixture of small round cells with amphophilic or basophilic periodic acid-Schiff (PAS)-positive cytoplasm and large spherical and oval cells with abundant, granular, partly vacuolated PAS-negative cytoplasm. The small cells contained type 1 cytokeratin-positive microfilaments, numerous 250-500 nm endocrine-type secretory granules immunoreactive for adenocorticotropic hormone (ACTH) and beta-lipotropin. The large cells possessed ample cytoplasm filled with abundant vesicular smooth endoplasmic reticulum, numerous mitochondria possessing tubulovesicular cristae and frequent dense bodies. They lacked the features of pituitary endocrine cells or folliculostellate cells and were found to contain a panel of steroidogenic dehydrogenases and hydroxylases. The tumour was classified as a choristoma, in which two distinct cells types, corticotrophs and adrenocortical cells, were mixed. We suggest that, under continued ACTH stimulation, umcommitted stem cells may differentiate into adrenocortical cells. Alternatively, the presence of adrenocortical cells may be the result of heterotopia.

Adolescent↗

PubMed1996

Impaired autoregulation in an experimental model of chronic cerebral hypoperfusion in rats.

BACKGROUND AND PURPOSE: To verify the hypothesis that impaired autoregulation may contribute to cerebral swelling or hemorrhage after a sudden recovery of perfusion pressure, we studied the chronic effects of cerebral hypoperfusion on the autoregulatory responses of the pial arterioles in situ. METHODS: Eight to 12 weeks after a carotid-jugular fistula was created in rats, experiments were performed under alpha-chloralose and urethane anesthesia. Regional cerebral blood flow (rCBF) was determined by the hydrogen clearance method, and carotid pressure was measured. Using a closed cranial window, we determined the autoregulatory responses of the arterioles (30 to 50 microns) to both hypertension induced by norepinephrine and sudden fistula closure at various mean arterial pressures (MAPs). RESULTS: rCBF on the fistula side was reduced by 27%. Carotid pressure was significantly lower than normal but was immediately increased by fistula closure. The pial arterioles showed marked elongation and enlargement. During induced hypertension, the arterioles in the fistula group started to dilate at an MAP lower than that of the control group (130 versus 180 mm Hg, respectively). The arterioles constricted when the fistula was occluded at normal MAP. However, when the fistula was occluded at an MAP higher than 130 mm Hg, the vessels dilated. CONCLUSIONS: It was demonstrated that (1) chronic hypoperfusion induced impairment of the upper limit of autoregulation and (2) sudden fistula closure under hypertensive conditions caused vasodilation of the arterioles. These findings suggest that rapid restoration of perfusion pressure is possibly followed by a pressure breakthrough phenomenon in a chronically hypoperfused cerebrovasculature.

Animals↗

PubMed1995

Diagnostic significance of serum neuron-specific enolase and myelin basic protein assay in patients with acute head injury.

BACKGROUND: Neuron-specific enolase (NSE) and myelin basic protein (MBP) in the peripheral venous blood (PVB) have been reported to be sensitive markers for judging the prognosis of patients with head injury. However, to our knowledge, the levels of NSE and MBP in the internal jugular venous blood (IJVB) have never been studied. METHODS: In 25 patients with acute head injury, blood samples were taken from the internal jugular vein and the peripheral vein at the same time before any medical or surgical procedure was performed. The levels of NSE and MBP in the both venous blood samples were measured. The time interval between injury and sampling was 1.5-8.0 hours (mean 4.3 hours). The levels of NSE and MBP in the IJVB were compared to those in the PVB. The relationship between the clinical outcome and the serum levels of those was evaluated. RESULTS: The levels of NSE and MBP in the IJVB were almost equal to those in the PVB. The levels of NSE and MBP were significantly higher in the patients who died than in those who survived. In the survivors, the levels of NSE and MBP in the IJVB were 17.6 +/- 11.4 ng/ml and 1.4 +/- 1.5 ng/ml, whereas in the patients who died, both levels were elevated to 51.3 +/- 27.3 ng/ml (p < 0.005) and to 11.3 +/- 9.5 ng/ml (p < 0.01), respectively. CONCLUSIONS: The assay of serum NSE and MBP levels provides a reliable laboratory indicator of the degree of brain damage and allows early prediction of the prognosis in patients with acute head injury.

Acute Disease↗

PubMed1995

Experimental model of chronic tonsillar herniation associated with early stage syringomyelia.

This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8-14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n = 6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extra-cellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n = 4) and those rats without tonsillar herniation (n = 4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.

Animals↗

PubMed1995

[Protective effect of human macrophage colony-stimulating factor on fungal infection (2). In vitro effect of human macrophage colony-stimulating factor on systemic aspergillosis and in vitro effect on the activities of macrophage].

We studied the protective effect of human macrophage colony-stimulating factor (M-CSF) of fungal infection due to systemic aspergillosis in normal mice. We also examined the effect of M-CSF against the activities of mouse peritoneal macrophage which were relating to the phagocytosis, the killing, the production of superoxide after contacting with phorbol myristate acetate and the production of nitric oxide after contacting with interferon-gamma in vitro. M-CSF improved the median survival time and the survival rate of systemic aspergillosis. Combination therapy with M-CSF and amphotericin-B (AMPH-B) showed the therapy with either M-CSF or AMPH-B alone. M-CSF enhanced the activities of phagocytosis and the killing of ingested Candida albicans H and spores of Aspergillus fumigatus K by macrophage. Furthermore, M-CSF promoted the production of superoxide and nitric oxide in macrophage. These results indicate that M-CSF can enhance the fungicidal activity of macrophages by activation in vivo, thereby preventing the dissemination of fungal infection.

Amphotericin B↗

PubMed1995

[Protective effect of human macrophage colony-stimulating factor (hM-CSF) on fungal infection (1). In vivo effect of hM-CSF on systemic candidiasis and in vitro effect of hM-CSF on macrophages activities].

We studied the protective effect of human macrophage colony-stimulating factor (hM-CSF) on fungal infection due to systemic candidiasis in vivo and the activities of macrophages in vitro, in order to demonstrate the usefulness of M-CSF on fungal infection. The effect of hM-CSF on systemic candidiasis was examined by using normal and immunosuppressed mice. In addition, the effects of hM-CSF on the activity of reticuloendothelial system (RES) organ and on the phagocytic activity and NBT reduction activity of mouse macrophage were also examined in vitro. HM-CSF improved the survival rate of systemic candidiasis in both normal and immunosuppressed mice. Combination therapy with hM-CSF and fluconazole showed higher survival rate more than in the therapy with either hM-CSF or fluconazole alone. Furthermore, hM-CSF enhanced the activity of RES organ, phagocytosis by macrophages and NBT reduction by macrophages, significantly. These results indicate that hM-CSF enhances the phagocytic cactivity and candicidal activity by macrophages in vivo, thereby preventing dissemination of fungal infection.

Animals↗

PubMed1995

Basic fibroblast growth factor increases regional cerebral blood flow and reduces infarct size after experimental ischemia in a rat model.

BACKGROUND AND PURPOSE: The aim of this study was to ascertain whether basic fibroblast growth factors (bFGF) caused reduction in size of cerebral infarcts in Sprague-Dawley rats with experimental ischemia. METHODS: In the first experiment we induced permanent occlusion of the left middle cerebral artery (MCA). Within 5 minutes after MCA occlusion, we infused bFGF (100 ng in 0.1 mL of saline) in the bFGF-treated group (n = 14) and 0.1 mL of saline alone in the control group (n = 7) into the common carotid artery ipsilateral to MCA occlusion. We harvested the brains 24 hours after MCA occlusion and determined infarct size planimetrically as a percentage of hemisphere size. In the second experiment cerebral blood flow (CBF) was continuously measured for 120 minutes after MCA occlusion in the bFGF-treated group (n = 9) and in the control group (n = 8) with the use of laser-Doppler flowmetry. RESULTS: Infarct size in the bFGF-treated group decreased significantly in comparison with that in the control group (repeated-measures ANOVA, P < .0001). CBF in the transitional areas between the MCA and the anterior cerebral artery significantly increased in the bFGF-treated group in comparison with that in the control group (repeated-measures ANOVA, P < .005). An approximate 58% decrease in infarct size and a 40% increase in regional CBF were seen on bFGF treatment. CONCLUSIONS: The present study suggested that intracarotid administration of bFGF (100 ng) can reduce infarct size after MCA occlusion. It was speculated that the increased CBF in the penumbral areas of MCA may contribute to contraction of infarct size.

Animals↗

PubMed1995

[Characteristic neurological signs in patients with cervical disc disease].

In cervical radiculopathy, neurological findings for the upper extremities and the responsible level of the radices have been precisely detailed. However, in cases of cervical spondylotic myelopathy, it is not always easy to determine the responsible level of the cervical spine solely based on neurological findings. To disclose characteristic neurological lesions of the upper extremities, if any, for different locations of disc disease, 49 patients with cervical disc protrusion at single levels, confirmed by magnetic resonance imaging, were analyzed. Thirty-six patients demonstrated long tract signs (LTS) concomitant with segmental signs in the upper extremities, and 13 patients had no LTS. Except for deep tendon reflexes and the extent of dysesthesia in the upper extremities, there were no characteristic neurological findings, such as muscle atrophy, loss of muscle strength, extent of hypalgesia, or hypesthesia, pointing to the responsible compression site. In the 13 patients without LTS, the extent of dysesthesia and diminution of deep tendon reflexes proved to be completely in agreement with results for radiculopathy: 9 had protruded discs at the C56 level and described dysesthesia in the thumb and the index finger with deep tendon reflexes in the biceps and brachioradialis being diminished. The remaining 4 had protruded discs at the C67 level and described dysesthesia in the middle finger. Their deep tendon reflexes in the triceps were diminished. A clear contrast was observed for the patients with LTS. Four out of 36 patients had C34 protruded discs and did not complain of dysesthesia in any digits. Their deep tendon reflexes were exaggerated in all muscles in the upper extremities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

[Epidemiology of syringomyelia in Japan--the nationwide survey].

The nationwide epidemiological survey of syringomyelia was carried out in Japan by sending inquiries to neurologists, child neurologists, neurosurgeons and orthopedic surgeons for the period of 1991 and 1992. A total of 1,243 cases of syringomyelia were ascertained. Among them, 622 were men and 619 women, and the average age of onset was 28 years old. The classification by Barnett et al was used, presenting syringomyelia with Chiari malformation in 684 cases (51.2%), dysraphism in 47 (3.7%), post traumatic syringomyelia in 139 (11%), post-spinal arachnoiditis in 76 (6%), spinal cord tumor in 132 (10.5%) and others in 204. Its predominant clinical course was slowly progressive, but 202 cases (17.9%) showed rather stable course including spontaneous resolution in 29 cases. The main initial symptoms were numbness in 522 cases (42%), motor disturbance in 504 (40.5%), and pain in 296 (23.8%). Neurologic signs noted in the abnormality of deep tendon reflexes in 836 cases (67.3%), motor disturbance in 763 (60.4%) and positive pathological reflexes in 383 (30.1%). Sensory disturbance was found in 942 cases (75.8%) and the dissociated type were 559 out of them (59.3%). It is noteworthy that 982 out of 1,243 were documented by MRI and surgical operations such as foramen magnum decompression, syringo-subarachnoid shunt and others were performed in 829 cases. Syringobulbia was confirmed on MRI in 101 cases of syringomyelia in which spinal cord tumors were most frequently associated.

Adolescent↗

PubMed1994

Spinal cord intramedullary pressure. A possible factor in syrinx growth.

STUDY DESIGN: This study analyzed biomechanical characteristics of the cervical spinal cord, especially in relation to neck flexion. Intramedullary pressure was measured in different neck positions. OBJECTIVES: The results provided a rationale for dynamic changes in intramedullary pressure, with the flexed neck position playing a role in syrinx growth. SUMMARY OF BACKGROUND DATA: Dynamic changes in intramedullary pressure in the flexed position have been postulated to play an important role in syrinx growth. However, intramedullary pressure of the spinal cord has not been measured. METHODS: The authors designed a balloon method to assess, experimentally, intramedullary pressure dynamics of the spinal cord. A system was incorporated to examine the reliability of the balloons. Using 15 mongrel dogs, two balloons were embedded in the cervical spinal cord. Intramedullary pressure of the spinal cord was measured in several neck positions. In 5 of them, the same measurements were repeated when the spinal cord and roots were transected. RESULTS: When filled with a suitable volume of water, the balloons faithfully transmitted the pressure of the environment. No pressure differences were observed with the neck in the extended or neutral positions. However, when the neck was flexed, intramedullary pressure significantly increased. This increase in intramedullary pressure in the flexed neck position was not observed after spinal cord and roots were transected. CONCLUSION: The results indicated that the intramedullary pressure of the cervical spinal cord increases when the neck is flexed. This phenomenon might play an important role in syrinx growth.

Animals↗

PubMed1994

Anomaly of venous system in congenital occipital dermal sinus.

We report two cases of congenital occipital dermal sinus in which elongation of the vein of Galen, elevation of the straight sinus, division of the superior sagittal sinus, elevation of the confluence of sinuses, elevation of transverse sinus and narrowing of the torcular angle were observed in the venous phase of cerebral angiography. Enhanced computed tomography (CT) revealed enlargement of the supracerebellar cistern, elevation of the straight sinus and of the confluence of sinuses, but no evidence of intracranial lesions. In order to study the relationship between anomalies in the dural venous sinuses and congenital occipital dermal sinus, we examined both cases from an embryological viewpoint.

Arteriovenous Malformations↗

PubMed1994

The effects of a carotid-jugular fistula on cerebral blood flow in the cat: an experimental study in the acute period.

The purpose of the present study is to investigate the effects of feline carotid-jugular (CJ) fistula (Spetzler's model) on cerebral blood flow (CBF) in the acute period after creation of the fistula. Using laser-Doppler flowmetry, cortical CBF was measured on the fistula side of 11 cats. Temporary occlusion and opening of the fistula led to an immediate increase and decrease, respectively, in cortical CBF. However, CBF returned to baseline within 1 minute, on average. CO2 reactivity in the closed fistula was preserved. It is suggested that cerebral hemodynamic changes due to Spetzler's CJ fistula model are minimal in the acute period after fistulization.

Acute Disease↗

PubMed1994

Effects of acidic pH on the formation of vinblastine-induced paracrystals in Chinese hamster ovary cells.

The pH-related change in morphology of vinblastine (VLB)-induced paracrystals formed in Chinese hamster ovary (CHO) cells was examined immunohistochemically in order to determine both the mechanism of tubulin crystallization and the influence of acidic pHs on cytoskeletal microtubules. Lowering the extracellular pH (pHe) rapidly reduced the intracellular pH (pHi) in CHO cells. Lowering the pHi to near the neutral range significantly accelerated the growth of VLB-induced paracrystals, compared to that of paracrystals formed at a physiological pHe. However, further cytoplasmic acidification caused by the addition of sodium azide into the culture medium induced the disappearance of typical paracrystals and the appearance of a highly organized meshwork of tubulin appearing as short, thick filaments at the light microscopic level. Treatments using different concentrations of VLB at different pHe's showed that low pHi's (6.7 and 6.3) suppressed paracrystal-formation at lower concentrations of VLB (5 x 10(-6) M and 10(-5) M). At higher concentrations of VLB (5 x 10(-5) M and 10(-4) M), only short filaments were formed at pHi 6.3. Electron microscopy revealed that the filaments had a ladder-like structure probably consisting of a stacked series of fused rings. This indicates that paracrystals may be modified by extremely low pH. These results show that paracrystals are unstable in living cells and that their formation is regulated by environmental pH.

Acids↗

PubMed1994

Draining vein pressure increases and hemorrhage in patients with arteriovenous malformation.

BACKGROUND: Recent radiological studies have shown that arteriovenous malformations with impaired venous drainage may be susceptible to hemorrhage. To evaluate this hypothesis using a hemodynamic approach, we measured intravascular pressure during surgery in three patients with arteriovenous malformation. SUMMARY OF REPORT: In three patients we measured intravascular pressures in the draining venous system and the feeding arteries simultaneously before removal of arteriovenous malformations with marked segmental stenotic or occlusive draining veins and evidence of hemorrhage. The draining vein pressures at prestenotic (or preocclusive) sites in the three patients were 38, 25, and 40 mm Hg, respectively, all significantly above the normal cortical venous pressure, whereas pressure measurements in poststenotic sites and the sagittal sinus pressure in the venous drainage system approached normal values. The feeding artery pressures in the patients were lower than normal cortical artery pressure because of the arteriovenous shunt. CONCLUSIONS: Intraoperative vascular pressure measurements support the hypothesis that arteriovenous malformations with impaired venous drainage may be associated with a local increase in venous pressure and thus may be susceptible to hemorrhage.

Adolescent↗

PubMed1994

Aneurysmography for visualizing large aneurysms.

We report a case of a large cavernous sinus aneurysm, in which conventional angiography did not clearly demonstrate the exact form and the position of the neck. Superselective angiography performed with the catheter tip in the lumen of the aneurysm and with the internal carotid artery occluded just proximal to its neck is a new technique that demonstrates the morphological details of an entire aneurysm. With the use of cineangiography, the exact volume of the aneurysm was defined. The valuable aneurysmographic information obtained was useful in achieving occlusion of the aneurysm, while preserving the parent artery.

Carotid Artery, Internal↗

PubMed1994

Radiological study of symptomatic Rathke's cleft cysts.

We investigated the relationship between radiological findings and the nature of the cyst fluid and histological findings of six Rathke's cleft cysts. The results show that the majority (five of six cases) of symptomatic Rathke's cleft cysts exhibit no enlargement of the sella turcica on plain x-rays, which may be helpful in differentiating cystic pituitary adenoma in the radiological diagnostic process. Three cases with large cysts showing high-intensity T1-weighted magnetic resonance images harbored abundances of cholesterol crystal and hemosiderin pigment in the cyst walls. The high signal intensity in magnetic resonance images of Rathke's cleft cysts may be explained by hemorrhage and a deposition of cholesterol crystal and may be considered in certain cases of Rathke's cleft cyst, especially when they are large.

Adult↗

PubMed1994

Dural arteriovenous malformation involving the inferior petrosal sinus--case report.

A 59-year-old male presented with a dural arteriovenous malformation involving the inferior petrosal sinus manifesting as false-localizing ocular symptoms. Occlusion between the right inferior petrosal sinus and the right jugular bulb caused an unusual retrograde venous outflow from the inferior petrosal sinus to the cavernous sinus, thought to have been responsible for the chemosis, abducens nerve paresis, and orbital bruit. He was treated successfully with transarterial embolization and radiotherapy.

Cerebral Angiography↗