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Biomedical subjects

H Kanai

Publications and source records attributed to H Kanai.

At least 127 records · Page 7Linked to original sources
PubMed1992

Haloalkaliphilic maltotriose-forming alpha-amylase from the archaebacterium Natronococcus sp. strain Ah-36.

A haloalkaliphilic archaebacterium, Natronococcus sp. strain Ah-36, produced extracellularly a maltotriose-forming amylase. The amylase was purified to homogeneity by ethanol precipitation, hydroxylapatite chromatography, hydrophobic chromatography, and gel filtration. The molecular weight of the enzyme was estimated to be 74,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amylase exhibited maximal activity at pH 8.7 and 55 degrees C in the presence of 2.5 M NaCl. The activity was irreversibly lost at low ionic strength. KCl, RbCl, and CsCl could partially substitute for NaCl at higher concentrations. The amylase was stable in the range of pH 6.0 to 8.6 and up to 50 degrees C in the presence of 2.5 M NaCl. Stabilization of the enzyme by soluble starch was observed in all cases. The enzyme activity was inhibited by the addition of 1 mM ZnCl2 or 1 mM N-bromosuccinimide. The amylase hydrolyzed soluble starch, amylose, amylopectin, and, more slowly, glycogen to produce maltotriose with small amounts of maltose and glucose of an alpha-configuration. Malto-oligosaccharides ranging from maltotetraose to maltoheptaose were also hydrolyzed; however, maltotriose and maltose were not hydrolyzed even with a prolonged reaction time. Transferase activity was detected by using maltotetraose or maltopentaose as a substrate. The amylase hydrolyzed gamma-cyclodextrin. alpha-Cyclodextrin and beta-cyclodextrin, however, were not hydrolyzed, although these compounds acted as competitive inhibitors to the amylase activity. Amino acid analysis showed that the amylase was characteristically enriched in glutamic acid or glutamine and in glycine.

Amino Acids↗
PubMed1992

Synthesis of fibronectin by isolated glomeruli from nephrectomized hypertensive rats.

The accumulation of extracellular matrix (ECM) is an important feature of most forms of progressive glomerular diseases. In order to examine the relationship between ECM synthesis and glomerulosclerosis, we evaluated fibronectin synthesis by glomeruli with the immunoprecipitation of conditioned media from isolated glomeruli in 5/6 nephrectomized spontaneously hypertensive rats (5/6N-SHR). There was no difference in blood pressure between 5/6N-SHR and control SHR throughout the experiment. Two weeks after the nephrectomy, most of the glomeruli were intact and no difference in the synthesis of fibronectin was observed between either groups. Twenty weeks after the nephrectomy, marked glomerulosclerosis associated with an increase in urinary protein was revealed in 5/6N-SHR but no glomerular lesions in control SHR. The synthesis of fibronectin by isolated glomeruli increased in 5/6N-SHR compared to control SHR. The administration of enalapril or hydralazine + reserpine + hydrochlorothiazide markedly attenuated the glomerular sclerosis and urinary protein excretion to a comparable degree, although the later therapy reduced blood pressure more effectively. These antihypertensive therapies also suppressed fibronectin synthesis in the 5/6N-SHR group at week 20. In conclusion, increased synthesis of glomerular fibronectin appeared to contribute to the glomerulosclerosis caused by subtotal nephrectomy and hypertension.

Animals↗
PubMed1992

Albuminuria is not an aggravating factor in experimental focal glomerulosclerosis and hyalinosis.

It is widely known that the severity of glomerular sclerosis is proportional to the degree and chronicity of proteinuria and that the degenerative changes of glomerular epithelial cells that are associated with overflow albuminuria can be experimentally induced by the injection of large quantities of heterologous albumin. Such evidence suggests that autologous albuminuria per se may have a harmful effect on the kidneys. To examine the cause and effect relationship between renal lesions and albuminuria, we produced Adriamycin-induced experimental focal glomerular sclerosis in Nagase analbuminemic (NA) rats and control Sprague-Dawley (SD) rats and observed both the renal functional and histologic changes for 20 weeks. At week 4 after injection of Adriamycin glomerular epithelial lesions including foot process fusion were similarly revealed by an electron microscopic study in both groups in spite of the presence of a large difference in the amount of proteinuria (SD rats: 491 +/- 84 mg/day, NA rats: 43 +/- 30 mg/day) and albuminuria (SD rats: 383 +/- 73 mg/day, NA rats: 2 +/- 1 mg/day). At week 20, a light microscopic study showed the same degree of glomerular sclerosis and hyalinosis and tubulointerstitial changes associated with a decrease in inulin clearance in both groups. The increased glomerular accumulation of immunoglobulin M or complement 3 and glomerular trapping of aggregated human immunoglobulin G were also similar between the SD and NA groups. In summary, renal destruction of Adriamycin-nephropathy was not dependent on the degree of albuminuria. These results suggest that albuminuria is not an aggravating factor in focal glomerulosclerosis.

Albumins↗
PubMed1992

[A case of extraneural metastasis of medulloblastoma successfully treated with cisplatin and etoposide].

A patient who had been treated for cerebellar medulloblastoma presented progressive abdominal distension and tachypnea. Metastases of the tumor in the abdominal and thoracic cavity were confirmed by cytology. The authors treated the metastasis with a combination of intravenous administration of 20 mg/m2/day cisplatin and 60 mg/m2/day etoposide for two 5-day cycles. After chemotherapy, the patient recovered fully with time and follow-up radiological studies demonstrated no evidence of tumor recurrence. Combination chemotherapy with cisplatin and etoposide is to be considered effective for extraneural metastasis of medulloblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

A large aneurysm of the persistent primitive hypoglossal artery.

An aneurysm of a persistent primitive hypoglossal artery (PHA) particularly at its junction with the basilar artery, often poses therapeutic problems. This is attributable not only to the size and location of the aneurysm but also to the fact that the persistent PHA is functionally the single artery providing blood in posterior circulation. We report a 31-year-old man with a large aneurysm of the persistent PHA at its junction with the basilar artery and review the existing literature. We clipped the broad neck of the aneurysm through a lateral suboccipital craniectomy; however, the patient suffered a second episode of subarachnoid hemorrhage. Angiography disclosed a slipped clip incompletely obstructing the persistent PHA. He received no further treatment for the aneurysm because of his deteriorating condition. Direct surgical treatment, although it failed to obliterate the aneurysm neck in our patient, should be recommended for a persistent PHA aneurysm.

Adult↗
PubMed1991

Alpha 1-antichymotrypsin has a trophic effect on hippocampal neurons in vitro.

alpha 1-Antichymotrypsin (ACT) has been reported to be present in senile plaques, and ACT level is elevated in the sera of patients with Alzheimer's disease. We found that ACT has a neurotrophic activity in vitro, i.e., it enhanced neuronal survival under the culture conditions used. Hippocampal neurons were cultured in chemically defined medium containing ACT at various concentrations. In order to evaluate the number of surviving neurons semiquantitatively, enzyme immunoassay for microtubule-associated protein2 (MAP2) was carried out using anti-MAP2 antibody. Cells cultured in medium containing 4 micrograms/ml of ACT showed 1.8-fold more neurotrophic activity than those cultured without ACT.

Animals↗
PubMed1991

Dopa and dopamine cause cultured neuronal death in the presence of iron.

We examined the cytotoxicity of dopa and dopamine for cultured neurons by using a newly developed enzyme immunoassay for neurofilament protein to determine surviving neuronal numbers. Each of the two catechols caused neuronal death in the presence of iron with or without superoxide dismutase and catalase, while deferoxamine mesylate prevented neuronal loss. Lipid peroxidation of phospholipid liposomes was confirmed to be produced by the combination of the catechols and iron (Fe3(+)-ADP complex). Thus, it was strongly suggested that cultured neurons were killed via the peroxidative cleavage of cell membrane components provoked by the catechols and iron. This mechanism of neuronal loss may play an important role in the degeneration in the substantia nigra of Parkinson's disease, because the catechols and iron are abundant in this region.

Adenosine Diphosphate↗
PubMed1991

Ring-enhanced primary intracranial malignant lymphoma--report of two cases.

Two nonimmunosuppressed patients with primary intracranial malignant lymphoma demonstrated ring-enhanced lesion on postcontrast CT scans. One patient underwent total removal of the tumor and the other patient biopsy, both followed by whole brain irradiation. Histological examination revealed the tumors contained diffuse large cells and necrosis in the central region. The possible mechanisms of ring enhancement may represent central necrosis of the rapidly growing tumor, but is probably not related to the prognosis.

Aged↗
PubMed1991

Brain metastasis of thyroid papillary carcinoma--case report.

A rare case of brain metastasis of thyroid papillary carcinoma is reported. The cerebral metastasis was surgically treated without irradiation despite the presence of a spinal metastasis. No recurrence was demonstrated by computed tomography 1 year postoperatively. We suggest that surgery is indicated for a brain metastasis of thyroid papillary carcinoma even if other metastatic lesions are present.

Adenocarcinoma, Papillary↗
PubMed1991

Penile gangrene in a patient with diabetic nephropathy on continuous ambulatory peritoneal dialysis.

We report here a case of penile gangrene in a patient with diabetic nephropathy treated by continuous ambulatory peritoneal dialysis (CAPD). The patient demonstrated severe systemic arteriosclerosis. The main cause of the gangrene was considered to be circulatory insufficiency induced by severe arteriosclerosis. Several predisposing factors including chronic renal failure, long-term diabetes mellitus and CAPD-related metabolic changes such as abnormalities of lipid metabolism also appeared to have contributed to the arteriosclerotic changes. The prognosis in cases of this type is thought to be extremely poor.

Diabetic Nephropathies↗
PubMed1991

[A case of acute myocardial infarction due to simultaneous occlusion of the right coronary artery and left anterior descending coronary artery].

We reported a rare case of a 53-year-old man who experienced acute myocardial infarction due to simultaneous occlusion in the right coronary artery and the left anterior descending coronary artery. He also experienced thromboembolisms on several occasions. So anticoagulant therapy is necessary for patients with exceedingly poor LV function.

Angioplasty, Balloon, Coronary↗
PubMed1990

In vivo measurement of intra- and extracellular space of brain tissue by electrical impedance method.

An impedance method was applied to evaluate transcellular fluid shifts in ischaemic brain oedema. The admittances (apparent electrical conductivities) of tissues were measured at varied frequencies based on a simple model of an electrical equivalent circuit for tissues, which consisted of Re (resistivity of extracellular fluid), Ri (resistivity of intracellular fluid) and Cm (capacitance of cell membrane). Calculated were Re, Ri, Rinf (resistivity of total fluid), Re/Ri and alpha (Cole-Cole distribution index) of brain tissue by Cole-Cole an arc of a circle. During ischaemia induced by cat middle cerebral artery occlusion (MCAO), the parameters were examined continuously. After MCAO, cerebral blood flow (CBF) decreased to under 10 ml/100 g/min. Then Re and Re/Ri increased, but Ri decreased. These results indicated that fluid shift from extracellular (EC) to intracellular (IC) space occurred after ischaemic insult. Rinf showed no changes during ischaemia of 30 min, which demonstrated no changes of total fluid volume. Using this impedance technique, fluid accumulation and shift may be examined by changes of Re, Ri, Re/Ri and Rinf in various types of brain oedema in vivo.

Animals↗
PubMed1990

The extrarenal effects of atrial natriuretic peptide on body fluid distribution.

To study the effects of atrial natriuretic peptide (ANP) on body fluid volume regulation, we estimated the changes in intra- and extravascular fluid volume by measuring hematocrit (Hct), plasma protein concentration and water balance, and the changes in intra- and extracellular fluid volume by the electrical impedance method during intravenous infusion of ANP. We did two studies, as follows: ANP was infused into 18 patients with essential hypertension, 29 with renal parenchymal hypertension and 15 normotensives at 0.025 microgram/kg/min for 40 min. Both hypertensive groups showed greater natriuretic responses to ANP than normotensives. ANP infusion into essential hypertensive patients increased the urinary excretion of water by 125%, Na by 205%, Hct by 4.2% and plasma total protein (TP) by 5.2% (each P less than .001). In 9 patients (1 with renal hypertension and 8 normotensives) who did not show a natriuretic response (-2.1%), the infusion of ANP also significantly increased Hct (3.8%) and plasma TP (3.1%, each P less than .01). The electrical impedance method was applied to 12 subjects to simultaneously detect the intracellular (Ri) and extracellular resistivities (Re), of which reciprocals reflect the fluid volume in the extra- and intracellular spaces, respectively. ANP infusion increased Re in all subjects (3.96 +/- 0.16 [SE] v 4.03 +/- 0.16 omega.m, P less than .05), but decreased Ri in 7. Changes in urinary Na excretion correlated positively with those in both Re (r = 0.62, P less than .05) and Ri (r = 0.75, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Close correlation of intra-abdominal fat accumulation to hypertension in obese women.

The relation between intra-abdominal visceral fat accumulation and blood pressure was investigated in 67 obese women (mean body mass index, 33.6 +/- 3.1; average age, 50 +/- 11 years). As an index of intra-abdominal fat accumulation, the ratio of the intra-abdominal visceral fat area to subcutaneous fat area was determined using a computed tomographic section at the level of the umbilicus. When the obese subjects were divided into a hypertensive group and a normotensive group, the ratio of the intra-abdominal visceral fat area to subcutaneous fat area in the hypertensive group was significantly higher (0.53 +/- 0.33 versus 0.29 +/- 0.12, p less than 0.01). Significant correlations between the ratio of intra-abdominal visceral fat area to subcutaneous fat area and systolic blood pressure (r = 0.62, p less than 0.001) and diastolic blood pressure (r = 0.53, p less than 0.001) also were found. However, no significant difference existed in either the body mass index or the waist-to-hip circumference ratio between the hypertensive and normotensive groups. Plasma renin activity, aldosterone, epinephrine, and norepinephrine levels were not significantly different between the two groups. Moreover, the correlation between the ratio of the intra-abdominal visceral fat area to subcutaneous fat area ratio and blood pressure was found independent of age and body mass index by multiple regression analyses. We conclude that intra-abdominal fat accumulation itself may play an important role in the pathogenesis of hypertension in obesity.

Abdomen↗