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Biomedical subjects

Y Akagi

Publications and source records attributed to Y Akagi.

At least 145 records · Page 8Linked to original sources

Localization of aldose reductase in the human eye.

The presence of the enzyme aldose reductase is increasingly being linked to diabetic complications. The distribution of this enzyme in human cornea, lens, retina, and optic nerve has been studied using specific antibodies against purified human placental aldose reductase raised in both rabbit and goat. The antisera from both animals gave equal, specific reactions. In frozen sections of ocular tissues, significant aldose reductase localization was reproducibly demonstrated in the endothelium and epithelium of the cornea and in the basal cell layers of the conjunctiva. In the lens, staining was observed in the epithelium and superficial lens fibers. In retinal sections, the presence of aldose reductase was demonstrated in the Mueller's cells, especially near the inner limiting membrane. It was also found in some ganglion and cone cells. In the optic nerve, positive staining was observed in the axon. All other cells of the tissues examined revealed only weak, nonspecific staining.

Adult↗

Corneal endothelial changes caused by ophthalmic drugs.

Morphological changes were examined in the corneal endothelium of rabbits after administration of several drugs widely used in ophthalmology. After administration of epinephrine and dipivalyl epinephrine eye drops, swelling of corneal endothelial cells developed; however, these changes were reversible. No pathological changes were observed in the corneal endothelial layer following the administration of timolol, betamethasone, and gentamicin eye drops. Morphological changes were observed in the corneal endothelial layer after the subconjunctival injection of timolol, betamethasone, and gentamicin.

Animals↗

Aldose reductase localization in human retinal mural cells.

A hallmark of early diabetic retinopathy is the selective loss of the retinal mural cells (pericytes) from vessels. Using antibodies prepared against purified human placental aldose reductase, the presence of the enzyme aldose reductase can be demonstrated immunohistochemically in the cytoplasm of retinal mural cells of trypsin-digested human retinal vessels. This enzyme, which reduces various hexose sugars to their sugar alcohols, has been implicated in the pathogenesis of several diabetic complications.

Aldehyde Reductase↗

[Clinical effects of netilmicin].

In the present study, we used netilmicin for the postoperative complications and obtained the following results. 1. Netilmicin was used in totally 29 cases; 23 with localized peritonitis, 4 with generalized peritonetis and 2 with wound infection. Excellent effects were obtained in 2 cases, effective results in 24 cases and ineffective results in 3 cases. The effective rate was 89.7%. 2. Adverse reactions or abnormal clinical laboratory test results which might be attributable to the use of netilmicin were not noticed.

Adult↗

Uptake of D-glucose and L-proline by oligotrophic and heterotrophic marine bacteria.

The transport systems of the oligotrophic bacterium 486 for D-glucose and L-proline have been compared with those of the heterotrophic bacterium RP-303. Kinetic studies demonstrated that the rates of D-glucose and L-proline uptake by the two organisms were saturable processes. The apparent Km values of strain 486 for D-glucose and L-proline were 13.0 microM and 0.2 microM, respectively, whereas those of strain RP-303 were 3.2 microM for D-glucose and 1.8 microM for L-proline. Competition studies indicated that the D-glucose transport system of each bacterium was highly specific for D-glucose. The L-proline transport system of the oligotrophic bacterium 486 had a broad specificity, whereas that of the heterotrophic bacterium RP-303 had a narrow one.

Amino Acids↗

The localization of the motor neurons innervating the extraocular muscles in the oculomotor nuclei of the cat and rabbit, using horseradish peroxidase.

The localization of the motor neurons innervating the extraocular muscles in the oculomotor nuclei of adult cats and rabbits was investigated by means of retrograde labelling with horseradish peroxidase (HRP). The groups consisting of the motor neurons innervating an individual muscle lay in the nucleus as elongated columns extending in a longitudinal direction. The position of each group in the transverse section varied according to the rostro-caudal level of the nucleus. In the cat and rabbit, entire contralateral innervation of the superior rectus and entire ipsilateral innervation of three muscles of the inferior rectus, medial rectus and inferior oblique were similarly observed. However, the arrangement of individual motor groups differed considerably in both animals except for the group innervating the inferior rectus which was generally found in the ventral position running through the rostral two-thirds of the oculomotor nucleus. In the case of cats, the central caudal nucleus bilaterally innervated the levator palpebrae superioris. The motor neurons innervating this muscle in the rabbit (which lacks the central caudal nucleus) formed a rostro-caudal club-shaped column close to the group innervating the superior rectus. The aberrant cellular mass in the adjoining medial longitudinal fasciculus which belongs to the medial rectus appears to play an important role in the eye movement, because it commonly appears in various animals.

Animals↗

The sympathetic innervation of the ciliary body and trabecular meshwork of the cat. Fluorescence histochemistry and electron microscopy.

The ciliary body of the cat was investigated by fluorescence histochemistry and electron microscopy in an attempt to clarify its sympathetic innervation. Subconjunctival doses of 5-hydroxydopamine (5-OHDA) or 6-hydroxydopamine (6-OHDA) were given to establish the precise location of the sympathetic nerve terminals. The distribution of noradrenergic fibers and terminals was shown by fluorescence histochemistry to be sparse in the trabecular meshwork and the anterior portion of the ciliary muscle, but dense in the subepithelial tissue. The small and large dense core vesicles which occur in many nerve endings of the subepithelial tissue adjacent to the pigmented epithelial layer increased in electron density following the administration of 5-OHDA. Many degenerating nerve endings were found in the same region of animals treated with 6-OHDA. In contrast, there were few noradrenergic terminals in the ciliary muscle except for a portion of the smooth muscle which was shown to be dually innervated. The noradrenergic fibers in the subepithelial region and the trabecular meshwork may play an important role in aqueous secretion and outflow.

Adrenergic Fibers↗

Frequency and significance of tumor thrombi in esophageal varices in hepatocellular carcinoma associated with cirrhosis.

Histological examination of the wall of the stomach and esophagus in patients with hepatocellular carcinoma associated with cirrhosis demonstrated intravariceal tumor thrombi in 13 (23.6%) of 55 cases studied. There were distant hematogenous metastases in 31 of them, of whom 12 (38.7%) had variceal tumor thrombi. Tumor thrombi were of varying sizes, and tumor cells appeared either intact, degenerated or necrotic. In seven cases, there was a firm adhesion of thrombi onto the vascular wall suggesting possible mural infiltration, but no extravascular metastases were noted grossly. These findings suggest a possibility of metastasis of hepatocellular carcinoma to the stomach and esophagus via the portal vein. It is also suggested that the degree of varices is not increased by tumor thrombus formation per se, and that both varices and tumor thrombi are due to extensive hepatofugal collateral circulation. Considering that 12 of 13 cases of intravariceal tumor thrombi had lung metastases, a portal vein-varices-lung route is possible for lung metastasis beside the established route through the hepatic vein in hepatocellular carcinoma.

Adult↗