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Biomedical subjects

Y S Yu

Publications and source records attributed to Y S Yu.

At least 55 records · Page 3Linked to original sources

Chronic tonsillitis and IgA nephropathy.

The authors studied the effect of tonsillectomy for IgA nephropathy and the relationship between chronic tonsillitis and IgA nephropathy. Forty-five patients with IgA nephropathy were treated by tonsillectomy in our department. The effective rate of hematuria type IgA nephropathy was 86.2% and that of non-hematuria type 62.5%. We also determined the immunoglobulin composition of the tonsilla tissue in 18 IgA nephropathy patients and compared it with that of 18 chronic tonsillitis patients. The immunoglobin level of the IgA nephropathy group was higher than that of the contrast group, indicating that the disorder of tonsilla immunity may be one of the pathogenic factors for IgA nephropathy. Since no specific method has been available for the treatment of IgA nephropathy, we use tonsillectomy as an effective procedure.

Adolescent↗

[Restoration of opponens function with transplantation of free composites dorsal pedal skin flap containing m. extensor hallucis brevis].

Since 1983, we have used free dorsal pedal flaps with m. extensor hallucis brevis for two patients with serious thenar defects to restore their thumb function. The results were satisfactory, as most of oponens function was restored, however the power of the thumbs was inadequate. Functional restoration of the thumb after the loss of thenar muscles involves many aspects of microsurgery. This article discusses only the dissection of the muscle, the orientation of transferred muscle, etc.

Humans↗

Use of an epitope-tagged cDNA library to isolate cDNAs encoding proteins with nuclear localization potential.

We have combined epitope tagging with an expression cDNA library in order to isolate cDNAs encoding nuclear proteins. This system allows us to detect proteins expressed from the cDNA library by using antibodies against the epitope tag. As a tag, we used the 85-aa N-terminal peptide of the SV40 T antigen which lacks the nuclear localization signal (NLS). A strong expression vector, pEF204 [Kim et al., Gene 91 (1990) 217-223], was modified into an epitope-tagging vector, pTkim, by putting the tag-coding region and a cDNA cloning site immediately after its promoter. From cDNA libraries constructed using pTkim, we isolated eight cDNA clones whose tagged proteins were localized within the nuclei. From partial sequence analysis, two cDNAs were shown to code for the ribosomal (r-) proteins, simian L44 and human L21, and the others were shown to be new. Furthermore, six cDNAs including those encoding the r-proteins could direct a non-karyophilic T antigen [Fischer-Fantuzzi et al., Virology 153 (1986) 87-95] into nuclei, showing that they have NLSs. These results indicate that this system is useful for isolating new cDNAs which code for nuclear proteins.

Animals↗

The components of the proliferative membranes in retinopathy of prematurity: an electron microscopic study.

Electron microscopic examination of proliferative membranes in retinopathy of prematurity (ROP) was performed in order to evaluate the components of the membranes. The proliferative membranes were obtained from nine patients with ROP stage 5 during pars plicata lensectomy, vitrectomy, and delamination of membrane. Fibrous astrocytes, myofibroblasts, lymphocytes, macrophages, and calcification were found respectively in two cases, and fibroblast-like cells were found in one case. Varying amounts of collagen tissues were found in eight cases and vascular tissues in four cases. Most of membranes were hypocellular and composed mainly of collagen matrix. It is considered that fibrous astrocytes, myofibroblasts, fibroblasts, and vascular structures are involved in the formation of proliferative membranes of ROP, and that later these cells degenerate and disappear, and that finally only collagen matrix remains in the membranes.

Cataract Extraction↗

Myopia in premature infants at the age of 6 months.

The authors performed cycloplegic refractions in 180 eyes of 99 premature infants at the age of 6 months to evaluate the incidence and the degree of myopia according to the development and disease course of retinopathy of prematurity (ROP) and to investigate the effect of cryotherapy on the refractive error. The incidences of myopia were not different between premature infants without ROP and premature infants with spontaneously and totally regressed ROP (36.3%, 25.5%), and the degrees of myopia were low in both groups (-1.76 D, -2.25 D). In premature infants with totally regressed ROP after cryotherapy, the incidence of myopia was high (75.5%) but the degree of myopia was low (-3.03 D). In premature infants with cicatricial ROP, cryotreated or not, both the incidence and the degree of myopia were high (93.9%, -5.50 D). It is suggested that cryotherapy increases the incidence of myopia but the degree of myopia induced by cryotherapy is low.

Cryosurgery↗

Cryotherapy for retinopathy of incontinentia pigmenti.

A case with typical skin lesions of incontinentia pigmeti showed progressing retinal vascular abnormalities. So cryotherapy was done on avascular peripheral retina, and retinal vascular changes ceased. We propose that cryotherapy may be a good treatment method for progressing retinal vascular lesions of incontinentia pigmenti.

Cryosurgery↗

Medial transposition of the lateral rectus muscle in experimentally induced medial rectus paralysis.

When the oculomotor nerve is completely paralyzed, the affected eye shows severe outward displacement and poor cosmetic appearance. Past results of many surgical procedures for oculomotor palsy have been generally unsatisfactory. We tried a new surgical approach experimentally, in which the disinserted lateral rectus muscle was used as an adductor by medial transposition of the muscle. Five adult cats underwent disinsertion of the medial rectus muscle of both eyes to induce iatrogenic medial rectus paralysis. The disinserted medial rectus was removed as far back as possible to prevent reattachment. Then, the right lateral rectus muscle was disinserted and passed beneath the superior rectus muscle and resutured to the sclera 4mm superoposterior to the medial rectus insertion site. After excision of the bilateral medial rectus, a large exotropia of an average 47.6 delta (42.0-55.5 delta) was induced. The medial transposition of the right lateral rectus produced an average 36.6 delta (24.8-45.8 delta) correction of the exotropia. A satisfactory cosmetic result was achieved by this procedure.

Animals↗

Detection of specific proteins in the aqueous humor in primary open-angle glaucoma.

To elucidate the mechanism of increased intraocular pressure in primary open-angle glaucoma (POAG), the protein profiles of aqueous humor obtained from POAG patients were compared with those of cataract patients as a control group. Aqueous humor proteins were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and detected by the ultrasensitive silver staining technique. In 79% of the samples taken from POAG patients, protein bands of 140,000 or 160,000 daltons were stained, but none were stained from cataract patients. The presence of these protein bands revealed statistically significant differences between the two groups. Protein bands of 140,000 or 160,000 daltons were evenly visible at all ages in POAG patients, and the positivity of bands had no correlation with sex or initial intraocular pressure level. It is possible that the ultrastructural changes of the aqueous outflow pathway in POAG may be related to the changes in the aqueous protein, presence of 140,000 or 160,000 daltons protein bands.

Adult↗

Intraocular pressure and axial length in children.

The intraocular pressure and the anteroposterior length of the eye are of great clinical importance for the diagnosis and management, before and after surgery, of congenital glaucoma. It is well-known that normal intraocular pressure in children is different from the normal levels in adults. We performed measurements of intraocular pressure and axial length in 141 children who had been admitted for eye problems other than glaucoma. The intraocular pressures were measured with the Perkins hand-held applanation tonometer at the beginning of general anesthesia. Simultaneously, A-scan ultra-sound measurements of the axial lengths of the eyes were made. In 10 children under the age of two years, the intraocular pressure was 11.85 +/- 1.35 mmHg. In 79 children from two to seven years, the intraocular pressure was 12.80 +/- 1.73 mmHg. In 52 children from seven to 15 years, the intraocular pressure was 13.31 +/- 1.79 mmHg. The axial lengths of the eyes in children under the age of two years, from two to seven years, and from seven to 15 years, were 21.31 +/- 0.97 mm, 22.04 +/- 0.92 mm, and 23.22 +/- 1.00 mm, respectively. These results were considered to be guidelines for measuring intraocular pressure and axial length in children suspected of having congenital glaucoma. The differences of intraocular pressures stated by other authors are due to early measurement of the intraocular pressure at the beginning of general anesthesia.

Adolescent↗

Carbonic anhydrase II is induced in HL-60 cells by 1,25-dihydroxyvitamin D3: a model for osteoclast gene regulation.

Carbonic anhydrase II (CA II) generates the H+ required for osteoclast-mediated bone resorption in humans. We have developed the human promyelocytic cell line HL-60 as a model system with which to study the osteoclast-specific expression of the CA II gene. Treatment of the cell line with 1,25-dihydroxyvitamin D3 resulted in a dramatic de novo induction of CA II at both the protein and mRNA levels. CA II mRNA was also induced to a lesser extent by 12-O-tetradecanoyl phorbol 13-acetate. Treatment with dimethyl sulfoxide did not increase CA II mRNA. These findings indicate that the HL-60 cell line will be a useful model system to study the osteoclast-specific expression of the CA II gene.

Blotting, Northern↗

Primary glomerulonephritis in China. Analysis of 1001 cases.

The morphologic classification and clinical spectrum of 1,001 cases of primary glomerulonephritis (GN) in Jinling Hospital during 1980-1988 were analysed. It was found that the incidence of mesangial type lesion including mesangial proliferative GN, IgA nephropathy and IgM nephropathy ranks first (21.5%, 32.1% and 10.1% respectively), which is not only the commonest cause of patients clinically manifesting nephrotic syndrome and gross hematuria but also the predominant type of nephritis causing uremia and hypertension.

Adolescent↗

Separation of purine derivatives by polymer-bound nucleic acid bases.

Separation of a variety of purine bases, which include 7-methyl derivatives, was studied by using polyethyleneimine-coated silicagel which bound hypoxanthine, cytosine or guanine moieties. The separation behavior seems to be related to the interaction of imidazole part of purine derivatives with the resins through hydrogen bonding.

Chromatography, Affinity↗

Carbonic anhydrase II deficiency identified as the primary defect in the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.

The clinical, radiological, and pathological findings in three siblings affected with the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification have been reported. In an effort to explain the pleiotropic effects of the mutation producing this disorder, we postulated a defect in carbonic anhydrase II (CA II), the only one of the three soluble isozymes of carbonic anhydrase that is known to be synthesized in kidney and brain. We report here biochemical and immunological evidence for the virtual absence of CA II in erythrocytes of patients affected with this condition, whereas CA I level is not reduced. Levels of CA II in erythrocyte hemolysates from asymptomatic obligate heterozygotes are about half of normal. These findings: (i) elucidate the basic defect in one form of inherited osteopetrosis; (ii) provide genetic evidence implicating CA II in osteoclast function and bone resorption; (iii) explain previous observations that carbonic anhydrase inhibitors block the normal parathyroid hormone-induced release of calcium from bone; (iv) clarify the role of renal CA II in urinary acidification and bicarbonate reabsorption; and (v) suggest a method to identify heterozygous carriers for the gene for this recessively inherited syndrome.

Acidosis, Renal Tubular↗

Amino acid substitution and chemical characterization of a Japanese variant of carbonic anhydrase I: CA I Hiroshima-1 (86 Asp replaced by Gly).

An electrophoretic variant of red cell carbonic anhydrase I, designated CA I Hiroshima-1, has been observed in 12 apparently unrelated individuals during a survey of 13,019 individuals from the cities of Hiroshima and Nagasaki, Japan. Analyses of tryptic and chymotryptic peptide patterns of this CA I variant purified from 8 of the 12 individuals revealed the same altered peptides in each case. Examination of the amino acid sequence of an altered tryptic peptide purified from one of the variants showed that the aspartic acid residue at position 86 was replaced by a glycine residue. Thermostability studies demonstrated that all samples of CA I Hiroshima-1 were less stable than normal CA I. The specific esterase (p-nitrophenyl acetate) activities of the normal and variant CA I isozymes were essentially the same. The difference spectra of the normal and variant enzymes were essentially the same. The isoelectric focusing patterns of CA I Hiroshima-1 showed a different pattern of minor bands to those produced by normal CA I. The relative amounts of the normal and variant enzymes purified from single heterozygous individuals were similar.

Amino Acid Sequence↗