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Biomedical subjects

K Nakayasu

Publications and source records attributed to K Nakayasu.

At least 91 records · Page 5Linked to original sources
PubMed1984

Localization of type V collagen and type IV collagen in human cornea, lung, and skin. Immunohistochemical evidence by anti-collagen antibodies characterized by immunoelectroblotting.

Tissue distribution of Type V collagen in comparison with Type IV collagen was investigated by indirect immunofluorescence microscopy. Affinity-purified rat antibodies to Type IV and Type V collagens obtained from human placenta reacted specifically only with the corresponding type of collagen in both native and denatured conformations. In indirect immunofluorescent stainings of human skin, lung, and cornea tissues, Type IV and Type V collagens showed distinct distributions. Type IV collagen was distributed exclusively in basement membrane. However, Type V collagen had two characteristic features; a diffuse distribution in interstitium and the locations on or adjacent to basement membrane. On the basis of these findings and of biochemical characterization of the collagens, it is postulated that Type V collagen is an intermediate collagen, possibly having a function of binding or connecting of interstitial collagen fibrils with membranous collagen networks.

Adult↗
PubMed1981

Trichilemmal differentiation in seborrheic keratosis.

An 88-year-old woman who developed a nodule in a lesion of seborrheic keratosis on the frontal scalp was observed. Histopathologically, the nodule was characterized by lobular acanthosis consisting of glycogen rich clear cells and squamoid cells with squamous eddies and melanin blockade melanocytes. Each lobule was covered with an orthokeratotic horny layer which formed wedge-shaped masses in its central area without formation of an intervening granular layer. The clinical course and histopathological findings suggest that the tumor cells in seborrheic keratosis may tend to a new development of trichilemmal differentiation.

Aged↗
PubMedDate not supplied

Corneal wound healing: Immunohistological features of extracellular matrix following penetrating keratoplasty in rabbits.

PURPOSE: To study the distribution and the constituents of the extracellular matrix in the cornea during wound healing following penetrating keratoplasty (PKP). METHODS: Penetrating keratoplasty (PKP) was performed on albino rabbit eyes, and immunohistochemical techniques were used to determine the distribution of types I, III, IV collagens, large proteoglycans, chondroitin 6-sulfate, chondroitin 4-sulfate, and vimentin. The expression of these substances was determined at postoperative times of 3 days, 1 week, 2 weeks, 1 month, and 3 months. RESULTS: By day 3, staining for type IV collagen was observed along the host-graft junction. By day 7, staining for type III collagen, large proteoglycans, and chondroitin 6-sulfate had increased in the repair region but then decreased with increasing postoperative times. Epithelial wound healing required more than one month, whereas the remodeling of Descemet's membrane did not terminate until 3 months after PKP. CONCLUSION: These results suggest that type III collagen, large proteoglycans, and chondroitin 6-sulfate probably play important roles in corneal wound healing after PKP.

Animals↗
PubMedDate not supplied

Trial for new intraocular lens power calculation following phototherapeutic keratectomy.

PURPOSE: To determine an equation to calculate the intraocular lens (IOL) power for eyes that have undergone laser phototherapeutic keratectomy (PTK). METHODS: The Gullstrand series was used to determine the power and radius of curvature of a convex-plane IOL, which will alter the focal point from the cornea to the conjugate point on the retina using the ray tracing method. RESULTS: The radius of curvature of the anterior corneal surface (R), axial length (AXL), the predicted postoperative anterior chamber depth (ACD), and lens thickness (LT) were used in the following formula to calculate the refractive power of the IOL to be used: K = R/7.7, DC = 337.5/R, VC = lOOO/DC x 1.336 where VC is the posterior vertex focal length, A(1) = -(VC - ACD), B(1) = AXL - 0.5 x K - ACD - 0.103LT, S = l/A(1) + l/B(1), K is the proportional expression for anterior corneal curvature, DC = anterior corneal refractive power, A(1) = distance from anterior surface of IOL to posterior vertex focal point, B(1) = distance from the second principal point of IOL to the retina, S = 1/focal length of IOL in air. Using this equation, the power (in diopters) of the IOL in liquid was determined to be 1000/(l/S). 1. 336. In eyes that have undergone PTK, the keratometric value prior to cataract surgery is not used. Instead a value, R', is introduced. R' is defined as (R - 376/1376. dT), where R is the radius of corneal curvature prior to PTK and dT the amount of corneal tissue removed. The corneal thickness after cataract surgery, CT', was defined as CT - dT, where CT is the corneal thickness prior to PTK. CONCLUSION: The new equation appears to be useful for determining the IOL power, although it is important to select a lens that has the accurate predicted anterior chamber depth.

Aged↗
PubMedDate not supplied

Secondary keratoconus with corneal epithelial iron ring similar to Fleischer's ring.

BACKGROUND: Fleischer's ring is considered to be a characteristic of keratoconus, but we have seen a ring similar to Fleischer's ring in patients with secondary keratoconus, in which the cornea becomes thinner secondarily for undetermined reasons. CASES: We report 6 cases of secondary keratoconus with a corneal epithelial ring similar to the Fleischer's ring pattern. OBSERVATIONS: In these 6 cases (2 men and 4 women), the causes of secondary keratoconus were trachoma in 2 cases, trauma in 2 cases, keratitis in 1 case and unknown etiology in one case. All showed thinning of the cornea and a corneal iron ring similar to Fleischer's ring pattern. The corneal button obtained after keratoplasty in 1 case showed the deposition of hemosiderin in the corneal epithelium after staining with Prussian blue. At the same time we confirmed the existence of iron in the corneal epithelium by x-ray ultimate analysis. CONCLUSIONS: All 6 patients we encountered had a past history of corneal disease in their childhood except for 1 case with unknown etiology. Primary keratoconus is also considered to develop by the early teens at the latest. These facts led us to an assumption that the occurrence of some abnormalities in the cornea during the growth period may result in iron deposition in the epithelium and thinning of the stroma. In light of these facts, abnormalities of the iron metabolism must be thoroughly investigated in considering the etiology of keratoconus.

Adult↗
PubMedDate not supplied

The expression of laminin-5 and ultrastructure of the interface between basal cells and underlying stroma in the keratoconus cornea.

PURPOSE: We investigated the expression of laminin-5 and integrins, and the ultrastructure of the interface between basal cells and the basement membrane in the keratoconus cornea. These findings were compared to those in normal central cornea and limbus. METHODS: Frozen sections of the normal cornea (center and limbus) and the keratoconus cornea were immunostained with monoclonal antibodies against three chains of laminin-5 and integrins. To investigate the ultrastructure of the interface between basal cells and the underlying stroma, we used transmission electron microscopy. RESULTS: As compared to those in the normal central cornea, immunostaining patterns of the three chains of laminin-5 were thick and irregular in the keratoconus cornea and the normal limbus. Using electron microscopy analysis, the same characteristic structure of the interface between basal cells and the underlying stroma was recognized in the keratoconus cornea and the normal limbus. The expression of integrin alpha(6)beta(4) was restricted to the basal aspect of basal cells in the normal cornea. In the keratoconus cornea, however, integrin alpha(6)beta(4) was expressed in all aspects in basal and suprabasal cells. CONCLUSION The expression patterns of laminin-5 and the ultrastructure of the interface between basal cells and the basement membrane in the keratoconus cornea were similar to those in the normal limbus.

Adult↗
PubMedDate not supplied

Plus/minus screening of rabbit corneal endothelial cDNA library.

Plus/minus screening of the rabbit corneal cDNA library was performed using corneal and iris RNA as probes. Thirteen clones were isolated: three ferritin H-chains, a NADH-ubiquinone oxidoreductase B22 subunit, an alpha 1 type VIII collagen, a 25 KDa FKBP-506 binding protein (FKBP25), a thrombospondin 2, and six unknown clones. Although proteins translocated from these isolated mRNA are not corneal specific, they play an important role in the cornea. None of the isolated known mRNAs maps to chromosome 1, 16, or 20. These clones, thrombospondin excepted, were not observed in the high frequency clones in the profile of the aortic endothelial cDNA library.

Amino Acid Sequence↗
PubMedDate not supplied

Effect of cyclosporin A eyedrops on tear secretion in rabbit.

We investigated the tear secretion-stimulating effect of cyclosporin A (CyA) eyedrops in rabbits using Schirmer's method. The following findings were obtained: (1) CyA induced tear secretion in a concentration-dependent manner. CvA in 0.1% concentration showed the strongest effect in accelerating lacrimation, and this effect persisted from 3 to 8 hours after instillation. (2) CyA-induced lacrimation was inhibited by atropine sulfate, a muscarinic blocker. (3) CyA-induced lacrimation was also inhibited in a concentration-dependent manner by (D-Pro2, D-Trp7,9)-Substance P, which is a tachykinin-receptor-selective antagonist. (4) CyA-induced lacrimation was also inhibited by capsaicin, which is a stimulator that releases and depletes neurotransmitters from sensory nerve endings. We conclude from these pharmacological studies that, in the rabbit, CyA-induced tear secretion is mediated by both cholinergic and tachykinergic nerves.

Animals↗
PubMedDate not supplied

The ultrastructure of the lens capsule abnormalities in Alport's syndrome.

The ultrastructure of lens capsule abnormalities in Alport's syndrome is reported. An anterior lens capsule from a 29-year-old patient with lenticonus who was affected by Alport's syndrome was obtained at the time of surgery. The histopathologic findings showed the thickness of the anterior lens capsule was decreased and there were many vertical capsular dehiscences localized at the inner part of the lens capsule. Almost every dehiscence was limited to the inner two thirds of the capsule. One should be cautious in attempting intraocular lens implantation into the lens capsule of patients with Alport's syndrome, because the lens capsule may be fragile in this disease.

Adult↗
PubMedDate not supplied

Arg124Cys mutation of the betaig-h3 bene in a Japanese family with lattice corneal dystrophy type I.

To characterize severe lattice corneal dystrophy, we analyzed the betaig-h3 gene, clinical features, histological findings, and genotype-phenotype correlation in an affected Japanese family. Deoxyribonucleic acid was extracted from leukocytes in 16 members (12 affected and 4 unaffected) of a Japanese family with lattice corneal dystrophy type I. Exon 4 of the betaig-h3 gene was amplified and analyzed using molecular biological methods. Clinical and pathological data were also collected. We found a heterozygous point mutation that causes the disease phenotype. It was a single base-pair transition leading to an amino acid substitution (CGC-->TGC, Arg124Cys). The phenotypic variation within families was not recognized. The affected members in the pedigree demonstrated severe visual disturbance in the third decade and required keratoplasty. Histopathological examination revealed amyloid deposits consisting of short and thin amyloid fibers and lattice corneal dystrophy type I. The heterozygous Arg124Cys mutation reported in Caucasian lattice corneal dystrophy caused severe lattice corneal dystrophy consisting of short and thin amyloid fibers in a Japanese family. Based on our study of many members of the family, we are able to construct the natural course of this disorder from its earliest clinical findings through its late manifestations.

Adult↗
PubMedDate not supplied

Internal echo histogram examination has a role in distinguishing malignant tumors from benign masses in the breast.

We analyzed the histograms of reflecting ultrasound (US) from the internal areas of the masses of 50 lesions in the breast. The central average of gravity and the ratio between lower and higher width in the histograms were compared as the parameters. Statistical significance were found in both parameters between malignant tumors and benign masses (P<.001, P<.01). Therefore, analysis of histograms based on reflecting US was useful in making differential diagnoses of malignant tumors and benign masses in the breast.

Breast Neoplasms↗