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Biomedical subjects

Y Hashida

Publications and source records attributed to Y Hashida.

At least 19 recordsLinked to original sources
PubMed2001

Two patterns of opacity in corneal dystrophy caused by the homozygous BIG-H3 R124H mutation.

PURPOSE: To investigate the opacity pattern in corneas with an Arg124His (R124H) homozygous mutation of the BIG-H3 gene. METHODS: Slit-lamp examination was performed on eight patients with corneal dystrophy resulting from a genetically confirmed BIG-H3 R124H homozygous mutation. The birthplace of each patient also was determined. RESULTS: Slit-lamp examination disclosed two types of opacity patterns in corneas with the BIG-H3 R124H homozygous mutation. Type I (n = 4) is a spot-like opacity present in the anterior stroma in which the lesions are confluent. Type I is the same pattern that previous reports have shown to be caused by the BIG-H3 R124H homozygous mutation. The type II corneal opacity pattern (n = 4) is a reticular opacity in the anterior stroma with round translucent spaces. Type II opacity has not been reported previously in association with any corneal dystrophy. The patients with the type I opacity do not share a common birthplace; however, interestingly, the patients with the type II opacity traced their origin to Tottori prefecture in western Japan. CONCLUSION: The BIG-H3 homozygous R124H mutation induces the development of two distinct patterns of corneal opacity, the recognition of which can establish an accurate diagnosis of corneal dystrophy caused by the homozygous BIG-H3 R124H mutation independent of genetic analysis. In addition, genetic factors or circumstantial influences other than the gene responsible for the corneal dystrophy may influence the pattern of corneal opacity.

Adult↗
PubMed1998

Prolonged high intermittent positive-pressure ventilation induces airway remodeling and reactivity in young rats.

We postulated that prolonged exposure to intermittent positive-pressure ventilation (IPPV) with high pressure (HIPPV) alone without hyperoxia promotes the development of airway hyperresponsiveness and remodeling. To test this hypothesis, young rats were ventilated under halothane anesthesia with HIPPV (maximum inspiratory pressure at 32-35 cmH2O in 70% nitrous oxide and 30% O2) for 3.5-4 h daily for 6 days. Control rats were ventilated with low IPPV (maximum inspiratory pressure < 13 cmH2O) during the same time period with the same gas mixture. With the use of tracheal rings isolated from these rats and a setup in tissue baths, contractile responses to carbachol (10(-6) to 10(-2) mM), 5-hydroxytryptamine (5-HT; 10(-9) to 10(-5) mM) and KCl (1-100 mM) were examined isometrically. In tracheal rings from HIPPV rats compared with low-pressure IPPV rats, the concentration tension curves showed a significantly enhanced response to all agonists (P < 0.005). Sensitivity to carbachol, 5-HT, and KCl was also significantly increased (P < 0.05) compared with control rats as evidenced by decreases in EC50. Maximum tension (reactivity) to 5-HT and KCl in the HIPPV group increased significantly (P < 0.05), and there was a trend (P = 0.07) toward increased reactivity to carbachol in this group as well. Histological examinations of tracheal rings demonstrated epithelial squamous metaplasia in the HIPPV group. Morphometric studies demonstrated tracheal smooth muscle thickening (P < 0.05) without changes in the thickness of the mucosa or the lamina propria. When contractile responses were normalized for the smooth muscle cross-sectional area (i.e., stress), reactivity to all contractile agents was reduced, whereas reactivity to 5-HT still demonstrated significant increase (P < 0.005). Sensitivity of tracheal segments to all three agents was not affected by this normalization. These findings suggest that prolonged exposure to HIPPV without hyperoxia and the resultant overdistension of lung tissues (volutrauma) induced airway remodeling and airway hyperreactivity.

Animals↗
PubMed1997

Heterologous expression, purification, and properties of diol dehydratase, an adenosylcobalamin-dependent enzyme of Klebsiella oxytoca.

Recombinant adenosylcobalamin-dependent diol dehydratase of Klebsiella oxytoca overexpressed in Escherichia coli was purified to homogeneity. The enzyme has a low solubility and was extracted from the crude membrane fraction with 1% Brij 35 in a high recovery. Subsequent chromatography on DEAE-cellulose resulted in 4.9-fold purification of the enzyme in an overall yield of 65%. The enzyme thus obtained showed specific activity comparable to that of the wild-type enzyme of K. oxytoca. The apparent molecular weight determined by nondenaturing gel electrophoresis on a gradient gel was 220,000. The enzyme consists of equimolar amounts of the three subunits with apparent Mr of 60,000 (alpha), 30,000 (beta), and 19,000 (gamma). Therefore, the subunit structure of the enzyme is most likely alpha2beta2gamma2. The recombinant enzyme was also separated into components F and S upon DEAE-cellulose chromatography in the absence of substrate. Components F and S were identified as the beta subunit and alpha2gamma2 complex, respectively. Apparent Km for adenosylcobalamin, 1,2-propanediol, glycerol, and 1,2-ethanediol were 0.83 microM, 0.08 mM, 0.73 mM, and 0.56 mM, respectively. The three genes encoding the subunits of diol dehydratase were overexpressed individually or in various combinations in Escherichia coli. The alpha and gamma subunits mutually required each other for correct folding forming the soluble, active alpha2gamma2 complex (component S). Expression of the beta subunit in a soluble, active form (component F) was promoted by coexpression with both the alpha and gamma subunits, probably by coexistence with component S. These lines of evidence indicate that each subunit mutually affects the folding of the others in this heterooligomer enzyme.

Chromatography, Ion Exchange↗
PubMed1992

Experimental otitis media evaluated by magnetic resonance imaging: an in vivo model.

The use of magnetic resonance imaging in otitis media research is being explored in our laboratory. In this study, we present a new method for studying changes in the middle ear cleft due to an episode of induced otitis media in the chinchilla model. It uses gadolinium-diethylenetriamine pentaacetic acid, a magnetic resonance imaging contrast agent, to examine the uptake and washout characteristics of middle ear mucosa during an inflammatory episode. Parameters such as the time to maximum intensity of the mucosa and the washout rate of the contrast agent from the mucosa were significantly correlated to the duration of the infection.

Animals↗
PubMed1992

Temporal bone histopathologic findings of Waardenburg's syndrome: a case report.

A histopathological study of the temporal bones of a 3-year-old black girl who had bilateral deafness associated with Waardenburg's syndrome type II showed a similar pattern of pathology in both ears. The most striking findings were an absence of pigmentation in the inner ear and cochleosaccular abnormality. This is, to our knowledge, only the third report on human temporal bone histopathology in Waardenburg's syndrome and the first report of such a case with absence of pigment (melanin) in the inner ear. A possible association of hearing loss with absence of inner ear pigment in this case is discussed.

Child, Preschool↗
PubMed1991

Polycystic kidneys, pancreatic cysts, and cystadenomatous bile ducts in the oral-facial-digital syndrome type I.

Oral-facial-digital syndrome type I is a group of X-linked dominant conditions, lethal in utero in male individuals. Internal anomalies are less well documented than are external findings. We report a case of typical phenotype and absent family history of kidney disease in a 15-year-old white girl (46,XX) who died of renal failure and massive cerebral hemorrhage. At necropsy, the kidneys were greatly enlarged but of fairly normal shape. The cortex was replaced by thin-walled spherical cysts, 0.5 to 2.0 cm in diameter; the majority of the smaller cysts were located deep in the cortex, and the medulla contained lesser numbers of larger cysts. No distal urinary tract obstruction was present. Microdissection revealed cysts and diverticula located in all segments of the nephrons and collecting ducts. Uninvolved nephrons showed diffuse hypertrophy. These findings were correlated with immunoperoxidase stains using peanut lectin, Lotus tetragonolobus agglutinin, antibodies to cytokeratins, stage-specific embryonic antigen-1, Tamm-Horsfall protein, and epithelial membrane antigen. Other visceral anomalies included biliary cystadenomatous proliferation in the liver and pancreatic cysts. The renal changes are similar to those of autosomal dominant (adult-type) polycystic disease.

Adolescent↗
PubMed1990

Temporal bone histopathologic findings in Alagille's syndrome.

Six temporal bones obtained from four individuals with Alagille's syndrome, aged 4 months and 3, 6, and 7 years, were studied histopathologically. The external auditory canals and tympanic membranes were normal. Although the stapes, the interossicular joints, and the subarcuate fossae were slightly underdeveloped in the majority of cases, the other structures in the middle ear were almost normal. However, severe anomalies were observed in structures in the inner ear. In all cases, both the bony and membranous structures of the posterior semicircular canal were partially or totally absent, and, in three ears, those of the anterior semicircular canal were also partially absent; the lateral semicircular canal, however, was normal in all cases. The cochlea was observed to be shortened in only one case.

Abnormalities, Multiple↗
PubMed1990

A staged laryngotracheal reconstruction using alloplast (Proplast) in the canine model.

Standard laryngotracheal reconstructive procedures are constrained by the availability of grafting materials and the ability to repair large defects. Reconstruction utilizing alloplasts may be ideal, but previous results have generally been poor. We present a two-stage procedure using Proplast to reconstruct large laryngotracheal defects in 6 dogs. A custom-made Proplast implant was inserted into a strap muscle pocket and buccal mucosa was placed in the adjacent peritracheal tissue. The muscle-Proplast composite graft was rotated to repair a large defect (3.25 cm by 2.25 cm). All 6 dogs survived. Endoscopic and histologic studies over 12 months showed continued stabilization and maturation of the implant. We feel that Proplast may be used as an alternative to autograft for reconstructing large laryngotracheal defects when the procedure is staged to allow maximal fibrous ingrowth and the implant is protected from infection.

Aluminum↗
PubMed1990

Adrenal hemorrhage after liver transplantation.

During orthotopic liver transplantation, ligation and division of the right adrenal vein during recipient hepatectomy may lead to hemorrhagic infarction and/or hematoma formation in the right adrenal gland. Findings in seven liver transplant recipients included initially echogenic or anechoic suprarenal masses on ultrasound scans and inhomogeneous but predominantly hypoattenuating masses on computed tomographic scans. In patients who survived for 4 months or longer, hematomas resolved as early as 20 days and persisted as long as 11 weeks. There was autopsy proof of adrenal hemorrhage in three cases. The adrenal hematomas in this series produced no massive hemorrhages, adrenal insufficiency, or other clinical manifestations. Adrenal hemorrhage after liver transplantation should be recognized and specifically documented, but a hematoma that remains stable in size can be left alone.

Adrenal Gland Diseases↗
PubMed1990

Histopathologic study of otitis media in individuals with head and neck tumors.

Five temporal bones, each including the eustachian tube, were obtained from five adults with advanced malignant tumors of the head and neck. The specimens were from the side on which the tumor had occurred. Otitis media had been detected clinically in two cases, and was detected histopathologically in the other three. We discuss the possibility that otitis media might have been caused by tumor invasion of the paratubal area, by postoperative inflammation in the nasopharynx, or by an inflammatory reaction of tubal structures to radiotherapy, or that these conditions may have coexisted.

Adult↗
PubMed1990

Histologic study of eustachian tube cartilage with and without congenital anomalies: a preliminary study.

We investigated histopathologically the development of the eustachian tube (ET) cartilage at a cellular level in individuals with and without congenital anomalies. Fourteen specimens were obtained from 14 individuals ranging in age from 24 weeks' gestation to 3 years who had cleft palate or trisomy 21 (Down) syndrome; the 49 specimens in the nonanomaly (control) group were from 49 individuals ranging from 26 weeks' gestation to 85 years of age. All temporal bone specimens included the ET and its accessory structures, and all were processed and stained with hematoxylin and eosin for histologic study in a routine manner. The number of cartilage cells in the midcartilaginous portion of the ET was determined by light microscopy. In all groups, cartilage cell density of the ET decreased with increasing age. However, cell density tended to be higher at all ages for individuals with cleft palate and microtia versus controls, and tended to be lower at all ages for individuals with Down syndrome.

Adolescent↗
PubMed1988

Syndromatic paucity of interlobular bile ducts: hepatic histopathology of the early and endstage liver.

Morphologic findings of the liver in syndromatic paucity of intrahepatic bile ducts (SPIHBD) during infancy include paucity of interlobular bile ducts, features of "giant cell hepatitis," dilated lymphatics and veins in the portal tract, perisinusoidal fibrosis, and bile duct epithelial changes with a concentric layering of mesenchymal cells around bile ducts reminiscent of renal dysplasia. The latter change is characteristic of SPIHBD. Although the disease is characterized by paucity of bile ducts, morphometric studies show paucity of interlobular bile ducts in less than half of the patients during infancy. Reduced numbers of portal tracts and increased percentage of portal tracts devoid of bile ducts are more constant findings. It was impossible to predict from the early biopsy which patients would develop more severe portal fibrosis. Later in the disease portal fibrosis is variable and unevenly distributed, being more severe near the hilum regardless of the prior performance of a Kasai-type operation or the state of patency of the extrahepatic bile ducts. Hypoplasia of the extrahepatic bile ducts is the usual finding in SPIHBD, but if atresia of extrahepatic bile ducts is associated with intrahepatic paucity of bile ducts, the hepatic histopathology is that of PIHBD. Recognition of PIHBD would avoid unwarranted surgical procedures.

Autopsy↗
PubMed1988

Endothelial proliferation in paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a disorder of stem cells that is associated with venous thrombosis in multiple organ sites. We present a patient with necrotizing pharyngitis and intestinal infarction who has classic laboratory findings for PNH: positive complement-mediated acid and sucrose hemolysis and absence of decay accelerating factor (DAF) in peripheral blood leukocytes. Histopathologic examination of tissue from tonsil and large bowel demonstrated not only venous thrombosis but unusual proliferation of endothelial cells (papillary endothelial hyperplasia). This has not been described previously. We speculate that the endothelial cell in PNH may share in the defective regulation of complement activity. Venous thrombosis could precipitate or be a consequence of these vascular changes.

Adolescent↗
PubMed1987

Microdissection studies of the structural alterations induced in rat kidneys by experimental postischemic acute renal failure.

A unique opportunity presented itself for a morphologic study of experimental unilateral acute renal failure (ARF) in male rats. The ARF had been induced in the rats by temporary occlusion (1h) of the left renal artery. Twenty-nine rats were divided into subsets as follows: 2-3 h, 24 h, 1 week, 2, 4, 8, and 12 weeks following release of occlusion. Microdissection showed a heterogeneous population of abnormally structured proximal tubules in which the regressive lesions of tubular necrosis were combined with the progressive reaction of repair. The lesions demonstrated are reminiscent of those which have been described in ARF in the human and in experimental animals. Many proximal tubules in the 2- to 3-hour subset presented 1-3 disruptive lesions (DLs) while greater numbers of proximal tubules from the 24-hour group presented 1-5 DLs. Many proximal tubules presented no DLs, but nearly all from the 24-hour subset (97-100%) displayed a squamate appearance which paralleled and was caused by acute tubular necrosis. At 1 week, a dilated pars recta was common, but by this time, the squamate pattern had disappeared. Many casts were present. At 2 weeks, many fewer casts were present in proximal tubules and none were seen at 4, 8 or 12 weeks. The nephrons, particularly the proximal tubules, presented a variety of structural alterations at 2, 4, 8 and 12 weeks. Changes of special interest include (1) the presence of swan-necks; (2) a distinctive squamate appearance of the proximal tubules in the animals killed at 24 h; (3) a spiral, curled appearance caused by differential hyperplasia in animals at 4, 8 and 12 weeks, and (4) a tendency for ischemic lesions to involve all layers of the renal cortex.

Acute Kidney Injury↗
PubMed1987

Renal histopathology in Alagille's syndrome.

Various renal abnormalities have been reported in Alagille's syndrome (arteriohepatic dysplasia), usually as single case reports. The renal findings at autopsy of four patients with Alagille's syndrome, ranging in age from 4 1/2 months to 7 years, 2 of whom had evidence of renal dysfunction, are described and are compared with kidneys from patients with other cholestatic liver diseases of childhood. Two of the Alagille's patients had histologic findings suggestive of membranous nephropathy and special stains revealed accumulation of lipid in the glomerular and tubular basement membranes. Immunofluorescence of 1 revealed extensive accumulation of IgG and IgM. One patient had medullary cysts and mild interstitial fibrosis, and the fourth had a large subcapsular cyst and mild tubulointerstitial nephritis. All 4 cases, when examined with the electron microscope, revealed varying degrees of basement membrane thickening, splitting, and vacuolation with dense osmiophilic particles, most prominent in the patients with membranous nephropathy. These ultrastructural findings did not correlate with the degree of hyperlipidemia, but rather with the patient's age, and were also observed in other cholestatic diseases. The findings suggest that Alagille's syndrome is frequently associated with renal abnormalities, including lipid deposition, which may in some instances, lead to clinically significant renal impairment.

Basement Membrane↗
PubMed1986

Mesenchyme remaining in human temporal bones.

This study was conducted in order to gain basic information about mesenchyme remaining in the middle ear cleft in normal infants. Because no previous report has objectively described the quantity or quality of such postnatal remnants in normal infants, it has not been possible to accurately evaluate the significance of mesenchyme remaining in the middle ears of infants with pathologic conditions, such as otitis media and congenital anomalies. Thus, 53 temporal bones obtained from 41 individuals reported upon here--from 26 weeks' gestation to 8 years of age--will be controls for future studies of pathologic conditions. The children from whom these temporal bones were obtained had no anomalies of the ear (or any other known part of the body); nor did they have any pathologic conditions in the ear. The temporal bones were prepared for histologic study with hematoxylin and eosin staining and were examined under the light microscope. After areas of the mesenchyme in the histologic sections were projected and illustrated for each of 19 portions in the middle ear cleft under the microprojector, those areas were measured by compensating polar planimetry. The findings obtained in this study were as follows: The amount of mesenchyme remaining in the days after birth seemed to gradually decrease in volume with increased maturity and had nearly disappeared within the first year in normal infants. Where mesenchyme was noted in the temporal bones of infants over 1 year of age, it was usually present only in small niches.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1985

Conduction tissue anomalies in absence of the right superior caval vein.

The incidence of electrical instability of the heart is high in patients with absence of the right and persistence of the left superior caval vein when the latter connects to the coronary sinus. It has been suggested that a large coronary sinus may influence the susceptibility to arrhythmias. we studied the conduction tissues of 8 hearts from the cardiopathological collection of Children's Hospital of Pittsburgh. Six of these specimens had a persistent left superior caval vein connecting to the coronary sinus. There were 4 with absence of the right superior caval vein, 3 of which were in the group with persistent left veins. We evaluated the sinus node and the specialized atrioventricular junctional area, comparing them with known normals. The coronary sinus varied in size from through it. The size did not alter the histology of the adjacent conduction tissue. In contrast, the sinus node was abnormal in 3 of the 4 hearts with absent right superior caval vein. This may be the key factor in the development of arrhythmias when the right superior caval vein is absent or abnormal.

Atrioventricular Node↗