Biomedical subjects

Akira Kobayashi

Publications and source records attributed to Akira Kobayashi.

At least 91 records · Page 5Linked to original sources

PubMed1995

Immunoreactive Characteristics and Classification of Hyperparathyroidism.

Hyperparathyroidism is caused mainly by three different conditions: namely, secondary hyperplasia, primary hyperplasia, and adenoma with only a few cases due to carcinomas. Histological distinction among these diseases is still difficult. In an attempt to characterize the three conditions, 17 cases from patients with hyperparathyroidism and 12 with normal glands were investigated immunohistochemically using antibodies against PTH, PTHrP, Ki-67 (MIB-1), and chromogranin A. The normal glands showed a diffuse staining pattern for PTH, and focal staining for PTHrP and for chromogranin A. Secondary hyperplasia demonstrated either focal, diffuse, or mixed staining in one gland with the three antibodies. For the primary hyperplasias and adenomas, the cases could be divided into two groups. The first group (group I), including 1 case of primary hyperplasia and 3 cases of adenoma, showed a homogeneous staining pattern with all three antibodies. A heterogeneous staining pattern similar to secondary hyperplasia was found in the other 8 cases that formed the second group (group II). There were five types of cytologic staining patterns after immunostaining. In secondary hyperplasia and group II, several patterns appeared simultaneously. On the contrary, only one pattern was found in group I. The proliferative index (P1) from Ki-67 staining of group I was also significantly higher than in group II. A lower P1 was observed in the normal glands. The present results indicate that different immunohistochemical characteristics exist in primary hyperplasias and in adenomas.

Journal Article↗

PubMed1995

Immunolocalization of Parathyroid Hormone in Human Parathyroid Glands with Special References to Microwave Antigen Retrieval.

The subcellular localization of parathyroid hormone (PTH) in the normal human parathyroid glands with particular reference to microwave antigen retrieval was investigated using peroxidase-labeled PTH antibody, immunohistochemical, and immunoelectron microscopic methods. The results revealed that PTH granules existed mainly as pro-PTH on the trans side of Golgi and in the regions adjacent to Golgi apparatus. Only a small proportion of secretory granules were stored near the plasma membrane. Microwave irradiation was essential for the immunodetection of PTH. As the irradiative time extended from 1 to 30 min, the staining intensity increased, and the subcellular preservation decreased. Microwave irradiation for 15 mm (with the sections in citrate buffer) with a power output of 500 W is the most ideal for PTH antigen retrieval, as well as for subcellular preservation.

Journal Article↗

PubMedDate not supplied

Analysis of COL8A2 gene mutation in Japanese patients with Fuchs' endothelial dystrophy and posterior polymorphous dystrophy.

PURPOSE: To determine whether Japanese patients with Fuchs' endothelial corneal dystrophy (FECD) and posterior polymorphous dystrophy (PPMD) carry mutations in the COL8A2 gene, and to investigate the possible pathogenicity of the COL8A2 gene in these corneal dystrophies. METHODS: DNA analysis of the COL8A2 gene was performed in 15 unrelated Japanese patients with FECD, and 5 patients with PPMD using polymerase chain reaction and direct sequencing. Mutation screenings were also performed in 36 unrelated normal volunteers as controls, as well as slit-lamp and specular microscopy. RESULTS: Two types of heterozygous missense mutations of the COL8A2 gene (R155Q and T502M) in 5 of 15 FECD probands (R155Q, 3/30 chromosomes, 10.0%; T502M, 3/30 chromosomes, 10.0%) were found. No mutation was detected in the coding region of the COL8A2 gene in the remaining 10 patients with FECD nor in any of the 5 patients with PPMD. These two mutations were also found in normal Japanese volunteers (R155Q, 5/72 chromosomes, 6.9%; T502M, 11/70 chromosomes, 15.7%). The chromosomal frequency of the two mutations was not significant between the patients and normal controls. CONCLUSIONS: The R155Q and T502M mutations of COL8A2 may not be the causative defect in the Japanese FECD and PPMD patients examined in this study.

Aged↗

PubMedDate not supplied

Successful management of conjunctival intraepithelial neoplasia by interferon alpha-2b.

BACKGROUND: Interferon alpha-2b (IFN alpha 2b) was recently shown to be effective as an alternative therapy for conjunctival intraepithelial neoplasia (CIN). Herein, we report our successful management of CIN by the use of IFN alpha 2b. CASE: A 73-year-old woman presented with a complaint of irritation due to a tumorous lesion in her left eye. Slit-lamp microscope examination revealed a tumorous lesion involving the bulbar and palpebral conjunctiva as well as the limbus, from the 3-o'clock position to the 8-o'clock position. She had already undergone cryotherapy in the same eye in another hospital, twice for a lesion on the lower tarsal conjunctiva and once for a lesion on the upper tarsal conjunctiva. The histological diagnosis had been CIN. OBSERVATIONS: In treating this patient, IFN alpha 2b was injected subconjunctivally twice and also applied as eye drops for 12 weeks. Two weeks after the initial treatment, the tumorous lesion disappeared. During a 1-year follow-up period, no recurrence was noted. CONCLUSION: Topical and subconjunctival IFN alpha 2b is a valuable treatment option for CIN.

Administration, Topical↗

PubMedDate not supplied

Fornix and conjunctiva reconstruction by amniotic membrane in a patient with conjunctival mucosa-associated lymphoid tissue lymphoma.

BACKGROUND: Conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma is a rare, low-grade, non-Hodgkin's B-cell lymphoma. Herein, we report our successful management of the large conjunctival defect caused by resection of conjunctival MALT lymphoma by covering it with transplanted amniotic membrane. CASE: A 28-year-old Japanese man, who had been diagnosed histologically as having conjunctival MALT lymphoma in his left eye, was referred to us for treatment. The tumor was located on the lower bulbar and palpebral conjunctiva, and involved the fornix. Extensive resection of the conjunctival lesion was performed. Two pieces of amniotic membrane were used to reconstruct the fornix, bulbar, and palpebral conjunctival defect. OBSERVATIONS: Epithelialization over the transplantation was completed within 3 weeks when all sutures were removed. During the 6 months of follow-up, there was no recurrence or any postoperative complication, such as graft rejection, symblepharon, or chronic inflammation. CONCLUSIONS: We demonstrated for the first time that amniotic membrane can be used to cover a large defect on both bulbar and palpebral conjunctiva when such a low-grade malignancy as MALT lymphoma is extensively excised. Amniotic membrane transplantation was quite effective for the fornix and conjunctival reconstruction.

Adult↗

PubMedDate not supplied

Surgical treatment of limbal vernal keratoconjunctivitis by resection of a limbal lesion.

PURPOSE: To report our experience managing a limbal mass associated with limbal vernal keratoconjunctivitis (VKC) by surgical excision. METHODS: A 16-year-old girl was referred to our hospital with the chief complaints of itching and photophobia in both eyes. She had a 2-year history of gradually enlarging limbal gelatinous masses on the temporal limbus in both eyes, which were diagnosed as limbal papillae of VKC. As the symptoms in her left eye were more severe, surgical resection of the limbal mass in her left eye was performed to relieve mechanical stress on the eyelid, followed by a free conjunctival autograft taken from the supranasal bulbar conjunctiva. RESULTS: After excision of the mass, ocular inflammation and other symptoms gradually disappeared. At 12-month follow-up, there was no recurrence of the mass. Findings in a histological examination of the excised limbal lesion were consistent with those of limbal papilla of VKC. CONCLUSION: In recalcitrant cases of limbal VKC, in which the symptoms are apparently caused by an elevated limbal mass, surgical excision of the limbal mass can be one of the therapeutic modalities, and it may facilitate resolution of the symptoms caused by chronic limbal VKC.

Adolescent↗

PubMedDate not supplied

Does precipitation reduce tissue staining by indocyanine green dye solutions?

PURPOSE: Indocyanine green (ICG) dye precipitates when mixed with certain ophthalmic irrigation solutions. The purpose of this study is to investigate whether this precipitation reduces ICG staining of the anterior lens capsule. METHODS: ICG was diluted with each of the following solutions: BSS Plus, physiological saline, or Opeguard Neo. The products were then examined for green precipitate by light microscopy. The tissue staining capability of each ICG solution was tested at two different concentrations (0.5% and 0.0625%) in porcine lenses, regardless of whether the solution contained precipitate. RESULTS: Green precipitate was observed in both concentrations of ICG solutions diluted with BSS Plus, but not in the solutions diluted with either physiological saline or Opeguard Neo. As assessed with light microscopy, staining of the anterior lens capsule appeared weaker for all 0.0625% ICG solutions compared to the corresponding 0.5% ICG solutions. The precipitate that formed in the 0.5% ICG solution diluted with BSS Plus had little effect on the staining quality of the anterior lens capsule. In contrast, the 0.0625% ICG solution diluted with BSS Plus (w/precipitate) showed weaker staining in the lens capsule compared to the other two 0.0625% ICG solutions (w/o precipitate). CONCLUSION: These results suggest that precipitation of ICG may weaken its capability to stain the anterior lens capsule or other transparent ocular tissues. Therefore, ICG solutions that do not form a precipitate may be more capable of staining tissues at lower concentrations. As for other possibilities to explain the deterioration in staining, the effect of the composition of BSS Plus should also be considered.

Animals↗

PubMedDate not supplied

Cavernous hemangiomas of lungs and liver in an asymptomatic girl.

We describe a 15-year-old asymptomatic girl with multiple pulmonary nodules which turned out to be cavernous hemangiomas. The radiological findings of other organs revealed no abnormalities, excluding the liver, where multiple low-density areas were located. Thoracoscopy and laparoscopy revealed cavernous hemangiomas of the lung and liver. While liver cavernous hemangiomas are common, pulmonary hemangiomas are fairly rare. Although cavernous hemangiomas are classified as malformations, some of these lesions have been reported to grow. In pulmonary hemangiomas, some cases have an inexorable clinical course with hemoptysis, respiratory distress, and heart failure. In our case, the lesions have not remarkably progressed under observation for more than 2 years.

Adolescent↗

PubMedDate not supplied

Two-site substrate recognition model for the Keap1-Nrf2 system: a hinge and latch mechanism.

Cells are equipped with a number of transcriptional factors that safeguard against various environmental insults. Proteasomal protein degradation plays an important role in the Keap1-Nrf2 cytoprotection system, with molecular machinery similar to that for other environmental defense systems such as inflammatory and hypoxic responses. While Nrf2 protein stabilization is known to be redox-sensitive, the transcription factors NF-kappaB and HIF-1alpha for inflammatory and hypoxic responses, respectively, are also influenced by the cellular redox conditions. In this review we present the recently proposed two-site substrate recognition model of the Keap1-Nrf2 system, which regulates the cellular responses against oxidative and xenobiotic stresses. The implications of two destructive motifs in Nrf2, the ETGE and DLG motifs, which appear to function as a hinge and latch attenuating Keap1 activity in different redox states, are discussed.

Animals↗

PubMedDate not supplied

Bilateral corneal perforation in an infant with congenital alacrima.

A 9-month-old infant had bilateral corneal opacity with erosion in the inferior corneas. Clinical examination suggested the infant had congenital alacrima. After 1 week, both corneas perforated with collapsed anterior chambers. Therapeutic soft contact lenses with ofloxacin ointment 4 times daily were successful, and the perforations sealed within 1 week.

Anti-Bacterial Agents↗

PubMedDate not supplied

In vivo laser confocal microscopic analysis of human corneal epithelial sheet cultured on amniotic membrane.

BACKGROUND AND OBJECTIVE: Corneal epithelial sheet cultured on amniotic membrane ex vivo has been developed for the treatment of severe ocular surface disorders. In this study, human corneal epithelial sheets cultured on amniotic membranes were analyzed using a laser scanning confocal microscope. MATERIALS AND METHODS: Human corneal epithelial cells were cultured on four sheets of amniotic membrane, and they were examined layer by layer using the laser scanning confocal microscope. RESULTS: The superficial layer cells were mosaic in appearance. In the superficial layer, focal areas of slender and elongated cells were noted. In addition, highly reflective materials were noted. Basal epithelial cells of the corneal epithelium sheet at a slightly deeper plane displayed mosaic pattern with smaller cells. At a slightly deeper plane, the basement membrane of amnion showed relatively bright homogeneity. CONCLUSION: The laser scanning confocal microscope can examine the morphology of human corneal epithelial cells cultured on amniotic membranes.

3T3 Cells↗

PubMedDate not supplied

Temporary use of a customized, glued-on hard contact lens before penetrating keratoplasty for descemetocele or corneal perforation.

Descemetocele or corneal perforation makes it difficult to perform penetrating keratoplasty (PKP). To circumvent this difficulty, a polymethylmethacrylate hard contact lens with a diameter of 4.0 mm was customized and applied to the cornea with tissue adhesive prior to PKP in three patients, one with corneal perforation and two with descemetoceles. The results showed that this modified method facilitated trephination during PKP without complications in all three patients, suggesting that it may be applicable to other similar clinical situations.

Aged↗

PubMedDate not supplied

In vivo confocal microscopy in the acute phase of corneal inflammation.

Two cases of noninfectious keratitis were studied using in vivo corneal confocal microscopy in addition to routine slit-lamp biomicroscopy. A 10-year-old boy suffered from keratitis in his left eye due to a bee sting and a 20-year-old man had keratitis following corneal blunt trauma. In both cases, we found a honeycomb pattern at the anterior and mid-stromal level of the middle cornea. This honeycomb pattern disappeared in 1 week with steroid treatment. This pattern might be caused by syncytial cell bodies of activated keratocytes, by focal corneal stroma edema, or by polymorphonuclear leukocyte infiltration along with the keratocytes or along preformed channels within the corneal stroma known as Bowman channels. Further analysis in a large number of patients may aid in further understanding in vivo human corneal inflammation.

Acute Disease↗

PubMedDate not supplied

Indocyanine green staining for the triple corneal procedure.

BACKGROUND AND OBJECTIVE: In the triple corneal procedure, successful completion of capsulorhexis is of the utmost importance. Another use of indocyanine green dye for better visualization of the anterior lens capsule of mature cataract during the triple corneal procedure is described. PATIENTS AND METHODS: Four consecutive patients (mean age, 69.5 years) with both mature cataracts and corneal opacity underwent the triple corneal procedure. After trephination of the recipient cornea, the anterior capsule of the lens was stained with indocyanine green. A continuous curvilinear capsulorhexis (CCC) was performed, after which conventional triple corneal procedures were followed. RESULTS: In all four cases, this technique markedly improved visualization of the lens capsule and resulted in successful and easy manipulation of the CCC and subsequent removal of residual lens cortex. CONCLUSIONS: Staining of the anterior capsule of mature cataract in the triple corneal procedure clearly defines the border of the capsule, thus allowing easy and complete execution of CCC.

Aged↗

PubMedDate not supplied

Serotonin activity and liver dysfunction following hepatic ischemia and reperfusion.

Serotonin (5-hydroxytriptamine; 5-HT), which is stored in platelets, is known to induce vasoconstriction and promote platelet aggregation. More recent studies suggest that serotonin also plays a role in organ injury after ischemia and reperfusion. The purpose of this study was to characterize the role of 5-HT and platelet function in the pathogenesis of hepatic ischemia-reperfusion injury. Under the portocaval shunt, 60 or 90 min of complete warm ischemia of canine liver was induced by Pringle's maneuver, followed by reperfusion for 120 min. Time-matched, sham-operated animals served as controls. Hepatic tissue blood flow and various parameters of hepatic vein blood (ALT, LDH, platelet count and platelet aggregation) were measured before and after reperfusion. 5-HT levels in portal vein and hepatic vein were also assayed. Hepatic ischemia and reperfusion resulted in liver hypoperfusion, hepatocellular dysfunction, increased platelet aggregation, increased 5-HT levels, and hepatic microcirculation injury. These results suggest that the endogenous 5-HT released from platelet may contribute to liver tissue hypoperfusion following hepatic ischemia-reperfusion.

Alanine Transaminase↗

PubMedDate not supplied

White-light and laser confocal microscopic findings of rabbit conjunctiva.

BACKGROUND AND OBJECTIVE: To report laser and white-light confocal microscopic findings of ex vivo rabbit conjunctiva to investigate the potential application of these confocal microscopes as diagnostic devices for normal and pathologic conjunctiva. MATERIALS AND METHODS: Three male albino rabbits were killed and six eyeballs were removed with as much bulbar conjunctiva as possible. The bulbar conjunctiva approximately 5 mm away from the limbus was then subjected to an ex vivo laser and white-light confocal microscopic analysis. RESULTS: Using laser confocal microscopy, conjunctival epithelial cells, subepithelial conjunctival vessels, and sclera were clearly observed. By contrast, white-light confocal microscopy yielded images of conjunctival epithelium, subepithelial layers, and sclera that were not clearly defined. CONCLUSIONS: This study indicates that laser confocal microscopy has a superior ability to visualize ex vivo, non-fixed conjunctiva when compared with white-light confocal microscopy. It also suggests that the laser confocal microscope might be a useful, non-invasive, in vivo, "quasi-cytological" device for observing and diagnosing the conjunctival condition in humans.

Animals↗

PubMedDate not supplied

Successful treatment for combined pancreatoduodenal injury by a second-stage pancreatojejunostomy following pancreatoduodenectomy.

A case of combined pancreatoduodenal injury requiring pancreatoduodenectomy is described. A two-stage approach was used, which included a pancreatoduodenectomy followed by a tube pancreatostomy for complete external drainage of pancreatic juice and subsequent second-stage pancreatojejunostomy. This approach, first advocated by Miyagawa et al., enabled us to handle the normal soft pancreas without any complications. It is suggested that the described second-stage pancreatojejunostomy can be considered as an alternative method of restoring pancreatoenteric continuity following pancreatoduodenectomy in emergency cases.

Abdominal Injuries↗

PubMedDate not supplied

In vivo laser and white-light confocal microscopic findings of human conjunctiva.

BACKGROUND AND OBJECTIVE: To report in vivo laser and white-light confocal microscopic findings of human conjunctiva to investigate the potential application of these confocal microscopes as diagnostic devices for normal and pathologic conjunctiva. PATIENTS AND METHODS: Two healthy volunteers, 28- and 35-year-old men, participated in this study. The temporal bulbar conjunctiva, which was approximately 5 mm away from the limbus, was examined by in vivo laser and white-light confocal microscopic analysis. RESULTS: Using laser confocal microscopy, at least two different cell types could be distinguished in both subjects: conjunctival superficial epithelial cells and conjunctival basal epithelial cells. In contrast, conjunctival epithelial cells could not be visualized using white-light confocal microscopy. CONCLUSIONS: These results indicate that laser confocal microscopy, but not white-light confocal microscopy, can be used to visualize in vivo human conjunctiva. Further investigations in a large number of normal subjects and in patients with conjunctival pathologies are required to fully evaluate the usefulness of this device in daily clinical ophthalmology.

Adult↗