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Biomedical subjects

M Tamai

Publications and source records attributed to M Tamai.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Histological examination of the human retina with congenital stationary night blindness].

We report histological findings of the retina from an eye with congenital stationary night blindness. The case was an 82-year-old woman who showed a Schubert-Bornschein type electroretinogram, and whose eye was enucleated due to orbital invasion of paranasal malignant melanoma. The retina had a disorganized outer plexiform layer with displaced nuclei of the outer and inner nuclear layer. There was also outward displacement of the cone nuclei, formation of hyaline and serous drusen, and disorganized retinal pigment epithelium as the histological changes due to aging. The histological abnormality seen in the outer nuclear layer could be responsible for the electrophysiological abnormality in this case.

Aged↗
PubMed1995

[Case report of long-term survivor of advanced gastric cancer associated with peritoneal dissemination successfully treated with cancer chemotherapy].

We reported a case of gastric cancer with peritoneal dissemination, which was successfully treated by neoadjuvant chemotherapy and partial gastrectomy. A 71-year-old female visited to our hospital because of umbilical tumor (Sister Mary Joseph's node). UGI series showed a Borrmann 1 type gastric cancer and laparoscopic examination revealed peritoneal metastasis. Her abdominal cavity was treated with MTX and CDDP and she was given intravenous administration of 5-FU/LV. Repeated laparoscopy revealed complete disappearance of peritoneal seeding, and a partial gastrectomy was done. The histopathological findings of resected specimen showed the significant effects of preoperative chemotherapy. She has been living for more than 2 years with no recurrence after initial chemotherapy.

Adenocarcinoma↗
PubMed1995

[A study on the rhodopsin gene in Japanese retinitis pigmentosa--screening of mutation by restriction endonucreases and frequencies of DNA polymorphisms].

We analyzed 11 sites of the rhodopsin gene using polymerase chain reaction (PCR) amplification and restriction endonucleases in 30 unrelated Japanese patients with autosomal dominant retinitis pigmentosa (ADRP). No point mutation was found in any patient. The frequencies of the single nucleotide (nt) substitution at nt 269, nt 5145 and nt 5321 were examined in three groups, 38 unrelated patients with ADRP, 23 patients with autosomal recessive retinitis pigmentosa (ARRP), and 67 normal controls. There was no significant difference in the frequencies of substitution among these three groups. The frequencies of A269G, G5145A, and C5321A were 52%, 36%, and 5%, respectively. These values were different from those of the American population. The polymorphisms, A269G and G5145A, are useful as DNA makers for linkage analysis.

Asian People↗
PubMed1995

[A case of encapsulated filtering bleb after trabeculectomy].

A case of encapsulated filtering bleb after trabeculectomy is reported. A 57-year-old man with primary open angle glaucoma underwent a trabeculectomy one year ago. Six months after the operation the filtering bleb began to shrink and intraocular pressure (IOP) began to rise. It was suspected that the trabeculectomy site was obstructed by scarring, and so sclerostomy ab interno was performed in the site with a Nd: YAG laser. The IOP was higher elevated, however, and the bleb remained unchanged with severe conjunctival injection and aqueous inflammation. The next day trabeculectomy was performed in a new site and two weeks later a dome-shaped, prominent bleb was observed with an increase in the IOP. This was diagnosed as an encapsulated filtering bleb (Tenon's capsule cyst). Cystectomy of the bleb failed and it recurred, therefore, another trabeculectomy was added and the IOP was kept at a reasonable value. We believe that it is important to pay attention to an encapsulated filtering bleb as a complication of filtering surgery after laser therapy to the anterior chamber angle.

Conjunctiva↗
PubMed1995

[A case of spontaneous rupture of renal cell carcinoma].

There have been a few reports on the spontaneous rupture of renal cell carcinoma. A 67-year-old female patient complaining of vomiting and severe abdominal pain was referred to our hospital. Plain computerized tomography demonstrated large heterogenous mass in the right retroperitoneum. We suspected the hemorrhagic shock because of the rupture of the right kidney and therefore emergent laparotomy was performed. Simple nephrectomy for the right kidney was performed. A pathological report revealed renal cell carcinoma, granular cell subtype, grade 1, pT3a. The patient has been followed for one year and five months after the operation, there has been no evidence of local recurrence or distant metastasis of cancer. Thirteen cases of spontaneous rupture of renal cell carcinoma in the Japanese literature are reviewed.

Aged↗
PubMed1995

Effect of kanji and kana reading on cerebral blood flow patterns measured by PET.

To investigate the respective functions of pathways in processing visual information from different types of symbols, by positron emission tomography (PET) we examined the effect on cerebral blood flow (CBF) of reading the Japanese morphogram (kanji) versus the syllabogram (kana). Nine Japanese men were presented with three visual conditions in random order 2 minutes before the scan: eyes open controls, kanji morphogram reading, and kana syllabogram reading. Three words written in kanji or kana were shown, and subjects were instructed to read them silently and to identify the word unrelated logically to the other two. The reading and analyzing tasks activated wide areas of vision-related cortices. The comparison of the kanji and kana readings showed higher metabolism, with the former only in the posterior part of the primary visual cortex. Most of the CBF increases were common for both stimuli, although the patterns of these increases differed slightly. The correlation matrix of CBF change in the left hemisphere showed a ventral connection in kanji reading and a dorsal connection in kana reading. Our results suggest there is a functional differentiation in the brain between patterned and sequential perception when reading Japanese morphograms and syllabograms.

Adult↗
PubMed1994

Marked increase in [3H](R) alpha-methylhistamine binding in the superior colliculus of visually deprived rats after unilateral enucleation.

The binding of [3H](R)alpha-methylhistamine to histamine H3-receptors in visual structures of unilaterally enucleated rats was examined by quantitative autoradiography to clarify the involvement of histamine neurons in the visual system. [3H](R)alpha-Methylhistamine binding in the visually deprived superior colliculus, contralateral to the enucleated eye, was significantly increased 5, 15, 30 and 45 days after unilateral enucleation. Slight time-dependent increases in ligand binding were observed in the visual cortex, but the change was significant only 45 days after unilateral enucleation. Unilateral enucleation had no significant effect in the dorsal lateral geniculate nucleus at any time after enucleation. Continuous injection of (S)-alpha-fluoromethylhistidine, a specific inhibitor of L-histidine decarboxylase, attenuated the effect of unilateral enucleation in the superior colliculus. These results suggest that retinal deafferentation induced an increase in histamine H3-receptor binding sites, probably by selective adjustment of histamine neurons in response to unilateral enucleation.

Animals↗
PubMed1994

Ocular findings in patients with autosomal dominant retinitis pigmentosa and transversion mutation in codon 244 (Asn244Lys) of the peripherin/RDS gene.

OBJECTIVE: To identify phenotypic characteristics of a certain mutation in the peripherin/RDS gene. DESIGN: Case reports with clinical features and results of fluorescein angiography, electroretinography, kinetic visual field testing, dark adaptometry, and DNA analysis. SETTING: University medical center. PATIENTS: We studied the ocular findings in eight members of a Japanese family with autosomal dominant retinitis pigmentosa and cytosine-to-adenine transversion at the third nucleotide in codon 244 of the peripherin/RDS gene. This mutation resulted in a substitution of lysine for asparagine in amino acid 244 of peripherin/RDS, a photoreceptor-specific glycoprotein. RESULTS: Clinical findings of each affected member in this family showed a marked intrafamilial similarity, which may provide the natural course of the phenotype produced by the Asn244Lys mutation. Characteristic features include diffuse pigmentary retinal degeneration in the midperipheral and peripheral fundi associated with macular degeneration in the later stage, starting with bull's-eye maculopathy, and severely deteriorated electroretinographic findings in both rods and cones, even in the early stage. CONCLUSION: The mutation at codon 244 of the peripherin/RDS gene causes both rod and cone degeneration, although the precise mechanism of retinal degeneration is currently unknown.

Adult↗
PubMed1994

Development of pseudolymphoma of liver following interferon-alpha therapy for chronic hepatitis B.

A 42-year-old woman with biopsy-proven chronic hepatitis B, who had been treated with human leukocyte-derived interferon-alpha (huLe-IFN alpha) therapy for two months was found to have liver tumors on routine abdominal ultrasonography examination. She underwent laparotomy, and partial hepatectomy was performed under the clinical diagnosis of hepatocellular carcinoma. The lesions were diagnosed histologically as pseudolymphoma based on the massive infiltration of small mature lymphocytes and the presence of hyperplastic lymph follicles with germinal centers. Immunohistochemistry revealed polyclonal origin of the involved lymphocytes. The possible association between IFN alpha treatment and chronic hepatitis B with the development of pseudolymphoma is discussed.

Adult↗
PubMed1994

Immunosuppressive acidic protein in intraocular fluids.

The levels of immunosuppressive acidic protein (IAP) in the vitreous fluid or the aqueous humor were measured in patients with ocular diseases. Undiluted samples of vitreous humor were obtained during pars plana vitrectomy in patients with uveitis, proliferative diabetic retinopathy, and premacular fibrosis. In patients with intraocular tumors, vitreous samples were aspirated after enucleation. Aqueous humor was aspirated during cataract surgery, and levels of IAP were measured in patients with secondary cataract due to uveitis and senile cataract. Single radial immunodiffusion assay was used to quantify IAP levels. To determine the intraocular synthesis of IAP, we calculated the percentage of IAP in patients with uveitis. Patients with uveitis, tumors, and diabetic retinopathy had significantly higher levels of vitreous IAP than patients with premacular fibrosis. The percentage of vitreous IAP was higher in patients with uveitis than in those with tumors and diabetic retinopathy. Patients with uveitis also had markedly higher aqueous IAP levels than patients with senile cataract. In one patient with Behçet's disease, the IAP level was higher in the active stage than in the inactive stage. Our results suggest that immunosuppressive acidic protein could be produced in the eye and that it might modulate intraocular inflammatory processes.

Aqueous Humor↗
PubMed1994

[Distribution of the 70kD stress protein in corneas with alkali burns].

The immunolocalization of 70kD stress-protein (SP 70) was investigated in white rabbit corneas with alkali burns. Corneal alkali burn injuries were induced with 6 mm circular filter paper discs soaked in 1N NaOH. Corneas of 1, 3, 5, and 7 days after alkali injury were immunostained with mouse monoclonal anti-SP 70 antibody. In the control rabbit cornea, immunostaining for SP 70 was observed in the nuclei of the basal cells and of the wing cells. On day 1 after alkali injury, total epithelial defect was observed. Immunostaining for SP 70 was not seen in corneas with total epithelial defect. Three days after injury, epithelial resurfacing with corneal edema was observed. Basal cells showed immunostaining for SP 70 in their nuclei and cytoplasm. Five days after injury, irregular basal cells and a few wing cells with cytoplasmic processes were recognized. Both cells showed diffuse cytoplasmic and nuclear immunostaining for SP 70. Seven days after injury, the corneal wound was healed, and SP 70 was observed in the nuclei of the epithelial cells again. It appears that SP 70 has a role in corneal epithelial healing after alkali burn injury.

Alkalies↗
PubMed1994

Glutamate dehydrogenase isoenzymes in the bovine retina and human leukocyte.

In the present study, we investigated the enzymatical properties of the heat-labile and heat-stable glutamate dehydrogenases (GDHs) from the bovine retina and human leukocytes. Retinal GDHs were mitochondrial enzymes with an optimal pH of 7.5. Heat-labile (membrane-associated form) and heat-stable (soluble form) GDHs were found in the bovine retina as well as in the human leukocytes. At least 5 GDH isoenzymes were found in the retina and leukocytes by nondenaturing polyacrylamide gel electrophoresis. After heat treatment, the high-speed pellet obtained from centrifugation of the human leukocytes at 100,000 x g retained the 3 smaller isoenzymes but had lost the 2 larger isoenzymes. Both heat-labile and heat-stable GDH were found in the neuroretina, retinal pigment epithelium and optic nerve with high activities. Our results suggest that these tissues may be the main active sites of the GDH deficiency.

Animals↗
PubMed1994

A transient expression of alpha B-crystallin in the developing rat retinal pigment epithelium.

PURPOSE: To investigate the expression of alpha B-crystallin in the developing rat retina by immunohistochemical techniques. METHODS: Rat eyes were enucleated on embryonic day 18 and on postnatal days 1, 4, 9, 15, 19, and 90. The avidin-biotin-peroxidase technique was applied to show alpha B-crystallin immunostaining. After the cornea and lens were removed, the developing rat eyeballs were solubilized by 1% sodium dodecyl sulfate. Western blot analysis and enzyme-linked immunosorbent assay (ELISA) were performed to detect alpha B-crystallin in the extracts. RESULTS: From postnatal day 4 to postnatal day 9, alpha B-crystallin was present in retinal pigment epithelium, but it disappeared after postnatal day 15. alpha A-crystallin immunoreactivity was negative in retina and retinal pigment epithelium throughout development. The results of Western blot analysis and ELISA coincided with those of the immunostaining. CONCLUSIONS: These results show that retinal pigment epithelium in mammalian rat retina demonstrates alpha B-crystallin expression in the early developmental stages but loses it after 15 days of age.

Animals↗
PubMed1994

[Experimental research on choroidal circulation. 2. Choroidal blood flow increase elicited by electrical stimulation of parasympathetic nerve behind the eyeball in the cat].

The present studies were performed to examine whether the nerves behind the eye ball contain parasympathetic fibers which dilate the choroidal blood vessels. Choroidal blood flow in the cat (20 animals) was measured trans-sclerally with a laser Doppler flowmeter. Cats were anesthetized with pentobarbital sodium (30 mg/kg, i.v.) and artificially respirated after injection of pancuronium bromide (0.2 mg/kg/hr, i.v.). Electrical stimulation of the short ciliary nerve as well as of the nerve between the ciliary ganglion and accessory ciliary ganglion, where the sensory nerve is absent, elicited an increase choroidal blood flow in an intensity-dependent manner. Application of capsaicin, which is known to desensitize the polymodal nociceptive C-fibers, to these nerves did not abolish the increase in blood flow in response to electrical stimulation of the short ciliary nerve. Atropine, a muscarinic receptor antagonist, and phentolamine, an alpha-adrenoceptor blocking agent, had no effect on these responses. The results suggest that the blood flow increase elicited by stimulation of these nerves is mediated via activation of the atropine-resistant parasympathetic vasodilator fibers supplying the choroid in the cat.

Animals↗