Protective effect of astaxanthin nanoemulsion on mammalian inner ear hair cells

Background

Aminoglycoside antibiotics are used for treating certain acute infections. However, these drugs cause ototoxicity by inducing inner ear hair cell death.

Aims/Objectives

We investigated the protective effect of a nanoemulsion of the carotenoid astaxanthin on mammalian inner ear hair cells against neomycin-induced ototoxicity.

Material and Methods

Dose-response relationship, quantification of hair cell loss, and reactive oxygen species production were assayed in response to neomycin with and without astaxanthin in cultured utricles of CBA/N mice. In addition, auditory brain response (ABR) and hair cell loss after exposure to the nanoformulation and loud noise were examined in vivo in guinea pigs.

Results

Astaxanthin suppressed neomycin-induced reduction of hair cells by reducing the production of hydroxy radicals. Furthermore, hair cell loss in the second rotation of the cochlea was significantly lower in the astaxanthin group than in the noise-only group.

Conclusions and Significance

The blood-labyrinth barrier limits the successful delivery of drugs for inner ear complications. However, in the nanoemulsion form, astaxanthin can penetrate the round window (fenestra ovale) membrane, enabling topical administration. Thus, astaxanthin nanoemulsion could be useful in treating ototoxicity in individuals with inner ear complications.

Novel compound heterozygous mutations in the PLEC gene in a neonate with epidermolysis bullosa simplex with pyloric atresia

Epidermolysis bullosa (EB) is a heterogeneous group of inherited disorders characterized by the blistering of the skin and mucous membranes. Although the molecular basis of EB has been significantly elucidated, the precise phenotypes of the lethal types of EB have not been completely characterized. Herein, we report a severe case of EB with pyloric atresia (PA). The patient was a Japanese boy who not only had skin lesions but also various complications such as PA, dysphagia, hypotonia, infectious keratitis with corneal ulcer, obstructive uropathy and protein-losing enteropathy. Genetic analysis led to the identification of two novel compound heterozygous mutations in the last exon of the plectin (PLEC) gene. Based on this finding, EB simplex with PA was diagnosed. Immunostaining with anti-plectin antibodies revealed truncated plectin proteins lacking the C-terminus in the patient's skin. We also conducted a prenatal diagnosis in subsequent pregnancy. Our report further highlights the crucial role of plectin in many organs and provides valuable information regarding the phenotypes resulting from mutations in the PLEC gene.

Prevention of progressive hearing loss in a mouse model of diabetes by oral intake of eicosapentaenoic acid ethyl ester

BACKGROUND

The prevalence of hearing impairment in patients with diabetes was significantly higher, and the development of preventive methods is desirable.

AIMS/OBJECTIVES

This study examined the effects of eicosapentaenoic acid (EPA) administration on the prevention of early hearing loss in diabetic mice.

MATERIALS AND METHODS

Tsumura, Suzuki, Obese Diabetes (TSOD) mice were used as a model of diabetes and Tsumura, Suzuki, Non Obesity (TSNO) mice were used as controls. The animals were divided into three groups: the TSNO group and the TSOD (EPA-) group (provided sunflower oil), and the TSOD (EPA+) group (provided EPA). Auditory brainstem responses (ABRs) were measured and the cochlea was evaluated histologically.

RESULTS

The TSOD (EPA+) group showed a lower tendency to increase thresholds than the TSOD (EPA-) group. The TSOD (EPA+) group had a significantly lower ABR threshold than the TSOD (EPA-) group from 11 to 14 months of age at 4 kHz. Narrowing of the capillary lumens in the stria vascularis and thickening of the vessel wall in the modiolus were observed in the TSOD (EPA-) group.

CONCLUSIONS AND SIGNIFICANCE

It was suggested that the suppression of cochlear vascular atherosclerosis by EPA administration in TSOD mice suppressed early age-related hearing loss.

Effect of preservation on the physical and chemical properties of the temporal fascia

OBJECTIVE

The temporal fascia has been widely used in tympanoplasty. In addition, the preserved fascia has been also used in the ear surgery. In this study, we planned the experiments to determine whether physical and chemical properties of the fascia preserved at a low temperature.

METHODS

Preserved temporal fasciae from 21 patients were used in this study. The thickness of the temporal fascia was measured under a 3D laser microscope. The tensile strength was evaluated using a tensile tester. In addition, the chemical property evaluated was the biologic antioxidative potential of samples.

RESULTS

The results showed that the strength of the fascia was not affected by the retention period. The thick fascia tended to show the less tensile strength. The intensity was highest in middle-aged donors when compared to young and older donor. The antioxidative potentials did not affect the preservation.

CONCLUSION

The results suggested that the preserved temporal fascia could be safely used for tympanoplasty.

Oral administration of an herbal medicine to prevent progressive hearing loss in a mouse model of diabetes

OBJECTIVE

Tsumura Suzuki Obese Diabetes (TSOD) mice exhibit early age-associated hearing loss. Histopathological analysis of these mice shows narrowing of capillaries in the stria vascularis and chronic reduction of blood flow in the cochlea. In this study, we investigated the effect of oral administration of a herbal medicine or calorie restriction on hearing in TSOD mice.

METHODS

TSOD mice were divided into 4 groups: CR (calorie restriction), BF and DS (treated with the herbal medicines, Bofutsushosan and Daisaikoto, respectively), and the control group. Body weight, blood glucose levels, and auditory brainstem responses (ABRs) were measured. The cochleae were excised and evaluated histopathologically.

RESULTS

Blood glucose levels were suppressed in the CR, BF, and DS groups. In addition, the elevation of ABR thresholds was inhibited in the CR, BF, and DS groups. Cochlear blood vessels remained wide in the three treatment groups compared with the control group. These results suggested that the administration of these herbal medicines improved glucose tolerance and yielded results similar to those on calorie restriction.

CONCLUSION

Oral administration of 2 herbal medicines can prevent hearing function disorder in a model mouse of diabetes. The results may clarify the possibility of clinical application.

A study of hearing function and histopathologic changes in the cochlea of the type 2 diabetes model Tsumura Suzuki obese diabetes mouse

OBJECTIVES

This study used Tsumura Suzuki Obese Diabetes (TSOD) mice as a spontaneous type 2 diabetes model and Tsumura Suzuki Non-obesity (TSNO) mice as controls to investigate factors involved in the onset of hearing impairment.

METHOD

Body weight, blood glucose levels, and auditory brainstem responses (ABRs) were measured. The cochleae were excised and evaluated histopathologically.

RESULTS

The TSOD mice showed significant hyperglycemia at 2-7 months and severe obesity at 5-10 months; significantly elevated ABR thresholds at 8-10 months; and the capillary lumens in the cochlea stria vascularis were narrower in the TSOD mice than in the TSNO mice. At 17 months, India ink vascular staining of the TSOD mice's cochleae revealed decreased capillary density in the stria vascularis. The vascular area of capillaries in the stria vascularis and the vascular area were significantly smaller in TSOD mice. Histopathological analysis showed vessel wall thickening in the modiolus and narrowed capillaries in the stria vascularis, suggesting reduced blood flow to the inner ear.

CONCLUSION

The diabetes mice model used in our study showed early age-associated hearing loss, and histopathology showed findings of vessel wall thickening in the modiolus, narrowing of capillaries in the stria vascularis, and chronically reduced blood flow in the cochlea.

[Intravascular large B-cell lymphoma with low signal intensity lesions on T2 weighted spinal magnetic resonance image that were suspected to be hemorrhages]

A 79-year-old female had a spinal lesion that was definitely diagnosed as intravascular large B-cell lymphoma on the basis of skin biopsy findings, and she was treated by rituximab-containing chemotherapy. The spinal lesion showed high and low signal intensities on T₂ weighted magnetic resonance imaging (MRI) scans, those low signal intensity lesions were suspected to be hemorrhages. The hemorrhages were thought to have been caused by interaction between atypical lymphoma cells and the endothelial cells of spinal blood vessels, by hemorrhagic infarction or by rupture of the capillary endothelium due to interaction between rituximab and lymphoma cells. Intravascular large B-cell lymphoma cases rarely show low signal intensity on spinal T₂ weighted MRI scans.

Crystallization and X-ray diffraction studies of DNA-free and DNA-bound forms of EcoO109I DNA methyltransferase

EcoO109I DNA methyltransferase (M.EcoO109I) is a type II modification enzyme from the EcoO109I restriction-modification system identified in Escherichia coli strain H709c. M.EcoO109I recognizes double-stranded RGGNCCY (where R = A or G, Y = T or C and N is any base) and transfers a methyl group to the C5 of the inner cytosines from S-adenosylmethionine. To reveal the mechanism of substrate recognition by M.EcoO109I, DNA-free and DNA-bound forms of M.EcoO109I were successfully crystallized. Crystals of the DNA-free and DNA-bound forms belonged to space groups P4(2)2(1)2, with unit-cell parameters a = b = 120.5, c = 79.8 Å, and P2(1), with unit-cell parameters a = 55.8, b = 77.4, c = 117.4 Å, β = 93.5°, respectively.

Crystallization and preliminary X-ray crystallographic analyses of EcoO109I and its complex with DNA

EcoO109I is a type II restriction endonuclease that recognizes seven base pairs of the degenerate and discontinuous sequence RGGNCCY. The enzyme and its complex with DNA were successfully crystallized by the hanging-drop vapour-diffusion method using polyethylene glycols as precipitants. The crystal of EcoO109I belongs to space group I4, with unit-cell parameters a = b = 175.5, c = 44.6 angstoms, and that of the DNA complex belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 49.1, b = 71.8, c = 203.2 angstroms. Full sets of X-ray diffraction data from the enzyme and its complex with DNA were collected to 2.4 and 1.9 angstroms resolution, respectively.

[Surveillance on concurrent administration of quinolones and anti-inflammatory drugs in a community hospital]

Since convulsions associated with the concurrent administration of enoxacin and fenbufen were reported in 1986, the concurrent administration of quinolones and anti-inflammatory drugs has been regulated to be contraindicated or carefully administered. However, the real incidence of the co-administration is not clear. We surveyed the incidence of co-administration of these drugs from the prescriptions in a community hospital. Quinolones were prescribed in 1% of the out-patients, and anti-inflammatory drugs were co-administrated in 16% of quinolone-prescribed patients. Among quinolones prescribed, levofloxacin was used most frequently. And acetaminphen (including acetaminophen-combination) was most frequently prescribed with quinolones, and anti-inflammatory drugs, which is regulated to be carefully administrated with quinolones, were frequently co-prescribed. In medical practice, quinolones were revealed to be co-administered with anti-inflammatory drugs. Since our recent report suggests that each quinolone and each anti-inflammatory drug has different activity in their drug interaction, it should be necessary to recognize the interaction of these drugs separately for their effective and safe use in clinical field.

C.EcoO109I, a regulatory protein for production of EcoO109I restriction endonuclease, specifically binds to and bends DNA upstream of its translational start site

The EcoO109I restriction-modification system, which recognizes 5'-(A/G)GGNCC(C/T)-3', has been cloned, and contains convergently transcribed endonuclease and methylase. The role and action mechanism of the gene product, C.EcoO109I, of a small open reading frame located upstream of ecoO109IR were investigated in vivo and in vitro. The results of deletion analysis suggested that C.EcoO109I acts as a positive regulator of ecoO109IR expression but has little effect on ecoO109IM expression. Assaying of promoter activity showed that the expression of ecoO109IC was regulated by its own gene product, C.EcoO109I. C.EcoO109I was overproduced as a His-tag fusion protein in recombinant Escherichia coli HB101 and purified to homogeneity. C.EcoO109I exists as a homodimer, and recognizes and binds to the DNA sequence 5'-CTAAG(N)(5)CTTAG-3' upstream of the ecoO109IC translational start site. It was also shown that C.EcoO109I bent the target DNA by 54 +/- 4 degrees.

Characterization and overproduction of EcoO109I methyltransferase

In order to characterize EcoO109I methyltransferase, a recombinant Escherichia coli clone that overproduces the enzyme was constructed. The coding region of M.EcoO109I was joined to the lac promoter of an expression vector, pUC118, and the resulting plasmid was introduced into E. coli HB101. M.EcoO109I was purified homogeneously from IPTG-induced cells, and was found to consist of a monomer subunit. M.EcoO109I uniquely methylates the inner deoxycytidylate residue in the sequence 5'-(A/G)GGNCC(C/T)-3' to produce 5-methylcytosine. The enzyme was most active at pH 8.0-8.5 and 50 degrees C. The enzyme activity was not affected by the addition of Mg2+ or EDTA.

Evidence of horizontal transfer of the EcoO109I restriction-modification gene to Escherichia coli chromosomal DNA

A DNA fragment carrying the genes coding for EcoO109I endonuclease and EcoO109I methylase, which recognize the nucleotide sequence 5'-(A/G)GGNCC(C/T)-3', was cloned from the chromosomal DNA of Escherichia coli H709c. The EcoO109I restriction-modification (R-M) system was found to be inserted between the int and psu genes from satellite bacteriophage P4, which were lysogenized in the chromosome at the P4 phage attachment site of the corresponding leuX gene observed in E. coli K-12 chromosomal DNA. The sid gene of the prophage was inactivated by insertion of one copy of IS21. These findings may shed light on the horizontal transfer and stable maintenance of the R-M system.

Characterization of high- and low-molecular weight zinc-dependent acid phosphatases in bovine liver

We have purified two forms of Zn2+-dependent acid phosphatase (Zn2+-APase) from bovine liver, both of which require Zn2+ to hydrolyze the substrate p-nitrophenyl phosphate in an acidic environment. The apparent molecular weights of these two forms of Zn2+-APase were estimated to be about 100,000 and 62,000 by gel filtration, and about 44,000 and 31,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, respectively. The low-molecular weight (LMW) Zn2+-APase catalyzed the hydrolysis of myo-inositol-1-phosphate in the presence of 3 mM Mg2+ at physiological pH, but the high-molecular weight (HMW) enzyme did not. The LMW-Zn2+-APase of bovine liver was recognized by polyclonal antibodies developed against the Zn2+-APase of bovine brain, but the HMW-Zn2+-APase was not.

myo-Inositol monophosphatase in the brain has zinc ion-dependent tyrosine phosphatase activity

1. myo-Inositol monophosphatase (E.C. 3.1.3.25) hydrolyzes inositol monophosphate to form free myo-inositol, the precursor for the inositol phospholipid second-messenger signaling systems. The biochemical properties of the enzyme were examined in detail. 2. The enzyme exhibited significant hydrolytic activity only on phosphotyrosine among physiological substrates tested in the presence of Zn2+ ions in an acidic environment. 3. The enzyme was recognized and immunoprecipitated with polyclonal antibodies developed against the Zn2+-dependent tyrosine phosphatase of bovine brain. 4. These results indicate that myo-inositol monophosphatase exhibits Zn2+-dependent tyrosine phosphatase activity in an acidic environment and has immunological identity with a Zn2+-dependent tyrosine phosphatase.

Alteration of myo-inositol monophosphatase in Alzheimer's disease brains

myo-Inositol monophosphatase (E.C.3.1.3.25) catalyzes the hydrolysis of myo-inositol 1-phosphate in the presence of Mg2+ at a physiologic pH to form free myo-inositol, maintaining a supply that represents the precursor for inositol phospholipid second messenger signaling systems. In the present study the activity and protein level of myo-inositol monophosphatase were investigated in samples from normal human and Alzheimer's disease (AD) postmortem brains. The separation profile on Sephadex G-100 gel filtration chromatography revealed one major form of myo-inositol monophosphatase in crude extracts from both normal human and AD brains. In AD brains myo-inositol monophosphatase activity and its protein level were significantly higher than in control brains. The activity of myo-inositol monophosphatase per enzyme molecule was similar in control and AD brains. These results suggest that myo-inositol monophosphatase is upregulated in AD, probably reflecting compensatory mechanisms concerned with phospholipid metabolism.

Zinc-ion-dependent acid phosphatase exhibits magnesium-ion-dependent myo-inositol-1-phosphatase activity

We have purified bovine brain Zn(2+)-dependent acid phosphatase (Zn(2+)-APase), which requires Zn2+ ions to hydrolyze the substrate p-nitrophenyl phosphate (pNPP) in an acidic environment. The substrate specificity and metal requirement of Zn(2+)-APase at a physiological pH was also studied. The enzyme exhibited hydrolytic activity on myo-inositol-1- and -2-monophosphates, 2'-adenosine monophosphate, 2'-guanosine monophosphate, and the alpha- and beta-glycerophosphates, glucose-1-phosphate, and fructose-6-phosphate in 50 mM Tris-HCl buffer (pH 7.4) in the presence of Mg2+ ions, but not on pNPP and phosphotyrosine. Zn2+, Mn2+ and Co2+ ions were less effective for activation. Among the above substrates, myo-inositol-1-phosphate was the most susceptible to hydrolysis by the enzyme in the presence of 3 mM Mg2+ ions. The enzyme exhibited an optimum pH at around 8 for myo-inositol-1-phosphate in the presence of 3 mM Mg2+ ions. The Mg(2+)-dependent myo-inositol-1-phosphatase activity of the enzyme was significantly inhibited by Li+ ions. The Zn(2+)-dependent p-nitrophenyl phosphatase activity and Mg(2+)-dependent myo-inositol-1-phosphatase activity of the purified enzyme fraction exhibited similar behavior on Sephadex G-100 and Mono Q colomns. These findings suggest that Zn(2+)-APase also exhibits Mg(2+)-dependent myo-inositol-1-phosphatase activity under physiological conditions.

[Study of early gastric carcinomas with a pyloric stenosis]

From 1969 to 1989, 1106 cases of early gastric carcinomas were treated in our hospital, and 9 cases (0.8%) of an early gastric carcinoma with a pyloric stenosis were found among them. Five of these cases involved males and 4 cases females. The average age of these patients was 57.1 years. An accurate preoperative diagnosis was very difficult and 7 cases had been considered to be advanced gastric carcinoma preoperatively. In all these cases the lesions were found located on the pyloric ring or in the antral region. Further, all cases evidenced a submucosal infiltration and/or ulceration in the lesion. Most of the stenotic cases had lesions greater than 3.1 cm in diameter, with diameters of over 1.1 cm in the ulceration and the submucosal infiltration. Some early gastric carcinomas in the antral region with no pyloric stenosis also had lesions that were over this size.

[A clinicopathological study of early mucinous adenocarcinoma of the stomach]

From 1963 to 1986, 1126 cases (1300 lesions) of early gastric carcinoma were treated at Fukui Prefectural Hospital. Mucinous adenocarcinomas comprised 16 lesions in this series. These cases of mucinous adenocarcinoma were younger than all the other early carcinomas of the stomach and they often were locted in the lower third of the stomach. Macroscopically, most were types "Iia + IIc". Dividing them into 3 grouping: papillary, tubular, and signet ring cell types, depending on the microscopic appearance of the intramucosal carcinoma, the signet ring cell group differed from the other two as to age, macroscopic appearance, and region it occupied. An immunochemical study showed that CA19-9 stained positively in a mucous lake, much like a carcinoma cell, but that CEA stained little.

[Early carcinoma of the gastric remnant: pathological features relating to the interval between the initial and second surgery]

Twenty cases of early carcinoma of the gastric remnant have been treated at our hospital and examined clinico-pathologically. In 11 cases, the interval after the initial gastrectomy, due to the gastric carcinoma, was done was short compared with length of the interval of 9 cases after a gastrectomy for a benign gastric disease. There were two types of gastric remnant carcinomas in cases in which the interval extended 10 years. The first type developed at the site of the gastro-intestinal anastomosis, especially when the anastomosis was found to be joined by the Billroth II method, and the carcinoma was associated with a gastritis cystica polyposa (GCP). The other type showed a polypoid appearance except for the stomal site.

Development of a heart disease screening system for school children and its results in the Tokyo area in 1980

After the revision of the School Health Law in Japan the systems for heart disease screening for school children showed a great advance and the computerized devices for automatic evaluation of selected leads ECG and PCG were developed rapidly and have been improved in Japan. Two systems of heart disease screening for school children have been developed, that is, the Tokyo system and the "ECG-PCG for all children system". The Tokyo system utilizes a questionnaire, a physical examination by school physicians and a chest X-ray for the primary screening procedure and ECG-PCG for the secondary procedure. The "ECG-PCG for all children system" utilizes a questionnaire, a chest X-ray and ECG-PCG. The superiority of the ECG-PCG system was shown in comparison with the Tokyo system. Nearly twice as many cases of congenital heart disease were detected by the ECG-PCG system as compared with the Tokyo system, and many cases were disclosed for the first time. The "ECG-PCG for all children system" will probably be more popular in the near future in accordance with the advance of computerized systems.