Toshio Ishibashi

Effect of New Macrolide Roxithromycin upon Nasal Polyps Associated with Chronic Sinusitis

We often observe shrinkage of nasal polyps with low-dose long-term macrolide treatment, which was recently developed in Japan for the treatment of intractable chronic sinusitis. In order to assess the efficacy of this treatment for nasal polyps, we administered the new macrolide roxithromycin (RXM) (1 tablet: 150 mg a day) for at least 8 weeks to 20 patients with nasal polyps associated with chronic sinusitis. It was competent in controlling nasal polyp with the overall incidence of improvement being 52%. The combination of RXM with azelastine (1 mg twice/day), an inhibitor of mediator release, was examined in 20 other patients. It augmented the rate of improvement to 68%, but the increase was not significant. The incidence of improvement increased with time after the start of medication in both groups. Smaller polyps were more likely to decrease in size, but some larger polyps also markedly decreased in size. Associated allergic conditions and the extent of eosinophilic infiltration had no relation to the treatment result. We speculate that the mechanism of effectiveness of RXM is through its suppressive potency in cytokine production from inflammatory cells.

Role of respiratory viruses in children with acute otitis media

OBJECTIVE The role of viral infection in acute otitis media (AOM) has not been fully elucidated. We determined the presence of various respiratory viruses in middle ear fluid (MEF) specimens from children with AOM in order to determine whether viral infection or combined effects of viral and bacterial infection enhance or prolong the inflammation in the middle ear, thus worsening clinical outcome. METHODS Multiplex nested reverse transcription-polymerase chain reactions was carried out to detect influenza A and B viruses, respiratory syncytial virus (RSV) types A and B, parainfluenza virus types 1, 2, and 3; rhinovirus; and adenovirus in 93 MEF specimens from 79 children with AOM. And we examined whether viral infection with or without an identifiable bacterial infection affect clinical outcomes in AOM. We considered persistent MEF (fluid accumulation in the middle ear persisting up to 1 month after treatment), early recurrence of AOM (within 1 month after initial improvement), and recurrent AOM (more than three recurrences during 6 months of follow up) as indicators for evaluating clinical outcomes. RESULTS One or more respiratory viruses were detected in 39 specimens (42%); a total of 42 viral infections identified (three specimens were infected by two viruses). Of the 42 infections, RSV type A was detected in 29, adenovirus in eight, rhinovirus in three, and influenza virus in two. RSV accounted for 73% of viral detections. In children younger than 2 years, RSV infection combined with Streptococcus pneumoniae or Hemophilus influenzae infection carried a higher risk for persistent middle ear effusion than infection with RSV infection alone or those bacterial infection alone. CONCLUSIONS Accordingly, vaccination of young children against RSV as well as S. pneumoniae and H. influenzae is important in improving the prognosis in AOM.

Effect of noise exposure on blood-labyrinth barrier in guinea pigs

The influence of noise exposure on the endothelial transport system in the cochlea was investigated using cationic polyethyleneimine (PEI), since systemically administered PEI passes through the capillary endothelial cell and attaches to basal lamina (BL) anionic sites in the cochlea. Under general anesthesia, all guinea pigs were administered an intravenous injection of 0.5% PEI. Thirty minutes later, five animals were exposed to noise (10 kHz, broad band noise, 105 dB SPL) for 30 min, via speakers inserted into the external auditory canal. The remaining five animals (controls) were left without noise exposure for 1 h following PEI injection. All guinea pigs were then immediately sacrificed, and the bony labyrinths were removed. PEI distribution on the BL was assessed in the stria vascularis, spiral ligament, basilar membrane, spiral limbus and Reissners membrane throughout the cochlea with transmission electron microscopy. Compared to control animals, PEI distribution in the noise-exposed animals was significantly increased in the strial vessels of the basal and second turns and in Reissners membrane of all turns. In the spiral ligament, basilar membrane and spiral limbus, no significant difference in PEI distribution was observed between the control and noise-exposed animals. These findings indicate that noise exposure increases macromolecular transport in the stria vascularis but not in the spiral ligament, spiral limbus and basilar membrane and that systemically administered macromolecules are more readily transported to Reissners membrane by noise exposure.

Induction of KGF, Basic FGF, and TGFa mRNA Expression During Healing of Experimental TM Perforations

KGF (KGF), synthesized and secreted exclusively by stromal cells in epithelialized organs, specifically promotes proliferation of cells of epithelial origin, including keratinocytes. A related peptide, basic fibroblast growth factor (bFGF), has mitogenic properties for fibroblasts and endothelial cells. KGF expression is stimulated markedly in the skin during wound healing. To investigate the physiologic action of KGF in the healing of TM (TM) perforations, we examined KGF and KGF receptor (KGFR) mRNA transcript levels as well as those of bFGF and transforming growth factor-alpha (TGFalpha) in normal and wounded rat TM at varying intervals, using a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). We found KGF and TGFalpha mRNA expression to be induced rapidly, peaking 3 days after wounding and then declining. Expression of bFGF was induced gradually and remained increased until 7 days. In contrast, we found KGFR to be expressed in normal TM, remaining unchanged during TM repair. These results indicate that KGF and TGFalpha may mediate migration and proliferation of epithelial cells of the outer layer in the early stage of TM repair while bFGF may mediate the connective tissue reaction in the middle layer in a subsequent stage.

Induction of Growth Factor Expression is Reduced during Healing of Tympanic Membrane Perforations in Glucocorticoid-Treated Rats

The participation of growth factors in wound healing of tympanic membranes (TMs) is established. To determine the possible role of these growth factors in normal healing, we examined the regulation of keratinocyte growth factor (KGF), transforming growth factor–α (TGF-α), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) expression in wounded TMs of glucocorticoid-treated rats; these rats have severe wound healing abnormalities. Induction of KGF, TGF-α, and bFGF mRNA expression after TM injury was significantly reduced in these rats. Moreover, we found that the average number of bromodeoxyundine-positive cells in a glucocorticoid-treated group was significantly lower than that in controls. The data suggest that reduced expression of these genes might be partially responsible for the wound healing defects seen in these animals. These results provide a possible explanation for the beneficial effect of exogenous KGF, TGF-α, or bFGF in treatment of wound healing disorders of the TM.

Keratinocyte Growth Factor and its Receptor Messenger RNA Expression in Nasal Mucosa and Nasal Polyps

To examine the potential biologic role of fibroblast growth factors (FGFs) in nasal polyps and nasal mucosa during chronic inflammatory conditions, we investigated messenger RNA (mRNA) expression of three members of the FGF family — Acidic FGF, basic FGF, and keratinocyte growth factor (KGF) — in nasal polyp tissues, as well as in hyperplastic nasal mucosa. Using the sensitive method reverse transcription-polymerase chain reaction (RT-PCR), we demonstrated that of the examined FGFs, KGF had the most abundant mRNA expression in nasal polyps and nasal mucosa. We also found that significantly higher levels of KGF mRNA were expressed in nasal polyps than in nasal mucosa, whereas mRNA expression of acidic FGF and basic FGF was relatively low in these tissues. In addition, we showed that KGF receptor mRNA was present in most of the nasal mucosa; however, none or little was expressed in nasal polyps. These results suggest that KGF might play an important role in nasal epithelial proliferation and that excessive synthesis of KGF in nasal polyp stroma may contribute to hypertrophy of the nasal mucosa in patients with chronic sinusitis associated with nasal polyposis.

Expression of NeuroD and TrKB in developing and aged mouse olfactory epithelium

To better understand the roles of NeuroD, a member of the basic helix-loop-helix transcription factor family, during the differentiation of olfactory receptor neurons, we studied the expression of NeuroD in developing and aging mouse olfactory epithelium (OE). During embryonic period, NeuroD expression is confined in the basal compartment of OE. During neonatal period, NeuroD expression is detected in the middle compartment and in the basal compartment of OE. In the adult, the number of NeuroD expressing cells in the basal compartment significantly decreased, while the NeuroD- positive cells in the middle compartment was maintained throughout lifetime. This dual phase expression pattern of NeuroD suggests multiple roles of NeuroD in the neurogenesis of ORNs.

Keratinocyte Growth Factor and Receptor mRNA Expression in Cholesteatoma of the Middle Ear

Keratinocyte growth factor (KGF) is synthesized and secreted exclusively by stromal cells in epithelialized organs, and specifically promotes proliferation of cells of epithelial origin, including keratinocytes. Cholesteatoma is a proliferative form of keratinocyte dysregulation with aggressive growth that often leads to destruction of adjacent bone. We examined the expression of KGF, closely related peptides and their receptors in the development of cholesteatoma by comparing cholesteatoma with normal ear skin using the reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern blot analysis. All surgical specimens of cholesteatoma and most normal ear skin samples expressed detectable levels of KGF and KGF receptor (KGFR). Semiquantitative RT-PCR using beta-actin mRNA as an internal standard revealed significantly higher expression of KGF mRNA in cholesteatoma than in normal skin, while no significant difference in KGFR mRNA expression was noted between cholesteatoma tissue and normal skin. These results suggest that excessive KGF synthesis may contribute to the hyperproliferative state in cholesteatoma.

Multiplex Nested Reverse Transcription-Polymerase Chain Reaction for Respiratory Viruses in Acute Otitis Media

Because respiratory viruses play an important role in the causation and pathogenesis of acute otitis media (AOM), determining which virus has infected a child is important with respect to vaccines and antiviral drugs. In some instances, this information might be used to prevent the occurrence of AOM. We used a rapid, economical, and sensitive diagnostic system involving a multiplex nested reverse transcription–polymerase chain reaction (RT-PCR) assay to detect various respiratory viruses in clinical specimens of middle ear fluid (MEF) from children with AOM in our hospital. Multiplex RT-PCR was completed on 40 MEF samples from 28 infants and children less than 6 years old with AOM. Viral RNA was detected in 17 MEF samples (43%). Respiratory syncytial virus type A was present in 12 samples, adenovirus in 3, rhinovirus in 2, and influenza A (H3N2) in 1. The multiplex RT-PCR assay is recommended to clinical laboratories that are considering adoption of a molecular technique for viral diagnosis.

Hereditary hemorrhagic telangiectasis treated by the harmonic scalpel.

Hereditary hemorrhagic telangiectasis (HTT) is a familial autosomal dominant genetic disorder that causes abnormalities of the wall of peripheral blood vessels. Severe nosebleed often is the dominant symptom. A variety of therapies have been proposed for epistaxis control in HHT but with limited success.