Effect of myringotomy on prognosis in pediatric acute otitis media.

OBJECTIVE: In children with acute otitis media (AOM), we compared clinical outcomes between groups with and without myringotomy to elucidate the effect of this procedure on long-term clinical course and prognosis. METHODS: Fifty-nine children (29 male, 30 female) with tympanic membrane bulging or middle ear fluid (MEF) at initial presentation were assigned to one of two treatment groups. Group A received oral antibiotics and also underwent myringotomy at initial enrollment (36 cases), while group B received oral antibiotics without myringotomy (23 cases). Clinical outcomes were evaluated by otolaryngologic specialists using pneumatic otoscopy and tympanometry at 5, 10, 15, 30 days and 12 weeks and then every 2 weeks after the initial treatment. Otitis media with effusion (OME), early recurrence and recurrent AOM were used as the evaluation criteria for the prognosis. RESULTS: In group A, 6 children (16.7%) showed transition to OME, 11 (30.6%) showed early recurrence of AOM, and 9 (25.0%) developed recurrent AOM. In group B 10, 8, and 3 (43.5%, 34.8%, and 13.0%) showed these respective adverse outcomes. While early recurrence rates and recurrent AOM rates did not differ significantly between groups, progression of OME was significantly less frequent in group A than group B (P = 0.036). CONCLUSIONS: Lower rates of progression to OME in the group undergoing myringotomy suggested that myringotomy might be effective in preventing this outcome.

Inhibition of angiogenesis by growth factor receptor bound protein 2-Src homology 2 domain bound antagonists.

Growth factor receptor bound protein 2 (Grb2) is an intracellular adaptor protein that participates in the signal transduction cascades of several angiogenic factors, including hepatocyte growth factor, basic fibroblast growth factor, and vascular endothelial growth factor. We described previously the potent blockade of hepatocyte growth factor-stimulated cell motility, matrix invasion, and epithelial tubulogenesis by synthetic Grb2-Src homology 2 (SH2) domain binding antagonists. Here, we show that these binding antagonists block basic morphogenetic events required for angiogenesis, including hepatocyte growth factor-, vascular endothelial growth factor-, and basic fibroblast growth factor-stimulated endothelial cell proliferation and migration, as well as phorbol 12-myristate 13-acetate-stimulated endothelial cell migration and matrix invasion. The Grb2-SH2 domain binding antagonists also impair angiogenesis in vitro, as shown by the inhibition of cord formation by macrovascular endothelial cells on Matrigel. We further show that a representative compound inhibits angiogenesis in vivo as measured using a chick chorioallantoic membrane assay. These results suggest that Grb2 is an important mediator of key proangiogenic events, with potential application to pathologic conditions where neovascularization contributes to disease progression. In particular, the well-characterized role of Grb2 in signaling cell cycle progression together with our present findings suggests that Grb2-SH2 domain binding antagonists have the potential to act as anticancer drugs that target both tumor and vascular cell compartments.

Presence of human herpesviruses in young children with acute otitis media.

Some herpesviruses have been detected in middle ear fluid (MEF) of patients with acute otitis media (AOM), but their role in middle ear disease is unknown. We examined 73 middle ear fluid samples from 73 children with acute otitis media for the presence of four major herpesviral DNA, respiratory viral genomes, and bacterial DNA by multiplex polymerase chain reaction (PCR). Herpesviruses were detected in 16 specimens (22%), with 18 viral infections were identified overall. Respiratory viruses were detected in 35 specimens (48%), 39 viral infections overall. Bacterial DNA was detected in 51 specimens (70%), 60 bacterial infections overall. Clinical outcome was compared in patients with and without herpesvirus DNA, respiratory viral genomes, or bacterial DNA. Progression to otitis media with effusion (OME) was more common when herpesviral DNA was present. Presence of herpesvirus DNA may reflect an immunocompromised state that may make it difficult to eliminate bacteria from the middle ear after infection.

Factors associated with poor outcome in children with acute otitis media.

OBJECTIVE: To identify factors determining poor outcome in children with acute otitis media (AOM). MATERIAL AND METHODS: We considered the following factors in children with AOM: age; gender; the presence of group nursing; the presence of siblings; the duration of breastfeeding; and the type of bacteria isolated from the middle ear fluid (MEF) or nasopharynx. The 73 pediatric patients studied included 61 examined in outpatient clinics and 12 seen at a children's home. RESULTS: Of the 61 children examined in outpatient clinics, 32 (52%) had persistent MEF (fluid accumulation in the middle ear persisting for up to 1 month after treatment); 14 (23%) had early recurrence of AOM (within 1 month following an initial improvement); and 14 (23%) developed recurrent AOM (> 3 recurrences during 6 months of follow-up). Using univariate and multivariate analyses, age < 2 years was found to be significantly related to the development of recurrent AOM and an absence of group nursing was found to be significantly related to the development of early recurrence. Persistent MEF was significantly related to the development of recurrent AOM. There was no difference between bacterial species isolated from the MEF or nasopharynx in terms of clinical outcome. CONCLUSIONS: These findings indicate that particularly close long-term follow-up is necessary for children aged < 2 years and children with a middle ear effusion that persists for up to 1 month after treatment.

Changes in the Tullio phenomenon and the fistula sign in the course of endolymphatic hydrops.

We performed electronystagmography with caloric stimulation and studied vestibular evoked myogenic potentials (VEMPs) associated with changes in the Tullio phenomenon and the fistula sign during the clinical course of a patient with endolymphatic hydrops. The Tullio phenomenon and the fistula sign disappeared in association with a reduction in the caloric response, which implicates the ampullary function of the lateral semicircular canal. Even when no VEMP could be detected for the affected ear, the Tullio phenomenon and fistula signs were observed; thus, either these phenomena had a lower response threshold than the VEMPs, or saccular receptors were not involved in the Tullio phenomenon.

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.

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.

BACKGROUND: 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. METHODS: We report two cases of HHT in which recurrent nasal bleeding was successfully controlled using the Harmonic Scalpel. RESULTS: Use of the Harmonic Scalpel avoids the carbonization and incrustation of the nasal mucosa that commonly results from electrocautery and laser irradiation. Even during active bleeding, hemostasis can be achieved by repeated applications of the scalpel blade. CONCLUSION: This method can be performed quick and reliably on an outpatient basis. The Harmonic Scalpel may be the treatment of choice for recurrent epistaxis in HHT.

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-alpha (TGF-alpha), 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-alpha, and bFGF mRNA expression after TM injury was significantly reduced in these rats. Moreover, we found that the average number of bromodeoxyuridine-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-alpha, or bFGF in treatment of wound healing disorders of the TM.

Direct application of keratinocyte growth factor, basic fibroblast growth factor and transforming growth factor-alpha during healing of tympanic membrane perforation in glucocorticoid-treated rats.

Peptide growth factors and cytokines modulate both normal and impaired wound healing. Topical application of growth factors in the form of ear drops may counteract impairment of wound healing in the tympanic membrane (TM). We applied keratinocyte growth factor (KGF), transforming growth factor (TGF)-alpha or basic fibroblast growth factor (bFGF) to the perforated TMs of rats in which healing impairment had been caused by systemic administration of a glucocorticoid. Histologic studies of the injured TM, including anti-5-bromo-2'-deoxyuridine immunohistochemistry, were performed on the third day after wounding. In the control ear, epidermal migration was markedly inhibited by glucocorticoid treatment and no hyperplasia was observed in any layer at the perforation edge. TMs treated with KGF showed marked hyperplasia in the epithelial layer at the perforation edge. In the bFGF- and TGF-alpha-treated groups, hyperplasia was observed in the epithelial and intermediate layers of the TM near the malleus handle and annulus, while no hyperplasia was seen in any layer at the perforation edge. Only KGF, therefore, improved epidermal migration in the TM, while all the growth factors tested induced hyperplasia in the TM.

Isolation and analysis of retroviral integration targets by solo long terminal repeat inverse PCR.

Upon retroviral infection, the genomic RNA is reverse transcribed to make proviral DNA, which is then integrated into the host chromosome. Although the viral elements required for successful integration have been extensively characterized, little is known about the host DNA structure constituting preferred targets for proviral integration. In order to elucidate the mechanism for the target selection, comparison of host DNA sequences at proviral integration sites may be useful. To achieve simultaneous analysis of the upstream and downstream host DNA sequences flanking each proviral integration site, a Moloney murine leukemia virus-based retroviral vector was designed so that its integrated provirus could be removed by Cre-loxP homologous recombination, leaving a solo long terminal repeat (LTR). Taking advantage of the solo LTR, inverse PCR was carried out to amplify both the upstream and downstream cellular flanking DNA. The method called solo LTR inverse PCR, or SLIP, proved useful for simultaneously cloning the upstream and downstream flanking sequences of individual proviral integration sites from the polyclonal population of cells harboring provirus at different chromosomal sites. By the SLIP method, nucleotide sequences corresponding to 38 independent proviral integration targets were determined and, interestingly, atypical virus-host DNA junction structures were found in more than 20% of the cases. Characterization of retroviral integration sites using the SLIP method may provide useful insights into the mechanism for proviral integration and its target selection.

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 Reissner's 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 Reissner's 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 Reissner's membrane by noise exposure.

Megakaryocytic Maturation is Regulated by Maintaining a Balance Against Cytokine Induced-cell Proliferation: Steel Factor Retards Thrombopoietin-induced Megakaryocytic Differentiation While Synergistically Stimulating Mitogenesis; Hematopoiesis.

Using a factor-dependent cell line MO7ER, which contains a stably transduced human erythropoietin (EPO) receptor gene in human megakaryoblastic cell line MO7e and which resulted in concomitant expression of EPO receptor, c-Mpl and c-Kit, we investigated the biological effects of these cytokines in terms of cell growth and differentiation. Thrombopoietin (TPO), EPO and Steel factor (SLF) all stimulated MO7ER cell proliferation in a dose-dependent manner. Combined stimulation of cells with SLF plus either TPO or EPO resulted in striking synergistic enhancement of MO7ER cell growth as compared with each cytokine alone, whereas combination of TPO plus EPO showed only an additive effect on cell proliferation. With regards to cell differentiation, either TPO or EPO treatment induced enhancement of platelet glycoprotein (GP) IIb/IIIa and GPIb expression. SLF induced GPIIb/IIIa and GPIb expression, but the effect was much weaker than that of EPO or TPO. However, addition of SLF to either TPO- or EPO- containing cultures (which induced potent mitogenesis in MO7ER cells) resulted in suppression of these megakaryocyte specific antigens. Addition of low-dose cytosine arabinoside (Ara-C)(1 to 10 ng/ml) enhanced TPO- or EPO- induced megakaryocytic differentiation in MO7ER cells while mildly suppressing cell growth. Treatment the cells with low-dose Ara-C plus TPO plus SLF overrode the proliferative enhancing effects of SLF and induced GPIIb/IIIa and GPIb expression as efficient as TPO alone. Retardation of TPO-induced megakaryocytic maturation was also observed in normal murine bone marrow cells by combined stimulation with TPO and SLF as assessed by the numbers of acetylcholinesterase staining-positive cells and megakaryocyte nuclear polyploidy. These results suggest that megakaryocytic maturation is, at least in part, regulated by countering cytokine-induced cell proliferation.