Phloretin Ameliorates Succinate-Induced Liver Fibrosis by Regulating Hepatic Stellate Cells

BACKGRUOUND

Hepatic stellate cells (HSCs) are the major cells which play a pivotal role in liver fibrosis. During injury, extracellular stimulators can induce HSCs transdifferentiated into active form. Phloretin showed its ability to protect the liver from injury, so in this research we would like to investigate the effect of phloretin on succinate-induced HSCs activation in vitro and liver fibrosis in vivo study.

METHODS

In in vitro, succinate was used to induce HSCs activation, and then the effect of phloretin on activated HSCs was examined. In in vivo, succinate was used to generated liver fibrosis in mouse and phloretin co-treated to check its protection on the liver.

RESULTS

Phloretin can reduce the increase of fibrogenic markers and inhibits the proliferation, migration, and contraction caused by succinate in in vitro experiments. Moreover, an upregulation of proteins associated with aerobic glycolysis occurred during the activation of HSCs, which was attenuated by phloretin treatment. In in vivo experiments, intraperitoneal injection of phloretin decreased expression of fibrotic and glycolytic markers in the livers of mice with sodium succinate diet-induced liver fibrosis. These results suggest that aerobic glycolysis plays critical role in activation of HSCs and succinate can induce liver fibrosis in mice, whereas phloretin has therapeutic potential for treating hepatic fibrosis.

CONCLUSION

Intraperitoneal injection of phloretin attenuated succinate-induced hepatic fibrosis and alleviates the succinate-induced HSCs activation.

Increasing sample diversity in psychiatric genetics - Introducing a new cohort of patients with schizophrenia and controls from Vietnam - Results from a pilot study

OBJECTIVES

Genome-Wide Association Studies (GWAS) of Schizophrenia (SCZ) have provided new biological insights; however, most cohorts are of European ancestry. As a result, derived polygenic risk scores (PRS) show decreased predictive power when applied to populations of different ancestries. We aimed to assess the feasibility of a large-scale data collection in Hanoi, Vietnam, contribute to international efforts to diversify ancestry in SCZ genetic research and examine the transferability of SCZ-PRS to individuals of Vietnamese Kinh ancestry.

METHODS

In a pilot study, 368 individuals (including 190 SCZ cases) were recruited at the Hanoi Medical University's associated psychiatric hospitals and outpatient facilities. Data collection included sociodemographic data, baseline clinical data, clinical interviews assessing symptom severity and genome-wide SNP genotyping. SCZ-PRS were generated using different training data sets: (i) European, (ii) East-Asian and (iii) trans-ancestry GWAS summary statistics from the latest SCZ GWAS meta-analysis.

RESULTS

SCZ-PRS significantly predicted case status in Vietnamese individuals using mixed-ancestry (R² liability = 4.9%, p = 6.83 × 10^-8), East-Asian (R² liability = 4.5%, p = 2.73 × 10^-7) and European (R² liability = 3.8%, p = 1.79 × 10^-6) discovery samples.

DISCUSSION

Our results corroborate previous findings of reduced PRS predictive power across populations, highlighting the importance of ancestral diversity in GWA studies.

Irisin Regulates the Functions of Hepatic Stellate Cells

BACKGROUND

Hepatic stellate cells (HSCs) are known to play a fundamental role in the progression of liver fibrosis. Once HSCs are activated, they are involved in proliferation, migration, and contractility which are characteristics of liver fibrogenesis. Recent studies have shown that irisin, a myokine secreted during physical exercise, has a protective effect in various metabolic diseases, especially in renal fibrosis. However, whether irisin is involved in HSC activation and other processes associated with liver fibrosis has not yet been investigated. In this study, we reveal the role of irisin in HSC activation as well as in proliferation, migration, and contractile properties of HSCs in vitro.

METHODS

LX-2 cells, immortalized human HSCs, were treated with transforming growth factor beta 1 (TGF-β1), a core regulator of HSC fibrosis, with or without irisin, and markers of the aforementioned processes were analyzed. Further, an inflammatory response was stimulated with TGF-β1 and lipopolysaccharide (LPS) in combination with irisin and the expression of cytokines was measured.

RESULTS

Recombinant irisin significantly suppressed the expression of TGF-β1-stimulated fibrosis markers including alpha-smooth muscle actin and collagen type 1 alpha 1 and prevented the TGF-β1-induced proliferation, migration, and contractility of LX-2 cells. Additionally, irisin ameliorated the production of interleukin-6 (IL-6) and IL-1β induced by TGF-β1 and LPS treatments.

CONCLUSION

These findings suggested that irisin potently improved the progression of hepatic fibrosis by regulating HSC activation, proliferation, migration, contractility, and HSC-mediated production of inflammatory cytokine.

LY2405319, an analog of fibroblast growth factor 21 ameliorates α-smooth muscle actin production through inhibition of the succinate-G-protein couple receptor 91 (GPR91) pathway in mice

Fibroblast growth factor 21 (FGF21) is an important metabolic regulator expressed predominantly in the liver. In this study, we evaluated the role of LY2405319, an analogue of FGF21, in hepatic stellate cell (HSC) activation and in a methionine and choline-deficient (MCD)-diet induced mouse model of liver fibrosis. During liver injury, HSCs trans-differentiate into activated myofibroblasts which produce alpha-smooth muscle actin (α-SMA) and become a major cell type in hepatic fibrogenesis. Succinate and succinate receptor (GPR91) signaling has emerged as a regulator to promote α-SMA production in MCD diet- induced mice. Treatment with palmitate or MCD medium on LX-2 cells (HSCs) increased succinate concentration in the conditioned medium and cell lysate of LX-2 cells and increased production of GPR91 and α-SMA. However, LY2405319 administration ameliorates palmitate or MCD media-induced succinate production and decreases over-expression of GPR91 and α-SMA in LX2-cells. In an in vivo study, the MCD diet treatment caused increased steatohepatitis and liver fibrosis compared with the control diet in mice. Administration of LY2405319 improved steatohepatitis ameliorated GPR91 and α -SMA production in the liver, decreased succinate concentration in both liver and serum of MCD diet -induced mice. These results suggest that FGF21 reduces production of α-SMA by inhibiting the succinate-GPR91 pathway. We conclude that FGF21 acts as an inhibitor of the succinate-GPR91 pathway to control liver fibrosis. This suggests that FGF21 has therapeutic potential for treating liver fibrogenesis.

Monoclonal nicotine-specific antibodies reduce nicotine distribution to brain in rats: dose- and affinity-response relationships

Vaccination against nicotine is being studied as a potential treatment for nicotine dependence. Some of the limitations of vaccination, such as variability in antibody titer and affinity, might be overcome by instead using passive immunization with nicotine-specific monoclonal antibodies. The effects of antibodies on nicotine distribution to brain were studied using nicotine-specific monoclonal antibodies (NICmAbs) with K(d) values ranging from 60 to 250 nM and a high-affinity polyclonal rabbit antiserum (K(d) = 1.6 nM). Pretreatment with NICmAbs substantially increased the binding of nicotine in serum after a single nicotine dose, reduced the unbound nicotine concentration in serum, and reduced the distribution of nicotine to brain. Efficacy was directly related to antibody affinity for nicotine. Efficacy of the highest affinity NICmAb, NICmAb311, was dose-related, with the highest dose reducing nicotine distribution to brain by 78%. NICmAb311 decreased nicotine clearance by 90% and prolonged the terminal half-life of nicotine by 120%. At equivalent doses, NICmAb311 was less effective than the higher affinity rabbit antiserum but comparable efficacy could be achieved by increasing the NICmAb311 dose. These data suggest that passive immunization with nicotine-specific monoclonal antibodies substantially alters nicotine pharmacokinetics in a manner similar to that previously reported for vaccination against nicotine. Antibody efficacy is a function of both dose and affinity for nicotine.

Treatment of anal fissure with glyceryl trinitrate in patients referred for surgical management

BACKGROUND

A number of recent studies indicate that anal fissure may be treated by applying glyceryl trinitrate (GTN) ointment. The present study aims to determine the effectiveness and patient acceptability of GTN treatment for patients referred to a consultant surgeon.

METHODS

A prospective study of 65 consecutive patients referred to one surgeon (ALP) over a 12-month period was undertaken. All patients were offered 0.2% GTN ointment to be applied intra-anally four times daily for 4 weeks. Informed consent was obtained and review planned for 4 weeks.

RESULTS

Fourteen patients declined treatment and nine of the 14 (64%) subsequently underwent lateral sphincterotomy. Twelve of the 51 patients (18.5%) who accepted treatment could not complete it due to headache or persisting severe anal pain. Thirty-nine of the 51 patients (77%) were able to complete 4 weeks of treatment. Twenty-two of the 39 reported an improvement in symptoms. A total of 22 patients (43%) who started GTN treatment subsequently underwent lateral sphincterotomy.

CONCLUSIONS

Evidence from the present study suggests that GTN ointment has a place in the management of referred patients with severe and/or chronic anal fissure, but sphincterotomy remains an important treatment option for the majority.

Combination vaccines: choices or chaos? A practitioner's perspective

Combination vaccines are necessary and important for the continuing success of our immunization program, especially when more vaccines are added to the already crowded immunization schedule. However, the multiplicity of competing vaccine products, with various overlapping antigen menu and subtle immunologic differences, may be confusing to the busy practitioner. The cost-effectiveness of the use of combination vaccines will depend on a number of factors, including fair and competitive pricing, appropriate reimbursement for vaccine administration fees, and critical economic algorithms for vaccine selection and purchase.

Anti-inflammatory effect of adenovirus-mediated IkappaBalpha overexpression in respiratory epithelial cells

Many studies into basic biological characteristics of inflammation and tissue injury have implicated pro-inflammatory cytokine-mediated tissue injury in the pathogenesis of inflammatory lung diseases. Because transcription of most proinflammatory cytokines is dependent on the activation of nuclear factor (NF)-kappaB, NF-kappaB could be a good potential target to suppress the cytokine cascade. Cytokine-induced activation of NF-kappaB requires phosphorylation and subsequent degradation of IkappaBa. Therefore, the blocking NF-kappaB activation by IkappaBalpha could inhibit the pro-inflammatory cytokine-induced tissue injury. To evaluate whether blocking of NF-kappaB activation shows an anti-inflammatory effect, this study investigated the effect of adenovirus-mediated overexpression of IkappaBalpha super-repressor (IkappaBalpha-SR) on the pro-inflammatory cytokine expression in respiratory epithelial cells. The transduction efficiency of adenovirus was >90% in both A549 and NCI-H157 cells. Ad5IkappaBalpha-SR-transduced cells expressed high levels of IkappaBalpha-SR, which was resistant to tumour necrosis factor (TNF)-alpha-induced degradation. Adenovirus-mediated overexpression of IkappaBalpha-SR blocked cytokine-induced nuclear translocation of p65 and NF-kappaB deoxyribonucleic acid binding activity without affecting total cellular expression level of NF-kappaB. Ad5IkappaBalpha-SR transduction suppressed cytokine-induced interleukin-8 and TNF-alpha expressions at both ribonucleic acid and protein levels. These results suggest that blocking the nuclear factor-kappaB pathway by adenovirus-mediated overexpression of IkappaBalpha-super-repressor shows an effective anti-inflammatory effect in respiratory epithelial cells.

Bordetella pertussis detection by spectrofluorometry using polymerase chain reaction (PCR) and a molecular beacon probe

Bordetella pertussis was detected by spectrofluorometry following PCR incorporating a molecular beacon probe in the reaction. A DNA fragment from the tandem repeat sequence region (IS 481) of the genome of B. pertussis was amplified in presence of the probe complementary to an internal segment of the amplified DNA fragment. Fluorescein (FAM) and DABCYL were used as the fluorophore and quencher in the probe. The probe was characterized for its signal to noise ratio by homogeneous solution hybridization with a complementary oligonucleotide. Measurement of fluorescent signal at the emission maxima of FAM, immediately after a PCR was used to detect the B. pertussis target, with no additional steps. Presence of B. pertussis in a sample was also examined by agarose gel electrophoresis of the PCR product. A serial diluted stock of B. pertussis (ATCC strain #9797) and fourteen clinical isolates of B. pertussis were examined. The sensitivity of detection by fluorescent measurement was found to be at least in the range of 0.01-0.1 CFU per 10 microl of the sample and was equal to or better than that detected by agarose gel analysis.

Patient satisfaction after surgical treatment for fistula-in-ano

PURPOSE

The surgical treatment of fistula-in-ano frequently results in recurrence of the fistula or postoperative anal incontinence. Despite these problems, most patients are satisfied with the results of their surgery. To clarify this apparent discrepancy, we attempted to identify factors that affect patient's lifestyles and may contribute to their satisfaction.

METHODS

A questionnaire was mailed to 624 patients surgically treated for cryptoglandular fistula-in-ano at the University of Minnesota during a five-year period. Three hundred seventy-five patients returned their questionnaires. Patients who were followed up for a minimum of one year were included in this retrospective study. Associations between postoperative complications and patient satisfaction were identified by chi-squared tests and multiple logistic regression. Attributable fractions for patient dissatisfaction were calculated using study population dissatisfaction rates.

RESULTS

Patient satisfaction was strongly associated with fistula recurrence, difficulty holding gas, soiling of undergarment, and accidental bowel movements. Effects of incontinence on patient quality of life were also significantly associated with patient satisfaction as was the number of lifestyle activities affected by incontinence. Patients with fistula recurrence reported a higher dissatisfaction rate (61 percent) than did patients with anal incontinence (24 percent), but the attributable fraction of dissatisfaction for incontinence (84 percent) was greater than that for fistula recurrence (33 percent). Patient satisfaction was not significantly associated with age, gender, history of previous fistula surgery, type of fistula, surgical procedure, time since surgery, or operating surgeon.

CONCLUSION

Patient satisfaction after surgical treatment for fistula-in-ano is associated with recurrence of the fistula, the development of anal incontinence, and with the effects of anal incontinence on patient lifestyle. In our series of patients treated mainly with laying open of the fistula tract, patients with fistula recurrence had a higher dissatisfaction rate than did patients with anal incontinence. However, because anal incontinence was more prevalent than fistula recurrence, a higher fraction of dissatisfaction was attributable to anal incontinence.

Tympanic membrane and middle ear pathologic correlates in mucoid otitis media

OBJECTIVE

The goal of this study was to correlate tympanic membrane (TM) and middle ear (ME) pathologies in mucoid otitis media (MOM).

METHODS AND MATERIAL

Forty ears with MOM and 56 control ears were retrospectively evaluated for TM and ME pathologies. Comparisons of TM thicknesses in MOM versus control ears were correlated with the Student t test; chi(2) analysis was used to correlate pathologic findings of the TM and ME.

RESULTS

Thicknesses in all quadrants except the umbo were increased in MOM because of infiltration of inflammatory cells and fibrosis. The most common ME pathologies were granulation tissue and fibrosis. Significant correlations included (1) TM retraction and ME granulation tissue and fibrosis and (2) pars flaccida, posterosuperior, and anteroinferior thickness and ME granulation tissue and fibrosis.

CONCLUSION

TM changes are likely to occur in patients with otitis media with effusion (MOM), and their presence is a strong indication of underlying ME pathology.

Low cord blood type 14 pneumococcal IgG1 but not IgG2 antibody predicts early infant otitis media

Type-specific IgG1 and IgG2 antibodies to Streptococcus pneumoniae capsular polysaccharides 14 and 19F were measured in cord blood samples from 425 neonates, to determine which antibody subclass was most strongly associated with otitis media (OM) during the first 6 months of life (early OM). Early OM was significantly associated with type 14 IgG1 antibody in the lowest antibody quartile (P=.055) but not with type 19F IgG1 antibody or with either IgG2 antibody. IgG1 and IgG2 antibodies were significantly intercorrelated for type 14 (r=.52, P<.001) and type 19F (r=.38, P<.001). Multivariate analysis revealed that having type 14 IgG1 antibody in the lowest quartile, child care attendance, and sibling and maternal OM history were independent risk factors for early OM. Although type-specific pneumococcal IgG2 antibody concentrations were significantly higher than IgG1 concentrations, IgG2 antibodies apparently are not protective against OM during early infancy.

Identification of MUC5B mucin gene in human middle ear with chronic otitis media

OBJECTIVES

To identify the mucin gene and its expressing cells in the middle ear mucosa with chronic otitis media (COM), and to study the correlation between infiltration of inflammatory cells in the submucosa and expression of the mucin gene in the mucosal epithelium with COM.

STUDY DESIGN

Middle ear mucosal specimens removed from the inferior promontory area of 19 patients undergoing middle ear surgery for COM were studied.

METHODS

Sections were stained with H&E, Alcian blue-periodic acid Schiff (AB-PAS), polyclonal MUC5B antibody, and specific MUC5B riboprobe for histological, histochemical, immunohistochemical, and mucin mRNA analyses.

RESULTS

H&E staining revealed pseudostratified epithelia in 18 of the middle ear specimens with COM and cuboidal secretory epithelia in one. AB-PAS staining of epithelia revealed abundant secretory cells and their products (glycoconjugates). In situ hybridization and immunohistochemistry studies demonstrated that the secretory cells of the middle ear mucosa with COM expressed MUC5B mucin mRNA and its product MUC5B mucin.

CONCLUSIONS

The MUC5B mucin gene and its product were identified in the middle ear secretory cells of patients with COM. Its expression was extensive in pseudostratified mucosal epithelia and related to infiltration of inflammatory cells in the submucosa of the middle ear cleft with COM, suggestive that inflammatory cell products are involved in the production of MUC5B.

Histopathologic features of the temporal bone in patients with cystic fibrosis

OBJECTIVES

To investigate the lower than expected incidence of otitis media in patients with cystic fibrosis (CF) through histopathologic evaluation of temporal bones and to document pathologic findings in the inner ears of patients with CF who received long-term administration of antibacterial and diuretic agents.

DESIGN

Clinical records of patients who died of CF were reviewed. Their temporal bones were sectioned, stained with hematoxylin-eosin, and examined histologically. Additional sections were stained with Alcian blue and periodic acid-Schiff for comparison of goblet cell densities from middle ears and auditory tubes of patients with CF with those of control temporal bones. Results were analyzed using the t test.

SUBJECTS

Twenty-one temporal bones from 11 patients with CF and 13 bones from 8 age-matched patients without CF were selected.

RESULTS

All temporal bones with CF had well-pneumatized mastoids. Temporal bones from 2 patients (3 ears) revealed histological findings of chronic otitis media with effusion. There was a statistically significant reduction in the density of goblet cells in the medial (P = .002) and lateral (P = .05) walls in patients with CF who had no otitis media histologically compared with control temporal bones. Two patients with CF who had otitis media had increased densities of goblet cells. Inner ear damage, due to ototoxic drugs, was seen in most of the temporal bones from patients with CF.

CONCLUSION

Low densities of goblet cells in temporal bones with CF may contribute reduced amounts of viscous mucus, which can lead to a low incidence of otitis media.

Evaluation of the feasibility of and results of measuring health-status changes in patients undergoing surgical treatment for skeletal metastases

The goal of treating patients with skeletal metastases is to decrease pain and improve or maintain physical function. Assessment of the effectiveness of treatment should therefore include evaluation of patient-rated measures of quality of life. The primary objective of the study was to determine the feasibility of studying the effect of surgical treatment of skeletal metastases on quality of life. The secondary objective was to provide data that begin to characterize this effect. The characteristics of patients with skeletal metastases are heterogeneous, patient enrollment in the study may be low, high attrition occurs secondary to death, and well accepted health-status measures (such as the Short Form-36) may be ineffective at detecting changes in health status; therefore, it is difficult to study these patients. High attrition and adjuvant treatment with radiation or chemotherapy made it impractical to draw firm conclusions about the effect of surgical treatment, but a trend toward improvement in selected health-status measures for both physical and mental health was noted. Analysis of patient-rated health-status scores as predictors of survival indicates that improvement in these scores 6 weeks after surgery is associated with an increase in the length of survival following surgery.

Residual mesenchyme persisting into adulthood

PURPOSE

(1) To detect the presence of residual mesenchyme in temporal bones of adults and children above 5 years of age; (2) to evaluate its regression with increasing age, and; (3) to detect pathologic conditions associated with the presence of unresolved mesenchyme.

MATERIALS AND METHODS

We examined 1,404 human temporal bones of donors from 5 to 94 years of age for histopathologic evidence of mesenchyme. The presence of stellate (star-shaped) cells with interdigitating processes and large nuclei embedded in a structureless ground substance was labeled as "pure mesenchyme." Temporal bones showing these features and focal areas of fibrosis, fibroblasts, and capillaries were classified as showing "transitional mesenchyme." Selected sections were stained with Gomori's trichrome. Pathological features indicating otitis media and congenital anomalies of the ear were also documented. Case histories were reviewed, and any otologic complaints were noted. Statistical analysis was performed with the Chi-square test, analysis of variance, regression analysis, and confidence interval.

RESULTS

Mesenchyme was found in 2.07% of temporal bones of patients from 5 to 81 years of age. Of these, 92.1% had transitional mesenchyme, whereas 7.9% had pure mesenchyme. Seventy-six percent of the bones showed mesenchyme in the mastoid air cells. In all 3 bones with pure mesenchyme, it was present in the round window niche. Otitis media was associated with residual mesenchyme in 84.2% of the temporal bones. No pattern of regression of mesenchyme with increasing age was observed in temporal bones from patients over the age of 5 years.

CONCLUSIONS

Residual mesenchyme can be present in patients older than 5 years of age and can persist into adulthood, especially in the mastoid air cells. Persistence of mesenchyme is closely associated with evidence of otitis media.

Effects of estrogen on the condylar cartilage of the rat mandible in organ culture

PURPOSE

The effects of estrogen on bone have been well documented. However, very little is known about the regulatory role of estrogen on cartilage and, in particular, the secondary cartilage of the mandibular condyle. The aims of this study were to determine whether estrogen receptors are present in the condylar cartilage of the rat mandible and to assess the effect of varying 17beta-estradiol (E2) concentrations on the proteoglycan content of this tissue.

MATERIALS AND METHODS

Mandibular condyles of 16 female Sprague-Dawley rats were resected. Eighteen of these condyles were divided into three groups and the condylar cartilage was removed and placed in organ culture for 4 days with media containing different concentrations of estrogen: 10(-11) mol/L, 10(-8) mol/L, and 10(-6) mol/L. The cartilage then was analyzed for proteoglycan content along with six specimens not passed through the organ culture. Six intact mandibular condyles also were resected and placed in organ culture with the same varying E2 concentrations, and the condylar cartilage was analyzed for estrogen receptors along with two condyles not passed through the culture system.

RESULTS

Estrogen receptors were evenly distributed within the chondroblastic and hypertrophic zones in the control group and the group with 10(-11) mol/L E2. With E2 concentrations of 10(-8) mol/L and 10(-6) mol/L, there was a qualitative decrease in hypertrophic chondroblasts, thickness of the condylar cartilage, and a significant decrease in proteoglycan content.

CONCLUSIONS

This study shows the presence of estrogen receptors in the secondary cartilage of the rat mandibular condyle. Estrogen has the potential to cause a decrease in extracellular matrix and thickness of this cartilage.

Epidemiology of otitis media onset by six months of age

OBJECTIVE

Although early otitis media (OM) onset predicts later recurrent and chronic OM, little research has been directed at illuminating the role of prenatal exposures in early OM. This prospective study examined prenatal, innate, and early environmental exposures associated with acute otitis media (AOM) onset and recurrent OM (ROM) by age 6 months.

DESIGN AND METHODS

Prospective study of 596 infants from a health maintenance organization followed from birth to 6 months. Mothers completed monthly forms on prenatal exposures (diet, medications, and illnesses) and infant risk factors (eg, smoke exposure and child care) during pregnancy and until infants were 6 months old. Urine samples were collected when infants were 2 months of age and analyzed for cotinine and creatinine. Physicians and nurse practitioners examined infants at each clinic visit and completed standard ear examination forms.

RESULTS

Thirty-nine percent had an episode of AOM and 20% had ROM by age 6 months. Using Cox's regression models to control for confounding, respiratory tract infection (relative risk [RR] 7.5), day care (RR 1. 7), >1 sibling (RR 1.4), maternal, paternal, and sibling OM history (RR 1.6, 1.5, and 1.7, respectively) were significantly related to early OM onset. ROM was related to respiratory tract infection (RR 9. 5), day care (RR 1.9), conjunctivitis (RR 2.0), maternal OM history (RR 1.9), and birth in the fall (RR 2.6). Among prenatal exposures, only high prenatal dietary vitamin C intake was significantly inversely related to early AOM with univariate but not multivariate analysis.

CONCLUSION

Prenatal factors were not linked to early AOM onset with multivariate analysis, but environmental and innate factors play an important role in early AOM onset. Strategies to reduce exposure to environmental variables could reduce rates of early AOM, which could potentially result in declining rates of ROM and chronic OME.

Tympanic membrane/middle ear pathologic correlates in chronic otitis media

OBJECTIVE

To correlate pathologic findings of the tympanic membrane with pathologic changes in the middle ear cleft in chronic otitis media.

STUDY DESIGN

Retrospective.

MATERIAL AND METHODS

One hundred-fifty temporal bones from 97 subjects with chronic otitis media (defined as middle ear pathologic changes including granulation tissue, fluid, cholesteatoma, cholesterol granuloma, tympanosclerosis, and ossicular changes) were selected to correlate the presence of these middle ear pathologies with histopathologic changes of the tympanic membrane. The tympanic membrane pathologies included perforation, myringosclerosis, retraction, hemorrhage, fluid-filled cystic spaces, or dilated vessels. Temporal bones were also assessed for atelectasis. Fifty-six normal temporal bones were taken as controls for measurements.

RESULTS

Significant correlations between tympanic membrane and middle ear pathology included myringosclerosis and granulation tissue, myringosclerosis and ossicular pathology, retraction and cholesterol granuloma, retraction and cholesteatoma, retraction and ossicular pathology, perforation and ossicular pathology, and hemorrhage and granulation tissue. Additive effects of some pathologies were also observed. Almost half the bones with middle ear pathology had no associated tympanic membrane pathology, whereas multiple pathologic changes in the tympanic membrane generally showed underlying multiple pathologic changes in the middle ear.

CONCLUSION

When tympanic membrane pathology is detected otoscopically, its presence, alone or in combination, can be a strong indicator of underlying middle ear pathology. However, a normal-appearing tympanic membrane does not exclude the possibility of middle ear pathology. These findings suggest the need for other diagnostic tools such as multifrequency tympanometry and otoacoustic emissions to complement otoscopy for diagnosis of middle ear pathology, especially in a tympanic membrane that appears "normal."

Middle ear fluid cytokine and inflammatory cell kinetics in the chinchilla otitis media model

Streptococcus pneumoniae is the most frequent microbe causing middle ear infection. The pathophysiology of pneumococcal otitis media has been characterized by measurement of local inflammatory mediators such as inflammatory cells, lysozyme, oxidative metabolic products, and inflammatory cytokines. The role of cytokines in bacterial infection has been elucidated with animal models, and interleukin (IL)-1beta, IL-6, and IL-8 and tumor necrosis factor alpha (TNF-alpha) are recognized as being important local mediators in acute inflammation. We characterized middle ear inflammatory responses in the chinchilla otitis media model after injecting a very small number of viable pneumococci into the middle ear, similar to the natural course of infection. Middle ear fluid (MEF) concentrations of IL-1beta, IL-6, IL-8, and TNF-alpha were measured by using anti-human cytokine enzyme-linked immunosorbent assay reagents. IL-1beta showed the earliest peak, at 6 h after inoculation, whereas IL-6, IL-8, and TNF-alpha concentrations were increasing 72 h after pneumococcal inoculation. IL-6, IL-8, and TNF-alpha but not IL-1beta concentrations correlated significantly with total inflammatory cell numbers in MEF, and all four cytokines correlated significantly with MEF neutrophil concentration. Several intercytokine correlations were significant. Cytokines, therefore, participate in the early middle ear inflammatory response to S. pneumoniae.

Expression of glycoconjugates in human eustachian tubes with otitis media

OBJECTIVES

To characterize glycoconjugate expression in normal human eustachian tubes and study the alterations in glycoconjugate expression found in eustachian tubes with otitis media.

STUDY DESIGN

Using lectin histochemistry, alterations in glycoconjugates were studied in three normal temporal bones, in four temporal bones with mucoid otitis media (MOM), and in five with serous otitis media (SOM).

METHODS

Sections of previously processed temporal bones were decelloidinized, and then incubated with seven biotinylated lectins--WGA, SNA, MAA, BPA, PNA, UEA-1, and LcH--that reflect seven carbohydrate residues of glycoconjugates, respectively: GlcNAc/NeuNAc, NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, Gal beta(1-3) GalNAc, L-fucose, and alpha-mannose residues. Control sections were incubated with inhibitory carbohydrates or without biotinylated lectins.

RESULTS

In the normal temporal bones, five carbohydrate residues in goblet cells and cilia of the eustachian tube demonstrated moderate to strong activity--NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, GalNAc, Gal beta(1-3)GalNAc, and L-fucose. Two residues demonstrated weak activity--GlcNAc/NeuNAc and alpha-mannose. Temporal bones with MOM revealed increases in sialic acid and alpha-mannose, and a decrease in L-fucose. Residues of carbohydrates in the cilia of bones with SOM were notably decreased, especially for GalNAc, Gal beta(1-3)GalNAc, and NeuNAc alpha(2-6)GalNAc.

CONCLUSIONS

Glycoconjugates in the normal human eustachian tube are rich in GalNAc, Gal beta(1-3)GalNAc, L-fucose, and NeuNAc alpha(2-3/2-6) GalNAc, but low in alpha-mannose and sialic acid. Eustachian tubes from cases with SOM or MOM demonstrated alterations in glycoconjugate expression in cilia and goblet cells, which may reflect disorder of the carbohydrate metabolism during otitis media, especially in SOM.

Significance of epidermoid formations in the middle ear in fetuses and children

OBJECTIVE

To determine the incidence, size, and location of epidermoid formations (EFs), which have been suggested to be precursors of congenital cholesteatomas, in temporal bones from fetuses and children.

DESIGN

We examined temporal bones from 226 fetuses and children up to the age of 10 years for the incidence, size, and location of EFs.

RESULTS

Twenty-five EFs were identified in middle ears of 3 fetuses, 7 neonates, 9 infants, and 2 children aged 2 and 3 years. There was a male-female preponderance of 5:4. Generally, we saw EFs between the anterosuperior edge of the eardrum and the anterior limb of the tympanic ring, but 4 were below the level of the handle of the malleus. Their widths ranged from 25 to 300 microns. Keratinization was not observed in any EF. Contrary to previous reports, we found EFs not only in ears of fetuses, but also in ears of infants and children.

CONCLUSION

Although EFs may persist in some ears, possibly developing into congenital cholesteatomas, our findings do not provide direct support for this concept.

Evaluation of confounding effects in ROC studies

In many clinical studies, it is clear that external forces can affect the performance of diagnostic tests, as these factors influence the distributions of separator variables. A new estimator for the receiver operating characteristic (ROC) function is proposed; this estimator converges to the ROC function uniformly on the interval [0,1]. Using this new estimator, the author proposes to use Cox's proportional hazards regression model for the evaluation of confounding effects in ROC studies. The method can be used even when concomitant information is only available for the cases, for example, disease severity. A textbook example on prostate cancer is described for illustration.

Measuring health status in patients with skeletal metastases treated by surgery

Since the introduction of the Functional Living Index-Cancer (FLIC) > 10 years ago, a variety of general as well as disease-specific quality of life (QOL) instruments have been developed and used as a means of assessing the success of clinical interventions. Clinicians faced with selecting an appropriate QOL measurement tool will need guidance in both the selection of the instrument and its evaluation for applicability to the patient group under study. In our examination of this issue, we analyzed the results of administering the FLIC and the more general SF-36 questionnaire to a group of 17 patients who had undergone orthopaedic surgery to correct problems associated with bone metastatic cancer. Because the SF-36 has been widely adopted as a general Health Status evaluation tool and because of its extensive validation it may be considered a gold standard providing a means of assessing the validity of disease-specific instruments such as the FLIC. Using multivariate regression, we built a model in which five of the eight health status dimensions of the SF-36 account for 77% of the variation in the FLIC scores for this group of patients (R2 = 0.77). The implication of this result is that most of the information (i.e., 77%) provided by the FLIC could be equivalently obtained using the more general, more widely validated SF-36. Despite the small sample size, half of the regression coefficients in this model achieved a high level of statistical significance (p < 0.001). In addition, when applied to new patients, the model showed good predictive capability with relative error 2-20%. If these results can be replicated for other patient disease groups and in larger study populations, it may be possible to use the SF-36 as the primary QOL evaluation tool for cancer patients. The burden of this disease could then be more easily compared with that of other disease groups and the resulting standardization of QOL analysis would be simpler and more cost effective.

Low cord blood pneumococcal immunoglobulin G (IgG) antibodies predict early onset acute otitis media in infancy

Low maternally derived serum immunoglobulin G (IgG) antibodies to Streptococcus pneumoniae capsular polysaccharides (PS) combined with the inability of infants to produce anti-PS antibody may explain onset of otitis media in the first 6 months of life. To explore this relation, cord blood samples were assayed for anti-PS IgG antibodies from 414 of 592 infants enrolled in a study of early onset otitis media between 1991 and 1994. Infants' ears were examined at health supervision and illness visits for the first 6 months of life in a large Minneapolis-St. Paul, Minnesota, health maintenance organization. Antibodies to seven common pneumococcal serotypes (3, 4, 6B, 14, 18C, 19F, and 23F) were measured by enzyme-linked immunoabsorbent assay (ELISA). Cox's regression analysis revealed that among infants with a sibling otitis media history, those with low concentrations of type 14 or 19F anti-PS cord blood antibody had earlier otitis media onset than those with higher cord blood antibody concentrations (relative risks (RR) (95% confidence intervals (CI)) = 1.77 (1.05-2.99) and 1.89 (1.11-3.23), respectively). Day care attendance also increased risk (RR = 1.56, 95% CI 0.96-2.52). Breastfeeding, parental smoking, and low anti-PS antibody to pneumococcal serotypes 3, 4, 6B, 18C, and 23F did not significantly affect the risk of early otitis media.

Effects of brain injury on college academic performance

Brain injury, a leading cause of mortality, morbidity and disability in the United States, has serious consequences and substantial costs. Although previous studies have assessed a variety of outcomes subsequent to brain injury, documentation of performance prior to brain injury using a case-control approach has not been included; preinjury performance differences may confound the estimate of the effects of brain injury on performance. The primary objective of this study was to compare academic performance before and after brain injury in a population of university undergraduate students to determine the extent to which the academic career of the brain-injured person was altered from what would have been expected in the absence of such an injury. Cases included all undergraduate students in a major university, between the ages of 17 and 27, who incurred a brain injury requiring hospitalization between 1980 and 1984 (n = 99). Two comparison groups were used to determine whether changes in academic performance were specifically related to brain injuries or injuries in general: (1) injured controls, i.e. 121 students between the ages of 17 and 27 years, hospitalized for injuries other than to the central nervous system, and (2) uninjured academic controls, i.e. 198 students with out injuries requiring hospitalization during the study period, matched 2:1 to the brain-injured students by age, gender, and completed course credits categorized as < 90, > or = 90. Although there were no differences when the total groups, including both males and females, were compared, there was a significant pre- to postinjury decrease in the grade point average for female cases when compared to their uninjured academic controls (p < 0.02). This difference was related to the effects of brain injury, and not to the effects of injury in general. No such difference was observed for the males. There were also no differences when the total groups, including males and females, were compared relevant to return to school. However, a significantly higher proportion of the female cases, compared with their uninjured academic controls, did not return to school after their injury; similar findings were identified for the injured controls as well. Thus, these differences were not specific to brain injury but rather to injury in general. In spite of this observation, the difference between female cases who returned and those who did not return was associated with neurological deficits, especially upper left limb motor deficits, as the time of hospital discharge. The findings from this effort are suggestive of gender differences in the consequences of brain injury and serve as a basis for further studies to evaluate the magnitude of this problem.

Residual mesenchyme in temporal bones of children

The role of mesenchyme in the temporal bone is still poorly understood. A microscopic study of residual mesenchyme was undertaken in temporal bones of children from birth to 5 years of age. Residual mesenchyme was found to be located in the mastoid antrum and epitympanum more often than in the mesotympanum. The amount of mesenchymal tissue remaining in the temporal bones decreased with increasing age. Persistence of mesenchyme in the temporal bone was related to congenital morphologic ear anomalies and syndromes. There was also an association evident with pulmonary disease, but not with congenital heart defects. Persistent mesenchyme was also found to be significantly associated with chronic middle ear inflammation, and in cases of unilateral otitis media the ear with otitis media had more residual mesenchyme than the non-otitis media ear.

Roles of autolysin and pneumolysin in middle ear inflammation caused by a type 3 Streptococcus pneumoniae strain in the chinchilla otitis media model

Streptococcus pneumoniae cell wall and pneumolysin are important contributors to pneumococcal pathogenicity in some animal models. To further explore these factors in middle ear inflammation caused by pneumococci, penicillin-induced inflammatory acceleration was studied by using three closely related pneumococcal strains: a wild-type 3 strain (WT3), its pneumolysin-negative derivative (P-1), and into autolysin-negative derivative (A-1). Both middle ears of chinchillas were inoculated with one of the three pneumococcal strains. During the first 12 h, all three strains grew in vivo at the same rate, and all three strains induced similar inflammatory cell responses in middle ear fluid (MEF). Procaine penicillin G was given as 12 h to one-half of the animals in each group, and all treated chinchillas had sterile MEF at 24 h. Penicillin significantly accelerated MEF inflammatory cell influx into WT3-and P-1-infected ears at 18 and 24 h in comparison with the rate for penicillin-treated A-1-infected ears. Inflammatory cell influx was slightly, but not significantly, greater after treatment of WT3 infection than after treatment of P-1 infection. Interleukin (IL)-1beta and IL-6, but not IL-8, concentrations in MEF at 24 h reflected the penicillin effect on MEF inflammatory cells; however, differences between treatment groups were not significant. Results suggest that pneumococcal otitis media pathogenesis is triggered principally by the inflammatory effects of intact and lytic cell wall products in the middle ear, with at most a modes additional pneumolysin effect. Investigation strategies that limit the release of these products or neutralize them warrant further investigation.

Temporal bone study of Down's syndrome

OBJECTIVE

To study temporal bone histopathologic characteristics of the inner ear and middle ear cleft of patients with Down's syndrome.

DESIGN

Sixteen temporal bones from eight patients with Down's syndrome were studied. Ten temporal bones from subjects without pathologic ear lesions but with congenital heart disease served as controls. The two-dimensional graphic reconstruction method proposed by Guild and modified by Schuknecht was used to study the cochleas; measurement of the vestibules was based on Igarashi's method.

SETTING

The temporal bone collection of the Otitis Media Research Center, Department of Otolaryngology, University of Minnesota School of Medicine, Minneapolis.

RESULTS

Six bones showed short cochlea, and four of six had Mondini's cochlea. The overall cochlear lengths in this study group were notably shorter than those of the controls. The spiral ganglion cell population and two of three vestibular dimensions also were notably less than the controls. Middle ear findings included residual mesenchyme, stapes abnormality, otitis media, and large facial canal dehiscence.

CONCLUSIONS

The difficulties encountered in rehabilitation of patients with Down's syndrome caused by mental retardation can be compounded by the hearing loss caused by middle and inner ear abnormalities. A complete evaluation of hearing loss and therapy before starting the rehabilitation gives the most favorable outcome.

Duration of ventilating tubes: a test for comparing two clustered samples of censored data

A study of otitis media that requires a test for the comparison of two clustered samples of censored data is described. A method is proposed taking into account the within-subject correlation in the formation of the log-rank statistic.

High frequency hearing loss associated with otitis media

OBJECTIVE

Long-term effects of otitis media (OM) on hearing in both conventional and high frequency (HF) regions in children were studied.

DESIGN

Children with OM were enrolled in a prospective study of sequelae after tympanostomy tube insertion (intubation) and were examined serially at 6-mo intervals with audiometry and multifrequency tympanometry, and every 3 mo with tympanometry and otoscopy for at least 3, and up to 5 yr. Hearing thresholds in conventional and HF regions were compared with those of an age-matched control group of children who had 2 or fewer documented episodes of any type of OM since birth. Frequency of OM during follow-up, number of intubations, use of ototopical eardrops, age, and sex along with several other factors were analyzed for a relationship to HF hearing loss.

RESULTS

Otitis media history was associated with poorer HF hearing, but the presence of subtle residual middle ear dysfunction was not associated with an additional effect on HF hearing. Active middle ear disease significantly affected both conventional and HF thresholds. The number of intubations and frequency of OM during follow-up were significantly and positively associated with poorer HF thresholds. Several other factors, including middle ear appearance at intubation, presence of tympanosclerosis, age, male gender, and use of ototopical eardrops, were also associated with poorer HF hearing but failed to reach significance after their intercorrelation with number of intubations and frequency of OM was considered.

CONCLUSIONS

High frequency hearing loss was associated with OM after middle ear disease resolved and after middle ear dysfunction was excluded. Relatively poorer HF hearing thresholds found for older children with OM histories appeared to be attributable to time spent with ear disease. Children at greatest risk for HF hearing loss were those who required multiple intubations. Older children tended to have poorer hearing in both conventional and HF regions, suggesting that the effects of OM on hearing thresholds may be progressive.

The family study of otitis media: design and disease and risk factor profiles

Recurrent acute otitis media (RAOM) and chronic otitis media with effusion (COME) exhibit familial aggregation, but environmental risk factors (day care attendance, cigarette smoke exposure, and bottle feeding) are also important in their development. The Family Study of OM was designed to ascertain the RAOM/ COME status of families whose children participated in Otitis Media Research Center studies between 1978 and 1984. Probands were treated with tympanostomy tubes, and had their RAOM/COME status ascertained as criteria for entry into these studies. For the Family Study of OM parents were interviewed about their otitis media and risk factor history; mothers were interviewed about their children's history, and pertinent medical records were obtained. Members of 173 families were examined with otomicroscopy and multifrequency tympanometry; 19% of parents and 32% of siblings were classified as affected, which is substantially higher than RAOM/COME rates from previous reports. Risk factor profiles differed significantly (P < .001) between parents and their children. Younger generation (adjusted odds ratio [OR] = 4.18, 95% confidence interval [CI], 2.74, 6.36) day care attendance (OR = 1.96, 95% CI, 1.32, 2.91) and male gender (OR = 1.42, 95% CI, 1.03, 1.97) were significantly related to RAOM/ COME using logistic regression. Analyses confirm 1) higher disease rates in families with an affected member compared to existing studies of the general population, 2) increased risk of RAOM/COME associated with known risk factors, and 3) increased risk for parents irrespective of risk factors. Additional analyses will explore competing models of disease susceptibility using genetic models and known risk factors.

Immunogenicity and efficacy of Streptococcus pneumoniae polysaccharide-protein conjugate vaccines against homologous and heterologous serotypes in the chinchilla otitis media model

Cross-protection among pneumococcal serotypes within serogroups was measured in the chinchilla otitis media (OM) model because several serotypes that cause OM in children are closely related biochemically. Chinchillas were given tetravalent vaccine composed of pneumococcal capsular polysaccharides (PS; types 6B, 14, 19F, 23F) conjugated to an outer membrane protein complex, and 89% to 96% developed a > or = 2-fold serum IgG rise against vaccine PS. Vaccine efficacy was tested by inoculating middle ear hypotympanic bullae with Streptococcus pneumoniae types 6B, 6A, 19F, or 19A. OM severity in the vaccinated groups challenged with types 6B, 6A, and 19F but not 19A was significantly better than in the respective placebo groups. Culture-positive pneumococcal OM occurred in 38%, 62%, 0, and 78% of vaccinated chinchillas challenged with types 6B, 6A, 19F, and 19A, respectively, but in 88% of type 6B- and 100% of type 6A-, 19A-, and 19F-challenged placebo chinchillas.

Randomized trial of the efficacy of trimethoprim-sulfamethoxazole and prednisone in preventing post-tympanostomy tube morbidity

This study was designed to determine whether treatment with prednisone and trimethoprim-sulfamethoxazole would reduce first year post-operative morbidity in children with chronic otitis media with effusion undergoing tympanostomy tube insertion (intubation). Eighty children ages 6 months to 8 years were enrolled at intubation and randomized from age strata to receive active drugs or placebos for 14 days after surgery. They were examined with pneumatic otoscopy and tympanometry preoperatively and at 3 weeks and 3, 6, 9 and 12 months after surgery. Active drug treatment significantly reduced tube obstruction or extrusion in the first 3 postoperative months compared with placebos (4% vs. 17%, P = .01). However, rates of repeat intubation, otorrhea and recurrence of otitis media did not differ significantly in the two groups. Children with chronic otitis media with effusion treated with intubation may benefit from a 2-week course of prednisone and trimethoprim-sulfamethoxazole at the time of surgery. However, there is no apparent long term benefit of this treatment.

Protection of myocytes against free radical-induced damage by accelerated turnover of the glutathione redox cycle

The primary defence mechanism of myocytes against peroxides and peroxide-derived peroxyl and alkoxyl radicals is the glutathione redox cycle. The purpose of the present study was to increase the turnover rate of this cycle by stimulating the glutathione peroxidase catalysed reaction (2GSH-->GSSG), the glutathione reductase catalysed reaction (GSSG-->2GSH), or both. Neonatal rat heart cell cultures were subjected to a standardized protocol of oxidative stress using 80 mumol.l-1 cumene hydroperoxide (CHPO) for 0-90 min. The consequences of this protocol were described in terms of cellular concentrations of GSH, GSSG, NADPH and ATP, formation of malondialdehyde (MDA), release of GSSG and of ATP catabolites, depression of contraction frequency, cellular calcium overload, and enzyme release. Trolox-C, an analogue of vitamin E, accelerated the glutathione peroxidase reaction leading to lowering of GSH concentration and the GSH/GSSG ratio, less MDA formation, diminished negative chronotropy, delayed calcium overload, and less enzyme release. Glucose was used to accelerate the glutathione reductase reaction by supplying NADPH, leading to higher GSH concentration and a higher GSH/GSSG ratio, less MDA formation, diminished negative chronotropy, unchanged development of calcium overload, and less enzyme release. As a full turn of the glutathione redox cycle involves both the peroxidase and the reductase reactions, the combination of Trolox-C and glucose was superior to either of the two alone: 90 min following addition of CHPO together with Trolox-C and glucose, the GSH concentration and the GSH/GSSG ratio were almost normal, MDA formation was extremely low, calcium overload was markedly delayed, and enzyme release hardly occurred at all. Cells remained beating in the observation period of 30 min. We conclude that the capacity of the glutathione redox cycle to withstand oxidative stress can be increased by stimulation of either the peroxidase reaction or the reductase reaction, and that optimal redox cycling is achieved by stimulation of both reactions.

Desferrioxamine protects myocytes against peroxide-induced myocyte damage without affecting glutathione redox cycle turnover

The primary defense mechanism of myocytes against peroxide-derived free radicals is the glutathione redox cycle. The purpose of the present study was to investigate whether desferrioxamine protects myocytes against peroxide-induced cell damage, and if so, whether the turnover rate of the glutathione redox cycle is involved in this protection. Neonatal rat heart cell cultures were subjected to a standardized oxidative stress by a 90 min incubation with 80 mumol/l cumene hydroperoxide. The consequences of this stress protocol were described in terms of cellular concentrations of GSH, GSSG, ATP, ATP-catabolites, and Ca2+, formation of malondialdehyde to quantify lipid peroxidation, and enzyme release to quantify the relative number of irreversibly injured cells. Following pretreatment of cell cultures with 10 mmol/l desferrioxamine mesylate for 1 h, 80 mumol/l cumene hydroperoxide caused less malondialdehyde formation (at 90 min: 0.34 v 2.35 nmol), less ATP depletion (at 60 min: 16.7 v 3.6 nmol), less Ca2+ overload (at 30 min: 40 v 1500 nM) and less enzyme release (at 90 min: 4.6 v 60.5% of the cells) compared to cell cultures subjected to cumene hydroperoxide without pretreatment. However, in desferrioxamine pretreated cell cultures cumene hydroperoxide caused cellular GSH depletion (at 60 min: 19.5 v 20.8 nmol) and GSSG efflux (at 60 min: 6.3 v 6.0 nmol) which was not different from cell cultures subjected to cumene hydroperoxide without pretreatment. Added to the finding that in a cell-free system cumene hydroperoxide is a substrate for glutathione peroxidase, we conclude that desferrioxamine, by chelating free iron ions (1), prevented the formation of cumene alkoxyl and peroxyl radicals associated with protection of the myocytes, and (2) did not diminish rapid glutathione redox cycling leading to GSH depletion and GSSG efflux.

Comparison of two otitis media models for the study of middle ear antimicrobial pharmacokinetics

We compared two models of acute otitis media that estimate middle ear antimicrobial pharmacokinetics. Using a crossover study design, we compared a systemic drug administration model with a diffusion model we devised that measures the disappearance of antimicrobials from the middle ear. We induced acute otitis media in 14 chinchillas by inoculating S. pneumoniae into the middle ear, then administered 3 antimicrobials: amoxicillin, trimethoprim, and sulfamethoxazole. Next we collected middle ear fluid samples to analyze drug concentrations and compare rate constants for the systemic and diffusion models by analysis of variance. We found that amoxicillin K values were not affected by model testing sequence (p = 0.827) or model type (systemic versus diffusion, p = 0.310), nor were sulfamethoxazole K values: model testing sequence (p = 0.917), model type (p = 0.963). Trimethoprim K values were also not affected by model testing sequence (p = 0/760), but were by model type (p = 0.0001). Trimethoprim elimination from the diffusion model was faster (K = 0.33 +/- 0.17 versus 0.57 +/- 0.09 hr-1) than from the systemic model, although it appears this was caused by sampling before drug distribution into the middle ear was complete. In conclusion, it appears K values derived from either systemic antimicrobial administration or direct middle ear instillation are similar for assessing middle ear antimicrobial pharmacokinetics, and these models can be used interchangeably to study factors affecting otitis media treatment response.

A clinical profile of otitis media without an intact tympanic membrane

An otitis media with effusion algorithm developed by Paradise et al has become the basis for many studies of otitis media. However, it has been shown to be too ambitious (low specificity) and too optimistic (absence of fluid does not necessarily mean normal ears). We developed a four-point profile to characterize the condition of the middle ear, but it cannot be used when the eardrum is perforated (with a functioning tube or chronic perforation). We propose a three-point profile for use without an intact tympanic membrane, and we report the validation of the profile by findings at myringotomy and by the preoperative profile. This postoperative profile and the previously described profile for ears with an intact tympanic membrane should increase the accuracy of middle ear assessment in following the course of otitis media over time.

Determining otitis media severity from middle ear fluid analysis

Otitis media has a complex multifactorial pathogenesis, and the middle ear inflammatory response is typified by the accumulation of cellular and chemical mediators in middle ear effusion. However, specific biochemical and immunochemical factors that may be responsible for the severity or chronicity of otitis media have not been identified. Identification of factors involved in chronicity appears to be an essential step in the treatment and ultimate prevention of chronic otitis media. We analyzed 70 effusion samples from patients 1 to 10 years of age who had chronic otitis media with effusion for two cytokines (interleukin-1 beta and tumor necrosis factor alpha) and total collagenase. The highest concentrations of all three inflammatory mediators were found in purulent otitis media, and concentrations were higher in younger than in older patients. Mediator concentrations were similar in samples obtained from patients having their first myringotomy for otitis media with effusion and in those who had had multiple previous myringotomies. The multiresponse star, which incorporates several biochemical parameters in one graphic illustration, may best characterize the complex nature of middle ear inflammation.

Treatment evaluation in otitis media research

OBJECTIVE

An application of the clinical otitis media profile is proposed for the evaluation of treatments in clinical studies of otitis media.

METHODS

Methods include a statistical test of significance and measures of "treatment difference." This article focuses on the method, not any particular study; however, an example is given to illustrate the ideas.

CONCLUSIONS

The proposed method substantially increases powers of statistical tests, as compared with the use of a two-point scale algorithm, when applied to study changes of the middle ear condition over time or to compare treatment effects. The proposed evaluation method is applicable to any medical drug treatment for groups that may not be comparable, even with randomization, for baseline severity. Applied to surgical treatment, it can be used for long-term evaluation; however, short-term evaluation is impossible because the needed tympanometric, static admittance, and width measurements cannot be obtained in the presence of functioning tubes. To achieve this objective, it is necessary to use another profile or diagnostic procedure.

Piecewise exponential survival curves with smooth transitions

Several models of a population survival curve composed of two piecewise exponential distributions are developed. In one formulation the hazard rate changes at a point that is an unobservable random variable that varies between individuals. The population hazard function may decrease with age even when all individuals' hazards are increasing. In a second formulation, the population hazard function is modeled directly. Several models are fit to the survival history of a cohort of 5751 highly inbred male Drosophila melanogaster and the British coal mining disaster data.

Association between survival time and ordinal covariates

An application of the method of rank correlation is proposed for testing independence between a censored survival time and an ordinal covariate. The test statistic counts the number of concordances minus the number of discordances at each time with event(s) and adds across times; it is expressible as a score statistic within the proportional hazards framework. The proposed test includes, as a special case, a generalization of Jonckheere's test against ordered alternatives and as applied to the analysis of categorical data, it can be seen as a generalization of the Mantel-Haenszel procedure.

Acute otitis media increases middle ear susceptibility to nasal injection of Pseudomonas aeruginosa

Pseudomonas aeruginosa was injected intranasally into four groups of chinchillas to determine if these bacteria can invade the middle ear by way of the eustachian tube. One group completed penicillin treatment of bilateral penumococcal otitis media (POM), and the second group started penicillin treatment of bilateral POM at the time of P. aeruginosa injection. A third group had no POM, but completed a course of penicillin treatment before P. aeruginosa injection, and a fourth group had no POM and received no penicillin. Middle ear susceptibility to nasally injected P. aeruginosa was significantly higher in animals with POM (61%) than in animals without POM (32%, p = 0.001). Forced eustachian tube opening pressures did not correlate with P. aeruginosa susceptibility. Thus, P. aeruginosa, the principle pathogen of chronic suppurative otitis media, can invade the middle ear by way of the eustachian tube, and acute otitis media predisposes to middle ear infection by P. aeurginosa.

A test for linear trend in constant hazards and its application to a problem in occupational health

A score test is derived for testing a linear trend in constant hazards. The test is applied to prove the attenuation of healthy worker effects in the analysis of occupational mortality.

Buthionine sulfoximine reduces the protective capacity of myocytes to withstand peroxide-derived free radical attack

Mammalian heart myocytes have a limited capacity to withstand the deleterious effects of free radical generating compounds. To assess the role of the glutathione redox cycle relative to this capacity, rat heart cell cultures were subjected for 90 min to 80 mumol/l cumene hydroperoxide (CHPO) without and with prior glutathione depletion by buthionine sulfoximine. Preincubation of cultures with 125 mumol/l buthionine sulfoximine for 2 h and 17 h caused a reduction of glutathione by 33% and 82%, respectively, without concomitant increase of glutathione disulfide. Subsequent incubation with CHPO for 90 min caused slowing of NADPH consumption (in the first 20 min 27 pmol vs 68 pmol without pretreatment with buthionine sulfoximine for 17 h), which indicates that glutathione depletion reduced the turnover rate of the glutathione redox cycle. Pretreatment with buthionine sulfoximine for 17 h exaggerated the negative chronotropic effects of CHPO: the time elapsed to 50% of baseline contraction frequency fell from 5.7 +/- 1.4 min without buthionine sulfoximine to 3.7 +/- 0.4 min after pretreatment with buthionine sulfoximine (P < 0.02). The severity of CHPO-induced lipid peroxidation as assessed by malondialdehyde formation (2.23 +/- 0.51 vs 0.99 +/- 0.05 nmol in the first 20 min; P < 0.05) was increased by buthionine sulfoximine pretreatment, as was the extent of cell necrosis as assessed by release of alpha-hydroxybutyrate dehydrogenase (39.5 +/- 5.1 vs 29.0 +/- 12.9% in the first 45 min). A "sublethal" dose of 10 microM CHPO for 60 min caused no substantial HBDH release, no formation of malondialdehyde, and no exhaustion of cellular GSH (35 nmol/U HBDHt = 0). However, following pretreatment with buthionine sulfoximine, 10 microM CHPO for 60 min produced 12% HBDH release and extensive lipid peroxidation (1.95 nmol malondialdehyde/U HBDHt = 0). As the deleterious effects of CHPO were aggravated by glutathione depletion, we conclude that the glutathione redox cycle plays a major role in the protection of myocytes against peroxide-induced free radical attack.

Pneumococcal capsular polysaccharide-meningococcal outer membrane protein complex conjugate vaccines: immunogenicity and efficacy in experimental pneumococcal otitis media

Vaccines composed of pneumococcal capsular polysaccharides (PS) conjugated to outer membrane protein complex (OMPC) from Neisseria meningitides group B bacteria were tested in the chinchilla otitis media model. Monovalent (types 6B and 23F), bivalent (6B+23F), and tetravalent (6B+14+19F+23F) PS-OMPC conjugate vaccines elicited significant total serum antibody responses against all four PS. Type 6B vaccine elicited IgG, IgM, and IgA antibodies after a single dose and an anamnestic IgG response after a second vaccine dose on day 28. Type 6B and 19F vaccines prevented or greatly attenuated pneumococcal otitis media after direct middle ear challenge with the immunizing serotype, type 14 vaccine was not protective by this challenge route, and type 23F pneumococci were not sufficiently virulent in chinchillas to test vaccine effectiveness. The promising results with two serotypes suggest the PS-OMPC conjugates may be useful in human infants.

A clinical profile of otitis media

An otitis media with effusion algorithm developed by Paradise et al and tested by Cantekin et al has become the basis for many studies of otitis media. However, a two-point scale algorithm (otitis media with effusion-no otitis media with effusion) may be too ambitious (ie, low specificity) and too optimistic (ie, absence of fluid does not necessarily mean normal ear). We propose a four-point profile that characterizes the condition of the middle ear, and we report the validation of the profile against findings at myringotomy. Statistically, a four-point scale profile would substantially increase powers of statistical tests, compared with a two-point scale algorithm (in studies of the same size), when used to study changes of the middle-ear condition over time or to compare treatment effects.

Effects of glucose, Trolox-C, and glutathione disulphide on lipid peroxidation and cell death induced by oxidant stress in rat heart

OBJECTIVE

The aim was to find effective protection of myocytes against peroxide induced damage in terms of preservation of contractile activity, protection against lipid peroxidation, and protection against cell death.

METHODS

The components of the glutathione redox cycle, the production of malondialdehyde, cell contractions, and enzyme release from myocytes were measured in cultured neonatal rat heart cells before and after administration of cumene hydroperoxide, 80 mumol.litre-1. The protective action was tested of (1) glucose (10 mmol.litre-1) which stimulates the production of NADPH; (2) Trolox-C (0.16 mmol.litre-1) which is a water soluble analogue of alpha tocopherol and a scavenger of free radicals; and (3) GSSG (0.6 mmol.litre-1) which increases the intracellular concentrations of GSH and GSSG.

RESULTS

Although the three substances tested were equally effective in reducing the formation of malondialdehyde, exogenous GSSG afforded only slight protection against cumene hydroperoxide induced cell death, whereas glucose and Trolox-C were highly effective protectors. The depressant effect of cumene hydroperoxide on beating frequency was not influenced by preincubation with GSSG, nor by coadministration of glucose, but Trolox-C was able to diminish the negative chronotropic action of cumene hydroperoxide.

CONCLUSIONS

Effective protection against cumene hydroperoxide induced lipid peroxidation is not associated per se with effective protection against cumene hydroperoxide induced loss of beating frequency and cell death.