Heterogeneity of kinase inhibitor resistance mechanisms in GIST

Most GIST patients develop clinical resistance to KIT/PDGFRA tyrosine kinase inhibitors (TKI). However, it is unclear whether clinical resistance results from single or multiple molecular mechanisms in each patient. KIT and PDGFRA mutations were evaluated in 53 GIST metastases obtained from 14 patients who underwent surgical debulking after progression on imatinib or sunitinib. To interrogate possible resistance mechanisms across a broad biological spectrum of GISTs, inter- and intra-lesional heterogeneity of molecular drug-resistance mechanisms were evaluated in the following: conventional KIT (CD117)-positive GISTs with KIT mutations in exon 9, 11 or 13; KIT-negative GISTs; GISTs with unusual morphology; and KIT/PDGFRA wild-type GISTs. Genomic KIT and PDGFRA mutations were characterized systematically, using complementary techniques including D-HPLC for KIT exons 9, 11-18 and PDGFRA exons 12, 14, 18, and mutation-specific PCR (V654A, D820G, N822K, Y823D). Primary KIT oncogenic mutations were found in 11/14 patients (79%). Of these, 9/11 (83%), had secondary drug-resistant KIT mutations, including six (67%) with two to five different secondary mutations in separate metastases, and three (34%) with two secondary KIT mutations in the same metastasis. The secondary mutations clustered in the KIT ATP binding pocket and kinase catalytic regions. FISH analyses revealed KIT amplicons in 2/10 metastases lacking secondary KIT mutations. This study demonstrates extensive intra- and inter-lesional heterogeneity of resistance mutations and gene amplification in patients with clinically progressing GIST. KIT kinase resistance mutations were not found in KIT/PDGFRA wild-type GISTs or in KIT-mutant GISTs showing unusual morphology and/or loss of KIT expression by IHC, indicating that resistance mechanisms are fundamentally different in these tumours. Our observations underscore the heterogeneity of clinical TKI resistance, and highlight the therapeutic challenges involved in salvaging patients after clinical progression on TKI monotherapies.

Eutrophication of lake waters in China: cost, causes, and control

Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophication and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.

Safety and immunogenicity of heptavalent pneumococcal CRM197 conjugate vaccine in infants and toddlers

OBJECTIVES

The objectives of this study were (1) to determine the safety and immunogenicity of heptavalent pneumococcal CRM197 conjugate (PNCRM7) vaccine in infants and (2) to determine the effect of concurrent hepatitis B immunization during the primary series and the effect of concurrent diphtheria and tetanus toxoid and acellular pertussis [DTaP (ACEL-IMUNE)] and conjugate CRM197 Haemophilus influenzae type b [HbOC (HibTITER) immunization at time of the booster dose on the safety and immunogenicity of PNCRM7and these other concurrently administered vaccines.

METHODS

This was a randomized double-blinded study in 302 healthy infants in the Northern California Kaiser Permanente (NCKP) Health Plan. Infants received either PNCRM7 vaccine or meningococcal group C conjugate vaccine as a control at 2, 4 and 6 months of age and a booster at 12 to 15 months of age. Study design permitted the evaluation of immunology and safety of concurrent administration of routine vaccines. Antibody titers were determined on blood samples drawn before and 1 month after the primary series and the booster dose.

RESULTS

After the third dose of PNCRM7 geometric mean concentrations (GMCs) ranged from 1.01 for serotype 9V to 3.72 microg/ml for serotype 14. More than 90% of all subjects had a post-third dose titer of > or =0.15 microg/ml for all serotypes, and the percentage of infants with a post-third dose titer of > or =1.0 microg/ml ranged from 51% for type 9V to 89% for type 14. After the PNCRM7 booster dose, the GMCs of all seven serotypes increased significantly over both post-Dose 3 and pre-Dose 4 antibody levels. In the primary series there were no significant differences in GMCs of pneumococcal antibodies between the subjects given PN-CRM7 alone or concurrently with hepatitis B vaccine. At the toddler dose concurrent administration of PNCRM7 and DTaP and HbOC resulted in a near conventional threshold for statistical significance of a post-Dose 4 GMC for serotype 23F [alone 6.75 mirog/ml vs. concurrent 4.11 microg/ml (P = 0.057)] as well as significantly lower antibody GMCs for H. influenza polyribosylribitol phosphate, diphtheria toxoid, pertussis toxin and filamentous hemagglutinin. For all antigens there were no differences between study groups in defined antibody titers that are considered protective.

CONCLUSION

We conclude that PNCRM7 vaccine was safe and immunogenic. When this vaccine was administered concurrently at the booster dose with DTaP and HbOC vaccines, lower antibody titers were noted for some of the antigens when compared with the antibody response when PNCRM7 was given separately. Because the GMCs of the booster responses were all generally high and all subjects achieved similar percentages above predefined antibody titers, these differences are probably not clinically significant.

Unilateral cortical FLAIR-hyperintense Lesions in Anti-MOG-associated Encephalitis with Seizures (FLAMES): characterization of a distinct clinico-radiographic syndrome

OBJECTIVE

To characterize the clinical symptoms and magnetic resonance imaging (MRI) findings of unilateral cortical FLAIR-hyperintense Lesions in Anti-MOG-associated Encephalitis with Seizures (FLAMES).

METHODS

This is a case report and systematic review of the literature to identify cases of unilateral cortical FLAMES. Cases were reviewed to determine the frequency of clinical symptoms (seizures, headache, fever and cortical symptoms referable to FLAMES location), and to determine whether MRI abnormalities are restricted to the unilateral cortex in this syndrome.

RESULTS

We identified 20 cases of unilateral cortical FLAMES for review. Among them, 17/20 (85%) had seizures, 14/20 (70%) had headache, 13/20 (65%) had fever, 11/20 (55%) reported cortical symptoms referable to the FLAMES location, and 19/20 (95%) reported at least two of these four findings. On MRI 4/20 (20%) had some contralateral hemispheric cortical signal abnormality, and 6/20 (30%) had MRI findings concerning for meningeal inflammation.

CONCLUSIONS

In patients with unilateral cortical FLAMES, the clinical symptoms of seizures, headache, fever and cortical symptoms referable to the FLAMES location are frequent. Although initially described as a unilateral cortical encephalitis, bilateral cortical involvement and possible meningeal inflammation could indicate a broader disease spectrum. Recognition of this distinct clinico-radiographic syndrome may facilitate prompt diagnosis and treatment.

Sensorineural hearing loss in otitis media

Additional evidence is presented to support the hypothesis that both acute purulent otitis media (POM) and chronic suppurative otitis media (COM) can cause high frequency sensorineural hearing loss. In selected patients and in animals (chinchillas) in a pilot study using electrophysiological methods, both temporary threshold shifts and permanent threshold shifts of basal cochlear turn involvement were demonstrated in POM. Data of cochlear involvement in 475 ears with bilateral COM, 607 ears with unilateral COM, and 607 ears serving as controls were obtained from six centers in five countries. In group 1 (15 dB or greater), 43% of ears with unilateral COM and 42% of ears with bilateral COM showed losses, for a combined odds ratio eight times that in controls. In group 2 (30 dB or greater), 16% of ears with unilateral COM and 17% of ears with bilateral COM demonstrated, respectively, seven and ten times that in controls. These statistically significant findings influence clinical considerations.

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.

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.

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.

Survival from spinal cord injury

Mean survival of 110.5 months (9 yr. 2.5 months) for spinal cord-injured persons who died between 1963 to 1976 compared favorable with the figure of 52.8 months (4 yr, 4.8 months) calculated in 1955 by Dietrick and Russi [1]. If suicides were not considered, then mean longevity for the deceased patients would be 126 months (10 yr, 6 months). The leading causes of death were related to the cardiovascular system, respiratory system, suicide and the urinary tract.

Metabolites of a tobacco-specific lung carcinogen in nonsmoking women exposed to environmental tobacco smoke

BACKGROUND

Environmental tobacco smoke (ETS) is associated with lung cancer in nonsmokers. Most epidemiologic studies find a higher risk for lung cancer in nonsmoking women married to smokers than in those married to nonsmokers. We measured metabolites of a tobacco-specific lung carcinogen in urine from healthy, nonsmoking women exposed to ETS.

METHODS

We recruited women and their partners through advertisements. Couples completed questionnaires on smoking history and demographics, and both partners provided 100 mL of urine; 23 women had male partners who smoked in the home (i.e., exposed women), and 22 women had male partners who did not smoke (i.e., unexposed women). Urine samples were analyzed for nicotine, for cotinine, for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide (NNAL-Gluc), as well as for creatinine. NNAL and NNAL-Gluc are metabolites of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Unpaired Student's t tests were conducted on log-transformed values. All statistical tests are two-sided.

RESULTS

Urinary levels of nicotine, cotinine, NNAL, and NNAL-Gluc were statistically significantly higher in exposed women than in unexposed women. Geometric means for these compounds in exposed versus unexposed women, respectively, were as follows: nicotine, 0.050 nmol/mg of creatinine (95% confidence interval [CI] = 0.033 to 0.076) versus 0.008 nmol/mg of creatinine (95% CI = 0.004 to 0.014); cotinine, 0.037 nmol/mg of creatinine (95% CI = 0.022 to 0.061) versus 0.007 nmol/mg of creatinine (95% CI = 0.004 to 0.011); NNAL, 0.013 pmol/mg of creatinine (95% CI = 0.007 to 0.024) versus 0.004 pmol/mg of creatinine (95% CI = 0.002 to 0.007); and NNAL-Gluc, 0.027 pmol/mg of creatinine (95% CI = 0.016 to 0.045) versus 0.004 pmol/mg of creatinine (95% CI = 0.003 to 0.006).

CONCLUSIONS

Nonsmoking women exposed to ETS take up and metabolize the tobacco-specific lung carcinogen NNK, which could increase their risk of lung cancer. Within couples, the NNAL plus NNAL-Gluc level in exposed women compared with that of their smoking partners averaged 5.6%. Notably, epidemiologic studies have estimated the excess risk for lung cancer in nonsmoking women exposed to ETS as 1%-2% of that in smokers.

Thickness of the human round window membrane in different forms of otitis media

The thickness and morphologic characteristics of the round window membrane were evaluated in temporal bones from normal subjects as well as those with serous otitis media, purulent otitis media, and chronic otitis media. Temporal bones were studied in chronological order in six age ranges to determine the possibility of age-related differences. No significant difference in the mean thickness of the round window membrane was observed in terms of age groups in normal temporal bones or temporal bones from patients with otitis media; however, a significant difference in the mean thickness was observed in the various forms of otitis media compared with the normal round window membrane in all age groups. The membrane was thickest in patients with chronic otitis media when compared with that in normal subjects or those with serous or purulent otitis media. The epithelial layer (including the subepithelial space) and the fibrous layer were measured individually to determine in which layer the change in mean thickness occurred. These measurements showed an involvement of all layers of the round window membrane in those groups with otitis media, with maximal involvement of the combined epithelial layer and subepithelial space.

The clinical syndrome of specific antibody deficiency in children

Specific antibody deficiency (SAD) is an immune deficiency which has been reported in adults and children with recurrent respiratory tract infections; however, the clinical features of SAD are not well described. This study evaluated formally the clinical syndrome of SAD, by comparing the clinical features of children with SAD and those of children with recurrent infection but normal immune function tests. SAD was defined as an adequate IgG antibody response to less than 50% of 12 pneumococcal serotypes tested following 23-valent unconjugated pneumococcal immunization. An adequate IgG antibody response was defined as a post-immunization titre of >or= 1.3 microg/ml or >or= four times the preimmunization value. Seventy-four children with recurrent infection were evaluated where immune deficiencies other than SAD had been excluded. Eleven (14.9%) of these children had SAD. Clinical features differed between the group with SAD and the group with normal antibody responses. A history of otitis media, particularly in association with chronic otorrhoea was associated with SAD [relative risk (RR) of SAD in those with chronic otorrhoea 4.64 (P = 0.02)]. SAD was associated with allergic disease, particularly allergic rhinitis [RR of SAD in those with allergic rhinitis 3.77 (P = 0.04)]. These two clinical associations of SAD were independent in this study [RR of chronic otorrhoea in those with allergic rhinitis 0.85 (P = 0.28)]. SAD was not an age-related phenomenon in this population. SAD has a distinct clinical phenotype, presenting as recurrent infection associated with chronic otorrhoea and/or allergic disease, and the condition should be sought in children with these features.

Xenotransplantation of human lymphoid malignancies is optimized in mice with multiple immunologic defects

While it is known that mice with genetic immune defects are useful for establishing durable engraftment of human tumor xenografts, the relative role of components of host innate and adoptive immunity in engraftment has not been determined. We directly compared the ability of four strains of genetically immunodeficient mice (NOD/SCID, SCID, Nude and Rag-1-deficient) to successfully engraft and support the human cell lines Daudi, Raji, Namalwa and Molt-4 as subcutaneous tumors. We additionally examined the effect of further immunosuppression of the mice by whole body irradiation at a dose of 600 cGy for Nude and Rag-1 and 300 cGy for SCID mice and by administration of anti-natural killer (asialo-GM1) antibody on tumor growth. Mice with each of the defects supported xenografts to varying degrees. We found differences in growth characteristics in the cell lines tested, with Namalwa consistently producing the largest tumors. With all cell lines studied, optimal growth was achieved using NOD/SCID mice. Overall, tumor growth was somewhat enhanced by pretreatment with radiation with little additional benefit from the addition of anti-asialo-GM1 antibody. The importance of multiple components of the innate and adoptive immune system in xenotransplantation were best demonstrated when results in untreated NOD/SCID mice were compared to SCID, nude and RAG-1-deficient mice. The NOD/SCID mouse with or without additional immunosuppression provides the optimal model for the study of the biology and treatment of human leukemias and lymphomas.

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.

The bacteriology and cytology of chronic otitis media with effusion

The bacteriology and cytology of middle ear effusion from 729 children with persistent otitis media with effusion were studied. Thirty-five percent of these chronic effusions were culture-positive. Type b and non-type b Haemophilus influenzae, Streptococcus pneumoniae, Neisseria sp. and Staphylococcus epidermidis were the predominant isolates. Serous and mucoid effusion cultures yielded bacteria more often in younger than in older children. In addition bacteria were seen in 17% of the Gram-stained smears of the sterile effusions; Gram-positive cocci predominated in these effusions. Disparate effusion culture results were obtained in 32% of bilateral otitis media cases. Effusions which yielded H. influenzae and S. pneumoniae on culture had more polymorphonuclear leukocytes than did effusions which yielded S. epidermidis or Neisseria or were sterile. Phagocytic cells were equally prevalent in sterile effusions with or without bacteria on Gram stain. Phagocytic cells were seen less often in mucoid effusions from antibiotic-treated patients than in mucoid effusions from untreated patients. The results suggest that certain bacteria in chronic middle ear effusion contribute to the pathogenesis of this condition by eliciting a local inflammatory cell response.

A critical role for choline kinase-alpha in the aggressiveness of bladder carcinomas

Bladder cancer is one of the most common causes of death in industrialized countries. New tumor markers and therapeutic approaches are still needed to improve the management of bladder cancer patients. Choline kinase-alpha (ChoKalpha) is a metabolic enzyme that has a role in cell proliferation and transformation. Inhibitors of ChoKalpha show antitumoral activity and are expected to be introduced soon in clinical trials. This study aims to assess whether ChoKalpha plays a role in the aggressiveness of bladder tumors and constitutes a new approach for bladder cancer treatment. We show here that ChoKalpha is constitutively altered in human bladder tumor cells. Furthermore, in vivo murine models, including an orthotopic model to mimic as much as possible the physiological conditions, revealed that increased levels of ChoKalpha potentiate both tumor formation (P< or =0.0001) and aggressiveness of the disease on different end points (P=0.011). Accordingly, increased levels of ChoKalpha significantly reduce survival of mice with bladder cancer (P=0.05). Finally, treatment with a ChoKalpha-specific inhibitor resulted in a significant inhibition of tumor growth (P=0.02) and in a relevant increase in survival (P=0.03).

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.

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.

Comparative immunogenicity of vaccines prepared from capsular polysaccharides of group C Neisseria meningitidis O-acetyl-positive and O-acetyl-negative variants and Escherichia coli K92 in adult volunteers

Three structurally and antigenically similar capsular polysaccharides, two derived from group C Neisseria meningitidis (O-acetyl-positive and O-acetyl-negative variants) and one from Escherichia coli K92, which cross-reacts with polysaccharide from group C N. meningitidis, were compared for their ability to induce anticapsular and bactericidal antibodies to group C N. meningitidis in adult volunteers. All three vaccines elicited group C-specific serum antibodies. The vaccine derived from the O-acetyl-negative variant was the most immunogenic of the three vaccines. With use of radiolabeled O-acetyl-positive group C N. meningitidis polysaccharide antigen, the geometric mean titers of antibody in serum were 41.7 microgram/ml to the O-acetyl-negative variant, 22.8 microgram/ml to the O-acetyl-positive variant, and 7.1 microgram/ml to E. coli K92. Antibodies induced by all three vaccines were bactericidal for both of the group C N. meningitidis polysaccharide variants. An inverse relation between the comparative immunogenicity of the O-acetyl-negative polysaccharide and the virulence of group C N. meningitidis was found.

Normal patterns of angiogenesis and extracellular matrix deposition in chick chorioallantoic membranes are disrupted by mainstream and sidestream cigarette smoke

The adverse effects of cigarette smoke on mature blood vessels are well established, whereas little is known about the influence of smoke on blood vessel development. To determine if cigarette smoke alters angiogenesis, chick chorioallantoic membranes (CAMs) were exposed for 4 days to culture medium (control) or to mainstream (MS) or sidestream (SS) smoke solution, and then blood vessel patterns were compared in blind tests. In contrast to the normal tree-like branching of control blood vessels, smoke-treated CAMs often had vessels that ran parallel to each other without much branching. A significant increase in the number of fibroblasts was observed in histological sections of treated CAMs, and this increase correlated with alterations in extracellular matrix components. Many more matrix fibrils were observed in treated CAMs than in controls using scanning electron microscopy. Immunohistochemistry showed that type III collagen was distributed in a tight band adjacent to the endoderm in controls but was distributed throughout the mesoderm in both treatment groups. Western blots confirmed that both type I and type III collagen were more abundant in treated CAMs than in controls. Fibronectin, which was localized immunohistochemically in the basal laminae and mesodermal matrix of controls, increased in abundance in CAMs treated with SS smoke solutions. Hyaluronic acid, which was present in a dense band subjacent to the capillary plexus of control CAMs, was greatly reduced in MS-treated CAMs and was absent in SS-treated CAMs. These observations demonstrate that both MS and SS cigarette smoke solutions caused abnormal pattern formation of CAM blood vessels and altered the composition of the extracellular matrix in the CAM mesoderm.

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.

Decline of serum antibody in splenectomized children after vaccination with pneumococcal capsular polysaccharides

Asplenic persons are at increased risk of overwhelming sepsis caused by Streptococcus pneumoniae. Vaccination with polyvalent pneumococcal polysaccharide has been shown to stimulate a nearly normal antibody response in these individuals, indicating that active vaccination might prevent pneumococcal disease in this population. To obtain information on the duration of protective levels of pneumococcal antibody, 33 asplenic children were vaccinated and antibody levels were measured at intervals for up to 4 1/2 years after vaccination. Significant antibody decline was observed in children who had undergone splenectomy because of trauma, but antibody decline was not observed in children whose spleens had been removed because of hereditary spherocytosis. There was a highly significant difference in rates of antibody decline among the 12 antibody serotypes measured: types 1, 4, 6A, 7F, 8, 19F, and 23F showed the greatest decline. Based on measured rates of antibody decline, subprotective antibody levels (antibody nitrogen less than 300 ng/ml) for types 7F, 8, and 19F would be reached 1 to 2 years after vaccination; type 6A never reached the protective level; and antibodies against the remaining eight types either were within the protective range initially or did not show significant decline. Asplenic children may benefit from revaccination with certain antigen types (7F, 8, and 19F) 1 to 2 years after initial vaccination.

Experimental animal models for studying antimicrobial pharmacokinetics in otitis media

Antimicrobial treatment of otitis media, especially drug dosing considerations, is largely empiric, with few reported pharmacologic studies of drug distribution into the middle ear. A chinchilla animal model of serous and purulent otitis media has been used for some time to investigate mechanisms of disease pathogenesis. This model was adapted to investigate the penetration of amoxicillin, trimethoprim, and sulfamethoxazole into middle ear effusion. Purulent otitis media was produced by direct middle ear inoculation with type 7F Streptococcus pneumoniae. Serous otitis media was produced by eustachian tube obstruction using silastic sponge or Coeflex cement, but the Coeflex caused an undesirable local inflammatory response. The three antibiotics were administered to chinchillas with serous and purulent middle ear effusion. Plasma and ear fluid drug concentrations were measured by liquid chromatography and demonstrated the value of this model in assessing antibiotic penetration.

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.