Jumping combined exercise programs reduce fall risk and improve balance and life quality of elderly people who live in a long-term care facility.

AIM: The objective of this study was to determine whether regular combined exercise program, which consists strength, stretching and aerobic exercises and additional jumping training, improve balance, fall risk, quality of life and depression status of older people living in a residential care. METHODS: A total of 168 residents who live in a long term care facility were screened. The trial began with 78 eligible participants and they were randomly grouped as combined exercises program (COM) group that includes stretching, strength and aerobic exercises, and COM plus jumping (COMpJ) group. 66 of the participants finished the trial. The groups were convened three times a week for six weeks. Each group had a warm-up, effective training and a cooling down periods. The total exercising time was no longer than 45 minutes in each group. Berg balance test and Biodex Balance System for the assessment of the dynamic balance and fall risk, short form 36 (SF 36) for the health related quality of life and Geriatric Depression Scale (GDS) for evaluation of the depression status were used. RESULTS: The balance improvement and fall risk reduction were observed in both of the groups at the end of the trial; however, the improvements were statistically better in jumping combined group. Also health related quality of life improved in both groups. CONCLUSION: Regular group exercise in a long term care facility have several beneficial effects on the elderly residents in regard to balance improvement, fall risk reduction and quality of life. The addition of jumping to strength, stretching and aerobic exercises provides important contributions to balance improvement and fall risk reduction.

Conserved extended haplotypes discriminate HLA-DR3-homozygous Basque patients with type 1 diabetes mellitus and celiac disease.

The major susceptibility locus for type 1 diabetes mellitus (T1D) maps to the human lymphocyte antigen (HLA) class II region in the major histocompatibility complex on chromosome 6p21. In southern European populations, like the Basques, the greatest risk to T1D is associated with DR3 homo- and heterozygosity and is comparable to that of DR3/DR4, the highest risk genotype in northern European populations. Celiac disease (CD) is another DR3-associated autoimmune disorder showing certain overlap with T1D that has been explained by the involvement of common genetic determinants, a situation more frequent in DR3-rich populations, like the Basques. As both T1D- and CD-associated HLA alleles are part of conserved extended haplotypes (CEH), we compared DR3-homozygous T1D and CD patients to determine whether CEHs were equally distributed between both disorders or there was a differential contribution of different haplotypes. We observed a very pronounced distribution bias (P<10(-5)) of the two major DR3 CEHs, with DR3-B18 predominating in T1D and DR3-B8 in CD. Additionally, high-density single nucleotide polymorphism (SNP) analysis of the complete CEH [A*30-B*18-MICA*4-F1C30-DRB1*0301-DQB1*0201-DPB1*0202] revealed extraordinary conservation throughout the 4.9 Mbp analyzed supporting the existence of additional diabetogenic variants (other than HLA-DRB1*0301-DQB1*0201), conserved within the DR3-B18 CEH (but not in other DR3 haplotypes) that could explain its enhanced diabetogenicity.

HLA-Cw*0409N is associated with HLA-A*2301 and HLA-B*4403-carrying haplotypes.

The associations of HLA-B*4402 and HLA-B*4403 with alleles of HLA-A and HLA-Cw were investigated in panels of HLA-B*4403 and HLA-B*4402 homozygous individuals and in selected individuals carrying HLA-Cw*04 and HLA-B*4403. Some of these individuals were genotyped and also carried (HLA-DRB1*0701, DQB1*02). Among the latter, we studied individuals carrying the conserved extended haplotype (CEH) [HLA-Cw*04, B*4403, FC31, DRB1*0701, DQB1*02]. Four different common (HLA-Cw*, B*44) haplotypes were identified that extended to the HLA-A locus: HLA-A*0201, Cw*0501, B*4402; HLA-A*2902, Cw*1601, B*4403; HLA-A*2301, Cw*0401, B*4403; and HLA-A*2301, Cw*0409N, B*4403. We identified eight unrelated examples of the allele HLA-Cw*0409N. HLA-A*2301 was associated with both HLA-Cw*0401 and HLA-Cw*0409N, suggesting that HLA-Cw*0409N may have arisen from a mutation in a CEH. We estimate that approximately 2 to 5 in 1000 Caucasian individuals carry the allele HLA-Cw*0409N, making it one of the most frequent null HLA alleles known to date. Our findings demonstrate the first example of three different HLA-Cw-determined subtypes of a common or CEH carrying a shared HLA-B allele, in this case HLA-B*4403.

Inheritable variable sizes of DNA stretches in the human MHC: conserved extended haplotypes and their fragments or blocks.

The difference in sizes of conserved stretches of DNA sequence within the major histocompatibility complex (MHC) in human individuals constitutes an underappreciated genetic diversity that has many practical implications. We developed a model to describe the variable sizes of stretches of conserved DNA in the MHC using the known frequencies of four different kinds of small (< 0.2 Mb) blocks of relatively conserved DNA sequence: HLA-Cw/B; TNF; complotype; and HLA-DR/DQ. Each of these small blocks is composed of two or more alleles of closely linked loci inherited as one genetic unit. We updated the concept of the conserved extended haplotype (CEH) using HLA allele identification and TNF microsatellites to show that specific combinations of the four blocks form single genetic units (>/= 1.5 Mb) with a total haplotype frequency in the Caucasian population of 0.30. Some CEHs extend to the HLA-A and -DPB1 loci forming fixed genetic units of up to at least 3.2 Mb of DNA. Finally, intermediate fragments of CEHs also exist, which are, nevertheless, larger than any of the four small blocks. This complexity of genetic fixity at various levels should be taken into account in studies of genetic disease association, immune response control, and human diversity. This knowledge could also be used for matching CEHs and their fragments for patients undergoing allotransplantation.

Effects of chronic peanut consumption on energy balance and hedonics.

OBJECTIVE: To investigate the effects of chronic peanut consumption on energy balance and hedonics. DESIGN: Thirty-week, cross-over, intervention study. Participants were provided 2113+/-494 kJ/day (505+/-118 kcal/day) as peanuts for 8 weeks with no dietary guidance (free feeding-FF), 3 weeks with instructions to add peanuts to their customary diet (addition-ADD) and 8 weeks where peanuts replaced an equal amount of other fats in the diet (substitution-SUB). SUBJECTS: Fifteen, healthy, normal-weight (BMI of 23.3+/-1.8) adults, aged 33+/-9 y. MEASUREMENTS: Dietary intake, appetitive indices, energy expenditure, body weight and hedonics. RESULTS: During FF, peanut consumption elicited a strong compensatory dietary response (ie subjects compensated for 66% of the energy provided by the nuts) and body weight gain (1.0 kg) was significantly lower than predicted (3.6 kg; P<0.01). When customary dietary fat was replaced with the energy from peanuts, energy intake, as well as body weight, were maintained precisely. Participants were unaware that body weight was a research focus. Resting energy expenditure was increased by 11% after regular peanut consumption for 19 weeks (P<0.01). Chronic consumption of peanuts did not lead to a decline in pleasantness or hunger ratings for peanuts nor did it lead to any hedonic shift for selected snack foods with other taste qualities during any of the three treatments. CONCLUSIONS: Despite being energy dense, peanuts have a high satiety value and chronic ingestion evokes strong dietary compensation and little change in energy balance.

Hepatitis B surface antigen- and tetanus toxoid-specific clonal expansion of CD4+ cells in vitro determined by TCRBV CDR3 length and nucleotide sequence.

We demonstrate activation of primary human TCRBV-specific CD4+ cells in vitro towards hepatitis B surface antigen (HBsAg) and tetanus toxoid (TT) without the use of cell lines, clones or added cytokines. By multiplex PCR analysis and spectratyping, antigen-activated cells exhibited clonal T cell receptor expansion within specific and limited TCRBV families. The expanded CD4+ T cells were CD45RO. Three of four unrelated HBsAg responders showed CD4+ expansion within the TCRBV16 family. The response comprised predominantly single CDR3 sequences in all three donors and was completely monoclonal in one of them. However, the CDR3 lengths and sequences differed among the responders. Clonality induced by HBsAg in TCRBV16 was specific, reproducible and distinct from that induced by TT in terms of sequence, nucleotide addition and diversity (BD) or junctional (BJ) element usage. Thus, for the first time, we show monoclonal or oligoclonal expansion of primary human CD4- peripheral blood mononuclear cells (PBMC) in vitro in response to nominal protein antigen without manipulations utilizing exogenous IL-2. The ability to induce monoclonal/ oligoclonal responses to HBsAg now permits motif identification studies for determining the T cell role in nonresponsiveness to the HBsAg vaccine.

Incomplete penetrance of MHC susceptibility genes: prospective analysis of polygenic MHC-determined traits.

We propose an approach to understanding incomplete penetrance of disease susceptibility genes as a method of studying the underlying mechanisms of polygenic diseases. Incomplete penetrance is the failure of genetically susceptible individuals to exhibit a trait. We define as baseline penetrance that which occurs in genetically identical (monozygotic) twins of an index subject with a major histocompatibility complex (MHC)-associated disease or trait. We consider two mechanisms for incomplete baseline penetrance: an extrinsic (environmental) trigger and an intrinsic stochastic, gene-associated process. The latter can be detected for dominant expression because susceptibility genes in homozygotes (with their two intrinsic triggers) will be up to twice as frequently penetrant as those in heterozygotes. The extent of MHC and non-MHC gene contribution determines differences between baseline penetrance and apparent penetrance in MHC-identical sib pairs, sib pairs in general and MHC-identical unrelated individuals. Inheritance patterns in families do not reveal modes of inheritance of incompletely penetrant polygenic MHC-determined traits. A method is proposed to study such traits prospectively in persons presumed to be homozygous, heterozygous or non-carrying for susceptibility genes by determining trait expression in homozygotes, heterozygotes or non-carriers of trait-associated conserved extended MHC haplotypes. The method provides direct estimates of apparent penetrance rates, modes of genetic determination, and, if the trait is dominant, the origin of penetrance. When applied to dominant MHC susceptibility gene-determined immunoglobulin deficiencies in two populations, the ratios of affected haplotype homozygotes to heterozygotes near 2.0 were consistent with an intrinsic mechanism for baseline penetrance acting on the MHC susceptibility genes.

Prospective analysis suggests susceptibility genes for deficiencies of IgA and several other immunoglobulins on the [HLA-B8, SC01, DR3] conserved extended haplotype.

The extended major histocompatibility complex (MHC) haplotype [HLA-B8, SC01, DR3] is increased in frequency among patients with immunoglobulin (Ig)A deficiency and common variable immunodeficiency. Because the genomic region from HLA-B to HLA-DR/DQ is virtually the same on all instances of the haplotype in the general population, we reasoned that all independent instances of [HLA-B8, SC01, DR3] carry MHC susceptibility genes for these disorders. To define immunoglobulin deficiencies determined by genes on this haplotype and their mode of expression and penetrance, serum immunoglobulin class and IgG subclass concentrations were determined prospectively in homozygotes and heterozygotes of this haplotype and in Caucasian controls. Prevalence of individual immunoglobulin deficiencies in persons with [HLA-B8, SC01, DR3] ranged from 13% to 37%, significantly higher than rates in non-carriers or general controls. We found significantly increased frequencies of IgA and IgG4 deficiency only in homozygotes (13.3% and 30%, respectively) compared with heterozygotes (1.7% and 3.4%) or non-carriers (1.6% each), suggesting recessive expression. In contrast, IgD and IgG3 deficiencies were significantly more common in both homozygotes (36.7% and 30%) and heterozygotes (20.3% and 17.5%) compared with controls (4.9% and 3.4%), suggesting dominant inheritance. These results indicate multiple distinct susceptibility genes, some recessive and others dominant, for deficiency of IgA, IgD, IgG3 or IgG4 (but not for IgE, IgG1, IgG2 or IgM) on [HLA-B8, SC01, DR3]. These observations may also help to explain the observed associations of [HLA-B8, SC01, DR3] with both IgA deficiency and common variable immunodeficiency and the common occurrence of IgG subclass deficiencies in some patients with IgA deficiency.

The [HLA-B18, F1C30, DR3] conserved extended haplotype carries a susceptibility gene for IgD deficiency.

We showed previously that the conserved extended MHC haplotype [HLA-B8, SCO1, DR3] carries recessive susceptibility genes for IgA and IgG4 deficiency and dominant genes for IgD and IgG3 deficiency. [HLA-B18, F1C30, DR3] has similar class II and III regions to [HLA-B8, SC01, DR3] and is common in the Basques. We therefore studied serum immunoglobulin concentrations in Basque homozygotes, heterozygotes, and noncarriers of (FIC30, DRB1*0301, DRB3*02, DQA1*0501. DQB1*0201) (F1C30, DR3). As shown by others, no subjects were deficient in IgA, IgM, or IgG subclasses. In contrast, 29% of homozygotes and three of seven double heterozygotes with (SC01, DRB1*0301, DRB3*0101, DQA1*0501, DQB1*0201) (presumed homozygotes for IgD deficiency susceptibility genes) were IgD deficient. Thus, 32% of presumed homozygotes were IgD deficient compared with 1.6% of noncarriers. Of haplotype heterozygotes, 25% were IgD deficient. The high frequency of IgD deficiency in both homozygotes and heterozygotes for (F1C30, DR3) suggests a partially penetrant dominant susceptibility gene for IgD deficiency on [HLA-B18, F1C30, DR3].

Host-pathogen interactions in emerging and re-emerging infectious diseases: a genomic perspective of tuberculosis, malaria, human immunodeficiency virus infection, hepatitis B, and cholera.

On exposure to a pathogen, a host may resist infection, become subclinically infected, or progress through several stages from mild to severe infection. Chronic sequelae may or may not occur. Host factors, particularly host genes, influence many of these stages. We have used a model of the continuum of pathogenesis of infectious diseases to consider the effect of host genes on five pathogens of significant public health burden: Mycobacterium tuberculosis, Plasmodium species, human immunodeficiency virus, hepatitis B virus, and Vibrio cholerae. The relationships between these infections and polymorphisms in human leukocyte antigen, cytokines, other immune response, or pathogen receptor genes are reviewed. We discuss gene-gene interactions and their effects in complex settings, such as coinfections with several pathogens. Priorities for prevention and control of these pathogens include vaccines and antimicrobial drugs. Research on how host genes can influence vaccine responses and the efficacy of drugs or other interventions, as well as further research into the relationship of host genes to infectious disease outcomes, may lead to new strategies for prevention and control.

A simple estimate of the general population frequency of the MHC susceptibility gene for autoimmune polygenic disease.

We wished to determine the frequencies of the MHC and non-MHC susceptibility genes for polygenic autoimmune diseases like type 1 diabetes (IDDM). We used Mendelian inheritance and the Hardy-Weinberg equilibrium to calculate the frequencies of mating pairs and susceptible offspring under classical recessive and dominant inheritance of the MHC susceptibility gene. We then analyzed the distribution of haplotype sharing by affected sib pairs of the 4 MHC haplotypes in each of the kinds of mating pairs in terms of the frequency of the disease susceptibility gene. For IDDM, the analysis was consistent with a recessive, but not a dominant, MHC susceptibility gene of frequency 0.525 at a distribution of 55, 38 and 7% of affected sib pairs who share 2, 1 and 0 MHC haplotypes, respectively. A simple relationship was obtained: if inheritance is recessive, the MHC susceptibility gene frequency is the square root of the fraction of affected sib pairs who share no MHC haplotypes multiplied by 4. For recessive inheritance, affected sib pairs who share no haplotypes are solely in families where both parents are homozygous MHC-susceptible. Although homozygous MHC susceptibles represent over 25% of the population, only 2-3% of them are IDDM-susceptible at non-MHC susceptibility loci, also required for disease expression. Predictions from our analysis fit all published observations of the familial occurrence of disease. The analysis is general, simple and provides a single estimate (not a range) of the MHC susceptibility gene frequency. This approach should be applicable to other MHC-determined polygenic diseases.

Complex cytokine responses to hepatitis B surface antigen and tetanus toxoid in responders, nonresponders and subjects naive to hepatitis B surface antigen.

Some human subjects vaccinated with hepatitis B surface antigen (HBsAg) do not produce antibodies to the vaccine (nonresponders). The mechanism for nonresponse is unknown. To understand the response and nonresponse to nominal antigens better, we determined the level and kinetics of cytokine secretion in response to HBsAg and tetanus toxoid (TT) by peripheral blood mononuclear cells (PBMC) in vitro from HBsAg vaccine responders and nonresponders and from individuals naive to HBsAg. Proliferating PBMC secreted peak levels of interleukin-2 (IL-2) at 2 days and peak levels of tumor necrosis factor-beta (TNF-beta), interferon-gamma (IFN-gamma), IL-4 and IL-10 at 3-6 days post-stimulation. In contrast, nonproliferating PBMC (whether from nonresponders, naive subjects or weak responders) did not produce detectable levels of TNF-beta or IFN-gamma, nor was IL-4 or IL-10 produced significantly, and that produced had a different kinetic profile from that of proliferating PBMC. HBsAg-specific cytokine production by PBMC from strong responders broadly paralleled their cytokine responses to TT. Cellular cytokine mRNA levels measured by reverse transcriptase-polymerase chain reaction corroborated the secreted cytokine results. The anti-HBsAg- and anti-TT-specific T cell cytokine responses were mixed Th(1/2)-like and donor-specific. An HBsAg-specific cytokine response, but not a TT-specific cytokine response, was completely missing in nonresponders. These data suggest that the T cell defect of HBsAg nonresponse is not due to a skewed cytokine profile.

Prevention of otitis media with effusion by repeated air inflation in a monkey model.

OBJECTIVES: To test the following hypotheses that (1) middle ear (ME) air inflation prevents the development of otitis media with effusion in a monkey model of functional eustachian tube obstruction, and (2) ME inflation treatment of otitis media with effusion can cause artifactual clinical improvements due to fluid displacement from the tympanum to the adjacent airspaces. DESIGN: Randomized controlled trial. SUBJECTS: Twelve cynomolgus monkeys. INTERVENTIONS: Eustachian tube dysfunction was induced by botulinum paralysis of the right tensor veli palatini muscle in all monkeys. Before and on study days 9, 15, and 21 after paralysis, the presence or absence, and distribution of ME effusion were documented using magnetic resonance imaging (MRI). Right and left ears were examined twice daily for 21 days using tympanometry, and right ME air inflation (n = 6 ears) or sham inflation (n = 6 ears) was done immediately after those examinations if the ME pressure was -100 mm H2O or less. On 10 of the scheduled MRI evaluations, the MRI was repeated immediately after an inflation to document the possible redistribution of fluid within the ME caused by the maneuver. RESULTS: Middle ear pressure remained within normal limits for the follow-up period in 11 of the 12 nonparalyzed left ears, in none of the 6 sham-inflated right ears, and in 3 of the 6 air-inflated right ears. Three air-inflated right ears developed flat tympanograms (ie, days 14 through 16). Magnetic resonance imaging documented inflammation and fluid in 1 of the 11 nonparalyzed left ears and in all sham-inflated right ears. Lesser degrees of inflammation and effusion based on MRI evaluations were noted for the 3 air-inflated right ears that retained near-ambient pressures when compared with the right 3 ears that developed a flat tympanogram. The MRI measure of effusion quantity within the tympanum was decreased acutely after inflation, but was simultaneously increased in the adjacent airspaces of the temporal bone. CONCLUSIONS: Repeated air inflation prevented the development of otitis media with effusion in 50% of the ears with functional eustachian tube obstruction. Postinflation MRI documented the displacement of fluid by inflation from the tympanum to the mastoid and petrous air cells. Using standard clinical evaluations such as tympanometry and otoscopy, this fluid redistribution can cause a false diagnosis of improvement.

The effects of changing middle ear pressure and gas partial pressure on mucosal blood flow and vascular permeability in the chinchilla.

OBJECTIVE: To determine if middle ear (ME) gas composition and/or total pressure regulates local mucosal blood flow (MBF) and vascular permeability. The hypotheses tested are: (1) relatively high local CO2 tensions and/or low O2 tensions increase the ME MBF and vascular permeability; and (2) sub-atmospheric total ME pressure provokes similar effects. METHODS: The responses of ME MBF and vascular permeability parameters were measured during 60 min exposures of chinchilla MEs to one of two test gas mixtures (16.3% O2, 5.1% CO2, balance N2, or 5.3% O2, 15.6% CO2, balance N2) applied at different levels of underpressure (ref. ambient). In the first set of experiments (n = 19), mucosal perfusion parameters were recorded using a Laser Doppler Flowmeter for 60 min before and 60 min after exposure to the experimental conditions. In the second set of experiments (n = 19 chinchillas, 38 ears), the MEs were exposed to the gas mixtures and then maintained for 60 min at ambient pressure or at negative pressures of -200, -400, -600 mmH2O. Fifty minutes into the experiment, the animals were injected intravenously with 60 mg/kg of horseradish peroxidase (HRP). The animals were killed and existing effusion was aspirated, its volume recorded and then analyzed for total protein. From surface preparations of the ME mucosa, vascular leakage sites were measured as percent total surface area using an image analysis program with the threshold window set to discriminate HRP stain. RESULTS: Throughout the 120 min in the first set of experiments, the measured MBF parameters decreased in all exposure groups. Comparisons among groups for the absolute magnitude of the change from baseline showed that high local CO2 partial pressures decreased MBF and ME underpressures increased MBF, but the effects did not achieve statistical significance. The results of the second set of experiments demonstrated no effect of gas composition on any of the measured parameters of vascular permeability. All measures of permeability were linearly related to the magnitude of the underpressure. CONCLUSION: These data support a role for total ME pressure, but not CO2 partial pressure in regulating ME MBF and vascular permeability.

Treatment of chronic suppurative otitis media with topical tobramycin and dexamethasone.

OBJECTIVES: To investigate the safety and efficacy of a topical combination of tobramycin and dexamethasone in a primate model of chronic suppurative otitis media (CSOM) and to explore the contribution of the added topical steroid for the treatment of CSOM. DESIGN: Blinded, randomized, placebo-controlled trial. SUBJECTS: Sixty juvenile cynomolgus monkeys randomized into the following 6 treatment groups of 10 monkeys each: 0.3% tobramycin (group 1), combined 0.3% tobramycin-0.1% dexamethasone (group 2), combined 1.0% tobramycin-0.33% dexamethasone (group 3), 0.1% dexamethasone (group 4), vehicle (group 5), and phosphate-buffered saline solution (group 6). INTERVENTIONS: Chronic suppurative otitis media was established by inoculating the right ear with Pseudomonas aeruginosa. After 4 weeks of drainage, animals were treated according to the group assignment with 3 drops twice daily for 7 weeks. Hearing thresholds were monitored with repeated auditory brainstem response testing (ABR), and clinical response was monitored with repeated otoscopic examinations and cultures throughout the study. Cytocochleograms were evaluated for quantification of outer hair cell loss. RESULTS: Rapid resolution of otorrhea and eradication of P aeruginosa occurred in all groups receiving tobramycin. The inclusion of dexamethasone accelerated the resolution of otorrhea and negative yields of cultures compared with tobramycin alone. Otorrhea and positive culture findings persisted in the groups not treated with topical antibiotic. Results of ABRs at 4 and 8 weeks and cytocochleograms for outer cell hair loss were not affected by drug administration. Perilymph samples collected at the end of the study showed no detectable tobramycin. CONCLUSIONS: Combined tobramycin-dexamethasone ear drops were safe and effective in the monkey CSOM model. Dexamethasone enhanced the efficacy of tobramycin.

Genetics of the complement system.

After a brief history of complement genetics, general considerations and applications to our understanding of immune function, evolution, population structure and migration and forensic medicine, selected topics in complement genetics are presented. For individual complement proteins, genetic polymorphisms and deficiency states are described, as are the molecular bases of some of them. The clinical abnormalities exhibited by some patients with complement deficiency states are discussed, as are possible pathophysiologic mechanisms for them. The chromosomal location and the close linkage and a sharing of structural features by groups of complement proteins, such as the complotypes of the major histocompatibility complex, the regulators of complement activation, Clr and Cls, and the terminal components C6, C7 and C9, are presented in some detail. From these facts, the broad outlines are drawn of the evolution of the classical and alternative complement pathways from the lectin pathway and the terminal pathway from a common progenitor. From markers within the complotype region, rough conclusions are delineated regarding the evolution of C2, factor B, C4A and C4B alleles.

Validation by magnetic resonance imaging of tympanometry for diagnosing middle ear effusion.

This study was performed to correlate tympanometric gradient with measurements of effusion quantity by use of MRI during an experimental otitis media with effusion episode in 4 cynomolgus monkeys. Paired results for the intensity values of the T(2)-weighted MRI scans and the tympanometric width measured in the right ear of all animals before and on days 15, 21, 29, and 36 after botulinum paralysis of the tensor veli palatini muscle were analyzed. All right ears showed a progressive increase during the study period in the signal intensity of the MRI. Whereas the average middle ear pressures decreased, the average tympanometric widths demonstrated a progressive increase during the course of the experimental otitis media with effusion. Significant correlations between tympanometric width and MRI measures of effusion were documented, confirming the high predictive value of the tympanometric width for diagnosing the presence and quantity of middle ear effusion.

Circulating CD2+ monocytes are dendritic cells.

Low levels of CD2 have been described on subsets of monocytes, macrophages, and dendritic cells. CD2 is expressed on about one-third of circulating monocytes, at levels one-half log lower than on T or NK cells, representing 2-4% of PBMC. FACS analysis of CD2+ and CD2- monocytes revealed no significant difference in the expression of adhesion molecules (CD11a/b/c), class II Ags (HLA-DR, -DQ, -DP), myeloid Ags (CD13, CD14, CD33), or costimulatory molecules (CD80, CD86). Freshly isolated CD2+ and CD2- monocytes were morphologically indistinguishable by phase contrast microscopy. However, scanning electron microscopy revealed large prominent ruffles on CD2+ monocytes in contrast to small knob-like projections on CD2- monocytes. After 2 days of culture, the CD2+ monocytes largely lost CD14 expression and developed distinct dendrites, whereas the CD2- monocytes retained surface CD14 and remained round or oval. Freshly isolated CD2+ monocytes were more potent inducers of the allogeneic MLR and more efficiently induced proliferation of naive T cells in the presence of HIV-1 gp120 than did CD2- monocytes. After culture in the presence of GM/CSF and IL-4, CD2+ monocytes were up to 40-fold more potent than monocyte-derived dendritic cells or CD2- monocytes at inducing allogeneic T cell proliferation. These findings suggest that circulating CD2+ and CD2- monocytes are dendritic cells and the precursors of macrophages, respectively. Thus, dendritic cells are far more abundant in the blood than previously thought, and they and precursors of macrophages exist in the circulation as phenotypically, morphologically, and functionally distinct monocyte populations.

MRI validation of the accuracy of tympanometric gradient for the diagnosis of OME.

Tympanometry provides a rapid, non-invasive and objective assessment of middle ear (ME) status and is widely used for the clinical diagnosis and follow-up of otitis media with effusion (OME). ME pressure, acoustic admittance and tympanometric gradient are the main test parameters used in making assignments to diagnostic classes (i.e. presence or absence of effusion, effusion quantity). Of these, the tympanometric gradient was suggested to be more sensitive to the presence of effusion, but this has not been demonstrated conclusively and no standard definition of that gradient is accepted. In this study, 10 cynomolgus monkeys with experimental OME were used to compare the diagnosis of OME made using three different methods to estimate tympanometric gradient with that provided by simultaneous magnetic resonance imaging (MRI) of the ME. All three methods of tympanometric gradient measurement were highly correlated with the quantity of ME effusion measured by the MRI. Although not significant, the MRI results were better correlated with those for the 'width' method when compared to either the 'difference' or the 'ratio' method of gradient estimation. This study demonstrates the use of MRI as a gold standard for evaluating the accuracy of other methods to diagnose ME effusion.