Single CD271 marker isolates mesenchymal stem cells from human dental pulp

Mesenchymal stem cells (MSCs) are a promising tool in regenerative medicine due to their capacity to differentiate into multiple lineages. In addition to MSCs isolated from bone marrow (BMSCs), adult MSCs are isolated from craniofacial tissues including dental pulp tissues (DPs) using various stem cell surface markers. However, there has been a lack of consensus on a set of surface makers that are reproducibly effective at isolating putative multipotent dental mesenchymal stem cells (DMSCs). In this study, we used different combinations of surface markers (CD51/CD140α, CD271, and STRO-1/CD146) to isolate homogeneous populations of DMSCs from heterogeneous dental pulp cells (DPCs) obtained from DP and compared their capacity to undergo multilineage differentiation. Fluorescence-activated cell sorting revealed that 27.3% of DPCs were CD51⁺/CD140α⁺, 10.6% were CD271⁺, and 0.3% were STRO-1⁺/CD146⁺. Under odontogenic conditions, all three subsets of isolated DMSCs exhibited differentiation capacity into odontogenic lineages. Among these isolated subsets of DMSCs, CD271⁺ DMSCs demonstrated the greatest odontogenic potential. While all three combinations of surface markers in this study successfully isolated DMSCs from DPCs, the single CD271 marker presents the most effective stem cell surface marker for identification of DMSCs with high odontogenic potential. Isolated CD271⁺ DMSCs could potentially be utilized for future clinical applications in dentistry and regenerative medicine.     

Sensory innervation around immediately vs. delayed loaded implants:a pilot study

Although neurophysiological and psychophysical proof of osseoperception is accumulating, histomorphometric evidence for the neural mechanisms of functional compensation following immediate and delayed ...     

Growth inhibitory response and ultrastructural modification of oral-associated candidal reference strains （ATCC） by Piper betle L. extract

Candida species have been associated with the emergence of strains resistant to selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease mucosal fungal infections. This study aimed to investigate the effects of Piper betle extract on the growth profile and the ultrastructure of commonly isolated oral candidal cells. The major component of Po betle was identified using liquid chromatography-mass spectrophotometry （LC-MS/MS）. Seven ATCC control strains of Candida species were cultured in yeast peptone dextrose broth under four different growth environments： （i） in the absence of P. betle extract; and in the presence of P. beUeextract at respective concentrations of （ii） 1 mg.mL-1; （iii） 3 mg.mL-1; and （iv） 6 mg.mL- 1 The growth inhibitory responses of the candidal cells were determined based on changes in the specific growth rates （μ）. Scanning electron microscopy （SEM） was used to observe any ultrastructural alterations in the candida colonies. LC-MS/MS was performed to validate the presence of bioactive compounds in the extract. Following treatment, it was observed that the p-values of the treated cells were significantly different than those of the untreated cells （P〈0.05）, indicating the fungistatic properties of the P. beUe extract. The candidal population was also reduced from an average of 13.44× 10^6 to 1.78×10^6 viable cell counts （CFU）.mL-1, SEM examination exhibited physical damage and considerable morphological alterations of the treated cells. The compound profile from LC-MS/MS indicated the presence of hydroxybenzoic acid, chavibetol and hydroxychavicol in P. betle extract. The effects of P. betle on candida cells could potentiate its antifungal activity.     

Tumor Necrosis Factor-alpha-mutant Mice Exhibit High Frequency Hearing Loss

Exogenous tumor necrosis factor-alpha (TNF-α) plays a role in auditory hair cell death by altering the expression of apoptosis-related genes in response to noxious stimuli. Little is known, however, about the function of TNF-α in normal hair cell physiology. We, therefore, investigated the cochlear morphology and auditory function of TNF-α-deficient mice. Auditory evoked brainstem response showed significantly higher thresholds, especially at higher frequencies, in 1-month-old TNF-α^−/− mice as compared to TNF-α^+/− and wild type (WT); hearing loss did not progress further from 1 to 4 months of age. There was no difference in the gross morphology of the organ of Corti, lateral wall, and spiral ganglion cells in TNF-α^−/− mice compared to WT mice at 4 months of age, nor were there differences in the anatomy of the auditory ossicles. Outer hair cells were completely intact in surface preparations of the organ of Corti of TNF-α^−/− mice, and synaptic ribbon counts of TNF-α^−/− and WT mice at 4 months of age were similar. Reduced amplitudes of distortion product otoacoustic emissions, however, indicated dysfunction of outer hair cells in TNF-α^−/− mice. Scanning electron microscopy revealed that stereocilia were sporadically absent in the basal turn and distorted in the middle turn. In summary, our results demonstrate that TNF-α-mutant mice exhibit early hearing loss, especially at higher frequencies, and that loss or malformation of the stereocilia of outer hair cells appears to be a contributing factor.     

Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties

The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.     

Calcitonin and vitamin D3 have high therapeutic potential for improving diabetic mandibular growth

The goal of this study was to assess the effect of the intermittent combination of an antiresorptive agent (calcitonin) and an anabolic agent (vitamin D3) on treating the detrimental effects of Type 1 diabetes mellitus (DM) on mandibular bone formation and growth. Forty 3-week-old male Wistar rats were divided into four groups: the control group (normal rats), the control C1D group (normal rats injected with calcitonin and vitamin D3), the diabetic C1D group (diabetic rats injected with calcitonin and vitamin D3) and the diabetic group (uncontrolled diabetic rats). An experimental DM condition was induced in the male Wistar rats in the diabetic and diabetic C1D groups using a single dose of 60 mg?kg–1 body weight of streptozotocin. Calcitonin and vitamin D3 were simultaneously injected in the rats of the control C1D and diabetic C1D groups. All rats were killed after 4 weeks, and the right mandibles were evaluated by micro-computed tomography and histomorphometric analysis. Diabetic rats showed a significant deterioration in bone quality and bone formation (diabetic group). By contrast, with the injection of calcitonin and vitamin D3, both bone parameters and bone formation significantly improved (diabetic C1D group) (P < 0.05). These findings suggest that these two hormones might potentially improve various bone properties.     

Chemical composition of Galla chinensis extract and the effect of its main component(s) on the prevention of enamel demineralization in vitro

To determine the chemical composition of Galla chinensis extract(GCE) by several analysis techniques and to compare the efficacy of GCE and its main component(s) in inhibition of enamel demineralization,for the development of future anticaries agents,main organic composition of GCE was qualitatively determined by liquid chromatography-time of flight-mass spectrometry(LC-TOF-MS) and quantified by high-performance liquid chromatography-diode array detector(HPLC-DAD).Inorganic ions were tested by inductively coupled plasma-atomic emission spectroscopy and F was especially measured by ion chromatography.Then,bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times.Each cycle included 5-min applications with one of four treatments:4 g?L 21 GCE solution,4 g?L 21 gallic acid(GA) solution,1 g?L 21 NaF solution(positive control),deionized water(DDW,negative control),and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer.Acidic buffers were retained for calcium analysis.The main organic composition of GCE were GA and its isomer,and,to a lesser extent,small molecule gallotannins.The content of GA in GCE was 71.3%60.2%(w/w).Inorganic ions were present in various amounts,of which Ca was(13662.82) mg?g 21,and Zn was(6.860.1) mg?g 21.No F was detected in GCE.In pH cycling,GA showed an effect similar to GCE in inhibiting enamel demineralization(P.0.05).GA was found to be the main effective,demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.     

Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients

This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients （TECs）, when zirconia ceramics were coloured at green stage. Zirconia blocks （N=240; 6 mm x 7 mm x 7 mm） were manufactured from two materials namely, ICE Zirconia （Group 1） and Prettau Zirconia （Group 2）. In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid （shade A2）, Three different veneering ceramics with different TEC （ICE Ceramic, GC Initial Zr and IPS e.max Ceram） were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys （Esteticor Plus） veneered with ceramic （VM 13） （n= 16） acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine （0.5 mm-min-1）. Neither the zirconia core material （P=0.318） nor colouring （P=0.188） significantly affected the results （three-way analysis of variance, Tukey＇s test）. But the results were significantly affected by the veneering ceramic （P=0.000）. Control group exhibited significantly higher mean bond strength values （45.7__.8） MPa than all other tested groups （（27.1__.4.1）-（39.7__.4.7） and （27.4__.5.6）-（35.9___4.7） MPa with and without colouring, respectively） （P~0.001）. While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering ~ 1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered 1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.     

A Genome-Wide Association Study of Chronic Otitis Media with Effusion and Recurrent Otitis Media Identifies a Novel Susceptibility Locus on Chromosome 2

Chronic otitis media with effusion (COME) and recurrent otitis media (ROM) have been shown to be heritable, but candidate gene and linkage studies to date have been equivocal. Our aim was to identify genetic susceptibility factors using a genome-wide association study (GWAS). We genotyped 602 subjects from 143 families with 373 COME/ROM subjects using the Illumina Human CNV370-Duo DNA Bead Chip (324,748 SNPs). We carried out the GWAS scan and imputed SNPs at the regions with the most significant associations. Replication genotyping in an independent family-based sample was conducted for 53 SNPs: the 41 most significant SNPs with P < 10⁻⁴ and 12 imputed SNPs with P < 10⁻⁴ on chromosome 15 (near the strongest signal). We replicated the association of rs10497394 (GWAS discovery P = 1.30 × 10⁻⁵) on chromosome 2 in the independent otitis media population (P = 4.7 × 10⁻⁵; meta-analysis P = 1.52 × 10⁻⁸). Three additional SNPs had replication P values < 0.10. Two were on chromosome 15q26.1 including rs1110060, the strongest association with COME/ROM in the primary GWAS (P = 3.4 ×10⁻⁷) in KIF7 intron 7 (P = 0.072), and rs10775247, a non-synonymous SNP in TICRR exon 2 (P = 0.075). The third SNP rs386057 was on chromosome 5 in TPPP intron 1 (P = 0.045). We have performed the first GWAS of COME/ROM and have identified a SNP rs10497394 on chromosome 2 is significantly associated with COME/ROM susceptibility. This SNP is within a 537 kb intergenic region, bordered by CDCA7 and SP3. The genomic and functional significance of this newly identified locus in COME/ROM pathogenesis requires additional investigation.     

Expression of Mucins in Mucoid Otitis Media

A hallmark of mucoid otitis media (MOM, i.e., chronic otitis media with mucoid effusion) is mucus accumulation in the middle ear cavity, a condition that impairs transduction of sounds in the ear and causes hearing loss. The mucin identities of mucus and the underlying mechanism for the production of mucins in MOM are poorly understood. In this study, we demonstrated that the MUC5B and MUC4 were major mucins in MOM that formed distinct treelike polymers (mucus strands). The MUC5B and MUC4 mRNAs in the middle ear mucosa with MOM were up regulated 5-fold and 6-fold, compared with the controls. This upregulation was accompanied by the extensive proliferation of the MUC5B- and MUC4-producing cells in the middle ear epithelium. Further study indicated that the mucin hyperproduction was significantly linked to CD4⁺ and CD8⁺ T cells and/or CD68⁺ monocyte macrophages. It suggests that MUC5B and MUC4 expression may be regulated by the products of these cells.     

Hearing Loss is an Early Consequence of Npc1 Gene Deletion in the Mouse Model of Niemann–Pick Disease,Type C

Niemann–Pick disease, type C1 (NPC1) is a rare lysosomal lipidosis that is most often the result of biallelic mutations in NPC1, and is characterized by a fatal neurological degeneration. The pathophysiology is complex, and the natural history of the disease is poorly understood. Recent findings from patients with NPC1 and hearing loss suggest that multiple steps along the auditory pathway are affected. The current study was undertaken to determine the auditory phenotype in the Npc1^nih mutant mouse model, to extend analyses to histologic evaluation of the inner ear, and to compare our findings to those reported from human patients. Auditory testing revealed a progressive high-frequency hearing loss in Npc1^−/− mice that is present as early as postnatal day 20 (P20), well before the onset of overt neurological symptoms, with evidence of abnormalities involving the cochlea, auditory nerve, and brainstem auditory centers. Distortion product otoacoustic emission amplitude and auditory brainstem response latency data provided evidence for a disruption in maturational development of the auditory system in Npc1^−/− mice. Anatomical study demonstrated accumulation of lysosomes in neurons, hair cells, and supporting cells of the inner ear in P30 Npc1^−/− mice, as well as increased numbers of inclusion bodies, myelin figures, and swollen nerve endings in older (P50–P70) mutant animals. These findings add unique perspective to the pathophysiology of NPC disease and suggest that hearing loss is an early and sensitive marker of disease progression.     

Enhanced Vestibulo-ocular Reflex to Electrical Vestibular Stimulation in Meniere’s Disease

Meniere’s disease is characterized by sporadic episodes of vertigo, nystagmus, fluctuating sensorineural hearing loss, tinnitus and aural pressure. Since Meniere’s disease can affect different regions of the vestibular labyrinth, we investigated if electrical vestibular stimulation (EVS) which excites the entire vestibular labyrinth may be useful to reveal patchy endorgan pathology. We recorded three-dimensional electrically evoked vestibulo-ocular reflex (eVOR) to transient EVS using bilateral, bipolar 100-ms current steps at intensities of 0.9, 2.5, 5.0, 7.5 and 10.0 mA with dual-search coils in 12 unilateral Meniere’s patients. Their results were compared to 17 normal subjects. Normal eVOR had tonic and phasic spatiotemporal properties best described by the torsional component, which was four times larger than horizontal and vertical components. At EVS onset and offset of 8.9 ms latency, there were phasic eVOR initiation (M = 1,267 °/s²) and cessation (M = −1,675 °/s²) acceleration pulses, whereas during the constant portion of the EVS, there was a maintained tonic eVOR (M = 9.1 °/s) at 10 mA. However in Meniere’s disease, whilst latency of EVS onset and offset was normal at 9.0 ms, phasic eVOR initiation (M = 1,720 °/s²) and cessation (M = −2,523 °/s²) were enlarged at 10 mA. The initiation profile was a bimodal response, whilst the cessation profile frequently did not return to baseline. The tonic eVOR (M = 20.5 °/s) exhibited a ramped enhancement of about twice normal at 10 mA. Tonic eVOR enhancement was present for EVS >0.9 mA and disproportionately enhanced the torsional, vertical and horizontal components. These eVOR abnormalities may be a diagnostic indicator of Meniere’s disease and may explain the vertigo attacks in the presence of declining mechanically evoked vestibular responses.     

Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects

This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.     

Hyperpolarization-Activated Current (I h) in Vestibular Calyx Terminals: Characterization and Role in Shaping Postsynaptic Events

Calyx afferent terminals engulf the basolateral region of type I vestibular hair cells, and synaptic transmission across the vestibular type I hair cell/calyx is not well understood. Calyces express several ionic conductances, which may shape postsynaptic potentials. These include previously described tetrodotoxin-sensitive inward Na⁺ currents, voltage-dependent outward K⁺ currents and a K(Ca) current. Here, we characterize an inwardly rectifying conductance in gerbil semicircular canal calyx terminals (postnatal days 3–45), sensitive to voltage and to cyclic nucleotides. Using whole-cell patch clamp, we recorded from isolated calyx terminals still attached to their type I hair cells. A slowly activating, noninactivating current (I_h) was seen with hyperpolarizing voltage steps negative to the resting potential. External Cs⁺ (1–5 mM) and ZD7288 (100 μM) blocked the inward current by 97 and 83 %, respectively, confirming that I_h was carried by hyperpolarization-activated, cyclic nucleotide gated channels. Mean half-activation voltage of I_h was −123 mV, which shifted to −114 mV in the presence of cAMP. Activation of I_h was well described with a third order exponential fit to the current (mean time constant of activation, τ, was 190 ms at −139 mV). Activation speeded up significantly (τ = 136 and 127 ms, respectively) when intracellular cAMP and cGMP were present, suggesting that in vivo I_h could be subject to efferent modulation via cyclic nucleotide-dependent mechanisms. In current clamp, hyperpolarizing current steps produced a time-dependent depolarizing sag followed by either a rebound afterdepolarization or an action potential. Spontaneous excitatory postsynaptic potentials (EPSPs) became larger and wider when I_h was blocked with ZD7288. In a three-dimensional mathematical model of the calyx terminal based on Hodgkin–Huxley type ionic conductances, removal of I_h similarly increased the EPSP, whereas cAMP slightly decreased simulated EPSP size and width.     

Porphyromonas gingivalis Resistance to Polymyxin B Is Determined by the Lipid A 4'-Phosphatase, PGN_0524

Aim To elucidate the genetic basis for the pronounced resistance that the oral pathogen, Porphyromonas gingivalis （P. gingivalis）, exhibits towards the cationic antimicrobial peptide, polymyxin B. Methodology A genetic screen of P. gingivalis clones generated by a Tn4400-based random insertion mutagenesis strategy was performed to identify bacteria harboring novel genetic mutations that render P. gingivalis susceptible to killing by the cationic antimicrobial peptide, polymyxin B （PMB, 50μg·mL^-1）. Results P. gingivalis （ATCC 33277） is unusually resistant to the cationic antimicrobial peptide, PMB at relatively high concentrations （200μg·mL^-1）. Approximately 2,700 independent Tn4400 ＇-derived mutants ofP. gingivalis were examined for increased sensitivity to PMB killing at a relatively low dose （50 μg·mL^-1）. A single PMB-sensitive mutant was obtained in this phenotypic screen. We determined that the Tn4400＇ transposon was integrated into the gene encoding the lipid A 4＇-phosphatase, PGN 0524, demonstrating that this insertion event was responsible for its increased susceptibility of this clone to PMB-dependent killing. The resulting mutant strain, designated 0524-Tn4400＇, was highly sensitive to PMB killing relative to wild-type P. gingivalis, and exhibited the same sensitivity as the previously characterized strain, 0524KO, which bears a genetically engineered deletion in the PGN_0524 locus. Positive ion mass spectrometric structural （MALDI-TOF MS） analyses revealed that lipid A isolates from 0524-Tn4400＂ and 0524KO strains displayed strikingly similar MALDI-TOF MS spectra that were substantially different from the wildtype P gingivalis lipid A spectrum. Finally, intact 0524- Tn4400＇ and 0524KO mutant bacteria, as well as their corresponding LPS isolates, were significantly more potent in stimulating Toll-like receptor 4 （TLR4）-dependent E-selectin expression in human endothelial cells relative to intact wild-type P.. gingivalis or its corresponding LPS isolate. Co     

Circadian gene expression in the murine larynx

Objective

Symptoms of airway diseases are often associated with specific times of the day. For example, midnight worsening of cough is a frequent complaint of patients with laryngitis and bronchitis. We speculate that these symptoms are under the control of the circadian clock, and the clock genes in the airway epithelium play some important roles. In the present study, we tried to prove the time specific expressions of clock oscillating genes in the murine larynx.

Materials and methods

Adult wild-type C57/Bl6 mice and mCry1^−/−mCry2^−/− mutant mice were used for this study. We employed immunohistochemistry and/or Northern blotting for examining the circadian expression of mPer1, mPer2, C/EBPbeta, HNF3beta, and MUC5b.

Results

The expression of mPer2 mRNA showed a strong day–night expression difference, which was abolished after the lesion of the suprachiasmatic nucleus, and in mCry1^−/−mCry2^−/− mutant mice. mPER1 and mPER2 proteins both showed very similar expression profiles in the epithelium and submucosal glands with a peak in the evening and a trough in the early morning. Other nuclear proteins such as C/EBPbeta and HNF3beta did not show the rhythms. MUC5b protein showed circadian oscillation in the laryngeal submucosal gland.

Conclusion

In this study, we confirmed the existence of a local laryngeal clock which is controlled by the central clock in the suprachiasmatic nucleus. MUC5b protein in the submucosal mucous gland also showed circadian rhythm. We consider that these rhythmic expressions may cause the time specific symptoms among laryngeal diseases.     

Optimal continuous positive airway pressure level in korean patients with obstructive sleep apnea syndrome

Objectives

The aim of this study was to investigate optimal continuous positive airway pressure (CPAP) level, to examine the factors affecting optimal CPAP level, and to develop a predictive equation for optimal CPAP level in Korean patients with obstructive sleep apnea syndrome (OSAS).

Methods

A total of 202 patients with OSAS who underwent successful manual titration for CPAP treatment were included in this study. Correlations between the optimal CPAP level and baseline data including anthropometric and polysomnographic variables were analyzed. A predictive equation for optimal CPAP level was developed based on anthropometric and polysomonographic data.

Results

The mean optimal CPAP level in 202 patients with OSAS was 7.8±2.3 cm H₂O. The mean optimal CPAP level in the mild, moderate, and severe OSAS groups was 6.0±1.3, 7.4±1.9, and 9.1±2.1 cm H₂O, respectively. The apneahypopnea index (AHI) (r=0.595, P<0.001), arousal index (r=0.542, P<0.001), minimal SaO₂ (r=-0.502, P<0.001), body mass index (BMI) (r=0.494, P<0.001), neck circumference (r=0.265, P<0.001), and age (r=-0.164, P=0.019) were significantly correlated with optimal CPAP level. The best predictive equation according to stepwise multiple linear regression analysis was: Optimal CPAP level (cm H₂O)=0.681+(0.205×BMI)+(0.040×AHI). Forty-two percent of the variance in the optimal CPAP level was explained by this equation (R²=0.42, P<0.001).

Conclusion

A predictive equation for optimal CPAP level in Korean patients with OSAS was developed using AHI and BMI, which can be easily measured during the diagnostic process.