The clinical utility of anthropometric measures to assess adiposity in a cohort of prematurely born infants: Correlations with MRI fat quantification.

OBJECTIVE: To correlate magnetic resonance imaging (MRI) of body fat in preterm infants at the time of hospital discharge with same-day anthropometric measures, and to assess the clinical utility of body mass index (BMI), waist circumference (WC), and WC/length ratio as indicators of visceral fat. STUDY DESIGN: MRI performed prior to NICU discharge in 25 infants born preterm at <32 weeks gestation. Total body fat and visceral fat were quantified using a commercial software program. The Pearson correlation coefficient (r, 95% C.I.) was used to describe strength of association between MRI fat and anthropometric measures. RESULTS: BMI and weight at discharge were strongly correlated with total body fat (r = 0.95 and 0.89 respectively; p < 0.001). Total body fat as a % of body weight was moderately correlated with weight (r = 0.53), WC (r = 0.52), and BMI (r = 0.47). Weight, BMI, and ponderal index all were found to correlate with total visceral fat (r = 0.65, 0.64, 0.55 respectively) but WC did not (r = 0.28). WC/length ratio was not correlated with any MRI fat measurements. CONCLUSIONS: BMI and weight at discharge both correlate with MRI fat measurements. Our findings do not support the usefulness of measuring WC or WC/length ratio in preterm infants at term-equivalent age.

Cloning and expression of malarial pyrimidine enzymes.

We have cloned genes encoding three enzymes of the de novo pyrimidine pathway using genomic DNA from Plasmodium falciparum and sequence information from the Malarial Genome Project. Genes encoding dihydroorotase (reaction 3), orotate phosphoribosyltransferase (reaction 5), and OMP decarboxylase (reaction 6) have been cloned into the plasmid pET 3a or 3d with a thrombin cleavable 9xHis tag at the C-terminus and the enzymes were expressed in Escherichia coli. To overcome the toxicity of malarial OMP decarboxylase when expressed in E. coli, and the unusual codon usage of the malarial gene, a hybrid plasmid, pMICO, was constructed which expresses low levels of T7 lysozyme to inhibit T7 RNA polymerase used for recombinant expression, and extra copies of rare tRNAs. Catalytically-active OMP decarboxylase has been purified in tens of milligrams by chromatography on Ni-NTA. The gene encoding orotate phosphoribosyltransferase includes an extension of 66 amino acids from the N-terminus when compared with sequences for this enzyme from other organisms. We have found that other pyrimidine enzymes also contain unusual protein inserts. Milligram quantities of pure recombinant malarial enzymes from the pyrimidine pathway will provide targets for development of novel antimalarial drugs.

Magnetic resonance imaging in the evaluation of occult submucous cleft palate.

OBJECTIVE: To explore the application of magnetic resonance imaging (MRI) in the evaluation of patients with occult submucous cleft palate and to use the MRI information obtained to aid in the treatment decision to perform surgery versus behavioral speech therapy. DESIGN: Prospective study with magnetic resonance (MR) images of subjects suspected of having occult submucous cleft palate. SETTING: Hospital and university-based. PATIENTS: Two girls who were 4 years old at the time of palatal surgery. INTERVENTION: Furlow double-opposing Z-plasty. MAIN OUTCOME MEASURES: MR images and clinical speech evaluations. RESULTS: MR images provided evidence of an interruption of levator veli palatini muscle tissue in the midline and a substantial attachment of levator muscle tissue to the posterior border of the hard palate. In addition, MR images for both subjects demonstrated remarkably similar bilateral encapsulating sheaths that contained nonmuscular tissue, as confirmed subsequently during surgery. The encapsulating sheaths interrupted the normal progression of the levator muscle sling across the midline. The MR images led to the decision to perform surgery instead of speech therapy. Hypernasality was markedly reduced in both subjects after surgery. CONCLUSIONS: MRI is an effective technique for diagnosing occult submucous cleft palate and may be an important aid in the treatment decision regarding surgery versus behavioral speech therapy for patients diagnosed with occult submucous cleft palate.

Induced fatigue effects on velopharyngeal closure force.

This investigation studied the effects of induced velopharyngeal fatigue in speakers with normal mechanisms. Five adult female and 5 adult male subjects were used. A force sensing bulb was placed in the velopharynx to measure velopharyngeal closure force and intramuscular electrodes were inserted in the levator veli polatini muscle to sample muscle activation levels. The subjects' task was to repeat the syllable /si/100 times while an external load was placed on the velopharyngeal mechanism. The external load consisted of various levels of air pressure (0 as a control, 5, 15, 25, and 35 cm H2O relative to atmospheric pressure) delivered to the nasal passages via a tube and nasal mask assembly. Fatigue was defined as a declination of force across the series of syllables within a pressure condition and was depicted as the slope of a linear regression line that was fit to the data. The more negative the slope, the greater was the rate of fatigue. Within each experimental pressure condition, small cyclic variations in force were noted about each regression line that corresponded to individual breath groups. This type of declination, within breath groups, has been reported in the literature previously. Overall declination in force over an entire series of syllables and over several breath groups is a new finding. It was possible to induce such fatigue in most subjects, and greater rates of fatigue generally occurred at the higher levels of external loading, i.e., at 25 and 35 cm H2O. Two subjects, 1 male and 1 female, reached exhaustion. The female subject could not perform the syllable repetition task at 25 cm H2O, and the male subject could not complete the task at 35 cm H2O. Three subjects, 1 female and 2 males, exhibited virtually no force declination even at the highest level (35 cm H2O) of external loading. There were no discernable differences in patterns of fatigue or in initial velopharygeal closure force values between the male and female subjects.

Infant sleep position. Nursing practice and knowledge.

PURPOSE: (1) to examine the extent to which maternal/child health nurses caring for children accept the American Academy of Pediatrics recommendations on infant sleep position, (2) to determine if nurses are practicing according to the AAP recommendations, and (3) to determine the type of bedding utilized in the two institutions for infants. METHODS: Descriptive survey using 103 nurses in 2 institutions, and an observational assessment of nurses' practice. RESULTS: Findings revealed that 97% of the nursing staff were aware of the AAP recommendations, although only 67% agreed with the recommendations. The observational component of the investigation evaluated the sleep position during hospitalization of 206 infants < 6 months old on both the pediatric and maternity units of the two institutions. Fifty-five percent of the infants were observed to be in the side-lying position, 29% in the recommended supine (back) position, and 16% in the prone (abdomen) sleeping position. The recommended firm bedding was observed with 63% of the infants, whereas the remainder of the infants were observed to be on foam mattresses, extra blankets, or gel packs. CLINICAL IMPLICATIONS: Because side sleeping position was observed in the majority of infants, and one-third of the nurses queried disagreed with the AAP recommendations, education of nurses about Sudden Infant Death Syndrome prevention through "Back to Sleep" is still necessary.

A finite element model of the soft palate.

OBJECTIVE: As a step toward better understanding of normal and abnormal velar control, a finite element model of the soft palate was developed. DESIGN: A static two-dimensional midsagittal model of the velum was given physical dimensions to match that of a 10-year-old boy. Biomechanical properties of the tissues were inferred based on previous histologic studies. Velar movements were induced by the influence of three extrinisic velar muscles: the levator veli palatini, the palatoglossus, and the palatopharyngeus, which were simulated as external forces acting on the velar model. RESULTS AND CONCLUSIONS: Velopharyngeal opened and closed positions were simulated as well as a variety of intermediate steps between the two configurations. Velopharyngeal closure was also simulated in a manner appropriate for both high and low vowels. Future extensions of the model will incorporate the muscles as an intrinsic component of the model and will include a full time-dependent implementation, including inertial effects. Future studies will compare model predictions with experimental data from the laboratory, including both kinematic data and velopharyngeal closure forces.

An anatomic study of the tensor veli palatini and dilatator tubae muscles in relation to eustachian tube and velar function.

In a gross anatomic study of 20 sides in 16 human head specimens, the tensor veli palatini, the dilatator tubae, and the tensor tympani muscles were studied. The tensor veli palatini was observed to insert onto the anterior one-third of the pterygoid hamulus, whereas the dilatator tubae rounded the middle one-third of the pterygoid hamulus without an insertion. Thus, the dilatator tubae, not the tensor veli palatini, could serve to tense the anterior velum. An insertion from the superior pharyngeal constrictor muscle onto the posterior one-third of the hamulus could provide a curbing function for the dilatator tubae muscle. Adipose tissue, located at the hamulus, could provide lubrication for the tendinous fibers of the dilatator tubae as they round the hamulus. The dilatator tubae was observed to attach to the hook of the eustachian tube and is accepted as the tubal dilator. Observed on 13 of 20 sides in 11 specimens, the bulk of the dilatator tubae remained distinct from the tensor veli palatini despite a connective tissue alliance and intermingling of some muscle fibers. On 5 of 20 sides in 5 specimens, fibers of the dilatator tubae intermingled extensively with the tensor veli palatini. Of the 20 dilatator tubae muscles dissected, 2 were observed to be deficient. The tensor veli palatini was observed to be continuous with the tensor tympani. Full color versions of the figures are available at the following website: http://www.shc.uiowa.edu/papers/tensor/.

Velopharyngeal closure force and levator veli palatini activation levels in varying phonetic contexts.

The purpose of this study was to measure velopharyngeal closure force in varying phonetic contexts for normal men and women subjects. Levator veli palatini muscle activity was measured as well. Place and manner of articulation, voicing, and the effects of consonant sequencing were studied in different vowel contexts. When the data were grouped by sex of subject, no differences were found in absolute values of velopharyngeal closure force for the men versus women subjects. As expected, nonnasal consonants were produced with greater velopharyngeal closure force than nasal consonants. High vowels were produced with greater closure force than low vowels. Closure force was greater for voiceless than for voiced consonants but only for the men and only within /i/ and /u/ contexts. The lingua-dorsal consonant was associated with greater closure force than the lingua-apical consonant but only for the men and only in the high-back vowel environment. Significant differences in closure force were not found between fricatives or stops. A tendency for greater closure force for the fricative consonant was observed when the fricative followed rather than preceded the nasal consonant. Vowel identity had an effect on closure force during consonant production in the men in that closure force was greater for /s/ and /n/ in high versus low vowel contexts. Men exhibited a larger number of significant differences in closure force than did the women. The results suggest that velopharyngeal closure force is not controlled by a single muscle (the levator veli palatini) but that other muscles and mechanical factors are likely contributors.

Role of faulty visual search in the satisfaction of search effect in chest radiography.

RATIONALE AND OBJECTIVES: The authors tested the hypothesis that satisfaction of search effect, which is associated with the failure to detect native chest abnormalities in the presence of simulated nodules, is caused by reduced gaze on the native abnormalities. MATERIALS AND METHODS: Gaze dwell time of 20 radiologists was recorded for the region around abnormalities on images. Ten radiographs were reviewed, nine of which contained native abnormalities. Each image was seen with and without a simulated nodule. RESULTS: The decrease in the rate of true-positive findings in the detection of native abnormalities on images that contained simulated nodules confirmed the occurrence of a satisfaction of search effect. Gaze times on native abnormalities (up to the time of report of the abnormalities) were the same for images with nodules in which native abnormalities were missed (gaze time, 9.4 seconds) as they were for images without nodules in which native abnormalities were detected (gaze time, 9.5 seconds). Gaze time on missed native abnormalities was not affected by the presence (7.80 seconds) or absence (7.45 seconds) of nodules. CONCLUSION: Reduction in gaze dwell time on the missed abnormalities is not the cause of satisfaction of search errors in chest radiographs.

Levator veli palatini muscle activity in relation to intraoral air pressure variation in cleft palate subjects.

A comparison of the ranges of levator veli palatini EMG activity for speech versus a nonspeech task for subjects with cleft palate was the focus of this study. EMG values are also compared with subjects without cleft palate obtained in a previous study. Hooked-wire electrodes were inserted into the levator muscle of five adult subjects with cleft palate exhibiting mild hypernasality. Intraoral air pressure was measured concurrently. A blowing task was used to determine the subject's operating range for the levator muscle. Both the nonspeech and speech tasks were designed to sample the widest possible ranges of levator EMG activity. It was found that the subjects with cleft palate used a relatively high activation level for the levator muscle during speech, in relation to their total activation range, compared with the subjects without cleft palate. Implications are discussed in relation to possible anatomic and physiologic differences for cleft palate subjects compared to normal.

Levator veli palatini muscle activity in relation to intraoral air pressure variation.

The purpose of this investigation was to study the operating range of the levator veli palatini muscle for a nonspeech task (blowing) and to determine where in that range levator activity for speech lies. Ten adult subjects without speech or velopharyngeal abnormalities participated. Levator EMG activity for speech occurred in the lower region of the total range for blowing. In two subsequent experiments involving a subset of 4 subjects, it was found that overall effort may have had a small effect on levator activity apart from its role in velopharyngeal closure for aerodynamic purposes. The results of the main experiment are discussed in relation to the concept of threshold of fatigue as it may influence velopharyngeal control mechanisms.

Measurement of velopharyngeal closure force during vowel production.

The purposes of this study were to (a) design and test a new velopharyngeal closure force sensing bulb, and (b) use the closure force bulb to gather additional information on the variations in closure force associated with different vowels. The closure force sensing bulb possessed a flat frequency response to 30 Hz. Its output was highly linear relative to applied gram force. Reliable placement of the bulb in human subjects was achieved following prescribed placement criteria. The bulb was sensitive to small variations in velopharyngeal closure force. In agreement with some previous reports, high vowels were associated with greater velopharyngeal closure forces than low vowels. The results of this investigation support the notion that articulatory goals are specified for vowels. This vowel specificity was observed during production in both isolation and in context.

A quantitative histologic study of the normal human adult soft palate.

This study was designed to re-examine the same soft palates studied qualitatively in a previous investigation (Kuehn and Kahane, 1990), using a true-color image analysis system. The quantified measures of the areas of specific tissue types are reported. The results indicate that: (a) tendinous tissue is prominent anteriorly and comprises about 10% of total tissue in that region, (b) the relative proportion of glandular and connective tissue is fairly uniform across the length of the soft palate, averaging 22% and 36% respectively, (c) muscle tissue shows a pattern of increasing then decreasing amount from anterior to posterior with a maximum proportion of 23% in the midportion of the soft palate, (d) adipose tissue comprises 22% of total tissue area in the anterior segment and 17% of total tissue area in the posterior segment of the soft palate, (e) other tissue, primarily epithelium and vascular tissue, was found to be fairly constant anteriorly and increased in relative proportion to almost 30% of the total tissue area at the uvular base. The functional implications of these findings are discussed.

Levator veli palatini muscle activity in relation to intranasal air pressure variation.

Continuous positive airway pressure (CPAP) therapy can be used to reduce hypernasality by elevating the air pressure in the nasal cavities during speech. The purpose of this study was to determine whether increased intranasal air pressure loads the major muscle of velopharyngeal closure, the levator veli palatini. Nine subjects, four with cleft palate and five without cleft palate, were studied. Electromyographic activity was measured from the levator veli palatini muscle with several levels of air pressure delivered to the nasal cavities using a commercially available CPAP instrument. It was found that levator veli palatini activity was significantly greater for the positive air pressure conditions than for the atmospheric pressure conditions for both subject groups. This indicates that the levator veli palatini muscle acts against the resistive load produced by the increased intranasal air pressure. The results support the use of CPAP therapy as a method of resistance exercise for strengthening velopharyngeal closure muscles.

New therapy for treating hypernasal speech using continuous positive airway pressure (CPAP).

The purpose of this report is to introduce a new therapy technique for treating hypernasality. The instrumentation consists of a continuous positive airway pressure (CPAP) device that delivers air pressure by means of a hose and nasal mask assembly to the nasal cavities. This positive pressure is theoretically useful in providing resistance training to strengthen the velopharyngeal closure muscles. Speech drillwork is conducted in the patient's home and consists of production of VNCV syllables and short sentences with the nasal mask worn by the patient. Incremental changes in CPAP pressure and time per therapy session occur over an 8-week course of therapy. Six case studies are presented. The preliminary results suggest that CPAP therapy may be effective in reducing hypernasality in individuals exhibiting mild to moderate degrees of severity.

Muscle spindles in the velopharyngeal musculature of humans.

Seven muscles in the velopharyngeal region of humans were studied histologically to determine the presence of muscle spindles. Typical spindles were found in palatoglossus and tensor veli palatini with a greater number in the latter. Spindles were not found in levator veli palatini, palatopharyngeus, musculus uvulae, salpingopharyngeus, or the superior pharyngeal constrictor.

Speech status following uvulopalatopharyngoplasty.

The purpose of this study was to evaluate the adequacy of speech following uvulopalatopharyngoplasty surgery. Twenty UPPP subjects, all of whom exhibited obstructive sleep apnea syndrome, and 15 non-UPPP control subjects participated in the study. Evaluation included measures of nasal airflow, speech recordings with listener judgments, and a questionnaire survey. Nasal resonance in the UPPP subjects was found not to be deviant by a panel of four experienced judges. The UPPP subjects were differentiated from their non-UPPP pairs on the basis of significant phonation (voice) problems, and to a lesser extent, their articulation problems. It is suggested that dryness problems that remained in many subjects postoperatively may be related to the observed voice problems.

Histologic study of the normal human adult soft palate.

Detailed information about the tissue components of the soft palate is needed to construct biomechanical models that are functionally useful. Soft palates were removed from 10 adult cadavers, four males and six females. One-half of each palate was further divided into 10 blocks of equal anterior-to-posterior thickness. The face of each block was sectioned and stained using three different stains, thus providing a sample of 300 histologic slides. Each slide was carefully examined and major anatomic characteristics were noted and recorded. The results indicate that a typical adult soft palate consists of several major tissue layers including: (1) the oral aspect, which is glandular with a zone of adipose tissue located somewhat laterally; (2) the two middle layers are muscular with the more inferior layer consisting mainly of transverse levator veli palatini fibers and the overlying longitudinal layer of musculus uvulae fibers; (3) a superoanterior layer consisting of the tensor veli palatini tendon; and (4) a posteroinferior layer consisting of a mixture of tissue that is primarily glandular. The oral mucosa consists of stratified squamous epithelium with a basement membrane that is reinforced with a dense meshwork of elastic fibers. The nasal mucosa consists of pseudostratified ciliated columnar epithelium anteriorly and stratified squamous epithelium posteroinferiorly. The functional implications of these findings are discussed.

Voyager 2 at neptune: imaging science results.

Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.