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Biomedical subjects

M J McCutcheon

Publications and source records attributed to M J McCutcheon.

At least 19 recordsLinked to original sources
PubMed1998

Intra- and extracellular water dynamics on rehydration in cholera and noncholera patients.

To estimate the intra- and extracellular body water compartments during rehydration of patients with cholera and noncholera diarrhea by bioimpedance analyzer, we studied 30 patients with acute watery diarrhea. Total body water (TBW), intracellular water (ICW), and extracellular water (ECW) of severely dehydrated adult patients were measured with a dual frequency bioimpedance analyzer at different phases of rehydration. Fluid compartments between cholera and noncholera patients were compared. Cholera patients gained more TBW than noncholera patients during recovery. Unlike patients with noncholera diarrhea, the gain in cholera patients was mainly contributed by the ICW (1.5 +/- 1.6 vs 3.0 +/- 1.2 liters, respectively, P < 0.01). It was also observed that the recovery of the ICW compartment in cholera patients occurred rapidly within the first 2 hr after infusion. Differential dynamics of body water compartments in cholera compared to noncholera patients as observed in this study may contribute further to understanding the mechanism of dehydration in diarrheal disease, which might help in improving case management.

Adult↗
PubMed1997

A three-dimensional analysis of mandibular arch changes following curve of Spee leveling in nonextraction orthodontic treatment.

The present study was conducted to determine the effects of curve of Spee leveling on three-dimensional arch length and specific components of arch form. The mandibular pretreatment and posttreatment dental casts of 33 patients treated orthodontically without the extraction of teeth were digitized with a three-dimensional positioning transducer integrated with a graphics calculator. Statistical analysis was carried out with general linear models and the calculation of Pearson correlation coefficients of the relationships between the dependent variable of the curve of Spee leveling and the independent variables of arch length, arch depth, and three arch widths. The regression and correlation analyses essentially showed no relationship between the independent variables (arch length, arch depth, and the three arch widths) and the dependent variable (curve of Spee leveling). Although the three-dimensional arch length was increased after leveling of the curve of Spee in 24 of the 33 dental casts evaluated, the results from the statistical analyses indicated that this increased arch length was not necessarily the result of the curve of Spee leveling but may have been caused by other variables.

Computer Graphics↗
PubMed1994

Comparing abilities of children with profound hearing impairments to learn consonants using electropalatography or traditional aural-oral techniques.

Two groups of nine children with profound hearing impairments and low intelligibility were taught to produce the consonants /t,d,k,g,s,z,S/ using either electropalatographic (palatometry) or traditional aural-oral techniques. Testing was completed pre-, immediately post-, and 6 months post-treatment by examining productions of CV syllables (V = /i,a/) using electropalatography-determined linguapalatal contacts and listener identifications. Intelligibility was also measured using the CID Picture Speech Intelligibility Evaluation (SPINE) test. Both groups improved their consonant productions as a result of 26 50-minute sessions. Sessions were given twice daily over 3- to 4-week training periods. Immediately post-treatment, the electropalatography-trained subjects produced better consonants as measured by linguapalatal contact patterns and listener identifications. The linguapalatal-contact patterns learned by the electropalatography-trained group better matched normal speaker productions than did those of the traditionally trained group. Both groups showed equal improvement for both post-treatment conditions when tested with the CID SPINE test. Although further research is needed, the results of this study suggest that electropalatographic techniques are, at least, equal alternatives to traditional aural-oral speech training techniques for speakers with profound hearing impairments.

Acoustic Stimulation↗
PubMed1993

Application of the ILISPOT-IDIP system for the enumeration of different sizes of IgA spot forming cells in the murine small and large intestine.

The immunofluorescence-linked immunospot (ILISPOT) assay associated with the immunofluorescence digital image processing (IDIP) system was originally developed in our laboratory to allow enumeration of immunoglobulin (Ig) producing, spot forming cells (SFC) in a more objective and quantitative manner. In this study, the ILISPOT-IDIP system was further advanced in order to analyze different sizes of SFC (e.g., IgA producing cells) including large (L), medium (M), and small (S) cells which correspond to high (> 2.4 pg), medium (1.2-2.4 pg) and low (< 1.2 pg) IgA secreting cells by the adaptation of real time image processor and intensified video camera system. When the ILISPOT-IDIP system was used to characterize the frequency of IgA secreting cells among mononuclear cells isolated from different parts of the murine gastrointestinal (GI) tract including the small (upper, middle and lower sections) and large (colon and rectum) intestine, the small intestine contained higher numbers of IgA SFC (approximately 8.4 x 10(5) SFC/10(6) cells) when compared with large intestine (approximately 1.3 x 10(5) SFC/10(6) cells). Among the 3 areas of small intestine, the upper (approximately 3.7 x 10(5) SFC/10(6) cells) and middle (approximately 2.4 x 10(5) SFC/10(6) cells) parts had higher numbers of IgA SFC when compared to the lower small (approximately 2.3 x 10(5) SFC/10(6) cells) intestine. When these IgA producing cells in different parts of the intestine were classified into three groups according to the size of individual spots, the upper and middle intestine contained higher frequencies of large (approximately 20%) and medium (approximately 20%) SFC which corresponded to high and medium IgA secretors in comparison to the lower small (approximately 9%) and large (approximately 6%) intestine. In contrast, the lower small and large intestine were dominated by small SFC since approximately 85% of IgA producing cells were categorized as low secretors. Using the advanced ILISPOT-IDIP system, a unique distribution of different sizes (or secretion rates) of IgA producing SFC was elucidated in the different regions of the mouse small and large intestine.

Animals↗
PubMed1992

Esophageal speaker articulation of /s,z/: a dynamic palatometric assessment.

Esophageal talker linguapalatal contact patterns and durations during /s/ and /z/ productions were examined using dynamic palatometry instrumentation. It was found that sibilant groove narrowing is a physiologic compensation for a reduced air supply in esophageal speech. The place of esophageal /s, z/ articulation was on the anterior portion of the alveolar ridge as seen in normal speakers. Average medial groove width for esophageal /s/ was narrower than the 5-7-mm groove characteristic of normal speakers. Groove widths averaged 3 mm for /s/ and 4 mm for /z/. Systematic changes in groove widths across speech sounds, syllable position, and vowel context were also observed. Use of a narrower lingual groove was interpreted as a significant articulatory maneuver to meter out a limited intraoral air supply and effect more normal fricative durations.

Articulation Disorders↗
PubMed1992

Temporomandibular joint sounds and condyle/disk relations on magnetic resonance images.

This study compared the condyle/disk relationships on magnetic resonance images (MRIs) in a group of subjects with completely silent temporomandibular joints (TMJ) when tested clinically with those in subjects with readily discernible TMJ sounds. The sounds were recorded with an accelerometer as the transducer. Selected degrees of jaw separation were electronically determined and recorded with interocclusal wafers for use with the imaging process. Of the "silent joints" 89% were found to have sounds when tested with the accelerometer. These "subclinical" sounds tended to be of shorter duration and occurred at a greater degree of vertical opening than the clinically discernable sounds. The MRIs of the group with clinically discernable sounds tended to show a change in the relationship between the head of the condyle and the intermediate zone of the disk, at the degree of jaw separation of the sound occurrence, whereas no condyle/disk change occurred in the group with "clinically silent joints." It is likely that all joints create sound during function. The different characteristics of the subclinical sounds versus the clinical sounds may indicate differing sound origins.

Adult↗
PubMed1991

Immunofluorescence-digital image processing system for the quantitation of secreted immunoglobulin by single cells.

To quantitate the amount of secreted immunoglobulin (Ig) by a single cell, the immunofluorescence digital image processing (IDIP) system was adapted to the modified enzyme-linked immunospot (ELI-SPOT) assay. In this assay, an immunofluorescence (tetramethylrhodamine isothiocyanate) conjugated antibody was used for the detection of spots instead of the usual method of enzyme coupling. We have named this the immunofluorescence-linked immunospot (ILISPOT) assay. In addition to the quantitation of secreted Ig by single cells, this method allowed us to objectively determine the exact number of Ig producing spot forming cells (SFC). 96 well culture plates were pre-coated with goat anti-mouse Ig. The mouse IgM producing hybridoma (E-3-4) was incubated in the plates for 4 h at 37 degrees C. Cells were removed prior to the addition of biotinylated goat anti-mouse mu antibody. After overnight incubation, immunofluorescence conjugated avidin was added for the visualization of spots by the IDIP system. The IDIP system consists of a fluorescent microscope equipped with a video camera and computer. The gray scale of secreted IgM was initially established as a standard by the known amount of purified IgM. By using digital image processing, the number of spots and the gray scale of individual spots were computed. The shape and pattern of gray scale data were used to distinguish between the real spots and pseudo spots. This IDIP system could detect as little as 0.19 pg of secreted IgM (1.2 x 10(5) molecules) and an average of approximately 1.33 pg (8.3 x 10(5) molecules) produced by a single cell. Adaptation of the digital image processing system to the ILISPOT assay allowed the measurement of both the amount of Ig produced at the single cell level and also the exact numbers of SFC present in a totally objective fashion.

Animals↗
PubMed1988

Electrical impedance in assessing human body composition: the BIA method.

Fundamental aspects of the body impedance analysis (BIA) method were investigated to determine limitations. This method measures body impedance with a low-level (800 microA) 50-KHz current conducted through the tissues. A linear regression equation was proposed to relate impedance measurements to total body fat. The hydrostatic densitometric method (underwater weighing) was used to validate the proposed mathematical expression. A correlation coefficient of 0.98 between these two methods was obtained. The overall results from this study indicate the usefulness of the BIA method in determining percent body fat in humans provided body fluids are not perturbed several hours before the measurements.

Adipose Tissue↗
PubMed1987

The development of skill in producing word-final English stops.

This study examined production of word-final English /p/ and /b/ by subjects whose native language does not possess voiced stops in word-final position. Native Chinese adults resembled native English adults, native English children, and native Chinese children in producing /p/ with greater peak oral air pressure than /b/. However, unlike subjects in the other groups, the Chinese adults' /b/ was sometimes misidentified as /p/. This may have occurred, at least in part, because the Chinese adults produced a much smaller difference between /p/ and /b/ in labial closure duration and voicing than the other subjects. The English adults sustained voicing in /b/ significantly longer than subjects in the other three groups. To help determine the basis for this ability, the shape of oral air pressure waveforms was examined systematically. The percentage of "delayed" and "bimodal" waveforms, in which pressure stopped increasing, or decreased, prior to the release of labial constriction, was calculated for each group. Only the English adults showed more such waveforms for /b/ than /p/. Voicing continued 18 ms longer in /b/ tokens with delayed and bimodal waveforms than in tokens in which oral pressure increased continuously. The duration of closure voicing was correlated with the rate at which pressure increased in the English adults' /b/ waveforms. Previous aerodynamic modeling has shown that delayed and bimodal waveforms may result from an active enlargement of the supraglottal cavity. This, together with the pattern of between-group differences observed here, suggests that the English adults learned to enlarge the supraglottal cavity to sustain voicing in /b/. It appears that neither the children nor the Chinese adults had as yet acquired this skill.

Adult↗
PubMed1982

Flexible sorting decision and droplet charging control electronic circuitry for flow cytometer-cell sorters.

We describe sorting decision and droplet charging control electronic circuitry for a flow cytometer-cell sorter. The circuitry can handle up to five independent input signals and can sort in up to four directions. A sixth input channel is used to determine the presence or absence of an event requiring analysis. Sorting decisions are stored in a read-only memory semiconductor device. All the input signals for a given event are reexpressed as either 0 or 1 and are used to define an address in this memory which contains the desired sorting outcome for the event. A set of switches enables one to choose between many different procedures for relating input cell pulses to sorting outcomes by switching to different blocks of the memory. The circuitry has been found capable of purity of cell separation to the level permitted by "deadtime" in the preceding analog stages. It is in regular use with the Ontario Cancer Institute flow cytometer-cell sorter.

Cell Separation↗
PubMed1980

Quantitative studies on the precursors of cytotoxic lymphocytes. VI. Second signal requirements of specifically activated precursors isolated 12 h after stimulation.

It is shown that, in a mixed lymphocyte reaction, the production of cytotoxic T lymphocytes (CL) from cytotoxic T lymphocyte precursors (CLP) requires two signals which are separated time. Using a flow cytometer-cell sorter and a vital, fluorescent DNA stain, Hoechst 3342, CLP specific for the stimulator cells can be separated from other CLP and from stimulator cells 12 h after initiation of mixed lymphocyte cultures. These CLP are in a state of partial activation and can produce CL in the absence of stimulator cells if a second signal in the form of a concanavalin A-induced spleen cell supernate factor is added. Specific CL are also generated when the partially activated CLP are cultured with both nude spleen cells and stimulator cells. In this case it appears that an interaction between the stimulator cells and the nude spleen cells leads to production of the second signal.

Animals↗
PubMed1979

Fluorescence intensity resolution in flow systems.

The factor which can limit fluorescence intensity resolution in a flow cytometer of the type in which cells pass perpendicularly through a focussed laser beam depends on signal intensity. For the brightest sources (e.g. fluorescent DNA stains), the coefficient of variation (CV) is limited in our system to around 3% by stream hydrodynamics, unstable illumination intensity, nonstoichiometric staining, etc. The weakest detectable sources (e.g. fluorescent cell-surface labels) are limited in coefficient of variation by shot noise in the photomultiplier due to constant background light levels. Finally, over a fairly wide brightness range between these extremes, resolution is determined primarily by photoelectron statistical variation on the signal itself (i.e. "photon statistics"). Thus photon collection and detection efficiency (solid angle, barrier filter passband, detector quantum efficiency) become of primary importance.

Cells↗
PubMed1977

Measurement of cytoplasmic fluorescence depolarization of single cells in a flow system.

We have built a flow system in which we can analyze and sort individual viable cells on the basis of their cytoplasmic microviscosity. The average cytoplasmic microviscosity (or cytoplasmic structuredness) of a cell can be quantitated by exciting fluorescein molecules in the cytoplasm of the cell with a polarized light source and measuring the extent of depolarization of the fluorescent signal. Changes in the state of a cell (e.g., the reception of a signal inducing the cell to differentiate) often appear to be associated with changes in cytoplasmic microviscosity, these changes being detectable within hours of the inducing signal. An example of one such change is presented.

Bone Marrow↗
PubMed1975

Dynamic palatometry.

A computer-based instrumental system is described for continuous palatometry. Thin pseudopalatal plates (approximately 0.2 mm) with embedded electrodes are used to detect linguapalatal contact during speech articulation. Geometric configurations of such contacts are then derived and displayed to reveal articulatory characteristics.

Computers↗
PubMedDate not supplied

MR imaging of the vocal tract during vowel production.

Modeling of vocal tract behavior during speech production requires accurate measurements of the entire vocal tract. To accomplish this, magnetic resonance (MR) imaging was performed on a 0.5-T system with a custom-made, double-loop, wrap-around coil. A midsagittal section of the region from the glottis to the lips was imaged during sustained production of five American English vowels. A gradient-spoiled gradient-echo sequence was used to achieve a 4-second imaging time. Images showed clear profiles of the entire vocal tract and exhibited essential articulatory features of vowel production. It was possible to measure midsagittal widths at various points along the vocal tract with 1-mm resolution. The measurements were used to construct a tube model for prediction of the acoustic output of the vocal tract. It is concluded that risk-free MR imaging promises to be an important means of acquiring data for vocal tract modeling, with applications to speech pathology, linguistics, and artificial speech.

Humans↗