Biomedical subjects

D Waterman

Publications and source records attributed to D Waterman.

12 recordsLinked to original sources

PubMed2003

European experience with a novel noninvasive sensor for intra-amniotic or extra-amniotic evaluation of fetal oxygen saturation.

OBJECTIVE: We evaluated the feasibility of a new instrument for continuous fetal pulse oximetry during labor. The measuring sensor can be placed on the fetal back before or after rupture of membranes. METHODS: One hundred adult women who had completed 32 weeks of gestation and had an anticipated duration of labor greater than 30 minutes were included in the study. Patients with premature rupture of membranes for 24 hours or more, low placental localization, placenta previa or abruption, vaginal bleeding, acute infection, polyhydramnios, oligohydramnios, or uterine or congenital abnormalities were excluded. RESULTS: All sensors were placed successfully. The mean continuous recording time was 276 minutes. Peripheral oxygen saturation as measured by pulse oximeter values were obtained during a median of 64.05% of the recording time. No chorioamnionitis or endometritis was noted. CONCLUSION: The new sensor instrumentation was safe for mother and fetus and was well accepted by parents and physicians.

Adolescent↗

PubMed2001

Application of micro-scale sealed vessel thermal desorption-gas chromatography-mass spectrometry for the organic analysis of airborne particulate matter: linearity, reproducibility and quantification.

Micro-scale sealed vessel thermal desorption-gas chromatography-mass spectrometry (MSSV-TD-GC-MS) has been applied to the analysis of airborne particulate matter using the US NIST Standard Reference Material (SRM1649a) urban dust. We make qualitative comparisons with open system desorption and illustrate that caution should be used when using the technique without an open system comparison. We report linear responses over the same particulate mass range (1-5 mg) and good reproducibility [SD< or =0.62 mg kg(-1) (< or = 11%)]. We show linearity for a series of 10 n-alkanes and 10 polycyclic aromatic hydrocarbons (PAHs) in the SRM. The technique is also shown to be quantifiable (PAH concentrations typically 4-6 mg kg(-1)).

Gas Chromatography-Mass Spectrometry↗

PubMed2000

Quantification of polycyclic aromatic hydrocarbons in the NIST standard reference material (SRM1649A) urban dust using thermal desorption GC/MS

A thermal desorption GC/MS technique has been developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter using the NIST Standard Reference Material (SRM1649a) Urban Dust. The technique was developed using standard linearity tests in order to establish optimum sample weights and optimum desorption and chromatographic parameters. This direct analysis technique eliminates the use of solvents in the sample preparation (reducing volatile component losses) and also significantly reduces the sample preparation time (no extraction procedure). The technique has been shown to give linearity in terms of the overall TIC response as well as for a prominent series of n-alkanes (C20-C33) and 10 NIST priority PAHs, 8 of which have been quantified. The technique is reported to be uniquely sensitive (PAH concentrations 2-6 mg kg(-1)) and reproducible (MW = 178-228 SD < or =0.228 mg kg(-1), < or =7%; MW = 252 SD < or =0.922 mg kg(-1), < or =33%) over the range of sample weights (1-5 mg). Such sample weights illustrate that the technique can be equally applied to the analysis of airborne particulate samples collected over short time periods (24-48 h) using only commonly used low-volume collection devices.

Journal Article↗

PubMed1993

Symposium: Dream research methodology: Methodological issues affecting the collection of dreams.

This article focuses attention on the perennial issue of home versus laboratory recording situations for the garnering of dream reports. Studies into the experimental control over procedures for both waking and interviewing are reviewed. Against this background, an experiment into the relationship between REM/NREM sleep and visual imagery is reported. We found that, having corrected for total word count, visual imagery still made an independent contribution to REM reports. This finding is evaluated in the light of differential cognitive mechanisms underlying dream formation during sleep.

Journal Article↗

PubMed1993

EEG spectral power analysis of phasic and tonic REM sleep in young and older male subjects.

EEG spectral power was studied during periods of rapid eye movements (REMs) and tonic intervals in REM sleep of 7 young and 7 older male subjects. Significant symmetrical decreases in alpha and beta1 power at central and occipital sites, concurrent with an increase in frontal theta power, were observed during the production of REMs. The former findings are discussed as sleep analogues to changes in alpha and beta1 during waking, showing increased information processing and behavioural activation, and that of theta is tentatively presented as reflecting an increase in afferent thresholds. Independent of the phasic-tonic REM distinction, total EEG power markedly decreased as a function of time of night and did not interact with age. Significant age differences in the overall spectral composition of the EEG were obtained, namely, a lower level of delta power and a relative shift towards more power in frequencies above 12 Hz for the older group. Further, older subjects also demonstrated a more uniform topographical distribution of alpha and sigma power.

Journal Article↗

PubMed1992

Removal of ocular artifacts from the REM sleep EEG.

The present report concerns the first study in which electrooculographic (EOG) contamination of electroencephalographic (EEG) recordings in rapid eye movement (REM) sleep is systematically investigated. Contamination of REM sleep EEG recordings in six subjects was evaluated in the frequency domain. REM-active and REM-quiet series were obtained for each subject. Transfer coefficients and power spectra of EOG and EEG indicated that (a) increases in transfer coefficients beyond 4.5 Hz are brought about by residual EEG in the EOG, and (b) EOG-EEG contamination in the delta band is most pronounced in frontal, intermediate in central and negligible in occipital leads. It was found that correction of the REM-active series resulted in significant (c) reductions in power, (d) increases in interhemispheric coherences and (e) reductions in degree of lateral asymmetry. These effects were largest for frontal leads, but still marked for central ones. The results are discussed in the light of previous findings concerning models of hemispheric functioning during REM sleep.

Adult↗

PubMed1991

Aging and memory for dreams.

This study investigated the influence of aging on memory for home drams and the extent to which cognitive variables such as visual memory, visuospatial IQ, and verbal IQ could account for possible differences herein. Subjects were 80 men and women of ages 45 to 75 years. Memory for dreams was measured by narrative length and frequency of recall. With respect to both measures no significant age differences were noted. Over-all differences in dream recall seemed best explained by visual memory scores. Partial correlational analyses, however, indicated that the small age differences memory or on any of the other cognitive variables. Dream contents were scored for aggression, friendliness, emotion, activities, and the number of characters and objects. The incidence of emotions among women appeared to be lower beyond the age of 60. Comparisons with previous data for young adults indicated that large reductions in aggression, friendliness, and emotion occur before the age of 45.

Aggression↗

PubMed1979

Immunity of cholera in man: relative role of antibacterial versus antitoxic immunity.

Purified cholera toxoid is antigenic when given enterally and orally. Purified toxoid fails to provide protection against experimental challenge. Clinical cholera confers formidable protection against homologous or heterologous rechallenge. Failure to culture vibrios from intestinal fluid or stool of re-challenge volunteers suggests that the predominant immune mechanism is antibacterial rather than antitoxic.

Antibodies, Bacterial↗

PubMed1979

The problem of emesis during oral glucose-electrolytes therapy given from the onset of severe cholera.

In an attempt to obviate the need for intravenous fluids by preventing dehydration, 57 adult volunteers who experienced induced clinical cholera during a vaccine development programme were treated from the onset of diarrhoea with oral glucose-electrolytes therapy. 44 individuals with mild to moderately profuse diarrhoea (less than 8 L. total volume) were maintained in normal water and electrolyte balance with oral therapy alone. 13 individuals with severe diarrhoea (greater than 8 L. total volume) could not be maintained in balance with oral therapy alone, due chiefly to emesis during the first day of illness. Emesis occurred in the absence of significant dehydration or acidosis. Since emesis precludes effective early oral therapy in severe cases, domiciliary oral therapy is unlikely to eliminate cholera mortality. Rural diarrhoea treatment centres using oral therapy with limited amounts of intravenous fluids when needed, could reduce case fatality from cholera and related diarrhoeas virtually to zero with least expense.

Adolescent↗

PubMed1978

On localization for double Fourier series.

The localization theorems for Fourier series of functions of a single variable are classical and easy to prove. The situation is different for Fourier series of functions of several variables, even if one restricts consideration to rectangular, in particular square, partial sums. We show that the answer to the problem can be obtained by considering the notion of generalized bounded variation, which we introduced. Given a nondecreasing sequence {lambda(n)} of positive numbers such that Sigma 1/lambda(n) diverges, a function g defined on an interval I of R(1) is said to be of Lambda-bounded variation (LambdaBV) if Sigma|g(a(n)) - g(b(n))|/lambda(n) converges for every sequence of nonoverlapping intervals (a(n), b(n)) [unk]I. If lambda(n) = n, we say that g is of harmonic bounded variation (HBV). The definition suitably modified can be extended to functions of several variables. We show that in the case of two variables the localization principle holds for rectangular partial sums if LambdaBV = HBV, and that if LambdaBV is not contained in HBV, then the localization principle does not hold for LambdaBV even in the case of square partial sums.

Journal Article↗

PubMed1978

Food preferences of enlisted personnel in the Armed Forces.

A food preference survey, consisting of 378 food names, was administered to approximately 3,900 personnel of the U.S. Army, Navy, Air Force, and Marine Corps. The survey required the respondent to indicate how much he liked each food (hedonic scale) and how often he wanted it served (preferred frequency scale). Overall, food preferences showed relative popularity of beverages, breakfast foods, and entrées, unpopularity of soups and vegetables, and moderate popularity of the other food classes. Items of particularly high or low preference are statistically identified within each food class. The collection and presentation of these data are intended to assist menu planners of the Armed Forces, as well as others interested in this age group (young men under twenty-six years of age.

Adolescent↗

PubMed1977

Diarrhea caused by Escherichia coli that produce only heat-stable enterotoxin.

To determine the role of Escherichia coli heat-stable enterotoxin (ST) as a virulence factor in human diarrhea, a strain that elaborates only ST (E. coli 214-4) was fed to free-living volunteers in doses of 10(6), 10(8), and 10(10) organisms. Short-lived (1 day) mild illness consisting of abdominal cramps with vomiting or diarrhea occurred in three of five individuals fed 10(8). Typical travelers' diarrhea (loose stools, abdominal cramps, and low-grade fever for 2 to 3 days) was seen in four of five volunteers given 10(10); two had brief cholera-like purging of rice-water stools. Despite fever, there was no evidence of mucosal invasion. E. coli 214-4 became the predominant coliform in stools; coproculture isolates were uniformly negative for heat-labile enterotoxin (LT), whereas most produced ST. Ten of 13 individuals developed rises in antibody to somatic E. coli antigen, and none had rises in LT antitoxin. E. coli that elaborate only ST can cause diarrheal disease in adults.

Adolescent↗