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Biomedical subjects

M Russell

Publications and source records attributed to M Russell.

At least 109 records · Page 6Linked to original sources
PubMed1993

Radiovisiographic diagnosis of dental caries: initial comparison of basic mode videoprints with bitewing radiography.

Radiovisiography (RVG) is a commercially available, dental radiographic digital imaging system which is claimed to rival conventional techniques in terms of decreased radiation dose and the production of instantaneous images. The aim of this study was to compare in vitro the sensitivities and specificities derived from three examiners using conventional bitewing radiographic film (D and E speed) with those achieved by the same examiners using basic mode RVG bitewing videoprints of occlusal and approximal caries. Videoprints were used in this study, as they are the principal method of archiving radiovisiographic images, unless a separate compatible personal computer is used. The histological appearance of the subsequently sectioned teeth was used as the validating criterion. The in vitro results of basic mode RVG suggest that for occlusal caries, overall the sensitivity and specificity of RVG videoprints are similar to those of bitewing radiography. For approximal caries, the specificity of RVG videoprints was similar to that of bitewing radiography, but the sensitivity was slightly lower. Further work using the different modes available and electronically modified images is indicated.

Dental Caries↗
PubMed1993

Skin color, ancestry, and blood pressure among whites in Erie County, New York.

This study examines (1) the construct validity of a rank-order skin color measure and (2) interrelationships of skin color, ancestry, and blood pressure in a random survey of 763 white non-Hispanic and white Hispanic household residents in Erie County, NY. Skin color was significantly lighter among older respondents (P < .001) and among females (P < .0001). Skin color was lightest among Northern Europeans and darkest among Mediterraneans and white Hispanics (P < .0001). Higher systolic blood pressure was significantly associated with both darker skin color (P < .05) and northern European ancestry (P < .05). Several mechanisms to account for these findings are proposed.

Adult↗
PubMed1993

G protein amino-terminal alpha i2/alpha s chimeras reveal amino acids important in regulating alpha s activity.

Gs and Gi2 are heterotrimeric G proteins that stimulate and inhibit, respectively, the activity of a common effector, adenylyl cyclase. The Gs and Gi2 alpha subunit polypeptides, alpha s and alpha i2, are 65% homologous in primary sequence. A series of alpha i2/alpha s chimeras and alpha s point mutations were used to map sequences in the alpha s polypeptide that regulate alpha s activity. An amino-terminal region controlling the activation of alpha s was determined to reside within residues Lys-25 to Glu-101. Amino-terminal alpha i2/alpha s chimeras that disrupt this region in alpha s result in an activated alpha s. In contrast, replacement of this entire alpha s sequence with the analogous alpha i2 sequence produces a chimera whose activity is similar to that of the wild-type alpha s polypeptide. The regulation of alpha s activation by the amino-terminal sequence is independent of the intrinsic GTPase function. Inhibition of alpha s GTPase function by the mutation Gln-227 to leucine is additive with the amino-terminal chimera mutations. These mutations appear to independently alter the two rate-limiting steps in activation of the G protein alpha subunit, i.e., GTP hydrolysis and GDP dissociation, allowing subsequent GTP binding. Within this region of alpha s, Arg-42 is just amino-terminal to the G-1 sequence comprising part of the GDP/GTP binding pocket. The G-1 sequence interacts with the alpha- and beta-phosphoryl groups of GDP and GTP. Mutation of alpha s Arg-42 to lysine has modest effects on alpha s activation, but when placed in the background of the glutamine to leucine mutation the alpha sR42K+Q227L mutant polypeptide stimulates cAMP synthesis significantly more than observed with alpha sQ227L expression. Specific mutations in the amino terminus, therefore, have the ability to enhance alpha s activation by influencing the rate of adenylyl cyclase activation, which is independent of GTPase activity.

Adenylyl Cyclases↗
PubMed1993

Radiovisiography: an update.

Comparatively little has been published regarding the recently developed (and rapidly developing) digital imaging dental radiographic system known as radiovisiography (RVG). This paper reviews the existing literature, describes various modifications and updates which have been made and discusses the clinical implications of RVG.

Humans↗
PubMed1993

Expression of the EVI1 gene in chronic myelogenous leukemia in blast crisis.

The EVI1 gene encodes a nuclear, zinc finger, DNA binding protein expressed after provirus insertion into the Fim-3 or EVI1 loci in murine leukemia myeloid cells. EVI1 is also expressed by cells from AML patients with chromosome rearrangements involving band 3q26, the putative location of the EVI1 gene, but expression of this gene is not detected in normal bone marrow. We report expression of EVI1 by cells from a patient with chronic myelogenous leukemia in blast crisis (CML/BC) whose cells showed inv(3)(q22q26). In vitro culture of these cells resulted in macrophage differentiation and loss of EVI1 expression. Results in this patient suggest EVI1 expression played a role in CML blast transformation. Patients with CML/BC and other nonrandom chromosome abnormalities involving chromosome 3q26 should be evaluated for EVI1 expression.

Adult↗
PubMed1992

Animal histo-blood group ABO genes.

Sequences homologous to the human histo-blood group ABO genes are present in the genomic DNA of various mammals. We have PCR-amplified, subcloned, and sequenced a portion of these genes from several species of primates and found high conservation of the nucleotide as well as the deduced amino acid sequences during evolution.

ABO Blood-Group System↗
PubMed1992

Prevention of pre-PCR mis-priming and primer dimerization improves low-copy-number amplifications.

A Hot Start Polymerase Chain Reaction (PCR) entails the withholding of at least one reagent from the reaction mixture until the reaction tube temperature has reached 60-80 degrees C. Hot Start amplification with an AmpliWax vapor barrier uses a layer of solid wax to separate the retained reagent(s) and the test sample from the bulk of the reagents until the first heating step of automated thermal cycling melts the wax and convectively mixes the two aqueous layers. Wax-mediated Hot Start PCR greatly increases the specificity, yield, and precision of amplifying low copy numbers of three HIV targets. In the presence of 1 microgram of human placental DNA (1.6 x 10(5) diploid genomes) the specificity improvement entails considerable to complete reduction in the amplification of mis-primed sequences and putative primer oligomers. When mis-priming is negligible, the procedural improvement still suppresses putative primer oligomerization. Hot Start PCR with an AmpliWax vapor barrier permits routine amplification of a single target molecule with detection by ethidium stained gel electrophoresis; nonisotopically visualized probing suffices for confirmation. The improved amplification performance is evident for target copy numbers below approximately 10(3).

Base Sequence↗
PubMed1992

Stress and alcohol use: moderating effects of gender, coping, and alcohol expectancies.

A stressor vulnerability model of stress-induced drinking was tested in a stratified random sample of 1,316 Black and White adult drinkers. Stressors were highly predictive of both alcohol use and drinking problems among men who relied on avoidant forms of emotion coping or held strong positive expectancies for alcohol's effects and accounted for more than 35% of the variance in alcohol use among the subgroup of men who were high in both vulnerability factors. In contrast, stressors were negatively related among men who were low in both and were unrelated among women regardless of their coping or expectancies. These findings suggest that tension reduction theories of alcohol use are overly broad and that individual characteristics must be considered to account for stress-related effects on alcohol use and abuse.

Adaptation, Psychological↗
PubMed1992

Antecedents and outcomes of work-family conflict: testing a model of the work-family interface.

A comprehensive model of the work-family interface was developed and tested. The proposed model extended prior research by explicitly distinguishing between work interfering with family and family interfering with work. This distinction allowed testing of hypotheses concerning the unique antecedents and outcomes of both forms of work-family conflict and a reciprocal relationship between them. The influence of gender, race, and job type on the generalizability of the model was also examined. Data were obtained through household interviews with a random sample of 631 individuals. The model was tested with structural equation modeling techniques. Results were strongly supportive. In addition, although the model was invariant across gender and race, there were differences across blue- and white-collar workers. Implications for future research on the work-family interface are discussed.

Adaptation, Psychological↗
PubMed1992

Differences in skeletal muscle and bone mineral mass between black and white females and their relevance to estimates of body composition.

This study tested the hypothesis that black females have an increase in skeletal muscle and bone mineral mass compared with white females matched for age (+/- 5 y), weight (+/- 2 kg), height (+/- 3 cm), and menstrual status. Conventional [underwater weighing, whole body 40K counting (WBC), 3H2O dilution] and newly developed (dual-photon absorptiometry) techniques were used to provide ethnicity-independent estimates of body composition in 28 pairs of matched subjects. Black females had greater appendicular skeletal muscle (P less than 0.001), bone mineral (P less than 0.001), and total body potassium (TBK) (P = 0.05) compared with white females. Two classic coefficients used in body composition research [density of fat-free mass (FFM) for underwater weighing and TBK/FFM for WBC] differed significantly (P less than 0.05) between black and white females; currently applied coefficients underestimated fat in black females. This study confirms that black and white females differ in body composition and that errors in fat estimates occur when ethnicity is not accounted for in body composition models.

Absorptiometry, Photon↗
PubMed1992

Body-fat measurement in patients with acquired immunodeficiency syndrome: which method should be used?

Malnutrition is common in patients with acquired immunodeficiency syndrome (AIDS), which distorts the chemical contents in the fat-free mass (FFM) and alters the assumptions underlying the traditional methods for calculating body-fat content so that such measurements may not be accurate. In vivo neutron-activation analysis (IVNA) measures FFM independently of the traditional assumptions, thereby providing more accurate measurements of body fat. We compared seven methods for measuring body fat in 18 male patients with AIDS: IVNA, total body water (TBW by 3H2O dilution), total body potassium (TBK by 40K counting), dual-photon absorptiometry (DPA), bioelectrical impedance analysis (BIA), and two well-calibrated anthropometric methods. FatTBW and fatDPA were not significantly different from fatIVNA. FatTBW gave the highest correlation with fatIVNA and the smallest SEE of +/- 1.8% (1.1 kg). The traditional and widely available TBW and the newer DPA method provide reliable estimates of fatIVNA in patients with AIDS.

Absorptiometry, Photon↗
PubMed1992

Hemicrania continua: attacks may alternate sides.

Hemicrania continua (HC) is characterized by a continuous unilateral headache of moderate severity, occurring in 2 patterns; a continuous form in which headaches persist continuously without remission for years, and a remitting form, consisting of headache phases separated by periods of pain-free remission. The remitting form of HC must be distinguished from other cyclical headache disorders such as episodic paroxysmal hemicrania and episodic cluster headache. Characteristically, the headache of HC is unilateral and without sideshift. We now report a case of HC in which headaches alternate sides.

Aged↗
PubMed1992

Sociodemographic correlates of alcohol consumption among African-American and white women.

Correlates of abstention and heavier drinking were examined among 654 African-American and 474 white women, aged 19-70+, from a representative sample of households in Erie County, New York. Discriminant function analysis was employed to investigate the relationship between alcohol consumption and race, age, church attendance, family history of alcohol problems, household density, marriage, socioeconomic status (SES), employment and parity. Abstention was compared with drinking, and light/moderate drinking was compared with heavier drinking in the total sample and within each race. Compared to drinkers, abstainers were older, more religious, more likely to be African-American, or to be of lower SES. Racial differences in the correlates of abstention were found with respect to church attendance (positive association in African-Americans only), SES (negative association in African-Americans only), and household density (positive association in whites only). Compared to light/moderate drinkers, heavier drinking women were younger, less religious, more likely to be white, to have a positive family history, or to live in less crowded households. Racial differences in the correlates of heavier drinking were found with respect to church attendance (negative association in African-Americans only), parity (positive association in African-Americans only), and marital status (more heavier drinking among unmarried white women). Racial differences in the correlates of alcohol consumption document the need for further examination of the culture-specific determinants of women's drinking patterns.

Adult↗
PubMed1991

Remotely controlled positioning lasers.

Positioning lasers used in radiotherapy generally require little adjustment. When required, this is easy to do for sidelights, but can be difficult and time consuming for ceiling mounted lasers. For this purpose, we have modified a commercial positioning laser by incorporating a device for rotating the alignment adjustment screws. This device is driven by a pair of motors remotely controlled through a cable. Two units have been built and installed. In practice, experience with these drive units has shown that it is now easier to adjust the ceiling lasers than the sidelights. Adjustment sensitivity in both units is considerably better than 1 mm, so there is little problem aligning the laser quickly and accurately.

Equipment Design↗
PubMed1991

Quantity-frequency measures of alcohol consumption: beverage-specific vs global questions.

Estimates of alcohol consumption (ounces of absolute alcohol per day, AA) based on beverage-specific and global quantity-frequency (QF) questions were compared in a survey representative of the adult drinking population in New York State. Beverage-specific AA estimates were higher than global (0.72, 95% confidence intervals = 0.68, 0.76) compared to 0.49 (95% confidence intervals = 0.47, 0.51), although estimates were highly correlated (r = 0.75). Discrepancies between beverage specific and global AA estimates increased as the number of beverages and the amount drunk increased. Sociodemographic characteristics were not significantly related to differences between beverage-specific and global AA estimates after adjusting for the amount drunk; however, drinking patterns did influence the differences. It was concluded that beverage-specific QF questions are probably more valid measures of alcohol consumption than global QF questions, but that the global questions provide useful information. Parallel analyses of variant global QF questions employed in the first US Health and Nutrition Examination Survey obtained similar results.

Alcohol Drinking↗