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Biomedical subjects

M Russell

Publications and source records attributed to M Russell.

At least 91 records · Page 5Linked to original sources
PubMed1994

Asians have lower body mass index (BMI) but higher percent body fat than do whites: comparisons of anthropometric measurements.

We studied the correlations between body mass index (BMI) and percent body fat (fat%) measured by dual-photon absorptiometry (DPA) in 445 white and 242 Asian adults aged 18-94 y. In addition, comparisons in six circumferences and eight skinfold-thickness measurements between whites and Asians were made to explain the discrepancies. Although Asians had lower BMI, they were fatter than whites of both sexes. The correlations between fat% and BMI varied by BMI and sex and race. Comparisons in anthropometry show that Asians had more subcutaneous fat than did whites and had different fat distributions from whites. Asians had more upper-body subcutaneous fat than did whites. The magnitude of differences between the two races was greater in females than in males. Prediction equations developed for each sex and race, based on BMI alone, gave SEEs ranging from 4.4% to 5.7%. All were significantly improved to the range of 3.5-4.4% when age and several skinfold-thickness measurements were added.

Adipose Tissue↗
PubMed1994

Effects of enteral feeding products on survival from Escherichia coli peritonitis.

Male Fischer 344 rats were orally fed one of four diets (Osmolite HN, Alitraq, Impact, and Purina rodent chow). After 6 days, jejunal mucosal nitrogen content and thickness were normal in all groups. After 7 days, challenge with Escherichia coli intraperitoneally demonstrated no difference in survival for any dietary group. In a second study, acute protein-calorie malnutrition was induced by administering 5% dextrose orally for 10 days. Animals were refed for 7 days with one of the four diets. Serum albumin concentrations and intestinal mucosal nitrogen content and thickness returned to normal with each refeeding program. Challenge with E. coli after 7 days of refeeding, however, again demonstrated no difference in survival for any dietary group. Specialized enteral feeding products, containing additional amounts of arginine, glutamine, glutamate, RNA, and omega-3 fatty acids, are no more effective than a standard enteral feeding product or rat chow in maintaining intestinal anatomy or restoring anatomy following fasting. Furthermore, we found no survival advantage for the specialized products following E. coli peritonitis.

Animals↗
PubMed1994

Screening for pregnancy risk-drinking.

The efficacy of alcohol screening questionnaires, the TWEAK, T-ACE, NET, MAST, and CAGE, in detecting periconceptional risk-drinking, > or = 1 oz absolute alcohol/day, was investigated in 4743 African-American women attending an inner-city prenatal clinic who had reported ever drinking. Sensitivity, specificity, positive predictive value, efficiency, follow-up rates, and receiver operating characteristics of the questionnaires were examined to compare the overall effectiveness of the questionnaires and their performance at cut-points defining positive scores ranging from 1 to 3. Relatively little difference between TWEAK, T-ACE, and MAST was seen in the receiver operating characteristic accuracy indices; NET and CAGE lagged behind. Sensitivity/specificity scores for the two questionnaires most sensitive at cut-point 1 were TWEAK (87/72) and T-ACE (83/75). At cut-point 2, sensitivity was optimized with respect to specificity; TWEAK (79/83) was significantly more sensitive than T-ACE (70/85; p = 0.002). At cut-point 3, the two most sensitive tests were MAST (61/92) and TWEAK (59/94). In general, measures of merit were not greatly affected by the time between conception and the administration of the screens. Screening was most sensitive for women interviewed during the first 15 weeks of pregnancy; risk-drinkers tended to delay entry into prenatal care, increasing positive predictive values associated with screening later in pregnancy. This study confirms the utility, when screening for risk-drinking during pregnancy, of brief questionnaires that assess alcohol intake indirectly by asking women about their tolerance to alcohol's effects, psychological consequences of drinking, and significant others' concern about their drinking. It validates T-ACE and provides preliminary data indicating that TWEAK may outperform T-ACE.

Adolescent↗
PubMed1994

Acetylcholine muscarinic m1 receptor regulation of cyclic AMP synthesis controls growth factor stimulation of Raf activity.

Acetylcholine muscarinic m2 receptors (m2R) couple to heterotrimeric Gi proteins and activate the Ras/Raf/mitogen-activated protein kinase pathway and phosphatidylinositol 3-kinase in Rat 1a cells. In contrast to the m2R, stimulation of the acetylcholine muscarinic m1 receptor (m1R) does not activate the Ras/Raf/mitogen-activated protein kinase regulatory pathway in Rat 1a cells but rather causes a pronounced inhibition of epidermal growth factor and platelet-derived growth factor receptor activation of Raf. In Rat 1a cells, m1R stimulation of phospholipase C beta and the marked rise in intracellular calcium stimulated cyclic AMP (cAMP) synthesis, resulting in the activation of protein kinase A. Stimulation of protein kinase A inhibited Raf activation in response to growth factors. Platelet-derived growth factor receptor stimulation of phosphatidylinositol 3-kinase activity was not affected by either m1R stimulation or protein kinase A activation in response to forskolin-stimulated cAMP synthesis. GTP loading of Ras in response to growth factors was unaffected by protein kinase A activation but was partially inhibited by carbachol stimulation of the m1R. Therefore, protein kinase A action at the Ras/Raf activation interface selectively inhibited only one branch of the signal transduction network initiated by tyrosine kinases. Specific adenylyl cyclases responding to different signals, including calcium, with enhanced cAMP synthesis will regulate Raf activation in response to Ras.GTP. Taken together, the data indicate that G protein-coupled receptors can positively and negatively regulate the responsiveness of tyrosine kinase-stimulated mitogenic response pathways.

Adenylyl Cyclases↗
PubMed1994

Relationship of financial strain and psychosocial resources to alcohol use and abuse: the mediating role of negative affect and drinking motives.

Limited research has examined the relationship between financial strain and alcohol use and abuse. Building on affect regulation theory and recent research in the stress and alcohol literatures, this study developed and tested a model relating financial strain, social resources, personal resources, depression, and drinking to cope to alcohol use and abuse. Data were obtained from a random sample of 1,424 adults who indicated that they had drunk alcohol in the previous year. We tested and then revised our model using structural equation modeling analysis. Results supported the affect regulation model of financial strain and alcohol use and abuse. Generally, depression mediated the relationship between financial strain and drinking to cope, and drinking to cope mediated the relationship between depression and alcohol use and abuse. In addition, both gender and race moderated six of the relationships in our revised model.

Adult↗
PubMed1993

Involvement of Ras and Raf in the Gi-coupled acetylcholine muscarinic m2 receptor activation of mitogen-activated protein (MAP) kinase kinase and MAP kinase.

Stimulation of the acetylcholine muscarinic m2 receptor (m2R) expressed in Rat 1a fibroblasts results in the activation of the cytoplasmic mitogen-activated protein kinase (MAPK). Concomitant with carbachol stimulation of the m2R was the activation of MEK (MAPK kinase) and Raf. MEK is the dual function kinase that phosphorylates and activates MAPK. Raf is a serine/threonine kinase capable of phosphorylating and activating MEK. Carbachol stimulation of the m2R also activated Ras. Pertussis toxin treatment of Rat 1a cells inhibited the m2R-mediated activation of Ras, Raf, MEK and MAPK. In contrast, epidermal growth factor receptor-mediated activation of Ras, Raf, MEK and MAPK was pertussis toxin-insensitive. m2R activation of Ras, Raf, and MAPK was insensitive to inhibition by genistein, while the epidermal growth factor receptor-induced responses were inhibited by genistein. The findings demonstrate that both Ras and Raf can be regulated by seven-membrane-spanning receptors that selectively couple to Gi proteins.

Adenosine Triphosphate↗
PubMed1993

Effects of transforming growth factor beta 1 on growth and apoptosis of human acute myelogenous leukemia cells.

Because limited studies examined effects of transforming growth factor (TGF) beta 1 on growth of human acute myelogenous leukemia (AML) cells, we used factor-dependent and primary AML cells to assess TGF-beta 1 effects on human AML cell growth. OCI-AML1 cells were growth inhibited by TGF-beta 1 regardless of which growth factor was used as a stimulus. In contrast, AML-193 cells were resistant to TGF-beta 1 when grown with or without growth factors. UCSD/AML1 cells were sensitive to TGF-beta 1 inhibition when grown with most cytokines but were relatively resistant to TGF-beta 1 in the presence of macrophage colony-stimulating factor (M-CSF). Although cells grown from 5 of 6 AML patients were inhibited by TGF-beta 1, cells from 1 AML patient were growth stimulated by TGF-beta 1 in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), M-CSF, or mast cell growth factor (kit ligand). Thus, 3 growth patterns with TGF-beta 1 were observed: (a) sensitivity to growth inhibition; (b) resistance; and (c) factor-dependent resistance. Further studies showed that AML-193 and UCSD/AML1 cells expressed type II TGF-beta 1 receptors and that ability of TGF-beta 1 to decrease GM-CSF receptors did not correlate with growth inhibition. AML-193 cells and UCSD/AML1 cells grown with M-CSF could be propagated in 1 ng/ml TGF-beta 1, but UCSD/AML1 cells grown with GM-CSF and TGF-beta 1 died. Morphology and agarose gel analysis of DNA showed UCSD/AML1 cells underwent apoptosis when grown with GM-CSF and TGF-beta 1 but not with M-CSF and TGF-beta 1. Similar studies of OCI-AML1 cells showed that TGF-beta 1 induced apoptosis of cells grown in 5637 bladder cell-conditioned medium or GM-CSF. These studies indicate that human AML cells exhibit heterogeneous growth responses to TGF-beta 1 and that some effects of TGF-beta 1 on myeloid cells occur through programmed cell death.

Apoptosis↗
PubMed1993

Selective coupling of the human anaphylatoxin C5a receptor and alpha 16 in human kidney 293 cells.

The peptide C5a which is generated during the complement cascade is an important chemotactic factor involved in the inflammatory response. The C5a receptor (C5aR) primary sequence suggests that it has a serpentine structure of seven transmembrane domains which is typical of classical G-protein-coupled receptors. To investigate the signal transduction mechanism of C5a we transiently expressed the C5aR in combination with different G-protein alpha subunits in human kidney 293 cells and measured the PLC activity induced upon C5a stimulation. Cotransfection of C5aR and alpha 16 stimulated PLC while cotransfection of C5aR with either alpha q or alpha i2 did not.

Cell Line↗
PubMed1993

Neurotrophin 3 supports the survival of developing muscle sensory neurons in culture.

Target-dependent cell death of different sub-populations of sensory neurons may be regulated by different trophic factors. To investigate this possibility, we have taken advantage of the fact that the fractions of muscle sensory and cutaneous sensory neurons in chicken dorsal root ganglia (DRG) are probably different at different segmental levels, and we have compared the responses of chicken DRG from levels that do and do not innervate limb tissue to various growth factors in vitro. Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) both supported neurite outgrowth from DRG explanted from all segmental levels. In contrast, neurotrophin 3 (NT-3) supported robust neurite growth only from DRG explanted from the cervical or lumbar levels, which innervate limb muscles. Similarly, NGF and BDNF both promoted survival of dissociated neurons from limb and nonlimb segmental levels, whereas NT-3 promoted survival of more neurons from limb compared to nonlimb levels. This suggests that muscle sensory neurons, which are probably more prevalent at the cervical and lumbar levels, may be specifically affected by NT-3. To evaluate this possibility directly, we compared the survival of retrogradely labeled muscle and cutaneous neurons in NGF, BDNF, and NT-3. Identified muscle sensory neurons survived best in vitro in the presence of NT-3, while the survival of identified cutaneous sensory neurons was greatest in NGF. This work provides direct evidence for a potential role of NT-3 versus NGF in the survival of a specific subpopulation of DRG neurons.

Animals↗
PubMed1993

Potential impact of pulmonary artery catheter placement on short-term management decisions in the medical intensive care unit.

The purpose of this study was to examine the potential impact of pulmonary artery (PA) catheter placement on short-term management decisions in the medical intensive care unit (ICU). One hundred three patients were examined over an 18-month period. The predominant indications for PA-catheter placement included refractory congestive heart failure, airspace disease, uncertain cardiac filling pressures, or hypotension. In 58 (56%) of the 103 patients, management recommendations changed as a direct result of knowledge gained by PA catheter placement. These changes involved fluid therapy recommendations in 41 patients, vasopressor use in 17 patients, intravenous vasodilator use in 24 patients, and recommendations for the use of inotropic agents in 15 patients. Although 18 patients experienced early or late complications, major events were limited to a single pneumothorax requiring chest tube insertion and four episodes of bacteremia. No deaths were directly attributable to the catheter insertion. In critically ill patients in the medical intensive care unit, PA-catheter placement leads to changes in recommendations for management in a substantial portion of patients with little risk of life-threatening complications in those who receive such invasive monitoring.

Adolescent↗
PubMed1993

Headache and cortisol responses to m-chlorophenylpiperazine are highly correlated.

The serotonin receptor agonist m-chlorophenylpiperazine (m-CPP) stimulates the release of cortisol and prolactin, and induces migraine-like headaches. We have studied the neuroendocrine and headache responses to m-CPP in 8 subjects with migraine and 10 normal subjects. Each subject underwent two challenge tests, one with 0.25 mg/kg PO of m-CPP and the other with placebo, administered in a double-blind crossover format. Serial measurements of serum cortisol, prolactin, and m-CPP levels were made at 30-min intervals for 210 min following ingestion of the medication. The incidence and severity of headache was assessed by a structured telephone interview after each test. We confirmed that m-CPP stimulates the release of cortisol and prolactin, and may induce headache, in both migraine subjects and normal controls. The cortisol response as well as ratings of headache severity and duration directly correlated with plasma levels of m-CPP. There were highly significant associations between the cortisol response and both headache severity and duration, independent of m-CPP plasma levels. We did not find statistically significant differences between the migraine and normal subjects in terms of their neuroendocrine or headache responses to m-CPP.

Adult↗
PubMed1993

Changes in gene expression in the Ras/adenylate cyclase system of Saccharomyces cerevisiae: correlation with cAMP levels and growth arrest.

Levels of cyclic 3',5'-cyclic monophosphate (cAMP) play an important role in the decision to enter the mitotic cycle in the yeast, Saccharomyces cerevisiae. In addition to growth arrest at stationary phase, S. cerevisiae transiently arrest growth as they shift from fermentative to oxidative metabolism (the diauxic shift). Experiments examining the role of cAMP in growth arrest at the diauxic shift show the following: 1) yeast lower cAMP levels as they exhaust their glucose supply and shift to oxidative metabolism of ethanol, 2) a reduction in cAMP is essential for traversing the diauxic shift, 3) the decrease in adenylate cyclase activity is associated with a decrease in the expression of CYR1 and CDC25, two positive regulators of cAMP levels and an increase in the expression of IRA1 and IRA2, two negative regulators of intracellular cAMP, 4) mutants carrying disruptions in IRA1 and IRA2 were unable to arrest cell division at the diauxic shift and were unable to progress into the oxidative phase of growth. These results indicate that changes cAMP levels are important in regulation of growth arrest at the diauxic shift and that changes in gene expression plays a role in the regulation of the Ras/adenylate cyclase system.

Adenylyl Cyclases↗
PubMed1993

Individual differences in differentiation among alcohol expectancy domains.

Prior research indicates that alcohol-related outcome expectancies represent important etiological factors in the understanding of alcohol use/abuse. Although current multidimensional measures assess several substantively different domains of alcohol-related outcome expectancies, there is growing evidence that they may not possess adequate levels of discriminant validity. Therefore, the present study sought to examine whether reliable between-person differences exist in the ability to differentiate among alcohol expectancy domains. The focus of the study was on three sets of intrapersonal characteristics: cognitive resources, cognitive constraints, and alcohol-related experience. Data were collected via household interviews with a random sample of 1125 adults. Multiple regression analysis revealed that higher levels of cognitive resources were associated with increasing levels of differentiation among alcohol expectancy domains. Results are discussed in terms of implications for the development of new or revised multidimensional alcohol expectancy questionnaires. Directions for future research are also discussed.

Adult↗
PubMed1993

Radiovisiography--a preliminary subjective assessment in a hospital paediatric dentistry department.

Recent reports on radiovisiography (RVG) have concentrated mainly on the physical characteristics of this relatively new, digital imaging dental radiographic technique. This paper reports a preliminary assessment of the Mark 2 mobile system in routine use in a hospital paediatric dentistry department. The evaluation encompassed patient acceptability, ease of operation and the clinicians' subjective assessments of the images obtained. It was concluded that RVG is, in general, an acceptable alternative to conventional intra-oral radiography.

Adolescent↗
PubMed1993

Influence of socially desirable responding in a study of stress and substance abuse.

Socially desirable responding is the reluctance to admit unpopular beliefs or behavior in order to avoid making a negative impression. It poses a problem for researchers who rely on self-report of heavy drinking and drug use. The Marlowe-Crowne Social Desirability Scale (SDS), which measures socially desirable responding, was administered to 1933 respondents in a general population survey. The relationships between SDS and various self-report measures were examined. SDS was not correlated with gender or race, it increased with greater age and decreased with higher socioeconomic status. With age and socioeconomic status controlled, SDS had a moderate negative relationship with alcohol and drug use, and a strong negative relationship with variables reflecting the expression of anger. Correlations between drinking/drug use and such variables as age, marital conflict, and stressful life events were not substantially changed by controlling for SDS. It was concluded that social desirability response bias probably results in underestimates of rates of heavy drinking and drug use, but does not compromise the study of predictors of heavy drinking or drug use.

Adaptation, Psychological↗
PubMed1993

Use of the TWEAK test in screening for alcoholism/heavy drinking in three populations.

TWEAK is an acronym for Tolerance (T1 number of drinks to feel high; T2, number of drinks one can hold), Worry about drinking, Eye-opener (morning drinking), Amnesia (blackouts), and Cut down on drinking (K/C). In this study, two versions (T1 and T2) of the TWEAK were part of a questionnaire used to detect alcoholism or heavy alcohol intake in three populations, namely, alcoholics in treatment, patients in two outpatient clinics, and the general population. Similar to the CAGE and the 10-item brief MAST, the TWEAK identified most known alcoholics, but the TWEAK had a higher sensitivity and specificity than the CAGE and B-MAST in detecting alcoholism/heavy drinking in the clinical and general populations. Different cut-off values for tolerance (T1 and T2) are recommended for screening different populations.

Adolescent↗