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Biomedical subjects

G C Smith

Publications and source records attributed to G C Smith.

At least 91 records · Page 5Linked to original sources
PubMed2000

Quantification of right and left ventricular function by cardiovascular magnetic resonance.

Cardiac dysfunction is a major cause of cardiovascular morbidity and mortality. Accurate and reproducible assessment of cardiac function is essential for the diagnosis, the assessment of prognosis and evaluation of a patient's response to therapy. Cardiovascular Magnetic Resonance (CMR) provides a measure of global and regional function that is not only accurate and reproducible but is noninvasive, free of ionising radiation, and independent of the geometric assumptions and acoustic windows that limit echocardiography. With the advent of faster scanners, automated analysis, increasing availability and reducing costs, CMR is fast becoming a clinically tenable reference standard for the measurement of cardiac function.

Echocardiography↗
PubMed2000

Nitric oxide upregulates expression of DNA-PKcs to protect cells from DNA-damaging anti-tumour agents.

Nitric-oxide synthase (NOS) activity has been detected in many human tumours, although its function is unclear. Here we show that exposure of cells to nitric oxide (NO) results in a 4-5-fold increase in expression of the DNA-dependent protein-kinase catalytic subunit (DNA-PKcs), one of the key enzymes involved in repairing double-stranded DNA breaks. This NO-mediated increase in enzymatically active DNA-PK not only protects cells from the toxic effects of NO, but also provides crossprotection against clinically important DNA-damaging agents, such as X-ray radiation, adriamycin, bleomycin and cisplatin. The NO-mediated increase in DNA-PKcs described here demonstrates the presence of a new and highly effective NO-mediated mechanism for DNA repair.

Animals↗
PubMed2000

A new concept of the significance of regional distribution of prostaglandin H synthase 2 throughout the uterus during late pregnancy: investigations in a baboon model.

OBJECTIVE: We sought to identify regional differences in prostaglandin H synthase 2 messenger ribonucleic acid expressions in various intrauterine tissues in the pregnant baboon as an indicator of prostaglandin production capability to explain the various interactive roles of different intrauterine tissues in the processes that precede, promote, and complete labor. STUDY DESIGN: Prostaglandin H synthase 2 messenger ribonucleic acid expression was measured by reverse transcriptase-polymerase chain reaction or Northern blot analysis in the uterine fundus, lower uterine segment, cervix, amnion, chorion, and placenta during late pregnancy and spontaneous term labor in the pregnant baboon. Myometrial electromyography enabled clear relation of the findings to uterine contractile activity. RESULTS: There were dramatic increases of prostaglandin H synthase 2 messenger ribonucleic acid expressions during late gestation and during labor in the lower uterine segment, cervix, and decidua. The amniotic prostaglandin H synthase 2 messenger ribonucleic acid expression increased during labor. In contrast, the prostaglandin H synthase 2 messenger ribonucleic acid expressions in the uterine fundus, chorion, and placenta did not change during late gestation and labor. CONCLUSION: Demonstrated increased lower uterine segment and cervical prostaglandin H synthase 2 abundances would promote lower uterine segment elongation and cervical effacement. Engagement of the fetal presenting part would stimulate local prostaglandin H synthase 2 expression and obstruct diffusion of high forebag prostaglandin to the rest of the uterus, as reported previously in human pregnancy. These data support a new conceptual mechanistic framework for preparatory changes in the lower uterine segment and cervix preceding labor as precisely related to myometrial contractility changes.

Amnion↗
PubMed2000

The effects of interpersonal and personal agency on perceived control and psychological well-being in adulthood.

A theoretical model that links social support with global beliefs in primary control and provides a developmental perspective on how normative age-related changes alter control beliefs was examined with data from 482 adults aged 18 to 93. Generalized belief in primary control was hypothesized to have a direct positive effect on psychological well-being and to arise from two distinct sources: (a) interpersonal agency (obtaining positive ends through interactions with others) and (b) personal agency (achieving desired outcomes on one's own behalf). Age was believed to affect both types of agency indirectly as a result of age-related changes in physical health and emotional support. Although physical health was presumed to have a direct positive effect on psychological well-being, the effect of emotional support on well-being was mediated by interpersonal agency and perceived primary control. Structural equation modeling analyses with the EQS 5.4 program revealed good model fit (goodness-of-fit index = .98, comparative fit index = .94, root mean square residual [RMR] = .02, standardized RMR = .05, root mean square error of approximation = .06) after a negative direct path from age to generalized beliefs in primary control was added to the a priori model.

Adult↗
PubMed2000

A population study of birthweight and the risk of caesarean section: Scotland 1980-1996.

OBJECTIVES: 1. To describe the relation between birthweight and risk of emergency caesarean section at term; 2. to determine whether the relation between birthweight and caesarean section differed between male and female babies; and 3. to determine what proportion of the increased rates of caesarean section could be related to greater birthweights. DESIGN: Retrospective population study. SETTING: Data collected from Scottish Morbidity Record 1980 to 1996. POPULATION: All first singleton deliveries by emergency caesarean section and non-elective vaginal birth of live babies at 40 weeks of gestation (n = 120,854). MAIN OUTCOME MEASURE: Delivery by emergency caesarean section. RESULTS: There was a U-shaped relation between birthweight and the risk of caesarean section, with the lowest risk associated with weights in the range 3,000-3,500 g. Overall, male, were more likely to be delivered by caesarean section (relative risk = 1.2, 95% CI 1.2-1.3). The association between male sex and increased risk of caesarean section persisted after adjusting for birthweight, but only males weighing < 4,000 g were at increased risk of caesarean section compared with similarly sized females. Between 1980 and 1996, there were linear increases in the rate of caesarean section (from 7.1% to 10.7%, r2 = 0.8, P < 0.001) and median birthweight (from 3,360 g in 1980 to 3,420 g in 1996, r2 = 0.8, P < 0.001). The population attributable fraction of caesarean sections related to year of delivery 1981-1996 was not significantly altered by adjusting for birthweight (22.3% vs 21.6%). CONCLUSIONS: There is no evidence to suggest that increasing birthweights have contributed to increasing rates of caesarean section in Scotland between 1980 and 1996 among singleton first births non-electively delivered at 40 weeks of gestation.

Birth Weight↗
PubMed2000

Differential distribution of ERalpha and ERbeta mRNA in intrauterine tissues of the pregnant rhesus monkey.

Two estrogen receptor (ER) isoforms, ERalpha and ERbeta, have been described. However, no information is available in any species regarding the comparison of ERalpha and ERbeta levels in pregnant intrauterine tissues. We investigated 1) distribution of ERalpha and ERbeta mRNA in myometrium, amnion, choriodecidua, and placenta; 2) their abundance in intrauterine tissues at term not in labor (NIL) and in spontaneous term labor (STL); and 3) immunolocalization of ERalpha and ERbeta in pregnant rhesus monkey myometrium. Myometrium, amnion, choriodecidua, and placenta were obtained at cesarean section from monkeys in STL at 156-166 days gestational age (GA) (n = 4) and from control monkeys NIL at 140-152 days GA (n = 4). RT-PCR was conducted to determine ERalpha and ERbeta and glyceraldehyde-3-phosphate dehydrogenase mRNA abundance in four intrauterine tissues of the pregnant rhesus monkey. The cloned ERbeta PCR fragment was subjected to sequence analysis. ERalpha and ERbeta were localized in the myometrium by immunohistochemistry. We demonstrated that 1) rhesus monkey ERbeta shares >97% identity with human ERbeta in the region sequenced; 2) both ERs were expressed in myometrium, amnion, and choriodecidua but not in placenta in the current study; 3) ERalpha and ERbeta were differentially distributed in myometrium and amnion; 4) ERalpha and ERbeta were immunolocalized in myometrial smooth cells and smooth muscle and endothelial cells of the myometrial blood vessels. The biological significance of these quantitative differences in ER subtypes merits further study.

Amnion↗
PubMed2000

Prostaglandin dehydrogenase mRNA in baboon intrauterine tissues in late gestation and spontaneous labor.

The present study was designed to characterize prostaglandin dehydrogenase (PGDH) mRNA expression in critical intrauterine tissues of pregnant baboons in late gestation and at spontaneous labor. In addition, we determined regulatory effects of betamethasone in vivo on chorionic and placental PGDH mRNA expression. PGDH mRNA was present in chorion, decidua, lower uterine segment, fundal myometrium, and cervix in late gestation but undetectable in amnion. PGDH mRNA significantly decreased in decidua and cervix during late gestation and in chorion and fundus during spontaneous labor. PGDH mRNA in lower uterine segment, decidua, cervix, and placenta was unchanged during spontaneous labor from late gestation levels. Betamethasone had no effect on chorionic and placental PGDH mRNA expression. In summary, our data suggest that PGDH mRNA expression is tightly controlled in gestation- and tissue-specific manners. Decreased chorionic and fundal PGDH abundance during labor and decreased decidua and cervical PGDH mRNA in late gestation allow local uterine prostaglandin accumulation and assist prostaglandin transfer to myometrium. Local differences in PGDH function may regulate tissue- and region-specific requirements for prostaglandins to promote and complete labor.

Animals↗
PubMed2000

Planning by older mothers for the future care of offspring with serious mental illness.

OBJECTIVE: This study examined permanency planning by older mothers for their adult offspring with long-term mental illness, including extent of residential and financial planning, desire for future family care, and perceived need for and use of services to assist with planning. METHODS: Mail surveys were completed by 157 mothers (mean age, 67 years) from 41 states who lived with and provided care to adult offspring with serious mental disorders (mean age, 38 years). The offspring were mostly males (76 percent) and had diagnoses primarily of schizophrenia or schizoaffective disorder (60 percent), multiple diagnoses (20 percent), or bipolar disorder (16 percent). RESULTS: Only 11 percent of mothers reported definite plans for their offspring's future residence, and many had done little or no planning. Three-quarters of respondents hoped that another family member would assume care, yet only one-quarter thought such arrangements would definitely occur. Two-thirds of the respondents had completed financial plans. Although more than two-thirds expressed the need for services to help with planning, less than one-third had used such services. More than half reported awareness of age-related changes in themselves or their spouse as the primary reason for planning. CONCLUSIONS: Older parents of adults with long-term mental illness need professional help with planning for their offspring's future. This assistance should focus on mechanisms such as estate planning to enable case management and other services after parents' death. The involvement of nondisabled siblings in planning should also be encouraged.

Adult↗
PubMed2000

Quantification of pork belly and boston butt quality attribute preferences of South Korean customers.

U.S. packers must have quantitative criteria for selection of pork bellies and Boston butts for export to South Korea. Pork bellies (IMPS 409A) and Boston butts (IMPS 409A, 406B, 407) were selected from normal production in a U.S. pork packing plant and transported to Seoul, South Korea, via seafreighter in refrigerated containers (frozen < -5 degrees C) or via air freight (fresh > 0 degrees C; frozen < -5 degrees C). Participants at the Seoul Food Show were surveyed about their preferences for specific quality attributes of these cuts. Bellies were selected to differ in seam fat content (low = < 20%, moderate = 20 to 40%, high = > 40% extractable fat), lean color (pale = L* > 50, medium = L* 48-50, dark = L* < 48), weight (3.36, 4.04, or 5.36 kg), state of refrigeration and packaging (frozen, poly-wrapped; chilled, poly-wrapped; frozen, vacuum-packaged; chilled, vacuum-packaged), shape (round, wavy, square), and belly thickness (3.81, 4.32, or 4.90 cm). Boston butts were selected to differ in USDA marbling score (Slight, Small, Modest, Moderate, and Slightly Abundant), seam fat content (low = < 10%, moderate = 10 to 20% fat, high = > 20% extractable fat), lean color (pale = L* > 44, medium = L* 40-42, dark = L* < 38), weight (2.91, 3.82, or 4.66 kg), state of refrigeration and packaging (frozen, poly-wrapped; chilled, poly-wrapped; frozen, vacuum-packaged; chilled, vacuum-packaged), and shape (square, oblong, round). In Seoul, pork subprimals were tempered (if frozen), sliced, and arrayed by quality attribute and category in a retail display case. Over 4 d of testing, attendees (n = 210) of the food show were asked to rate the displayed samples for each quality attribute on a standardized ballot. Mid-weight (3.82 kg) Boston butts that displayed Moderate or higher USDA marbling scores with moderate amounts of seam fat, Japanese lean color scores of 2 or 4, round geometric shape, and that were vacuum-packaged and transported to Korea in the freshly chilled state best characterized the quality attribute preferences of respondents. Pork bellies that exhibited moderate amounts of seam fat, Japanese lean color scores of 3, square shape, belly thickness of 3.94 cm, approximate weight of 4.04 kg, and that were vacuum-packaged and transported to Korea in the freshly chilled state best met the quality needs of South Korean customers.

Animals↗
PubMed2000

Injection of beef strip loins with solutions containing sodium tripolyphosphate, sodium lactate, and sodium chloride to enhance palatability.

Beef strip loins (46 U.S. Choice loins and 49 U.S. Select loins) were used to evaluate the potential for enhancing beef tenderness, juiciness, and flavor by injecting fresh cuts with solutions containing sodium tripolyphosphate, sodium lactate, and sodium chloride. One half of each loin served as an untreated control, and the other half was injected with either distilled water (110% of raw weight) or a solution containing phosphate/lactate/chloride solution (107.5, 110, 112.5, or 115% of raw weight). All phosphate/lactate/chloride solutions were formulated to produce injected product concentrations of .25% sodium tripolyphosphate, .5% sodium chloride, and 2.5% sodium lactate. Ten additional U.S. Select loins were injected to 110% of raw weight with a phosphate-only solution (final product concentration of .25% sodium tripolyphosphate) for comparison with Select loins injected to 110% with phosphate/lactate/chloride and with distilled water. Steaks from each control and treated loin section were cooked to two final internal temperatures (66 degrees C and 77 degrees C) for sensory panel evaluation and shear force measurement. Injection of subprimal cuts with phosphate/lactate/chloride solutions improved tenderness (P < .05), juiciness (P < .05), and cooked beef flavor (P < .10) of strip loin steaks and was especially effective for maintaining tenderness and juiciness of steaks cooked to the higher final internal temperature. Injection of Select loins with a solution containing only sodium tripolyphosphate was not effective for improving beef tenderness or juiciness and tended to impart off-flavors characterized by sensory panelists as soapy and sour. Injection of fresh cuts with phosphate/lactate/chloride solutions could assist the beef industry's efforts to improve product quality and consistency.

Animals↗
PubMed2000

Effects of a unique application of electrical stimulation on tenderness, color, and quality attributes of the beef longissimus muscle.

This study evaluated effects of four uniquely applied beef carcass electrical stimulation (ES) treatments on USDA grade factors, muscle color, subprimal purge loss, cooked steak weight loss, and cooked steak tenderness. One side of each (n = 284) beef carcass was subjected to ES using one of four treatments (medium voltage for medium duration, MVMD; medium voltage for long duration, MVLD; high voltage for medium duration, HVMD; or high voltage for long duration, HVLD) and was compared to its corresponding non-ES control side. Electrical stimulation of beef sides was applied focusing on middle meats while preventing severe contraction of the round and chuck. From matched (ES and control) sides of 120 carcasses (10 each of Select, low Choice, and upper two-thirds of Choice in each of the four ES treatments), longissimus steaks (2.5 cm thick) were cooked and used for Warner-Bratzler shear force (WBS) analysis. Mean marbling scores (n = 284) for stimulated sides did not differ (P = .923) from those for control sides within ES treatment classes. Mean values for CIE L*, a*, and b* of lean color (n = 284) were higher (P < .05) for MVMD, MVLD, HVMD, and HVLD treated sides than for the respective control sides. When WBS values for steaks were adjusted to an equal visual degree of doneness, WBS values (n = 120) were lower (P < .05) for ES treated sides than for control sides for all four types of ES application treatments. Treatment responses were not influenced by USDA Quality Grade group. For those carcasses for which the control sides had WBS values greater than 4.5 kg, matching sides treated with MVMD, MVLD, HVMD, or HVLD had WBS values less than 4.5 kg 50, 88, 60, and 75% of the time, respectively. Mean cooked steak weight loss (n = 120), adjusted to an equal visual degree of doneness, and mean purge loss (n = 24) did not differ with ES treatment.

Animals↗
PubMed2000

Implant strategies during feeding: impact on carcass grades and consumer acceptability.

Anabolic growth promotants influence beef grade factors and Warner-Bratzler shear force of steaks. No study has assessed the consumer acceptability of beef derived from implanted cattle. This study determined beef carcass grades and consumer acceptability for cooked beef from unimplanted (control) cattle and from cattle implanted with one of seven different implant strategies (initial implant/implant at 59 d = Encore & Component T-S/no implant, Ralgro/Synovex Plus, Ralgro/Revalor-S, Revalor-S/Revalor-S, Revalor-S/no implant, no implant/Synovex Plus, and Synovex Plus/no implant). British crossbred steers (n = 448) were allocated randomly into one of eight pens for each of the control and seven treatment groups. Carcass quality and yield grade (n = 403) and Warner-Bratzler shear force (n = 298) data were collected by trained personnel. Twenty steaks per control or treatment group were selected randomly for use in consumer sensory evaluation. Steaks were evaluated by consumers for overall like, tenderness like, tenderness level, flavor like, flavor intensity, and juiciness level using 9-point, end-anchored hedonic scales. Control carcasses had smaller (P < .05) longissimus muscle areas than carcasses in all treatment groups except those receiving Encore & Component T S/no implant, Ralgro/Synovex Plus, or Revalor S/no implant. Control carcasses had higher (P < .05) marbling scores than carcasses in all treatment groups except those receiving Ralgro/Revalor-S or Encore & Component T-S/no implant. Steaks from control steers had lower (P < .05) Warner-Bratzler shear force values than steaks from steers given Revalor-S/no implant. Consumer ratings for tenderness like and tenderness level were influenced (P < .05) by implant strategy. Effects of implant strategy on overall like, flavor like, and flavor intensity approached significance (P = .07 to .09). Consumers rated steaks from unimplanted steers as more tender (tenderness level; P < .05) than steaks from all treatment groups except that involving Encore & Component T-S/no implant. Consumers rated steaks from unimplanted steers as more desirable (P < .05) for tenderness like than steaks from all treatments except those involving Encore & Component T-S/no implant or Revalor-S/no implant. Although use of implants in this study resulted in heavier hot carcass weights and larger ribeyes, some of the implant strategies reduced consumer preference of tenderness of steaks.

Adult↗
PubMed2000

Interventions to reduce microbiological contamination of beef variety meats.

Hot water and solutions of acetic acid, lactic acid, or trisodium phosphate applied by immersion or spraying, chlorine solution applied by immersion, and exposure to steam in a pasteurization system, in a cabinet, or in combination with vacuum were evaluated for their effectiveness in reducing levels of bacterial contamination on samples of beef cheek meat, large intestine, lips, liver, oxtail, and tongue. Treated samples (five per treatment) and controls were analyzed for aerobic plate counts (APCs) on tryptic soy agar and for total coliform counts (TCCs) and Escherichia coli counts (ECCs) on Petrifilm. Acetic acid (2%) immersion and trisodium phosphate (12%) spraying and immersion for 10 s were among the most effective treatments in 16, 15, and 14, respectively, of 18 comparisons for reducing APCs, TCCs, and ECCs on four or more of the six variety meats tested. Acetic acid (2%) spraying, lactic acid (2%) immersion, and hot water (78 to 80 degrees C) spraying for 10 s were among the most effective treatments for reducing APCs, TCCs, and ECCs on four or more of the six variety meats. Chlorine (0.005%) immersion and steam were among the least effective treatments for reducing APCs, TCCs, and ECCs on variety meats. The results indicated that interventions applied to decontaminate beef carcasses can also be considered for decontamination of variety meats.

Animals↗
PubMed2000

Microbial populations on animal hides and beef carcasses at different stages of slaughter in plants employing multiple-sequential interventions for decontamination.

Multiple-sequential interventions were applied commercially to reduce beef carcass contamination in eight packing plants. The study evaluated microbial populations on animal hides and changes in carcass microbial populations at various stages in the slaughtering process. Sponge swab samples yielded mean (log CFU/100 cm2) total plate counts (TPC), total coliform counts (TCC), and Escherichia coli counts (ECC) on the exterior hide in the ranges of 8.2 to 12.5, 6.0 to 7.9, and 5.5 to 7.5, respectively, while corresponding contamination levels on carcass surfaces, after hide removal but before application of any decontamination intervention, were in the ranges of 6.1 to 9.1, 3.0 to 6.0, and 2.6 to 5.3, respectively. Following the slaughtering process and application of multiple-sequential decontamination interventions that included steam vacuuming, pre-evisceration carcass washing, pre-evisceration organic acid solution rinsing, hot water carcass washing, postevisceration final carcass washing, and postevisceration organic acid solution rinsing, mean TPC, TCC, and ECC on carcass surfaces were 3.8 to 7.1, 1.5 to 3.7, and 1.0 to 3.0, respectively, while corresponding populations following a 24 to 36 h chilling period were 2.3 to 5.3, 0.9 to 1.3, and 0.9, respectively. The results support the concept of using sequential decontamination processes in beef packing plants as a means of improving the microbiological quality of beef carcasses.

Abattoirs↗
PubMed2000

Somatisation. What is it?

BACKGROUND: Patients with a strong somatic conviction despite an absence of objective measures of physical disease are vexing and frustrating for doctors. OBJECTIVE: This paper describes the phenomenon of somatisation and the common forms of presentation. DISCUSSION: Somatisation--the expression of distress in somatic form--is perhaps the commonest of the psychiatric phenomena seen in general practice. It is usually accompanied by degrees of depression and anxiety. General practitioners have a special opportunity for recognition and early intervention in order to prevent the development of chronic somatizing states.

Humans↗
PubMed2000

Management of somatoform disorders.

BACKGROUND: Physical illness, where there is no apparent disease, is a problem for doctors and the health system. Such an illness is also a cause of distress and anguish for patients and families. General practitioners are inevitably involved. OBJECTIVE: This paper describes the technique of re-attribution used to reduce patients' somatic focus, and presents principles for the management of chronic somatizers. DISCUSSION: General practitioners have a critical role to play with somatizing patients. For those patients presenting occasionally, or for the first time, with somatoform symptoms, GPs have the opportunity, through education, reassurance and re-attribution, to prevent reinforcement of the somatic perception and to reduce illness behaviour. In the care of patients with chronic somatizing disorders, GPs have an equally important role as case managers and carers, in order to prevent unnecessary medical interventions and to help maximise patient functioning.

Chronic Disease↗
PubMed1999

Purification and DNA binding properties of the ataxia-telangiectasia gene product ATM.

The human neurodegenerative and cancer predisposition condition ataxia-telangiectasia is characterized at the cellular level by radiosensitivity, chromosomal instability, and impaired induction of ionizing radiation-induced cell cycle checkpoint controls. Recent work has revealed that the gene defective in ataxia-telangiectasia, termed ATM, encodes an approximately 350-kDa polypeptide, ATM, that is a member of the phosphatidylinositol 3-kinase family. We show that ATM binds DNA and exploit this to purify ATM to near homogeneity. Atomic force microscopy reveals that ATM exists in two populations, with sizes consistent with monomeric and tetrameric states. Atomic force microscopy analyses also show that ATM binds preferentially to DNA ends. This property is similar to that displayed by the DNA-dependent protein kinase catalytic subunit, a phosphatidylinositol 3-kinase family member that functions in DNA damage detection in conjunction with the DNA end-binding protein Ku. Furthermore, purified ATM contains a kinase activity that phosphorylates serine-15 of p53 in a DNA-stimulated manner. These results provide a biochemical assay system for ATM, support genetic data indicating distinct roles for DNA-dependent protein kinase and ATM, and suggest how ATM may signal the presence of DNA damage to p53 and other downstream effectors.

Ataxia Telangiectasia↗