Persistent genital human papillomavirus infection as a risk factor for persistent cervical dysplasia

BACKGROUND

Cervical dysplasia, also referred to as squamous intraepithelial lesion (SIL) in cytology or cervical intraepithelial neoplasia in histopathology, is thought to have the potential to advance in progressive stages to cervical cancer. However, not all cases of SIL progress, and most of the mild lesions spontaneously regress. Factors that govern regression, persistence, and progression of SIL are poorly understood.

PURPOSE

Our analysis sought to identify factors that determined persistence or regression of SIL.

METHODS

Seventy subjects with histopathologically confirmed cervical dysplasia were followed at 3-month intervals for 15 months. At each visit, the cervix was evaluated by Pap smear and colposcopy, and exfoliated cervicovaginal cells were analyzed for human papillomavirus (HPV) DNA. For each subject, data from every two consecutive visits were grouped as a pair. Persistent SIL was considered present if a lesion was detected at a visit (t) as well as at the next visit (t + 1) and absent if a lesion was detected at visit t but not at visit t + 1. A statistical model for time-dependent data correlated persistent SIL with various risk factors.

RESULTS

Age, ethnicity, education, sexual behavior, smoking, and the use of oral contraceptives did not correlate with persistent SIL. The risk of persistent SIL was associated with continual HPV infection in visits t and t + 1 (HPV positive by Southern blot analysis: odds ratio [OR] = 3.91, and 95% confidence interval [CI] = 1.58-9.65; HPV positive by polymerase chain reaction [PCR]: OR = 2.42, and 95% CI = 1.03-5.67) and a persistent high viral load (OR = 4.07, and 95% CI = 1.35-12.30). When typed by PCR, individuals with type-specific persistent infection in visits t and t + 1, and particularly those with a continual high viral load (OR = 4.97; 95% CI = 1.45-17.02), had the highest risk for persistent SIL compared with those with a low level of type-specific persistent infection or non-type-specific persistent infection. The presence of persistent HPV infection in visits t-1 (the preceding time interval) was also predictive of persistent SIL in visits t and t + 1, although the strength of association was weaker, suggesting that persistent HPV and SIL occur synchronously.

CONCLUSION

HPV infection and its associated cervical lesions tend to occur concurrently, and type-specific persistent HPV infection, particularly with a high viral load, produces chronic cervical dysplasia.

IMPLICATIONS

The natural history of genital HPV infection directly influences the prognosis of cervical dysplasia as measured by persistence of the lesion. Testing for HPV infection may be valuable in the clinical management of women with cervical dysplasia.

Weight maintenance and additional weight loss with liraglutide after low-calorie-diet-induced weight loss: the SCALE Maintenance randomized study

OBJECTIVE

Liraglutide, a once-daily human glucagon-like peptide-1 analog, induced clinically meaningful weight loss in a phase 2 study in obese individuals without diabetes. The present randomized phase 3 trial assessed the efficacy of liraglutide in maintaining weight loss achieved with a low-calorie diet (LCD).

METHODS

Obese/overweight participants (≥18 years, body mass index ≥30 kg m(-2) or ≥27 kg m(-2) with comorbidities) who lost ≥5% of initial weight during a LCD run-in were randomly assigned to liraglutide 3.0 mg per day or placebo (subcutaneous administration) for 56 weeks. Diet and exercise counseling were provided throughout the trial. Co-primary end points were percentage weight change from randomization, the proportion of participants that maintained the initial ≥5% weight loss, and the proportion that lost ≥5% of randomization weight (intention-to-treat analysis). ClinicalTrials.gov identifier: NCT00781937.

RESULTS

Participants (n=422) lost a mean 6.0% (s.d. 0.9) of screening weight during run-in. From randomization to week 56, weight decreased an additional mean 6.2% (s.d. 7.3) with liraglutide and 0.2% (s.d. 7.0) with placebo (estimated difference -6.1% (95% class intervals -7.5 to -4.6), P<0.0001). More participants receiving liraglutide (81.4%) maintained the ≥5% run-in weight loss, compared with those receiving placebo (48.9%) (estimated odds ratio 4.8 (3.0; 7.7), P<0.0001), and 50.5% versus 21.8% of participants lost ≥5% of randomization weight (estimated odds ratio 3.9 (2.4; 6.1), P<0.0001). Liraglutide produced small but statistically significant improvements in several cardiometabolic risk factors compared with placebo. Gastrointestinal (GI) disorders were reported more frequently with liraglutide than placebo, but most events were transient, and mild or moderate in severity.

CONCLUSION

Liraglutide, with diet and exercise, maintained weight loss achieved by caloric restriction and induced further weight loss over 56 weeks. Improvements in some cardiovascular disease-risk factors were also observed. Liraglutide, prescribed as 3.0 mg per day, holds promise for improving the maintenance of lost weight.

Subcutaneous adipose tissue releases interleukin-6, but not tumor necrosis factor-alpha, in vivo

We measured arterio-venous differences in concentrations of tumor necrosis factor-alpha (TNF alpha) and interleukin-6 (IL-6) across a sc adipose tissue bed in the postabsorptive state in 39 subjects [22 women and 17 men; median age, 36 yr (interquartile range, 26-48 yr); body mass index, 31.8 kg/m2 (range, 22.3- 38.7 kg/m2); percent body fat, 28.7% (range, 17.6-50.7%)]. A subgroup of 8 subjects had arteriovenous differences measured across forearm muscle. Thirty subjects were studied from late morning to early evening; 19 ate a high carbohydrate meal around 1300 h, and 11 continued to fast. We found a greater than 2-fold increase in IL-6 concentrations across the adipose tissue bed [arterial, 2.27 pg/mL (range, 1.42-3.53 pg/mL); venous, 6.71 pg/mL (range, 3.36-9.62 pg/mL); P < 0.001], but not across forearm muscle. Arterial plasma concentrations of IL-6 correlated significantly with body mass index (Spearman's r = 0.48; P < 0.01) and percent body fat (Spearman's r = 0.49; P < 0.01). Subcutaneous adipose tissue IL-6 production increased by the early evening (1800-1900 h) in both subjects who had extended their fasting and those who had eaten. Neither deep forearm nor sc adipose tissue consistently released TNF alpha [across adipose tissue: arterial, 1.83 pg/mL (range, 1.36-2.34 pg/mL); venous, 1.85 pg/mL (range, 1.44-2.53 pg/mL); P = NS: across forearm muscle: arterial, 1.22 pg/mL (range, 0.74-2.76 pg/mL); venous, 0.99 pg/mL (range, 0.69-1.70 pg/mL); P = NS]. Although both IL-6 and TNF alpha are expressed by adipose tissue, our results show that there are important differences in their systemic release. TNF alpha is not released by this sc depot. In contrast, IL-6 is released from the depot and is thereby able to signal systemically.

Radioimmunoassay of leptin in human plasma

Recent studies suggest that leptin, the ob gene product absent in ob/ob mice, is a negative regulator of adiposity. We developed an RIA to measure human leptin in plasma or serum. The minimum detectable concentration by the assay is 0.5 microg/L leptin and the limit of linearity is 100 microg/L. Recovery of leptin added to serum was 99-104% over by the linear range of the assay. The RIA agreed reasonably well with rough quantification by Western blot (RIA = 0.90 blot + 3.7 microg/L, Sy/x = 10.9 microg/L). CVs within- and between-run ranged from 3.4% to 8.3% and from 3.6% to 6.2%, respectively. Variation in plasma leptin concentrations in specimens collected on consecutive mornings was large (CVs of 10.9% and 22.5%). After an overnight fast, leptin concentrations were similar to those 1-2 h after 1-2 meals. Plasma leptin concentrations in specimens from 83 lean and obese adults correlated directly with body mass index (BMI; kg/m2): r = 0.72, P &lt;0.001. Correlations were significantly improved by separating results by gender (men r = 0.84, women r = 0.87; p &lt;0.001). The increase in leptin concentrations with increasing BMI was greater in women than in men (slope 2.53 vs 0.97 microg/L per unit BMI, respectively). Leptin concentrations determined in lean subjects (BMI between 18 and 25) were higher in women (7.36 +/- 3.73 microg/L) than in men (3.84 +/- 1.79 microg/L) (P &lt;0.001). Plasma leptin varied little with age and no significant difference was observed between whites and blacks. We conclude that: (a) plasma leptin concentrations are accurately and precisely measured by this new RIA; (b) leptin concentrations vary little due to short-term fasting, age, or race; but (c) plasma leptin concentrations are gender specific.

An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein

Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (approximately 0.15 g.kg-1.h-1 for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle protein synthesis were also greater after exercise than at rest (291 +/- 42% vs. 141 +/- 45%). Muscle protein breakdown was not significantly affected by hyperminoacidemia either at rest or after exercise. We conclude that the stimulatory effect of exogenous amino acids on muscle protein synthesis is enhanced by prior exercise, perhaps in part because of enhanced blood flow. Our results imply that protein intake immediately after exercise may be more anabolic than when ingested at some later time.

Nutrition support in clinical practice: review of published data and recommendations for future research directions. National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.

Relationship between insulin sensitivity and plasma leptin concentration in lean and obese men

Alterations in the production of or the sensitivity to leptin, the protein encoded by the ob gene, cause obesity and diabetes in rodents. We evaluated the isolated relationship between leptin and insulin sensitivity in lean and obese humans. Three groups of subjects who were carefully matched for either insulin sensitivity (determined by the modified intravenous glucose tolerance test and minimal model analysis) or adiposity (determined by hydrodensitometry) were studied: 1) lean insulin-sensitive men (percentage body fat, 15 +/- 1%); 2) lean insulin-resistant men (percentage body fat, 16 +/- 1%), matched on percentage body fat and fat mass with the lean insulin-sensitive group; and 3) obese insulin-resistant men (percentage body fat, 31 +/- 3), matched on insulin sensitivity with the lean insulin-resistant group. Basal plasma leptin concentrations were significantly lower in the lean insulin-sensitive than in the lean insulin-resistant men (1.90 +/- 0.4 vs. 4.35 +/- 1.21 ng/ml, P < 0.05) despite identical body composition. Plasma leptin in the obese men (9.27 +/- 1.4 ng/ml) was significantly higher than values in the two lean groups (P < 0.01). Marked alterations in plasma glucose and insulin concentrations induced by glucose and tolbutamide injection did not cause any change in plasma leptin levels. These results demonstrate that insulin resistance is associated with elevated plasma leptin levels independent of body fat mass. However, plasma insulin itself does not acutely regulate leptin production.

Ambulance personnel and critical incidents: impact of accident and emergency work on mental health and emotional well-being

BACKGROUND

The association between mental health and occupational factors among ambulance personnel has not been thoroughly investigated in the UK.

AIMS

To identify the prevalence of psychopathology among ambulance personnel and its relationship to personality and exposure to critical incidents.

METHOD

Data were gathered from ambulance personnel by means of an anonymous questionnaire and standardised measures.

RESULTS

Approximately a third of the sample reported high levels of general psychopathology, burnout and posttraumatic symptoms. Burnout was associated with less job satisfaction, longer time in service, less recovery time between incidents, and more frequent exposure to incidents. Burnout and GHQ-28 caseness were more likely in those who had experienced a particularly disturbing incident in the previous 6 months. Concerns about confidentiality and career prospects deter staff from seeking personal help.

CONCLUSIONS

The mental health and emotional well-being of ambulance personnel appear to be compromised by accident and emergency work.

Integrin-specific activation of Rac controls progression through the G(1) phase of the cell cycle

Adhesion to fibronectin through the alpha5beta1 integrin enables endothelial cells to proliferate in response to growth factors, whereas adhesion to laminin through alpha2beta1 results in growth arrest under the same conditions. On laminin, endothelial cells fail to translate Cyclin D1 mRNA and activate CDK4 and CDK6. Activated Rac, but not MEK1, PI-3K, or Akt, rescues biosynthesis of cyclin D1 and progression through the G(1) phase. Conversely, dominant negative Rac prevents these events on fibronectin. Mitogens promote activation of Rac on fibronectin but not laminin. This process is mediated by SOS and PI-3K and requires coordinate upstream signals through Shc and FAK. These results indicate that Rac is a crucial mediator of the integrin-specific control of cell cycle in endothelial cells.

Adipose tissue leptin production and plasma leptin kinetics in humans

Abdominal adipose tissue leptin production was determined in vivo by arteriovenous balance in 14 lean and obese men (mean BMI 27.0 +/- 1.9, range 21.4-45.2). Blood samples were taken simultaneously from an abdominal vein that drains subcutaneous adipose tissue and from a radial artery. Adipose tissue blood flow was measured by xenon washout. Abdominal vein leptin concentrations (mean 8.9 +/- 2.4 ng/ml, range 2.1-36.5 ng/ml) were consistently greater than arterial values (mean 6.6 +/- 1.9 ng/ml, range 1.7-28.2 ng/ml) (P < 0.001). The net rate of abdominal adipose tissue leptin production (mean 3.2 +/- 0.5 ng x 100 g(-1) x min(-1)) correlated directly with percentage body fat (rs = 0.59, P = 0.016). Estimated whole-body leptin production rate (797 +/- 283 ng x person(-1) x min(-1)) correlated directly with percent body fat (rs = 0.93, P < 0.0001) and with regional leptin production (rs = 0.81, P < 0.001). In contrast, the rate of leptin clearance from plasma (mean 1.50 +/- 0.23 ml x kg(-1) x min(-1)) and plasma leptin half-life (mean 24.9 +/- 4.4 min) was unrelated to adiposity (rs = 0.06, P = 0.30; rs = 0.16, P = 0.30, respectively). These results provide direct evidence that leptin is produced by adipose tissue in humans and that the rate of production is directly related to adiposity. A combination of greater leptin production per unit of body fat and increased production from expanded total body fat mass, rather than alterations in leptin clearance, account for the increase in plasma leptin concentrations observed in obese humans.

Lipid metabolism during endurance exercise

Endogenous triacylglycerols represent an important source of fuel for endurance exercise. Triacylglycerol oxidation increases progressively during exercise; the specific rate is determined by energy requirements of working muscles, fatty acid delivery to muscle mitochondria, and the oxidation of other substrates. The catecholamine response to exercise increases lipolysis of adipose tissue triacylglycerols and, presumably, intramuscular triacylglycerols. In addition, increases in adipose tissue and muscle blood flow decrease fatty acid reesterification and facilitate the delivery of released fatty acids to skeletal muscle. Alterations in fatty acid mobilization and the relative use of adipose and intramuscular triacylglycerols during exercise depend, in large part, on degree of fitness and exercise intensity. Compared with untrained persons exercising at the same absolute intensity, persons who have undergone endurance training have greater fat oxidation during exercise without increased lipolysis. Available evidence suggests that the training-induced increase in fat oxidation is due primarily to increased oxidation of non-plasma-derived fatty acids, perhaps from intramuscular triacylglycerol stores. Fat oxidation is lower in high-intensity exercise than in moderate-intensity exercise, in part because of decreased fatty acid delivery to exercising muscles. Parenteral lipid supplementation during high-intensity exercise increases fat oxidation, but the effect of ingesting long-chain or medium-chain triacylglycerols on substrate metabolism during exercise is less clear. This review discusses the relation between fatty acid mobilization and oxidation during exercise and the effect of endurance training, exercise intensity, and lipid supplementation on these responses.

Nutrition support in clinical practice: review of published data and recommendations for future research directions. Summary of a conference sponsored by the National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family. (Journal of Parenteral and Enteral Nutrition 21:133-156, 1997).

Total parenteral nutrition and cancer clinical trials

Twenty-eight prospective randomized controlled clinical trials evaluating the use of total parenteral nutrition (TPN) in cancer patients were identified through a search of major indexing sources. The data were pooled across studies to increase the ability to detect therapeutic effects. The impact of publication bias and the quality of reporting each trial were used to critically assess the conclusions drawn from the pooled analysis. The authors conclude that TPN may be useful when used preoperatively in patients with gastrointestinal tract cancer. It appears to be beneficial in reducing major surgical complications (pooled P = 0.01) and operative mortality (pooled P = 0.02). No statistically significant benefit from TPN could be demonstrated in survival, treatment tolerance, treatment toxicity, or tumor response in patients receiving chemotherapy or radiotherapy. An increase in the risk of developing an infection in chemotherapy patients given TPN (pooled P less than 0.0001) underscores the importance of demonstrating significant benefits in randomized trials before TPN is used routinely in these patients.

Basic fibroblast growth factor modulates integrin expression in microvascular endothelial cells

During angiogenesis capillary endothelial cells undergo a coordinated set of modifications in their interactions with extracellular matrix components. In this study we have investigated the effect of the prototypical angiogenic factor basic fibroblast growth factor (bFGF) on the expression and function of several integrins in microvascular endothelial cells. Immunoprecipitation experiments with antibodies to individual subunits indicated that microvascular cells express at their surface several integrins. These include the alpha 1 beta 1, alpha 2 beta 1, and alpha 3 beta 1 laminin/collagen receptors; the alpha 6 beta 1 laminin receptor; the alpha 5 beta 1 and alpha v beta 1 fibronectin receptors; the alpha 6 beta 4 basement membrane receptor; and the alpha v beta 3 and alpha v beta 5 vitronectin receptors. Treatment with bFGF caused a significant increase in the surface expression of the alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha 6 beta 1, alpha 6 beta 4, and alpha v beta 5 integrins. In contrast, the level of expression of the alpha 1 beta 1 and alpha v beta 3 integrins was decreased in bFGF-treated cells. Immunoprecipitation of metabolically labeled cells indicated that bFGF increases the biosynthesis of the alpha 3, alpha 5, alpha 6, beta 4, and beta 5 subunits and decreases the production of the alpha v and beta 3 subunits. These results suggest that bFGF modulates integrin expression by altering the biosynthesis of individual alpha or beta subunits. In accordance with the upregulation of several integrins observed in bFGF-treated cells, these cells adhered better to fibronectin, laminin, vitronectin, and type I collagen than did untreated cells. The largest differences in beta 1 integrin expression occurred approximately 72 h after exposure to bFGF, at a time when the expression of the endothelial cell-to-cell adhesion molecule endoCAM was also significantly upregulated. In contrast, a shorter exposure to bFGF (24-48 h) was required for the maximal induction of plasminogen activator production in the same cells. Taken together, these results show that bFGF causes significant changes in the level of expression and function of several integrins in microvascular endothelial cells.

Differential modulation of cell phenotype by different molecular weight forms of basic fibroblast growth factor: possible intracellular signaling by the high molecular weight forms

To study possible functional differences of the 18-kD and high molecular weight forms of basic fibroblast growth factor (bFGF), we have examined the effect of endogenous production of different bFGF forms on the phenotype of NIH 3T3 cells. Cells transfected with cDNAs coding for either 18-kD bFGF (18-kD bFGF) or all four molecular forms (18, 22, 22.5, 24 kD; wild type [WT] bFGF) exhibit increased migration and decreased FGF receptor number compared to parental cells. However, migration and FGF receptor number of cells transfected with a cDNA coding only for high molecular weight bFGF (22, 22.5, and 24 kD; HMW bFGF) were similar to that of parental cells transfected with vector alone. Cells expressing HMW, 18 kD, or WT bFGF grew to high saturation densities in 10% serum. However, only cells expressing HMW or WT bFGF grew in low serum. Cell surface or metabolic labeling of the different cell types followed by immunoprecipitation with anti-bFGF antibody showed primarily cell surface-associated 18-kD bFGF. In addition, when cells expressing exclusively HMW bFGF were transfected with a cDNA coding for 18-kD bFGF, migration was increased, bFGF receptors were down-regulated, and 18-kD bFGF was found on the cell surface. Cells expressing 18-kD bFGF transfected with a cDNA encoding FGF receptor-2 lacking the COOH-terminal domain (dominant negative bFGF receptor) exhibited a flat morphology and decreases in migration and saturation density. Cells expressing HMW bFGF transfected with the dominant negative bFGF receptor continued to grow to a high saturation density, proliferated in low serum, and exhibited no morphological changes. These results indicate that increased cell migration and FGF receptor down-regulation are mediated by the extracellular interaction of 18-kD bFGF with its cell surface receptor. Growth in low serum may be stimulated by the intracellular action of HMW bFGF through mechanisms independent of the presence of a cell surface receptor. Thus, the different molecular forms of bFGF may act through distinct but convergent pathways.

Hyperacuity and amblyopia

The most frequent cause of visual loss in childhood is functional amblyopia, an abnormality of visual acuity usually associated with either anisometropia (unequal refractive errors) or strabismus (turned eye) during early development. The usual clinical investigation of the visual acuity of amblyopes involves discrimination of the high contrast letters of a Snellen chart; however, there are other aspects of acuity, for example, grating acuity (the high spatial frequency limit of vision) and Vernier acuity (the smaller perceptible misalignment). Because of the extreme precision of Vernier acuity compared with either grafting or Snellen acuity, it is considered to be a form of hyperacuity which requires very precise positional information. In an effort to understand the nature of the neural abnormalities which cause the reduced acuity of amblyopes, we have measured here the Vernier acuity of amblyopic observers using an extended Vernier grating stimulus, and compared these results with their Snellen acuity and grating acuity. The results showed that different acuity losses are associated wih anisometropic versus strabismic amblyopia. When scaled with respect to their grating acuity, anisometropic amblyopes, like normals, showed hyperacuity, even at high spatial frequencies, while strabismic amblyopes showed severe losses in Vernier acuity. Snellen letter acuity showed a similar deficit relative to grating acuity in strabismic but not in anisometropic amblyopes. Contrary to some previous theories which have considered that all forms of amblyopia share a common neural basis, these results strongly support the view that different neural losses are associated with amblyopias of different aetiologies.

Gene-gene effects on central processing of aversive stimuli

Emotional reactivity and regulation are fundamental to human behavior. As inter-individual behavioral variation is affected by a multitude of different genes, there is intense interest to investigate gene-gene effects. Functional sequence variation at two genes has been associated with response and resiliency to emotionally unpleasant stimuli. These genes are the catechol-O-methyltransferase gene (COMT Val158Met) and the regulatory region (5-HTTLPR) of the serotonin transporter gene. Recently, it has been proposed that 5-HTT expression is not only affected by the common S/L variant of 5-HTTLPR but also by an A to G substitution. Using functional magnetic resonance imaging, we assessed the effects of COMT Val(158)Met and both 5-HTT genotypes on brain activation by standardized affective visual stimuli (unpleasant, pleasant, and neutral) in 48 healthy subjects. Based on previous studies, the analysis of genotype effects was restricted to limbic brain areas. To determine allele-dose effects, the number of COMT Met158 alleles (i.e., lower activity of COMT) and the number of 5-HTT low expressing alleles (S and G) was correlated with the blood oxygen level-dependent (BOLD) response to pleasant or unpleasant stimuli compared to neutral stimuli. We observed an additive effect of COMT and both 5-HTT polymorphisms, accounting for 40% of the inter-individual variance in the averaged BOLD response of amygdala, hippocampal and limbic cortical regions elicited by unpleasant stimuli. Effects of 5-HTT and COMT genotypes did not affect brain processing of pleasant stimuli. These data indicate that functional brain imaging may be used to assess the interaction of multiple genes on the function of neuronal networks.

AGA technical review on parenteral nutrition

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the Committee on September 13, 2001, and by the AGA Governing Board on May 18, 2001.

Metabolically healthy and unhealthy obese--the 2013 Stock Conference report

Obesity is closely associated with cardiovascular diseases and type 2 diabetes, but some obese individuals, despite having excessive body fat, exhibit metabolic health that is comparable with that of lean individuals. The 'healthy obese' phenotype was described in the 1980s, but major advancements in its characterization were only made in the past five years. During this time, several new mechanisms that may be involved in health preservation in obesity were proposed through the use of transgenic animal models, use of sophisticated imaging techniques and in vivo measurements of insulin sensitivity. However, the main obstacle in advancing our understanding of the metabolically healthy obese phenotype and its related long-term health risks is the lack of a standardized definition. Here, we summarize the proceedings of the 13th Stock Conference of the International Association of the Study of Obesity. We describe the current research and highlight the unanswered questions and gaps in the field. Better understanding of metabolic health in obesity will assist in therapeutic decision-making and help identify therapeutic targets to improve metabolic health in obesity.

Development of alcohol-associated cues and cue-induced brain activation in alcoholics

The objective of this study was to develop new standardized alcohol-associated cues and assess their effects on brain activation with functional magnetic resonance imaging (fMRI). Pictures of alcoholic and neutral beverages and affectively neutral pictures were presented to 44 abstinent alcoholics and 37 age-matched healthy control subjects. We assessed the skin conductance response, and the elicited arousal and valence. Alcoholics and control subjects did not differ in arousal, valence or skin conductance response evoked by alcohol-associated and affectively neutral stimuli, while nonalcoholic beverages were rated as more unpleasant and arousing by alcoholics compared with control subjects. In the fMRI pilot study, alcohol and abstract pictures were presented to six abstinent alcoholics and induced a significant activation of brain areas associated with visual emotional processes such as the fusiform gyrus, parts of the brain reward system (basal ganglia and orbitofrontal gyrus) and further brain regions in the frontal and parietal cortices associated with the attention network. These observations suggest that standardized pictures of alcoholic beverages can be used to assess brain circuits involved in the processing and evaluation of alcohol cues.

Functional analysis of 150 deletion mutants in Saccharomyces cerevisiae by a systematic approach

In a systematic approach to the study of Saccharomyces cerevisiae genes of unknown function, 150 deletion mutants were constructed (1 double, 149 single mutants) and phenotypically analysed. Twenty percent of all genes examined were essential. The viable deletion mutants were subjected to 20 different test systems, ranging from high throughput to highly specific test systems. Phenotypes were obtained for two-thirds of the mutants tested. During the course of this investigation, mutants for 26 of the genes were described by others. For 18 of these the reported data were in accordance with our results. Surprisingly, for seven genes, additional, unexpected phenotypes were found in our tests. This suggests that the type of analysis presented here provides a more complete description of gene function.

Obstetric antecedents of intraventricular hemorrhage and periventricular leukomalacia in the low-birth-weight neonate

OBJECTIVE

Neonatal intraventricular hemorrhage and periventricular leukomalacia have a strong correlation with eventual neurologic deficit. Our objective was to correlate obstetric factors with the development of these lesions.

STUDY DESIGN

Seven hundred forty-five consecutive inborn neonates with birth weights from 500 to 1750 gm were divided into three clinical groups: premature rupture of membranes, refractory preterm labor with intact membranes, and delivery initiated by the physician for maternal or fetal indications. Neonatal neurosonography was performed on days 3 and 7 of life and results were described as normal or abnormal. Abnormal scans included intraventricular hemorrhage seen within 3 days and echodense or echolucent periventricular leukomalacia seen within 7 days of life. Major abnormalities included intraventricular hemorrhage grades 3 and 4, intraventricular hemorrhage with periventricular leukomalacia, and echolucent periventricular leukomalacia. Abnormal scans were correlated with groups of origin and clinical and histologic chorioamnionitis.

RESULTS

Abnormal scans occurred in 33% of cases of premature rupture of membranes and in 38.9% of cases of preterm labor compared with 17.7% of physician-initiated cases (p < 0.000001). Major lesions occurred in 17.6% of cases of premature rupture of membranes, 21.4% of cases of preterm labor, and 1.1% of physician-initiated cases (p < 0.0000001). Clinical chorioamnionitis occurred in 19.7% of cases of premature rupture of membranes, 11.9% of cases of preterm labor, and 1.1% of physician-initiated cases (p < 0.001) and was associated with a significant increase in the incidence (p < or = 0.005) and severity (p < or = 0.007) of these lesions. Histologic chorioamnionitis occurred in 59.9% of cases of premature rupture of membranes, 43.2% of cases of preterm labor, and 8% of physician-initiated cases and did not correlate significantly with the incidence or severity of abnormal scans. These findings were independent of gestational age.

CONCLUSIONS

The incidence and severity of intraventricular hemorrhage and periventricular leukomalacia were significantly increased in premature rupture of membranes and preterm labor compared with the physician-initiated cases. Clinical chorioamnionitis increased the incidence and severity of these lesions.