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PubMed2005

Sympathetic nervous system, genes and human essential hypertension.

The sympathetic nervous system (SNS) is the first line of defense in the response to environmental stress through its regulation of second-to-second changes in blood pressure (BP). Both the activity of the SNS and the therapeutic responses to SNS agonists and antagonists are known to be highly variable in the population. "Small" changes caused by single nucleotide polymorphisms (SNPs) of SNS genes may have considerable impact on SNS function and individualized hypertension treatment. In this review, we first describe the physiology of the SNS and its influence on cardiovascular and renal mechanisms of BP regulation. A thorough review of the role of genetic variability of various SNS genes in relation to the development of BP and essential hypertension (EH) follows. Given the vast number of SNS components, evaluations of multiple SNPs from multiple SNS genes are necessary for future association studies of BP and EH. One way to surpass the limitations and inconsistencies of previous association studies is to use a gene-based approach also referred to as indirect association, which takes all common variation within a candidate gene into account. In order to determine how SNS genes are differentially expressed or silenced, activated or inactivated against various environmental backgrounds, it is important to assess not only environmental and lifestyle risk factors such as diet, climate, chronic stress, but also personality characteristics such as hostility and coping styles. Uncovering relevant gene-gene and gene-environment interactions within the SNS cascade will not only enable early detection of EH risk but will also aid in the treatment of hypertensives through both non-pharmacological and pharmacological means.

Animals↗
PubMed2006

Association analysis of 6,736 U.K. subjects provides replication and confirms TCF7L2 as a type 2 diabetes susceptibility gene with a substantial effect on individual risk.

Recent data suggest that common variation in the transcription factor 7-like 2 (TCF7L2) gene is associated with type 2 diabetes. Evaluation of such associations in independent samples provides necessary replication and a robust assessment of effect size. Using four TCF7L2 single nucleotide polymorphisms (SNPs; including the two most associated in the previous study), we conducted a case-control study in 2,158 type 2 diabetic subjects and 2,574 control subjects and a family-based association analysis in 388 parent-offspring trios all from the U.K. All SNPs showed powerful associations with diabetes in the case-control analysis, with strongest effects at rs7903146 (allele-wise relative risk 1.36 [95% CI 1.24-1.48], P = 1.3 x 10(-11)). Data were consistent with a multiplicative model. The family-based analyses provided independent evidence for association at all loci (e.g., rs4506565, 62% transmission, P = 7 x 10(-5)) with no parent-of-origin effects. The frequency of diabetes-associated TCF7L2 genotypes was greater in cases ascertained for positive family history and early onset (rs4606565, P = 0.02); the population-attributable risk, estimated from the least-selected cases, is approximately 16%. The overall evidence for association for these variants (P = 4.4 x 10(-14) combining case-control and family-based analyses for rs4506565) exceeds genome-wide significance criteria and clearly establishes TCF7L2 as a type 2 diabetes susceptibility gene of substantial importance.

Adult↗
PubMed2006

Considerations in the design of hyperinsulinemic-euglycemic clamps in the conscious mouse.

Despite increased use of the hyperinsulinemic-euglycemic clamp to study insulin action in mice, the effects of experimental parameters on the results obtained have not been addressed. In our studies, we determined the influences of sampling sites, fasting duration, and insulin delivery on results obtained from clamps in conscious mice. Carotid artery and jugular vein catheters were implanted in C57BL/6J mice (n = 6-10/group) fed a normal diet for sampling and infusions. After a 5-day recovery period, mice underwent a 120-min clamp (2.5-mU . kg(-1) . min(-1) insulin infusion; approximately 120-130 mg/dl glucose) while receiving [3-(3)H]glucose to determine glucose appearance (endoR(a)) and disappearance (R(d)). Sampling large volumes (approximately 100 mul) from the cut tail resulted in elevated catecholamines and basal glucose compared with artery sampling. Catecholamines were not elevated when taking small samples ( approximately 5 mul) from the cut tail. Overnight (18-h) fasting resulted in greater loss of total body, lean, and fat masses and hepatic glycogen but resulted in enhanced insulin sensitivity compared with 5-h fasting. Compared with a 16-mU/kg insulin prime, a 300-mU/kg prime resulted in hepatic insulin resistance and slower acquisition of steady-state glucose infusion rates (GIR) after a 5-h fast. The steady-state GIR was expedited after the 300-mU/kg prime in 18-h-fasted mice. The GIR and R(d) rose with increasing insulin infusions (0.8, 2.5, 4, and 20 mU . kg(-1) . min(-1)), but endoR(a) was fully suppressed with doses higher than 0.8 mU . kg(-1) . min(-1). Thus, common variations in experimental factors yield different results and should be considered in designing and interpreting clamps.

Animals↗
PubMed2006

Contextual interference effect on acquisition and retention of pistol-shooting skills.

The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three "stages" with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Following a 20-min. safety and skill instructional session, Blocked group practiced 10 trials in a row at each stage, while Serial group performed 5 trials in a row for each of the three stages and then repeated the cycle. Both groups completed a total of 30 practice trials over the three stages. A 10-min. rest interval was provided prior to a retention test which included 9 trials (3 trials at each stage in a blocked format). Results based on the data of Stage III, the most complex skill among the three stages, showed a pattern consistent with previous findings that practicing in the serial schedule depressed performance during initial training but maintained the performance better at retention, relative to the blocked practice.

Adolescent↗
PubMed2001

The dual-task SRT procedure: fine-tuning the timing.

In the standard sequential reaction time study, subjects are presented with a repeating sequence of targets to which they must respond as rapidly as possible. With practice reaction times decrease, suggesting a learned ability to exploit the repeating patterns in the display. In a common variation, a second task is interposed, typically a tone-counting task in which subjects must keep track of the frequency with which particular tones occur. In the canonical experiment, these tones appear at varying times in the interval between the subjects' response to a target and the next target. Data are presented that show that this latter variable (the RSOA, response-secondary stimulus onset asynchrony) actually plays an important but previously hidden role in these experiments. A model based on an extension of the notion of the psychological refractory period is introduced to explain these findings.

Adult↗
PubMed1981

Effect of label format on information recall in patients receiving prescription medications.

Many patients receive their filled prescriptions without verbal instructions and must rely on the label as their only source of information. A two-phase study was designed to measure differences in recall information when two common variations in label format were employed. Phase I: Does the patient comprehend label directions better if numbers are typed as words or as numerals? Phase II: Does the addition of preprinted auxiliary labels affect recall of directions? In Phase I, 100 patients were asked to read a label expressing three numbers as words and an additional 100 read the same label using numerals. In Phase II, patients saw the label using numerals with either zero, one, two, or three auxiliary labels attached. Each label was seen by 50 patients. Patients were scored on a point system based on their ability to repeat label directions. There was no significant difference in information recall between label format groups (p greater than 0.05). Only 44% of the patients could remember all directions, 13% could remember no information, and 63% failed to read the auxiliary labels. These results suggest that pharmacists should place less reliance on label format and the use of auxiliary labels to communicate information and spend more time verbally counseling their patients on the proper use of their medications.

Drug Labeling↗
PubMed1999

A research programme for testing the biological homology concept.

The classical homology concept has served as a heuristic principle for organizing the enormous wealth of information on comparative anatomical patterns across a wide range of organisms. However, the classical homology concept reaches its limit as knowledge of the evolutionary, genetic and developmental processes that underlie these anatomical patterns increases. The biological homology concept places the known anatomical patterns into a mechanistic context and asserts that character identity is based on common variational properties in this chapter a research programme for testing the biological homology concept that involves the following steps is outlined: (1) identifying of two or more putative homologues is a clade; (2) determining the phylogenetic distribution of the putative homologues; (3) describing the intra- and interspecific variation patterns of each putative homologue; (4) describing the development of each putative homologue, and determining if modes of development and distribution of homologues are phylogenetically congruent; and (5) providing and testing a model of how differences in modes of development between putative homologues effect differences in variational tendencies. The goal is to demonstrate a link between developmental and variational differences of two homologues.

Animals↗
PubMed1999

[Effect of mutation (T1762A1764) on hepatitis B virus core promoter activity].

OBJECTIVE: With the knowledge that the substituted mutation of T1762A1764 in hepatitis B virus (HBV) core promoter (CP) region was the most common variation during chronic HBV infection, we proceed to study the role that the mutation T1762A1764 plays in effecting the core promoter. METHODS: Seven patients with fulminant hepatitis and one asymptomatic HBV carrier were investigated for screening T1762A1764 mutation by cloning and PCR products direct sequencing. PCR products containing HBV precore/core gene regulatory sequences were directly cloned into chloramphenicol acetyltransferase (CAT) expressing plasmid. CAT assay was done to compare CAT expressing level after transfecting into HepG2 cell line and transient expression. RESULTS: Results reveal that T1762A1764 mutation was the main factor that represses CAT expression in vitro. CONCLUSION: Among the several other variations within hepatitis B virus' core promoter region, T1762A1764 mutation has mainly affected the down-regulating activity of core promoter.

Adult↗
PubMed2000

Effect of Val34Leu polymorphism on the activation of the coagulation factor XIII-A.

Coagulation factor XIII (FXIII) is a protransglutaminase involved in the last step of the coagulation cascade by stabilising the fibrin clot. Recently, a common variation (FXIII Val34Leu) has been associated with a decreased risk of myocardial infarction and deep venous thrombosis. Val34Leu is critically located near the thrombin activation site of FXIII-A. In this study we investigated its effects on the activation of FXIII. Both recombinant and platelet-derived FXIII Val34Leu variants were shown to be more susceptible to thrombin cleavage than the wild type FXIII. The rate of enzymatic activation of FXIII Val34Leu was found increased, however, the specific activity of fully activated wild type FXIII and the Val34Leu mutant did not differ. During the course of thrombin-induced activation of FXIII fibrin gamma-chain dimerisation and alpha-chain polymerisation developed more rapidly with the Val34Leu mutant. The increased rate of fibrin stabilisation brought about by the Val34Leu FXIII seems to be paradoxically associated with a protective effect against pathological thrombosis.

Animals↗
PubMed2001

Vascularization of the thumb. Anatomy and surgical applications.

Microsurgical procedures require rapid and atraumatic dissection of vessels. The authors have tried to schematize the most common variations of the palmar arteries, dividing the thumb into three segments, delimited from the MCP and interphalangeal flexion crease. If a vascular anastomosis has to be carried out in the first segment, the arteries that intersect the palmar surface of such a region do not generally hold much interest for the surgeon as far as size and constancy are concerned. One therefore can avoid frustration while searching in vain for such an artery by starting dissection in the dorsal compartment, where there is a much better chance of finding an artery suitable in every aspect. In replanting a thumb in the second segment, the ulnar collateral artery should be the artery that is looked for first, because it is usually the biggest, the most superficial, and nearly always is composed of a single trunk (Fig. [figure: see text] 18). Let us not forget, however, that the contralateral artery can frequently have all the necessary requirements for an adequate anastomosis. In the third segment, the layout of the vessels is rather difficult to schematize; if it is true that the inverted Y or H shape can make a microanastomosis easier in cases of distal reimplantation (Fig. 19), it is also true that such a pattern is impossible to foresee, and, therefore, the interest of such classification is more academic than practical. Skin loss coverage at the thumb level greatly differs from the that of fingers. In the past few years, a multitude of useful new flaps has been presented by different authors. Their accomplishment (especially those of the last generation, who base their survival on extremely fine vascular axes) presupposes an adequate knowledge of surgical and microsurgical anatomy. Surgeons dealing with this type of pathology should be capable of performing all of the possible flaps because each may be indicated in specific situations.

Arteries↗
PubMed2000

[Popliteal artery entrapment syndrome].

Popliteal Artery Entrapment Syndrome (PAES) is an uncommon congenital anomaly. It arises due to compression of the popliteal artery by tendomuscular structures often combined with an anomalous position of the artery. Mostly young men are suffering of this disease. There are four common variations of this anomaly. We report on a 14 year old patient who had an acute 24 hours duration right leg ischemia caused by PAES. Using a posterior approach to the popliteal artery, following division of the accessory slip of gastrocnemius muscle we performed an arteriotomy and a floating thrombus was removed. The artery was reconstructed by direct continuous suture. One year postoperatively the boy has no complaints, peripheral pulse is palpable.

Adolescent↗
PubMed2001

[Genetic risk factors in ischemic cardiopathy].

Coronary artery disease is a complex disease, characterized by a myriad of interactions between environmental and genetic factors. There is a growing interest about the genetic components. This research field is rapidly growing, and could offer new diagnostic and therapeutic tools in a near future. This paper will focus on common variations in several candidate genes. They have been categorized into three groups, according to different pathophysiological mechanisms: 1) lipid metabolism; 2) hemostatic balance; 3) non-lipid metabolism.

Hemostasis↗
PubMed2001

[Association between E-selectin Leu554Phe polymorphism and blood pressure in the Stanislas cohort].

We investigated the relationship between polymorphisms of the E-selectin gene, SELE (L/F554, S/R128 and 98G/T), a cell adhesion molecule, and interindividual variability in blood pressure and changes over time. The study population was extracted from the Stanislas Cohort (1006 families), a cohort of nuclear families volunteering for a free health check-up and recruited by the Centre of Preventive Medicine in Nancy (CMP) between 1993 and 1994. For this specific study, 359 men and 337 women were selected from families that had already visited the CMP 11 years before the recruitment of the Stanislas Cohort. Measurements of blood pressure at the time -11 years (t-11) and at the time of recruitment (t0), and all other measurements necessary for the analysis (BMI, lipids, SELE genotypes) were available. Pregnant women or subjects taking antihypertensive, lipid lowering or anti-inflammatory medications were excluded from the study. During the follow-up period, systolic and diastolic blood pressure (SBP and DBP) were lower in SELE F554 allele carriers than in those with the L/L554 genotype (p < or = 0.05), whereas longitudinal changes were not related to any SELE polymorphism. Multiple regression analysis showed that at t-11 SELE L/F554 polymorphism was associated with both SBP and DBP levels (p < or = 0.01 and p < or = 0.05, respectively). However, these associations were no longer present at t0. Our results suggest an age-specific effect of the SELE L/F554 polymorphism on blood pressure levels. If confirmed in other studies, these findings would suggest that assessment of common variation in an adhesion molecule could be useful in predicting blood pressure.

Adult↗
PubMed2002

A comparative electromyographical investigation of muscle utilization patterns using various hand positions during the lat pull-down.

This study aimed at investigating the effects of different hand positions on the electromyographic (EMG) activity of shoulder muscles during the performance of the lat pull-down exercise. Ten healthy men performed 3 repetitions of the lat pull-down exercise using their experimentally determined 10RM (repetition maximum) weight. Four different common variations of the lat pull-down were used: close grip (CG), supinated grip (SG), wide grip anterior (WGA), and wide grip posterior (WGP). Normalized root mean square of the EMG (NrmsEMG) activity for the right posterior deltoid (PD), latissimus dorsi (LD), pectoralis major (PM), teres major (TM), and long head of the triceps (TLH) were recorded using surface electrodes and normalized using maximum voluntary contractions. Repeated measures analysis of variance for each muscle detected statistical differences (p < 0.05) in myoelectric activity among hand positions during both the concentric and eccentric phases of the exercise. During the concentric phase, NrmsEMG results for the LD included WGA > WGP, SG, CG. For the TLH: WGA > WGP, SG, CG and WGP > CG, SG. For the PD: CG, WGA, SG > WGP. For the PM: CG, WGA, SG > WGP. During the eccentric phase, the LD produced the following patterns: WGA > WGP, SG, CG and WGP > CG. The TLH pattern showed WGA > SG and CG. For the PD: CG > WGA, WGP. The results indicate that changes in handgrip position affect the activities of specific muscles during the lat pull-down movement. Also, performance of the lat pull-down exercise using the WGA hand position produces greater muscle activity in the LD than any other hand position during both the concentric or eccentric phases of the movement.

Adolescent↗
PubMed2002

Interaction between a common variant of the cholesteryl ester transfer protein gene and the apolipoprotein E polymorphism: effects on plasma lipids and lipoproteins in a cohort of 7-year-old children.

BACKGROUND AND AIM: Common variations in genes, such as apolipoprotein E (apo E) and cholesteryl ester transfer protein (CETP), are major determinants of plasma lipid and lipoprotein levels. As both apo E and CETP contribute to the reverse transport of cholesterol to the liver, the effects of variations at the CETP locus may very well interact with the apo E genotype. METHODS AND RESULTS: As part of an ongoing study, the combined effects of the apo E genotype and heterogeneity at the CETP gene locus on plasma lipids and lipoproteins were studied in a birth cohort sample of 257 Dutch prepubescent boys and girls (aged 6.7-8.1 years). The children with an apo E2E3 genotype (carrying the epsilon 2 allele; arg158-->cys) had lower concentrations of low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apo B) than those with an apo E4E3 (carrying the epsilon 4 allele; cys112-->arg) or apo E3E3 genotype (homozygous for the parent epsilon 3 allele). These associations were statistically significant in children who were homozygous (p = 0.004 for LDL; p = 0.002 for apo B) or heterozygous (p < 0.0001 for LDL and apo B) for the absence of the Taq-IB polymorphism at the CETP gene locus (B2 allele), but not in those homozygous for the presence of this variant (B1B1). The highest plasma high-density lipoprotein cholesterol (HDL-C) concentrations were observed in children with the CETP B2B2 genotype. The difference in HDL-C levels between the CETP genotype groups was statistically significant only in E2E3 carriers (p = 0.01). The LDL/HDL ratio was significantly lower in E2E3 carriers, but not when combined with a CETP B1B1 genotype. CONCLUSION: These findings indicate that the apo E genotype and heterogeneity at the CETP gene locus have an additive and interactive influence on plasma lipid and lipoprotein levels in children.

Analysis of Variance↗
PubMed1999

[Anatomic variations of the ostiomeatal complex and their correlation with chronic sinusitis: CT evaluation].

OBJECTIVE: To explore the relationship between anatomic variations in the ostiomeatal complex (OMC) and chronic sinusitis. METHODS: Coronal plane CT scans of the paranasal sinuses showing the ostiomeatal complex including the middle turbinate, uncinate, ethmoid bulla, agger nasi and Haller cell were analyzed in 297 individuals (594 sides). Statistical analyses were carried out with SPSS 5.0. RESULTS: There were 81.14% of OMC noted to have at least one variation. The anatomic variations included paradoxical curvature of the middle turbinate (13.97%), the pneumatized middle turbinate (34.85%), uncinate hyperplasia(19.36%), deviation of uncinate (45.27%), large ethmoidal bulla (30.30%), large agger nasi (0.70%) and Haller cell (1.00%). The correlation between variations and chronic sinusitis was significant (P < 0.01). CONCLUSION: The occurrence of OMC variation is common. The variations may be one of the causes of chronic sinusitis. Therefore, properly handling the variations was important in the endoscopic sinus surgery.

Adolescent↗
PubMedDate not supplied

ECG interpretation: what is different in children?

While the electrical waveforms and basic approach to electrocardiogram (ECG) interpretation are similar for pediatric and adult patients, some important differences must be recognized to provide appropriate care for infants and children. Maturational changes that occur over the early childhood years result in differences in normal heart rates, interval durations, and ventricular dominance. Any arrhythmia seen in adults can occur in the pediatric patient; however, the most common variations from normal rhythms are sinus arrhythmia, bradycardia, and supraventricular tachycardia. Nurses caring for infants and children must recognize the important similarities and differences in rhythm strip interpretation between the adult and the pediatric patient.

Adolescent↗
PubMed2003

[Association between AvaII exon 13 polymorphism at the LDL receptor gene different and serum lipid levels in normotensives and essential hypertensives in Shanghai].

OBJECTIVE: To investigate the AvaII polymorphism of low density lipoprotein receptor gene in both health and essential hypertension populations, and to evaluate the association of AvaII polymorphism with level of blood lipid. METHODS: Using polymerase chain reaction (PCR), AvaII polymorphism was studied in 109 health individuals and 319 patients with essential hypertension. RESULTS: There were three kinds of genotype: (+/+), (+/-), (-/-). The frequencies of the three genotypes were shown as follows: (+/+) 0.9%, (+/-) 27.5%, (-/-) 71.6% in health population and (+/+) 1.2%, (+/-) 33.9%, (-/-) 64.9% in essential hypertension population, respectively. The frequencies of the two alleles were shown as follows: (+) 14.7%, (-) 85.3% in health population, (+) 18.2%, (-) 81.8% in essential hypertension population and (+) 17.3%, (-) 82.7% in the community, respectively. In male essential hypertension cases, the genotypes were associated with serum TC and LDL-C level in the following order: (-/-) < (+/-) (P < 0.05). In women and healthy population, there was a similar trend but not statistically significant (P > 0.05). CONCLUSIONS: A significant association was found between the common variation of LDL-R gene and serum TC and LDL-C levels. (+) Allele was associated with elevated level of serum TC and LDL-C, but (-) allele was associated with a low level of serum TC and LDL-C. The frequencies of (-) allele in both group were related to serum low level TC while LDL-C was much higher than that reported in the western countries. These data indicated that genetic factors which resistant to hypercholesterolemia in Chinese people were different from those findings in West while might be one of the reasons to explain why that serum TC level in Chinese was lower than people in the western countries.

Adult↗