Endothelium‐dependent hyperpolarizations: Past beliefs and present facts

Endothelium‐dependent relaxations are attributed to the release of various factors, such as nitric oxide, carbon monoxide, reactive oxygen species, adenosine, peptides and arachidonic acid metabolites derived from the cyclooxygenases, lipoxygenases, and cytochrome P450 monooxygenases pathways. The hyperpolarization of the smooth muscle cell can contribute to or be an integral part of the mechanisms underlying the relaxations elicited by virtually all these endothelial mediators. These endothelium‐derived factors can activate different families of K⁺ channels of the vascular smooth muscle. Other events associated with the hyperpolarization of both the endothelial and the vascular smooth muscle cells (endothelium‐derived hyperpolarizing factor (EDHF)‐mediated responses) contribute also to endothelium‐dependent relaxations. These responses involve an increase in the intracellular Ca²⁺ concentration of the endothelial cells followed by the opening of Ca²⁺‐activated K⁺ channels of small and intermediate conductance and the subsequent hyperpolarization of these cells. Then, the endothelium‐dependent hyperpolarization of the underlying smooth muscle cells can be evoked by direct electrical coupling through myoendothelial junctions and/or the accumulation of K⁺ ions in the intercellular space between the two cell types. These various mechanisms are not necessarily mutually exclusive and, depending on the vascular bed and the experimental conditions, can occur simultaneously or sequentially, or also may act synergistically.     

Monocyte chemoattractant protein‐1 and CC‐chemokine receptor‐2 in severe hypercholesterolaemia

Objectives: To investigate whether plasma concentrations of monocyte chemoattractant protein‐1 (MCP‐1) and the gene expression of its receptor on the monocyte cell surface CCR‐2 were elevated above normal in subjects with asymptomatic, isolated hypercholesterolaemia and if statin treatment could influence this cytokine. Methods: The investigation was designed as a cross sectional study followed by a single, blind, treatment study of patients receiving pravastatin 80?mg/day for 8 weeks. The study included 23 patients with severe hypercholesterolaemia (LDL>5.2?mmol/L) and 39 normocholesterolaemic controls. Blood samples were obtained from patients and controls at baseline and from patients at end of the study and analysed for lipoproteins and inflammatory mediators: MCP‐1, high‐sensitivity C‐reactive protein (HS‐CRP). Isolated peripheral mononuclear cells were analysed for CCR‐2 gene expression. Results: Mean plasma LDL‐C was significantly higher in patients than in controls. No difference in plasma MCP‐1 levels or CCR‐2 gene expression was seen between the groups at baseline, nor were there any differences in plasma concentrations of CRP. After treatment with pravastatin, LDL‐C decreased by 31%. Treatment did not significantly affect the levels of MCP‐1 or CCR‐2 gene expression, nor was CRP affected by treatment with pravastatin. Conclusions: Our study does not support the view that MCP‐1 plasma levels and CCR‐2 gene expression in circulating monocytes are directly responsible for the monocyte recruitment into the arterial intima in patients with severe asymptomatic hypercholesterolaemia. In addition, the inflammatory response of a high concentration of LDL‐C in isolated asymptomatic hypercholesterolaemia is minute.     

Interleukin‐6 and lipopolysaccharide‐binding protein in acute appendicitis in children

The aim of the study was to evaluate the diagnostic accuracy of interleukin‐6 (IL‐6) and lipopolysaccharide‐binding protein (LBP) in children with acute appendicitis (AA) and to compare this with the diagnostic accuracy of routinely used C‐reactive protein (CRP) and white blood cell (WBC) count. Eighty‐two consecutive children admitted to our Department because of suspected AA were enrolled in this prospective study and classified into two groups: group 1 (49 children who underwent surgery for AA) and group 2 (33 children with no surgery with diagnosis of non‐specific abdominal pain or sonographic mesenteric lymphadenitis). There were no negative appendectomies during the time of the study. The patients were further classified into three subgroups: subgroup 1A (43 patients with advanced AA), subgroup 2A (11 patients with mesenteric lymphadenitis) and subgroup 2B (10 patients with non‐specific abdominal pain). The perforation rate was 32.7?%. WBC count and serum CRP, IL‐6 and LBP were measured on admission. Area under receiver operating characteristic (ROC) curve (AUC), sensitivity, specificity and predictive values were evaluated. Serum IL‐6 and LBP were significantly higher in group 1 than in group 2. The highest AUC for AA was that for IL‐6 (0.776), followed by WBC count (0.684), CRP (0.637) and LBP (0.635). In conclusion, only IL‐6, determined on admission, showed medium diagnostic accuracy, while other laboratory markers showed low diagnostic accuracy for AA in children. The new laboratory markers therefore do not significantly improve the diagnosis of AA.     

Macrophages sense and kill bacteria through carbon monoxide–dependent inflammasome activation

Microbial clearance by eukaryotes relies on complex and coordinated processes that remain poorly understood. The gasotransmitter carbon monoxide (CO) is generated by the stress-responsive enzyme heme oxygenase-1 (HO-1, encoded by Hmox1), which is highly induced in macrophages in response to bacterial infection. HO-1 deficiency results in inadequate pathogen clearance, exaggerated tissue damage, and increased mortality. Here, we determined that macrophage-generated CO promotes ATP production and release by bacteria, which then activates the Nacht, LRR, and PYD domains-containing protein 3 (NALP3) inflammasome, intensifying bacterial killing. Bacterial killing defects in HO-1–deficient murine macrophages were restored by administration of CO. Moreover, increased CO levels enhanced the bacterial clearance capacity of human macrophages and WT murine macrophages. CO-dependent bacterial clearance required the NALP3 inflammasome, as CO did not increase bacterial killing in macrophages isolated from NALP3-deficient or caspase-1–deficient mice. IL-1β cleavage and secretion were impaired in HO-1–deficient macrophages, and CO-dependent processing of IL-1β required the presence of bacteria-derived ATP. We found that bacteria remained viable to generate and release ATP in response to CO. The ATP then bound to macrophage nucleotide P2 receptors, resulting in activation of the NALP3/IL-1β inflammasome to amplify bacterial phagocytosis by macrophages. Taken together, our results indicate that macrophage-derived CO permits efficient and coordinated regulation of the host innate response to invading microbes.     

Correlations between serum amyloid A protein and C‐reactive protein in infectious diseases

Serum amyloid A (SAA) protein is an acute phase reactant that has recently become of increasing interest as a marker for disease and treatment monitoring. We have correlated SAA levels to those of C‐reactive protein (CRP) in sera from 98 patients admitted to an infectious diseases clinic because of viral and bacterial infections, including hepatitis A and B, cytomegalovirus infection, varicellae‐zoster, infectious mononucleosis, influenza A, bacterial pneumonia, streptococcal pharyngitis, bacterial sepsis and severe bacterial sepsis. The study population was chosen from the clinical setting as representatives of these frequently encountered patient groups. SAA levels correlated significantly with CRP levels (r²=0.757, p<0.001) for the entire studied population. Furthermore, positive correlations were found in viral (r²=0.572, p<0.001) and bacterial (r²=0.666, p<0.001) infections. Positive correlations were also observed when the values were compared in accordance with CRP levels higher and lower than 100?mg/L (r²=0.689, p<0.001; CRP>100; r²=0.397, p<0.001; CRP<100). Because SAA is more sensitive than CRP for the detection of minor inflammatory stimuli, as in the viral and low CRP groups, we conclude that SAA can be of use in several viral infections, as well as in non‐invasive and early invasive bacterial infections.     

Increased levels of C‐reactive protein and interleukin‐6 in hyperhomocysteinemic subjects

Objective. Elevated plasma homocysteine concentration is considered to be an independent risk factor for cardiovascular disease. However, the mechanisms by which hyperhomocysteinemia are related to vascular disease are unclear. High‐sensitivity C‐reactive protein (CRP), a marker of inflammation, has been reported to be an independent predictor of future myocardial infarction among clinically healthy individuals. Interleukin (IL)‐6 is a regulator of CRP and has a key role in initiation of inflammation. The aim of this study was to investigate whether individuals with increased plasma homocysteine concentrations have altered levels of serum CRP and IL‐6. Material and methods. Serum concentrations of CRP and IL‐6 were measured in 39 individuals with hyperhomocysteinemia and in 39 control subjects matched for gender, age and body mass index (BMI). In addition, the inflammatory effect of IL‐6 on peripheral blood mononuclear cells was measured. Results. Compared to controls, hyperhomocysteinemic subjects have elevated serum levels of CRP and IL‐6 (p?0.001 and p<0.005, respectively). Importantly, this raised level of IL‐6 was also seen in hyperhomocysteinemic individuals without accompanying hypercholesterolemia or cardiovascular disease. IL‐6 increased the release of monocyte chemoattractant protein‐1 from peripheral blood mononuclear cells, with particularly enhancing effects in cells from patients with hyperhomocysteinemia. Conclusions. These data suggest that enhanced inflammation may be associated with homocysteine‐related cardiovascular disease, possibly involving IL‐6‐related mechanisms.     

Twelve‐month maintenance treatment of heroin‐dependent outpatients with buprenorphine

The aim of this study was to assess the efficacy of 1‐mg, 3‐mg, and 8‐mg/day doses of buprenorphine in the maintenance treatment of heroin‐dependent patients over a 12‐month treatment period. Subjects were allocated randomly to three dosage groups. Participants consisted of 123 male heroin dependents who met the DSM‐IV criteria for opioid dependence and were seeking treatment. Their mean age was 31.4 years ranging from 16 to 64 (SD=9.4). Subjects received buprenorphine at a dose of 1?mg, 3?mg, or 8?mg/day and were treated in an urban outpatient clinic, offering a 1‐h weekly individual counselling session. Days retained in treatment were measured. Overall, 49 patients (39.8%) completed the 12‐month study. Completion rates by dosage group were 7 (17.1)% for the 1‐mg dose group, 16 (39%) for the 3‐mg dose group, and 26 (63.4%) for the 8‐mg dose group. Retention in the 8‐mg dose group was significantly better than in the 1‐mg dose group (p=0.00002) and in the 3‐mg dose group (p=0.027); other comparison (1‐mg dose with 3‐mg dose) was also significant (p=0.027). The results support the efficacy and safety of buprenorphine for outpatient treatment of heroin dependence and seem to indicate that the highest dose (8?mg) of buprenorphine was the best of the three doses for Iranian heroin dependents to increase their retention in treatment.     

Thrombin‐stimulated platelet aggregation is inhibited by kallikrein in a time‐ and concentration‐dependent manner

Both elevated plasma total homocysteine and cigarette smoking are associated with an increased risk of occlusive cardiovascular disease. We examined whether smoking cessation for a mean time of 10-11 weeks lowered plasma total homocysteine concentrations in men and women with (n = 59) and without (n = 55) established cardiovascular disease. Blood tests were available for 58 quitters and 29 subjects who did not stop smoking. Compared with subjects who continued to smoke, quitters had statistically significant higher HDL cholesterol concentrations, but plasma total homocysteine concentrations did not differ between the two groups. Likewise, no differences were found between quitters and non-quitters whose baseline homocysteine concentrations were above the 75th percentile.     

Patient‐treatment matching with anti‐craving medications in alcohol‐dependent patients: A review on phenotypic,endophenotypic and genetic indicators

Objectives: Craving plays an important role in the development and maintenance of alcohol dependence and in relapse after periods of abstinence. Anti‐craving compounds, such as acamprosate, naltrexone or serotonergic compounds, are found to be only moderately effective. These moderate effects might be due to inadequate matching of specific patients to specific treatments. In 1999, Verheul et al. proposed a three‐pathway model of craving in alcoholics, which hypothesised that reward drinkers would better respond to naltrexone, relief drinkers to acamprosate and obsessive drinkers to serotonergic compounds. However, these matching hypotheses are not yet validated. This article reviews the literature on predictors and matching variables of the effectiveness of pharmacological interventions in alcohol dependent patients directed at the reduction of craving and the prevention of relapse.

Methods: Studies were selected through a literature search in September 2004, focusing on matching or predicting variables for anti‐craving compounds in the treatment of alcoholics. Matching or predicting variables were categorised as either phenotypic (e.g., level of baseline anxiety), endophenotypic (e.g., physiological cue reactivity) or genetic (e.g., µ opioid receptor polymorphisms).

Results: Studies using clinical or phenotypic effect modifiers have produced inconsistent and rather disappointing results. In contrast, the predictive value of genetic effect modifiers are quite promising (e.g., µ opioid receptor polymorphisms). No studies that looked at endophenotypic predicting or matching variables were identified.

Conclusion: It is concluded that phenotypic matching variables might be too distal, i.e., far removed from the pathogenic process, and that matching research should shift its attention toward more proximal variables (e.g., genetic and endophenotypic variables).     

A memory‐shape temperature‐dependent nickel‐titanium device for colonic anastomosis in laparoscopic surgery

Minimally invasive surgery is a growing issue in medicine and is also increasingly being used for colonic surgery. With this procedure, the involved colon is dissected laparoscopically, exteriorized through a small incision and the segment containing the tumor is resected. The anastomosis is done extraperitoneally either by hand suture or with a stapler. Our study was designed to evaluate the feasibility of using a memory‐shape compression anastomosis clip (CAC) to perform colonic anastomosis in laparoscopy. Ten patients who were scheduled for laparoscopic colonic surgery entered the study. In five patients, the anastomosis was performed with the CAC and in five patients, with a stapler. To perform anastomosis with CAC, the two edges of the resected colon are placed parallel. Two 5‐mm incisions are made close to the edges, where the CAC is introduced in an open position after being cooled in ice water at 0°C, using a special applier. The applier introduces the clip which clamps the two bowel loops together, creating a small incision through the clamped walls, and then releasing the clip inside the intestine. The two 5‐mm incisions are then sutured. The clip is expelled with the stool within five to seven days after the operation, creating a perfect uniform anastomosis. Neither group had complications related to the anastomosis. Our study shows that the use of the CAC for colonic laparoscopic surgery is simple, very efficient and shortens operation time. It creates a uniform anastomosis, coming close to the no‐touch concept in surgery, may prevent infection, and is low in cost compared to the stapler.     

C‐reactive protein,genetically elevated levels and risk of ischemic heart and cerebrovascular disease

We tested whether genetically elevated levels of C‐reactive protein (CRP) cause increased risk of ischemic heart disease and ischemic cerebrovascular disease. Levels of CRP >3mg/L, compared with levels <1mg/L, associated with a 1.6‐ and 1.3‐fold increased risk of ischemic heart disease and ischemic cerebrovascular disease. Genotype combinations of the 4 CRP polymorphisms associated with up to a 64% increase in CRP levels, resulting in a theoretically predicted increased risk of up to 32% for ischemic heart disease and up to 25% for ischemic cerebrovascular disease. However, these genotype combinations did not associate with increased risk of ischemic heart and cerebrovascular disease.     

Insulin‐like growth factor (IGF)‐I,IGF‐II and IGF‐binding protein (IGFBP)‐3 levels in Arab subjects with coronary heart disease

Objective. Insulin‐like growth factors (IGF‐I, IGF‐II) and their binding protein (IGFBP‐3) may be risk markers for coronary heart disease (CHD). This study aimed to assess the levels and determinants of the serum levels of IGF‐I, IGF‐II and IGFBP‐3 in Arab patients with established CHD. Material and methods. Two groups of subjects were matched for age, gender, BMI and waist–hip ratio (WHR): (i) CHD (n = 105), median age 51.0 (range 40.0–60.0) years; (ii) controls (n = 97) aged 49.0 (range 37.0–60.0) years. We measured fasting serum levels of glucose and lipoproteins (total cholesterol, triglycerides, LDL, HDL, apo B), insulin, HOMA‐IR, IGF‐I, IGF‐II and IGFBP‐3 and compared the results between groups. The effects of body mass and the metabolic syndrome (MS) on IGF levels were also examined, and linear correlations were sought between the various parameters. Results. The levels of IGF‐I, IGF‐II and IGFBP‐3 were significantly lower (all p<0.01) for the CHD group than for the control group. These differences were not influenced by BMI or with the presence of MS. In CHD, there were no significant correlations between levels of IGF‐I and IGF‐II and age, BMI, WHR, lipoprotein concentrations and insulin sensitivity, although IGFBP‐3 had weakly significant relationships with some of the lipoproteins. Conclusions. Levels of IGF‐I, IGF‐II and IGFBP3 are reduced in male Arab patients with CHD, and did not appear influenced by traditional CHD risk factors such as age, BMI, insulin sensitivity and presence of MS. Perturbations in the IGF/IGFBP‐3 axis may be potential additional targets for pharmacological manipulation in CHD.     

CCM3 signaling through sterile 20–like kinases plays an essential role during zebrafish cardiovascular development and cerebral cavernous malformations

Cerebral cavernous malformation is a common human vascular disease that arises due to loss-of-function mutations in genes encoding three intracellular adaptor proteins, cerebral cavernous malformations 1 protein (CCM1), CCM2, and CCM3. CCM1, CCM2, and CCM3 interact biochemically in a pathway required in endothelial cells during cardiovascular development in mice and zebrafish. The downstream effectors by which this signaling pathway regulates endothelial function have not yet been identified. Here we have shown in zebrafish that expression of mutant ccm3 proteins (ccm3Δ) known to cause cerebral cavernous malformation in humans confers cardiovascular phenotypes identical to those associated with loss of ccm1 and ccm2. CCM3Δ proteins interacted with CCM1 and CCM2, but not with other proteins known to bind wild-type CCM3, serine/threonine protein kinase MST4 (MST4), sterile 20–like serine/threonine kinase 24 (STK24), and STK25, all of which have poorly defined biological functions. Cardiovascular phenotypes characteristic of CCM deficiency arose due to stk deficiency and combined low-level deficiency of stks and ccm3 in zebrafish embryos. In cultured human endothelial cells, CCM3 and STK25 regulated barrier function in a manner similar to CCM2, and STKs negatively regulated Rho by directly activating moesin. These studies identify STKs as essential downstream effectors of CCM signaling in development and disease that may regulate both endothelial and epithelial cell junctions.     

NO/cGMP/PKG信号通路与血管钙化的关系

骨、牙齿之外的非骨性组织发生钙化,伴有或不伴有组织的坏死或损伤,均称为异位钙化。心血管系统的异位钙化包括血管钙化和心脏瓣膜钙化。以往认为血管钙化是钙盐在细胞内和细胞外基质的被动沉积,然而新近的研究发现血管钙化是一个主动的、可调控的生物学过程,与骨组织的骨化过程有相似之处,     

Haemoglobin,C‐reactive protein and androgen levels in uncomplicated and complicated pregnancies of women with polycystic ovary syndrome

Objective. We studied a possible association between pregnancy complications and blood/serum levels of haemoglobin, C‐reactive protein, sex hormones and lipids in women with polycystic ovary syndrome. Material and methods. Twenty‐one women with polycystic ovary syndrome were followed prospectively from the first trimester to delivery. Women with pregnancy complications (n = 10) were compared to women without complications (n = 11). Outcome measures were blood/serum levels of haemoglobin, C‐reactive protein, dehydroepiandrosterone sulphate, androstenedione, testosterone, sex hormone binding globulin, free testosterone index, oestrogens and lipids. Results. Haemoglobin levels were higher in complicated pregnancies compared to uncomplicated pregnancies throughout the complete pregnancy, while C‐reactive protein levels were higher for complicated pregnancies at gestational weeks 19 and 32. Serum levels of lipids, androgens and oestrogens did not differ throughout pregnancy. Conclusion. In women suffering from polycystic ovary syndrome, pregnancy complications were associated with elevated blood/serum levels of haemoglobin and C‐reactive protein. Androgen, oestrogen and lipid levels did not differ between groups.     

Extracellular matrix protein expression in cerebrospinal fluid from patients with tropical spastic paraparesis associated with HTLV‐I and Creutzfeldt‐Jakob disease

The cerebrospinal fluid (CSF) is in direct contact with the extracellular space of the CNS, thus biochemical processes in the CNS could potentially be reflected in the CSF. Changes in extracellular matrix (ECM) proteins can be studied through their analysis in the CSF. ECM plays an essential role in CNS homeostasis and several proteins such as laminin (LN), fibronectin (FN), thrombospondin (TS) and heparan sulphate proteoglycan (HS, perlecan) form part of its structure. Possible changes in the levels of these proteins were investigated in two different pathologies —tropical spastic paraparesis/HTLV‐I‐associated myelopathy (TSP/HAM) (n=25) and Creutzfeldt‐Jakob disease (CJD) (n=19)—and compared with those in a control group with or without neurological disease (n=25). CSF analyses were carried out using monoclonal or monospecific polyclonal antibodies. In comparison with the control group, it was found that TSP/HAM patients presented significantly higher levels of LN, TS and HS, while in CJD patients the levels of FN, TS and HS were increased. In CJD patients the HS level was almost double that of the TSP/HAM patients. These results suggest a distinct pattern of ECM proteins in CSF in relation to the type of neurological disease. TSP/HAM is a chronic motor disease that affects the white matter of the spinal cord, while CJD is a subacute dementia that affects cerebral neurons and their synapsis.     

Biological variation and reference intervals for circulating osteopontin,osteoprotegerin, total soluble receptor activator of nuclear factor kappa B ligand and high‐sensitivity C‐reactive protein

Objective. Monitoring inflammatory diseases and osteoclastogenesis with osteopontin (OPN), osteoprotegerin (OPG), total soluble receptor activator of nuclear factor kappa B ligand (total sRANKL) and high‐sensitivity C‐reactive protein (hsCRP) has recently attracted increased interest. The purpose of our study was to determine reference intervals, variability caused by sampling time, biological variation and stability after repeated freeze–thaw cycles of circulating levels of OPN, OPG, total sRANKL and hsCRP. Material and methods. Plasma OPN and plasma OPG concentrations were determined with sandwich ELISA; serum total sRANKL concentration was determined using a two‐site sandwich ELISA; and hsCRP was analysed by turbidimetry in 300 Danish blood donors (183 M and 117 F) with a median age of 43 years (range 18–64 years). Variability due to biological variation and sampling time was studied in serial samples from 38 healthy subjects. Results. The 95th percentiles in the donors were 76?µg/L for OPN, 4.2?pmol/L for OPG, 40.2?nmol/L for total sRANKL and 12?mg/L for hsCRP. The overall medians for both genders were 51?µg/L, 2.2?pmol/L, 0.66?nmol/L and 1.0?mg/L, respectively. We found a significant correlation between hsCRP and OPN (rho = 0.173; p<0.003). The biological within‐subject variations were calculated to be 8.2?% for OPN, 8.8?% for total sRANKL and 50?% for hsCRP. Conclusions. Reference intervals have been established with a high analytic performance for OPN and an acceptable analytic performance for OPG and total sRANKL. The study revealed low biological variation for OPN and total sRANKL and high biological variation for hsCRP.     

Promotion and Tenure for Community‐Engaged Research: An Examination of Promotion and Tenure Support for Community‐Engaged Research at Three Universities Collaborating through a Clinical and Translational Science Award

Introduction

Community‐engaged health research, an approach to research which includes the participation of communities, promotes the translation of research to address and improve social determinants of health. As a way to encourage community‐engaged research, the National Institutes of Health required applicants to the Clinical and Translational Science Award (CTSA) to include a community engagement component. Although grant‐funding may support an increase in community‐engaged research, faculties also respond to the rewards and demands of university promotion and tenure standards. This paper measures faculty perception of how three institutions funded by a CTSA support community‐engaged research in the promotion and tenure process.

Methods

At three institutions funded by a CTSA, tenure track and nontenure track faculty responded to a survey regarding perceptions of how promotion and tenure committees value community‐engaged research.

Results

Faculty view support for community‐engaged research with some reserve. Only 36% agree that community‐engaged research is valued in the promotion and tenure process.

Discussion

Encouraging community‐engaged scholarship requires changing the culture and values behind promotion and tenure decisions. Institutions will increase community‐engaged research and more faculty will adopt its principles, when it is rewarded by promotion and tenure committees.     

35例妊高征患者硫酸镁治疗前后外周血NO和cGMP的变化

1引它一氧化氮（NO）是由内皮细胞释放的强烈的血管舒张因子，具有舒张血管，调节血压的作用［‘·‘j。近来的研究发现一氧化氨祛少是妊娠高血压综合征（妊高征）发病的关键环节之－［’］。本研究通过测定好高征患者硫酸镁治疗前后外周血中一氧化氛及其第二信使环磷鸟耷（CGMP）的水平，探讨硫酸镁治疗妇高征的作用机制。2资料及方法2·l一般资料1996年11月至1997年4月期间在河南医科大学第三附属医院妇产科住院治疗的中、重度妊高征患者35例，年龄25～35岁，孕龄34～39周，无其他产科并发症或内科合并症。患者均只使用硫酸镁治疗，硫…