Effect of thrombolytic therapy on platelet expression and plasma concentration of PECAM-1 (CD31) in patients with acute myocardial infarction

OBJECTIVE: Cholelithiasis is a common problem in hospitals of the Peruvian Andes; however, its prevalence in Andean communities is unknown. To estimate the prevalence of gallstone disease in this locale, we conducted a cross-sectional community study in three high-altitude Peruvian rural villages (i.e., > 3000 m above sea level). METHODS: We examined 911 volunteers > 15 yr of age from three villages for gallstone disease by history and ultrasonography. Risk factors for gallstone disease were examined in 382 volunteers from one village. RESULTS: The age-adjusted prevalence of gallstone disease ranged from 4-10% in men and from 18-20% in women. Women had significantly higher age-adjusted prevalence rates than did men. The prevalence of gallstone disease increased significantly with age and decreased significantly with alcohol consumption. Although not statistically significant, we found a positive association between gallstone disease and body mass index. CONCLUSION: The results of this study indicate that gallstone disease, commonly perceived as a disease of the developed world, is also a common problem in high-altitude Peruvian communities.     

Effects of timolol and betaxolol on choroidal blood flow in the rabbit

Endothelium-dependent hyperpolarization of vascular smooth muscle cells (VSMCs) plays a crucial role in regulating vascular tone, especially in resistance vessels. It has been proposed that metabolites of arachidonic acid (AA), formed by cytochrome P-450 monooxygenase (P450), are endothelium-derived hyperpolarizing factors (EDHFs). These metabolites have been reported to mediate dilation to endogenous vasoactive compounds, such as bradykinin and acetylcholine. However, it is not known whether these metabolites of AA contribute to dilation of human resistance vessels. This is important since it has been proposed that EDHF serves as a compensatory mechanism to maintain dilation in disease states. Therefore, we studied the effect of AA on vessel diameter and VSMC membrane potential in isolated human coronary microvessels. Arterioles (81+/-5 microm, n=70) were dissected from right atrial appendages at the time of cardiac surgery and cannulated at a distending pressure of 60 mm Hg and zero flow. Changes in internal diameter were recorded with videomicroscopy. Some vessels were impaled with glass microelectrodes to measure membrane potential of VSMCs while internal diameters were simultaneously recorded. After constriction (47+/-2%) with endothelin-1, AA (10(-10)to 10(-5)mol/L) induced substantial dilation of human coronary microvessels, which was abolished by removal of the endothelium. Treatment with 17-octadecynoic acid (17-ODYA, 10(-5) mol/L; a P450 inhibitor) attenuated maximal dilation to AA (49+/-9% versus 91+/-4% [control]; P<0.05 versus control), whereas indomethacin (INDO, 10(-5) mol/L; a cyclooxygenase inhibitor) and N omega-nitro-L-arginine methyl ester (L-NAME, 10(-4) mol/L; a NO synthase inhibitor) were without effect. Both 17-ODYA and miconazole (10(-5) mol/L, a chemically distinct P450 inhibitor) further reduced the dilation to AA in the presence of INDO. The presence of 40 mmol/L KCl or charybdotoxin (10(-8) mol/L, a blocker of large-conductance Ca2+-activated K+ channels) impaired dilation to AA (19+/-9% [KCI] versus 76+/-5% [control] and 47+/-6% [charybdotoxin] versus 91+/-3% [control]; P<0.05 for both). After depolarization with endothelin-1 (-26+/-1 mV from -48+/-3 mV [before endothelin]), AA (10(-5)mol/L) in the presence of INDO and L-NAME induced hyperpolarization of VSMCs (-57+/-5 mV). In the presence of 17-ODYA together with INDO and L-NAME, endothelin produced similar depolarization (-26+/-2 mV from - 48+/- 3 mV), but hyperpolarization to AA was reduced (-33+/-2 mV; P<0.05 versus absence of 17-ODYA). AA metabolites formed primarily by P450 produce potent endothelium-dependent dilation of human coronary arterioles via opening of Ca2+-activated K+ channels and hyperpolarization of VSMCs. These findings support an important role for P450 metabolites in the regulation of human coronary arteriolar tone.     

Effect of sulfur content on non metallic inclusions of heavy rail steel

Due to the inaccurate control of raw materials and operation in the actual production process, the sulfur content and non-metallic inclusions in the steel fluctuate greatly, which seriously affects the cleanliness of steel. To accurately control the size, shape and quantity of non-metallic inclusions such as manganese sulfide in heavy rail steel, the effect of sulfur content on non-metallic inclusions in heavy rail steel was studied in the laboratory. To investigate the changes of the number and morphology of non-metallic inclusions in steel under different sulfur contents, the sulfur content of test steel was increased to 70×10-6, 110×10-6 and 140×10-6, respectively. During the experiment, the test steel was heated and melted in a tubular furnace according to a certain heating rule, and then cooled naturally in the furnace. Subsequently, the non metallic inclusions in steel were scanned by automatic inclusions analyzer, and the relationship between sulfur content and the composition, size, form and quantity of non-metallic inclusions in steel was obtained. The results indicate that most of the inclusions in the steel are composite MnS with oxides as nucleating cores. With the increase of sulfur content, the quantity density of composite MnS, MnO-SiO2 and MgO-Al2O3-SiO2-CaO inclusions increase, while the CaO-SiO2 and MgO-CaO-SiO2 inclusions decrease. The average size of inclusions increases with the increase of sulfur content, and the number of inclusions with different sizes also increases, especially for inclusions with sizes of 2-10μm which increase obviously. During solidification, MnS can be separated from molten steel with sulfur content of (70-140)×10-6. In addition, the higher the sulfur content is, the earlier MnS inclusions precipitate and the more the MnS content is.     

硫含量对重轨钢中非金属夹杂物的影响

摘要：实际生产过程中由于原料和操作控制不精确,钢中硫含量和非金属夹杂物波动较大,严重影响钢的洁净度。为了准确控制重轨钢中硫化锰等非金属夹杂物的尺寸、形态和数量,在实验室开展了硫含量对重轨钢中非金属夹杂物的影响研究。钢中硫质量分数增至70×10-6、110×10-6、140×10-6后随炉冷却,采用全自动夹杂物分析仪对钢中非金属夹杂物进行统计,获得了硫含量与钢中非金属夹杂物成分、尺寸、形态和数量的关系。结果表明,钢中夹杂物大部分为以氧化物为形核核心的复合型MnS;随着硫含量的升高,复合型MnS、MnO-SiO2和MgO-Al2O3-SiO2-CaO型夹杂增多,CaO-SiO2和MgO-CaO-SiO2夹杂减少;夹杂物平均尺寸随硫含量的升高而增大,且不同尺寸的夹杂物均有所增加,尺寸为2~10μm增多最明显;硫质量分数为(70~140)×10-6的钢液凝固过程液相中都能单独析出MnS,且硫含量越高,MnS析出越早,含量越多。     

Prostate-specific antigen in the diagnosis of organ-confined treatable prostate carcinoma

Prostate cancer is now the most common cancer and the second most common cause of death from cancer among men. Several studies have shown a frequency of autopsy-detected cancer of 40% in men over 50 years of age. In contrast, the lifetime probability of prostate cancer being diagnosed clinically is only 8%. Thus histologically documented prostate cancer only becomes clinically relevant if the tumors are > 0.5 cm3 and the life expectancy exceeds 10 years. Therapy with curative intention is only possible for organ confined disease. Because disease specific survival is about 80-90% after 10 years for conservative treatment of organ confined disease, early detection of prostate cancer is useful for patients with a life expectancy > 10 years. Organ confined prostate cancer is usually asymptomatic. The use of prostate specific antigen (PSA) combined with digital rectal examination (DRE) results in a 2-3 fold increase in prostatic carcinoma detection rate, especially of organ confined disease, by PSA. In men with a minimally elevated PSA-value of 4-10 ng/ml (Hybritech Assays), 25% will have a prostatic carcinoma regardless of the finding of the DRE, which would have reached clinical significance in the follow-up. The indication for biopsy should be established at an early date. There is no support for the common opinion that early detection programs detect clinically unimportant cancers. 95% of tumor volumes are > 0.5 cm3. Furthermore only 3-5% of subjects show prostate cancer in detection programs though 8% will develop clinical symptoms of prostate cancer during their lifetime. This difference is a reason for longitudinal programs with PSA and DRE control once a year, as proposed by the American Cancer Society and the American and Canadian Urological Association, in contrast to other health care organizations, which would wait with general screening until data from prospective randomized trials with beneficial effects of screening are available. To introduce prostate cancer therapy with curative intention for symptomatic patients as well, the cancer should be detected below a PSA level of 10 ng/ml. Insufficient specificity of PSA (2-4 patients have to undergo biopsies to detect one cancer patient) is still an unsolved problem.     

New aspects on the superplasticity of fine-grained 7475 aluminum alloys

Thermomechanical processes were developed which give fine grain sizes of 6 and 8 μm in the 7475 Al alloy. Superplastic properties of this material were evaluated in the temperature range of 400 °C to 545 °C over the strain-rate range of 2.8 x 10^-4 to 2.8 X 10^-2 s^-1. The maximum ductility exhibited by the alloy was approximately 2000 pct, and optimum superplasticity was achieved at a strain rate of 2.8 X 10^-3 s^-1 which is higher by an order of magnitude than other 7475 Al alloys. This result is attributed to the presence of fine dispersoids which maintain the fine grain size at high homologous temperatures. The flow stress and strain-rate sensitivity strongly depend on the grain size. The superplastic 7475 Al alloy has strain-rate sensitivities of 0.67 (6 μm) and 0.5 (13 μm) and an activation energy which is similar to the one for grain boundary diffusion of aluminum. Microstructural investigation after superplastic tests revealed zones free of dispersoid particles at grain boundaries primarily normal to the tensile direction. These dispersoidfree zones (DFZs) appear even after 100 pct elongation and are occasionally as large as 5 μm across. This result demonstrates the importance of diffusional flow in superplastic deformation of the fine-grained 7475 Al alloy especially at low elongations.     

Characterisation of ACTH peptides in human skin and their activation of the melanocortin-1 receptor

Alpha-Melanocyte-stimulating hormone (alpha-MSH) is a proopiomelanocortin (POMC)-derived peptide, which is produced in the pituitary and at other sites including the skin. It has numerous effects and in the skin has a pigmentary action through the activation of the melanocortin-1 (MC-1) receptor, which is expressed by melanocytes. Recent evidence suggests that the related POMC peptides such as adrenocorticotrophin (ACTH), which is the precursor of alpha-MSH, is also an agonist at the MC-1 receptor. By using immunocytochemistry, we confirmed the presence of alpha-MSH in human skin where staining was evident in keratinocytes and especially strong in melanocytes and possibly Langerhans cells. ACTH was also present and tended to show the strongest reaction in differentiated keratinocytes. Immunostaining was also observed for the prohormone convertases, PC1 and PC2, which are involved in the formation of ACTH and its cleavage to alpha-MSH, respectively. The amounts of immunoreactive ACTH exceeded those of alpha-MSH. Using HPLC we identified for the first time the presence of ACTH1-39, ACTH1-17, ACTH1-10, acetylated ACTH1-10, alpha-MSH, and desacetyl alpha-MSH in epidermis and in cultured keratinocytes. The ability of these peptides to activate the human MC-1 receptor was examined in HEK 293 cells that had been transfected with the receptor. All peptides increased adenylate cyclase in these cells with the following order of potency: ACTH1-17 > alpha-MSH > ACTH1-39 > desacetyl alpha-MSH > acetylated ACTH1-10 > ACTH1-10. ACTH1-17 also increased the dendricity and melanin content of cultured human melanocytes indicating that the peptide was able to activate MC-1 receptors when present in their normal location. However, as found with alpha-MSH, not all cultures were responsive and, as we have previously suggested, we suspect that this was the result of changes at the MC-1 receptor. Nevertheless, it would appear that ACTH peptides can serve as natural ligands of the MC-1 receptor on human melanocytes and their presence in the skin suggests that, together with alpha-MSH, they may have a role in the regulation of human melanocytes.     

Modern maternity care: does safety have to take the meaning out of birth?

Contractile responses to serotonin (5-HT) of fundic smooth muscle strips isolated from both control and streptozotocin (STZ)-induced diabetic rats were investigated. Contrary to carbachol (CCh) which causes contractile hyperactivity in DM, 5-HT response tended to decrease in DM compared to that of the control. Pindolol (10(-5)M) increased the value of EC50 of the concentration-response to 5-HT about 2.5 times in both the control and DM. After treatment with pindolol, the maximal tension to 5-HT in DM significantly decreased compared to that of the control. Pindolol showed no effect on the contractile response to CCh. Pindolol significantly inhibited the relaxation caused by isoproterenol in DM more than in the control. Mianserin (10(-5) M) increased the EC50 of the response to 5-HT about 2-2.5 times in both groups, but did not cause a significant difference between the control and DM. The Ca(2+)-induced contraction caused hyperreactivity in DM in the presence of 10(-6) M CCh, but that in DM was not significantly different from the control in the presence of 10(-6) M 5-HT. Pretreatment of phorbol 12-myristate 13-acetate (PMA, 10(-5) M) significantly attenuated the response to 5-HT in the control, but not in DM. Results suggest that the contractile response to 5-HT in DM is related to the altered Ca2+ signal transduction system via disturbed protein kinase C (PKC) activity, and that there are alterations of receptor characteristics and of the density in 5-HT receptor subtypes, especially 5-HT1A, during DM development.     

Inhibitory activity of loratadine and descarboxyethoxyloratadine on histamine-induced activation of endothelial cells

BACKGROUND: The allergic inflammatory reaction is characterized by leucocyte adherence and infiltration processes which are controlled by the expression of adhesion molecules on the surface of vascular endothelium. One of the main mediators implicated in allergic reactions is represented by histamine. Histamine is a potent activator of endothelial cells (EC): it induces the expression of P-selectin on the surface of endothelium and the secretion of IL-6 and IL-8. OBJECTIVES: Loratadine (L), a histamine H1-antagonist, and one of its active metabolites, descarboxyethoxyloratadine (DCL), were studied at different concentrations for their ability to reduce the histamine-induced activation of human umbilical vein EC (HUVEC). METHODS: HUVEC were stimulated in the presence of histamine at 10(-6) M, 10(-5) M and 10(-4) M. We assessed by ELISA the expression of P-selectin on EC surface, as well as cytokine production in EC supernatants of 24 h culture. RESULTS: Our results showed that for a 10(-4) M-histamine stimulation, L and DCL have a similar inhibitory effect on P-selectin expression (IC50 = 13 x 10[-9] M and 23 x 10[-9] M, respectively). L and DCL inhibited significantly IL-6 and IL-8 secretion induced by histamine with a more powerful efficiency of the active metabolite. For the dose of 10(-4) M histamine, a 50% inhibition of IL-6 secretion was obtained for a dose of DCL equal to 2.6 x 10(-12) M whereas the same magnitude of effects were only reached for a higher concentration of L (0.3 x 10[-6] M). Similar results were obtained for IL-8 (IC50 = 0.2 x 10[-6] M for L and 10[-9] M for DCL). Analysis of IL-8 mRNA expression by RT-PCR was in accordance with these data. CONCLUSION: These results demonstrate that both L and DCL are active to reduce the histamine-induced activation of EC. Interestingly, DCL seems to be effective at lesser concentrations especially to inhibit cytokine secretion.     

Thoracolumbar epidural blockade as adjunct to high dose fentanyl/midazolam anesthesia in coronary surgery: effects of sternotomy

The present study tests the hypothesis that the changes in myocardial lactate metabolism in the early period of coronary surgery are caused by raised adrenergic activity, and that these are preventable by the addition of thoracolumbar epidural blockade to high dose fentanyl/midazolam anesthesia. Twenty-seven male beta 1-blocked patients undergoing coronary surgery were included in a prospective, controlled, randomized study. High dose fentanyl/midazolam anesthesia alone (control) or supplemented with thoracolumbar epidural blockade (treatment) was used. Measurements were performed before the induction of anesthesia and after sternotomy. After sternotomy adrenaline (A) and noradrenaline (NA) had decreased and were both in the low range, especially in the epidural group (P < 0.01). Arterial pressures decreased in both groups, especially in the epidural group, where coronary perfusion pressure (CPP) decreased from 61 (42-88) to 48 (33-64) mm Hg; Systemic vascular resistance (SVR) decreased with 30% in the epidural group (P < 0.01), but not significantly in the control group. The myocardial fractional extraction of lactate decreased in both groups, from 33 (10-45) to 13 (0-42)% in the control group (P < 0.01), and from 36 (19-43) to 10 (2-20)% in the epidural group. It is concluded that high dose fentanyl/midazolam anesthesia prevents hyperadrenergic activity in the early phase of coronary surgery, but cannot eliminate changes in myocardial lactate metabolism. The addition of the thoracolumbar epidural blockade to high dose fentanyl/midazolam anesthesia offers no obvious benefits in the early phase of coronary surgery.     

The effects of histamine H2 receptor agonist, antagonist and antineoplastic agent on the in vitro growth of PB CFU-GM from normal individuals and HL-60 leukemia cells

Colony forming unit of granulocytes and macrophages from peripheral blood (PB CFU-GM) represents stem and/or progenitor cells from human blood. In this paper, the effects of histamine H2 receptor agonist 4-methylhistamine (4-MH) and its antagonist ranitidine (Ranit) on the growth of PB CFU-GM cultured in methylcellulose system were studied and their differential effects on normal PB CFU-GM and leukemic HL-60 cells were compared with the effect of the antineoplastic agent cytosine arabinoside (Ara-C). It was found that the histamine H2 receptor agonist 4-MH stimulated the growth of PB CFU-GM when 4-MH was added at the concentrations from 10(-9) mol.L-1 to 10(-6) mol.L-1 among which the dose 10(-8) mol.L-1 exerted most potent stimulating effect (the PB CFU-GM colony numbers was 137.68% +/- 8.20% vs the control, P < 0.01). In contrast, the antagonist Ranit showed inhibitory effect on the growth of PB CFU-GM when at the concentrations 10(-9)-10(-5) mol.L-1 cultured for 14 d in the same methylcellulose system. The inhibition rate was 23.73% +/- 1.16% (10(-9) mol.L-1) and 41.42% +/- 6.75% (10(-6) mol.L-1), respectively. Although both Ranit and Ara-C could inhibit the growth of PB CFU-GM in vitro, Ranit exerted much greater inhibition on HL-60 leukemic cells than on normal PB CFU-GM at the dose of 10(-6) mol.L-1 (100% inhibition for HL-60 and < 50% inhibition for PB CFU-GM). However, the inhibition rate of Ara-C for both HL-60 and PB CFU-GM was 100% at the intensive chemotherapeutic dose of 10(-5) mol.L-1. It would appear that the histamine H2 receptor agonist 4-MH possesses stimulating effect on the growth of PB CFU-GM similar to its effect on CFU-GM from bone marrow as documented before. It is suggested that the histamine H2 receptor antagonist Ranit has, to some extent, potential in the treatment of myeloid leukemia, especially when combined with antineoplastic agent Ara-C at suboptimal doses.     

Effects of calcitonin gene-related peptide on wound contraction in denervated and normal rat skin: a preliminary report

The aim of the present study was to observe the effect of calcitonin gene-related peptide (CGRP) on wound contraction in both denervated and normal areas. A total of 100 Wistar rats, each of which had a 2 x 2 cm full-thickness skin defect on the back, were divided into two main control groups and six corresponding experimental groups in which 10 x 10(-9) M and 10 x 10(-12) M synthetic rat CGRP were given intraperitoneally and intradermally. Contraction was assessed weekly with planimetry, and mean surface areas (mm2 +/- SD) of related groups were compared. Complete closure took 4 weeks for the normal control group and 8 weeks for the denervated control group (p < 0.05). The 10 x 10(-12) M CGRP with both types of application showed a decrease in the length of time for complete closure to 3 weeks in the normal experimental groups (p < 0.05), but complete closure still took 4 weeks in normal groups in which 10 x 10(-9) M CGRP was given (p < 0.05). Any dosage of CGRP given intraperitoneally showed no change in the closure period in the denervated experimental groups (p > 0.05). CGRP showed a trophic effect on healing by an increased rate of contraction in the rat model. However, the neural supply to the wound area seemed to be intact because of the necessity of axonal transfer of CGRP.     

锂离子电芯用电极对温度与SOC的敏感性

采用阻抗谱技术,对2.8 A·h 18650电芯进行拆解解析,单独分析正负极电极在不同温度下(25、10和-5℃),不同荷电状态下的阻抗变化.结果表明:在不同温度下,在20%~100%荷电状态下,负极作为控制电极,其反应电化学阻抗是正极的数倍,尤其是在-5℃,达到了4倍,负极是电芯一致性问题中动力学因素的控制主因;在0~20%荷电状态下,在10和25℃下,正极的反应电化学阻抗要远远大于负极,正极成为控制端.结合目前电动车上动力电池的实用荷电状态一般在20%~95%,针对该2.8 A·h 18650电芯,提高负极电极的一致性是核心所在.同理,对其他类型电芯而言,在电芯设计过程中,在综合考虑成本的前提下,需要更有针对性地提高正负极的一致性标准,从而更为有效地改善整个电芯产品的一致性.      

Riboflaven and bilirubin response during phototherapy

Twenty-four jaundiced neonates were studied, 12 in the treatment group and 12 in the untreated group. Patients were randomly selected to receive oral riboflavin. The mean 24-hr bilirubin decrease was determined during phototherapy. Blue light (420-470 nm) energy ranged from 6-10 muW/cm2. The observed 24-hr bilirubin decreased was compared with the expected decrease based on an energy-dose-response relationship. Riboflavin-treated infants received either 6-7 mu W/cm blue light energy or 810 muW/cm (same as control group). Those infants receiving less energy than the control group (8-10 muW)cm2 had a mean 24-hr bilirubin decrease (3.05 mg/100 ml/24 hr) equal to the control group (3.09 mg/100 ml/24 hr). Those riboflavin-treated infants receiving energy equal to the control group showed a greater decline (5.2 mg/100 ml/24 hr) in their mean 24-hr bilirubin. Although effective, additional in vivo studies are required to clarify the full effects, especially on DNA, of using photosensitizers such as riboflavin in the presence of bilirubin and blue light energy (420-470 nm).     

Suppressed anti-aggregating and cGMP-elevating effects of sodium nitroprusside in platelets from patients with stable angina pectoris

Short bowel syndrome (SBS) in the newborn results in limited intestinal absorptive capacity, leading especially to fatty acid (FA) malabsorption. It is unknown whether adaptation occurs in time in FA absorption, and whether this adaptation is chain-length dependent. The aid of the present study was to prospectively evaluate FA absorption and excretion during SBS in the newborn. Twenty-one neonates who underwent small bowel resection (of variable length) for various reasons (necrotizing enterocolitis, intestinal atresia, meconium peritonitis, cloacal extrophy, etc) were studied. Eight neonates had SBS, defined as a small bowel remnant of less than 50% of the original small bowel length related to gestational age. The mean remaining small bowel length in the SBS group was 34% (24% to 42%). The non-SBS control group consisted of 13 neonates who had only minor small bowel resections. The mean remaining bowel length for the non-SBS group was 95% (70% to 100%). The results show that the total fractional excretion of FA (FE-FA) at 2 weeks and 1, 2, 3, and 4 months postsurgery was 51% +/- 37%, 33% +/- 24%, 51% +/- 65%, 53% +/- 27%, and 7% +/- 2% in patients with SBS, versus 12% +/- 8%, 24% +/- 10%, 9% +/- 3%, 8% +/- 3% and 17% +/- 14% in the non-SBS controls, respectively (P < .05 by ANOVA). There appeared to be an amelioration in time in FA absorption, especially in the SBS group, after 3 months. FE-FA was chain-length related, being considerably less for C10 and C12 than for C14 and longer amounts. An amelioration of absorption occurred in the SBS patients, especially with the longer-chain FA. On the basis of the study data, the authors conclude that in the initial adaptation phase shorter chain lengths are better absorbed than longer chain lengths; however, in the latter FA group, substantial adaptation occurs with time.     

Aorto-intestinal fistula as a possible cause of endoscopically undetermined gastrointestinal hemorrhage

Elastin peptides are present in human blood. As elastin receptors exist on several cell types, especially endothelial cells, this investigation was carried out to study the effect of elastin peptides on vascular tone. For this purpose, rat aortic rings were mounted in an organ bath for isometric tension measurements. Elastin peptides (kappa-elastin) were added in the concentration range of 0.1 ng/ml to 1 microgram/ml, concentrations similar to those found in the circulating blood. In rat aortic rings, precontracted or not with noradrenaline (10(-6) M), elastin peptides induced an endothelium-dependent vasodilation. The pretreatment of aortic rings with N-omega-nitro-L-arginine methyl ester (10(-5) M), an inhibitor of nitric oxide (NO) production, or with indomethacin (10(-5) M), an inhibitor of cyclooxygenase, prevented elastin peptide-induced vasodilation. These findings suggest that elastin peptides act through the synthesis of prostanoids, leading to the production of NO. Moreover, this relaxant effect of elastin peptides was decreased or inhibited when aortic rings were treated with lactose (10(-5) to 10(-2) M) or laminin (10(-6) to 10(-4) mg/ml) whereas lactose or laminin was unable to inhibit acetylcholine-induced vasodilation. These findings suggest that the inhibitory effects of lactose and laminin are specific for elastin peptide receptors and are in agreement with previous studies on these receptors. As there is evidence of the degradation of elastin in several vascular diseases, the concept that elastin peptides may contribute to the control of vascular tone is discussed.     

六辊精密冷连轧机带钢截面和边缘降调控性能研究

带钢截面和边缘降调控功效研究是板形控制技术的核心之一,也是冷连轧机板形自动控制系统模型的主要设计依据.以六辊精密冷连轧机为例,提出了包含各项影响因素和调控手段的冷连轧机截面和边缘降控制方程;通过有限元仿真计算得到了弯辊和窜辊等调节手段下的板形调控性能参数,其结果对冷连轧机辊形设计、弯辊窜辊工艺规程的制定,特别是对带钢截面、边缘降闭环自动控制系统的实现,具有重要的参考价值.     

Shivering threshold during spinal anesthesia is reduced in elderly patients

BACKGROUND: Both accidental and perioperative hypothermia are common in the elderly. The elderly are at risk because their responses to hypothermia may be delayed or less efficient than in those of younger subjects. For example, the vasoconstriction threshold during isoflurane anesthesia is approximately 1 degree C less in elderly than younger patients. However, the extent to which other cold defenses are impaired in the elderly remains unclear, especially in those older than 80 yr. Operations suitable for spinal anesthesia provided an opportunity to quantify shivering thresholds in patients of varying ages. Accordingly, the hypothesis that the shivering threshold is reduced as a function of age during spinal anesthesia was tested. METHODS: Twenty-eight ASA Physical Status 1-3 patients undergoing lower extremity orthopedic procedures were studied. Spinal anesthesia was induced without preanesthetic medication, using bupivacaine sufficient to produce a dermatomal level near T9. Electrocardiogram signals were recorded at 10-min intervals. Subsequently, an observer masked to patient age and core temperature identified the onset of sustained electromyographic artifact consistent with shivering. The tympanic membrane temperature triggering shivering identified the threshold. RESULTS: Three patients did not shiver at minimum core temperatures exceeding 36.2 degrees C. Fifteen patients aged < 80 yr (58 +/- 10 yr) shivered at 36.1 +/- 0.6 degrees C; in contrast, ten patients aged > or = 80 yr (89 +/- 7 yr) shivered at a significantly lower mean temperature, 35.2 +/- 0.7 degrees C (P = 0.002). The shivering thresholds in seven of the ten patients older than 80 yr was less than 35.5 degrees C, whereas the threshold equaled or exceeded this value in all younger patients (P = 0.0002). CONCLUSIONS: Age-dependent inhibition of autonomic thermoregulatory control in the elderly might be expected to result in hypothermia. That it usually does not suggests that behavioral regulation (e.g., increasing ambient temperature, dressing warmly) compensates for impaired autonomic control. Elderly patients undergoing spinal anesthesia, however, may be especially at risk of hypothermia because low core temperatures may not trigger protective autonomic responses. Furthermore, hypothermia in the elderly given regional anesthesia may not be perceived by the patient (who typically feels less cold after induction of the block), or by the anesthesiologist (who does not observe shivering). Consequently, temperature monitoring and management usually is indicated in these patients.     

Behavior therapy better than placebo treatments: Fact or artifact?

N. Brody's (see record 1990-12934-001) comment on our meta-analysis (T. G. Bowers and G. A. Clum; see record 1989-16477-001) seems to suggest that the efficacy of behavior therapy has not been established relative to placebo control conditions, especially for "neurotic conditions." The comments appear directed at defending an earlier meta-analysis (Priouleau, Murdock, & Brody, 1983) that concluded that psychotherapy was not more efficacious than a placebo control. We agree with Brody regarding the need for increased use of the heteromethod approach and longer follow-up for psychotherapy studies. However, we do not agree that the 10 studies Brody selected do not support the effectiveness of behavior therapy relative to placebo controls. Although a set of 10 studies is probably too small to allow robust conclusions, we noted a median effect size of .63 for those studies of neurotic conditions, relative to a placebo control. These results were very similar to our overall findings from 69 studies. Furthermore, available follow-up data suggest moderate effect sizes exist for those studies. We also comment on the existence of Type I and Type II errors of inference in reviews and meta-analyses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uniqueness of limit cycles in models for microparasitic and macroparasitic diseases

Understanding the sources of variation in a community's diet is vital for development work, as well as being a source of anthropological and cultural insights. Previous surveys in the South American Andes suggest that nutrient deficiencies may be widespread; however, such interpretations have remained tentative since variance in Andean populations' diet has not been thoroughly examined. In this paper we consider the variation in diet due to variation in age, sex, and socioeconomic status and variation attributed to inter- and intraindividual variation in the diet. One to six days of dietary data (mean = 3.1) were collected via 24 h recalls from 221 residents of a small, rural community in highland Ecuador. The contribution of various food groups to the diet varied with land holdings and age but not sex. For example, animal-derived foods contribute more and tubers contribute less to the diet of the households with > or = 5 Ha, and sweets contribute more to the diet of children. The interindividual variation in energy and nutrient intake was low and the intraindividual variation high relative to developed countries. The consequence are twofold. First, because interindividual variability is low, group mean intake can be estimated relatively easily, facilitating group comparisons. Second, because intraindividual variation is high, individual nutrient intake cannot be easily estimated, which will decrease the ability to detect associations between nutrient intake and health measures. This knowledge of the sources of dietary variation can lead to better study and survey designs in the rural Andes and elsewhere in the developing world.