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991.
992.
Two groups of captive macaques (M. fascicularis) were studied at the Primatological Laboratory, Kassel University, Germany. One group (D) included the animals born to high-ranking mothers, another (H) comprised those whose mothers were low-ranking. The first group was a despotic community in which conflicts occurred mainly between single individuals, and the male leader was the controlling animal. The second group was an egalitarian community split into two mutually hostile subgroups; the conflicts were less severe, and the male leader could control only his own subgroup. 相似文献
993.
994.
American media are the most violent in the world, and American society is now paying a high price in terms of real life violence. Research has confirmed that mass media violence contributes to aggressive behavior, fear, and desensitization of violence. Television, movies, music videos, computer/video games are pervasive media and represent important influences on children and adolescents. Portraying rewards and punishments and showing the consequences of violence are probably the two most essential contextual factors for viewers as they interpret the meaning of what they are viewing on television. Public health efforts have emphasized public education, media literacy campaign for children and parents, and an increased use of technology to prevent access to certain harmful medial materials. 相似文献
995.
We report uncultured rod-shaped magnetotactic bacteria from natural waters that biomineralize magnetic crystals in two different size ranges. Electron spectroscopic imaging of whole bacteria deposited over formvar-coated grids permitted a better visualization and measurement of the magnetosomes. All magnetosomes of individual bacteria could be observed by this technique. The magnetosomes formed one large chain, composed of three to four columns of crystals, disposed in parallel to the main axis of the bacteria. The magnetosomes ranged from 19 to 136 nm in length and 14 to 112 nm width. Smaller magnetosomes (less than 80 nm in length) localized mostly in extremities of the bacterial body while larger preferentially localized in the middle part of the cell. Electron spectroscopic diffraction and X-ray microanalysis indicate that both types of magnetosomes contain magnetite (Fe3O4). In projection, most magnetosomes seem to present pseudo-hexagonal morphologies described for magnetite. As the aspect ratios for smaller and larger magnetosomes are different, we suggest that different levels of control on biomineralization of magnetosomes may exist. 相似文献
996.
997.
Lifestyle and 15-year survival free of heart attack, stroke, and diabetes in middle-aged British men
SG Wannamethee AG Shaper M Walker S Ebrahim 《Canadian Metallurgical Quarterly》1998,158(22):2433-2440
BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by local or diffuse wall motion abnormalities in the right ventricle (RV), associated with recurrent ventricular tachycardia (VT) of RV origin. Brain natriuretic peptide (BNP) was first isolated from a porcine brain extract. In humans, BNP is expressed predominantly in the ventricles of failing hearts, and its expression has been observed primarily in myocytes in the interstitial fibrous area in dilated cardiomyopathy. We hypothesized that BNP is increasingly secreted from the residual myocytes within the atrophic tissue in patients with ARVD. METHODS AND RESULTS: Plasma BNP levels were measured in 17 patients with ARVD, 12 patients with idiopathic RV outflow tract tachycardia (RVOT), and 120 control subjects. We performed cardiac catheterization, RV endomyocardial biopsy, electron- beam CT, and biventricular endomyocardial mapping in the ARVD patients. There was a significant increase in plasma BNP levels in the ARVD patients compared with the RVOT patients and control subjects (61.4+/-59.6 pg/mL versus 8.3+/-5. 5 pg/mL and 9.3+/-5.8 pg/mL; P<0.0001, respectively). The plasma BNP levels had no correlation with any of the hemodynamic data, but they had a significant correlation with the RV ejection fraction (r=-0. 588, P=0.025) and with the fractionated-area scores (r=0.705, P=0. 005). Light microscopic immunohistochemistry showed strong BNP immunoreactivity in residual myocytes with fibrofatty replacement. CONCLUSIONS: These results suggest that plasma BNP levels were not increased in RVOT patients but were increased in ARVD patients, and that the increased BNP levels indicate the severity of both the RV dysfunction and the arrhythmogenic substrate. 相似文献
998.
WC Nahas AM Lucon E Mazzucchi AG Scafuri ED Neto LE Ianhez S Arap 《Canadian Metallurgical Quarterly》1998,160(4):1244-1247
PURPOSE: A shortage of organs for transplantation has forced surgeons to optimize the use of marginal organs, such as kidneys with arterial disease. We present a retrospective study of the outcome of donors with renal artery disease and recipients of kidneys from living related and unrelated donors. MATERIALS AND METHODS: Kidneys with vascular abnormalities from healthy living donors were grafted into 11 recipients. These kidney transplants comprised 1.8% of those performed at our institution. The vascular abnormalities were aneurysms in 3 cases, atherosclerotic lesions in 4 and fibromuscular dysplasia in 4. After nephrectomy all abnormalities were corrected under hypothermic conditions during bench surgery except in 3 cases of ostial atherosclerotic plaque, which was left in the donors. The renal artery was anastomosed to the external iliac artery in 5 cases and to the internal iliac artery in 6. The ureter was reimplanted using an extravesical technique. RESULTS: All patients had immediate diuresis and no delayed post-transplant graft dysfunction was observed. One patient died of an unrelated cause and 3 had post-transplant graft function loss due to acute vasculopathy in 1, post-diarrhea with acute arterial thrombosis in 1 and recurrence of the hemolytic-uremic syndrome in 1. All remaining patients are well with median serum creatinine of 1.4 mg./dl. (normal 0.4 to 1.4). All donors are well and normotensive with normal renal function. CONCLUSIONS: The use of kidneys with arterial disease from living donors with unilateral disease is safe. Complete informed consent regarding the risks and benefits by donor and recipient is mandatory. 相似文献
999.
DM Novy HS Collins DV Nelson AG Thomas M Wiggins A Martinez GA Irving 《Canadian Metallurgical Quarterly》1998,79(7):820-822
OBJECTIVE: To determine what percentage of patients have none of the five nonorganic behavioral processes known as Waddell signs, and the relational pattern between Waddell signs and somatic complaints, disturbed functional performance, negative treatment attitudes, physical pathology, depression, generalized anxiety, and MMPI-2 validity scales. DESIGN: Case series survey. SETTING: A referral-based multidisciplinary pain center affiliated with a state medical school. PATIENTS: Seventy-five consecutive patients with chronic back pain. INTERVENTION: Medical evaluation and completion of self-report inventories. MAIN OUTCOME MEASURE: Total number of Waddell signs, physical pathology, and pain intensity ratings were assessed by a physician during an initial medical evaluation. Degree of disturbed functional performance and psychological symptoms were assessed by self-report measures at the initial evaluation. RESULTS: Sixty-four percent of the patients had no Waddell signs. Total number of Waddell signs yielded positive and statistically significant correlations (p < or = .05) with depression, disturbed functional performance, somatic complaints, and pain intensity ratings. Correlations of slightly smaller and statistically nonsignificant magnitudes were revealed for Waddell signs with generalized anxiety, negative treatment attitudes, and physical pathology. Waddell signs were unrelated to age, duration of pain, gender, number of lumbar surgeries, and MMPI-2 validity scales. CONCLUSIONS: Taken together, multiple Waddell signs and some of their correlates present various factors that might interfere with optimal response to treatment. 相似文献
1000.
EE Yiannaki AG Tzioufas M Bachmann J Hantoumi V Tsikaris M Sakarellos-Daitsiotis C Sakarellos HM Moutsopoulos 《Canadian Metallurgical Quarterly》1998,112(1):152-158
Aflatoxin M1 (AFM1) is the principal hydroxylated aflatoxin metabolite present in the milk of dairy cows fed a diet contaminated with aflatoxin B1, (AFB1) and the metabolite is also present in the milk of human nursing mothers consuming foodstuffs containing the toxin. AFM1 is usually considered to be a detoxification product of AFB1 and this appears warranted if the biological endpoints involved are carcinogenicity and mutagenicity. However, it may not be a valid conclusion in the case of cytotoxicity. The metabolism of AFM1 and AFB1 have been studied in vitro using human liver microsomes. Formation of primary metabolites associated with metabolic activation to the respective epoxides reflected the differences between the carcinogenic potentials of the two toxins and, similar to AFB1, the conjugation of AFM1 epoxide with reduced GSH was catalyzed by mouse, but not human liver cytosol. Although the majority of the binding of [3H]AFB1 to microsomal protein was dependent on metabolic activation, a high level of retention of [3H]AFM1 by microsomes, nonextractable in methanol and unrelated to metabolic activation, was observed. It appears possible that this property is related to the high cytotoxicity of AFM1. Experiments using human cell line cells either expressing or not expressing human cytochrome P450 enzymes in assays of acute toxicity (MTT assays) have demonstrated a directly toxic potential of AFM1 in the absence of metabolic activation, in contrast to AFB1. Caution therefore needs to be exercised in designating the formation of AFM1 as essentially detoxification when considering a biological response in which cytotoxicity may play a significant role, e.g., immunotoxicity. 相似文献