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At least 127 records · Page 7Linked to original sources
PubMed1996

Factors modifying protective effect of anti-CD18 antibodies on myocardial reperfusion injury in dogs.

Anti-CD18 monoclonal antibodies (MAb) have demonstrated variable protection against neutrophil (PMN)-mediated myocardial reperfusion injury. To identify factors contributing to this variability, open-chest dogs underwent coronary artery occlusion for 90 min followed by reperfusion for 3.5 h. Ten minutes before reperfusion the dogs received saline (n = 18) or one of three anti-CD18 MAb: MHM.23, R15.7, or PLM-2 (2, 1, and 1 mg/kg and n = 19, 8, and 4, respectively). Collateral flow was measured with radioactive microspheres, area at risk was assessed with monastral blue dye, and infarct size was measured postmortem by triphenyltetrazolium chloride. In vitro, all three MAb bound to canine PMNs, but only MHM.23 and R15.7 inhibited their adherence to keyhole limpet hemocyanin-coated plastic. In vivo, only MHM.23 and R15.7 significantly reduced infarct size after adjusting for the effect of collateral flow. MHM.23 afforded protection in dogs with moderate ischemia (epicardial collateral flow > 0.1 ml.min-1.g-1, infarct size reduced 46%) but not in dogs with more severe ischemia. Only R15.7 was effective in dogs with severe ischemia. Although MHM.23 and R15.7 produced similar inhibition of tissue PMN accumulation, as reflected by myeloperoxidase activity. R15.7 markedly inhibited H2O2 production by PMNs after exposure to platelet-activating factor, whereas MHM.23 had only a minimal effect. The effectiveness of different anti-CD18 MAb in preventing reperfusion injury appears to be 1) highly dependent on the specific anti-CD18 MAb employed, 2) predicted only partially by in vitro binding to PMNs, static in vitro tests of PMN adherence, or the extent of inhibition of PMN accumulation in vivo, 3) related more to their ability to inhibit oxidant release from activated PMNs, and 4) strongly influenced by the severity of myocardial ischemia before reperfusion.

Animals↗
PubMed1990

[Do elevated blood and cerebrospinal fluid glucose levels and other factors modify the density of cerebrospinal fluid and the spread of isobaric spinal anesthesia?].

When isobaric spinal anesthesia is applied the level of analgesia is of special interest. This level is influenced by many factors of varying importance. One major factor is the relation between cerebrospinal fluid (CSF) density and the density of local anesthetic solutions. The density of CSF changes with the concentrations of its constituents, e.g., glucose or protein. Because glucose concentrations in CSF change in parallel with blood glucose levels, this may have effects on CSF density and the spread of spinal anesthesia. In 43 patients in two groups (diabetic n = 32, non-diabetic n = 11) the influence of CSF density on the analgesia level achieved with isobaric spinal anesthesia was investigated with special reference to increased glucose levels in blood and CSF. The influence of body height and weight, age and CSF protein content were also studied. There were no statistically significant correlations between any of these factors and the extension of analgesia. The mean blockade level was 1.6 segments lower in the non-diabetic group: this difference was statistically not significant (P greater than 0.05). Anesthesia spread faster in the diabetic group, but this difference was also not significant (P greater than 0.05). For bupivacaine 0.5% alone a density of 1.0010 g/cc was found, while for bupivacaine 0.5% with epinephrine (1:200,000) the density measured was 1.0022 g/cc. There is no correlation (r2 = 0.083) between CSF glucose concentration and CSF density, other factors such as sodium, chloride or CO2, apparently being more important. With CSF density ranging between 1.000 and 1.003 g/cc there was no correlation with the blockade level (r2 = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1977

Factors modifying ischemic injury in the isolated rat heart.

The extent of ischemic injury has been studied in the isolated working rat heart utilizing an aortic ball valve that reduces the coronary flow. A number of factors were tested including high heart rate, noradrenaline, acidosis, alkalosis, high afterload, beta-blockade, glucose-insulin-potassium (GIK), palmitate and methylprednisolone. Mechanical performance, myocardial contents of ATP, creatine phosphate, glycogen and lactate and the leakage of creatine phosphokinase (CK) from the myocardium to the perfusion buffer were measured and used for determination of the ischemic injury. Tachycardia, noradrenaline and palmitate are factors that markedly increase the ischemic injury in this preparation. GIK and probably metoprolol decrease the release of CK compared with the controls.

Adenosine Triphosphate↗
PubMed1996

Superantigen as a modifying factor in HIV infection.

Superantigen is characterized as a potent stimulator of T cells through its unique interaction with major histocompatibility complex class II molecule and the V beta chain of T cell receptor. It has been reported that symptoms in several infectious diseases are associated with superantigen activity, i.e., abnormal reaction due to excess activation of T cells. However, the implications of superantigen in human immunodeficiency virus (HIV) infections have not been well elucidated. In this article, we review the possible mechanisms by which superantigens may modify HIV infections. In conclusion, superantigen is considered to be a factor that aggravates the immunodeficient state in HIV-infected patients through activation of HIV expression in infected T cells and monocytes, and facilitation of CD4 T cell depletion. Since exogenous superantigen is most likely to be provided by microbial infections such as Staphylococcus aureus infection, countermeasures against these complicating infections may be important to avert the detrimental impact of superantigens.

CD4 Antigens↗
PubMed2003

[Evaluation of selected factors modifying blood loss after total hip arthroplasty and techniques for the prevention of protracted postoperative bleeding].

The aim of this work was to evaluate blood loss in total hip arthroplasty patients, to determine the effect of some factors on bleeding including age, gender, blood group, body build, bone density, and hip replacement technique, and to develop a method for preventing excessive and protracted postoperative bleeding. Altogether, 59 patients with degenerative hip disease were enrolled. Postoperative bleeding was determined after 12 and 24 hours from surgery by measuring the volume of blood in flasks connected to Redon suction drains. The mean volume of blood lost after hip arthroplasty was 797.3 mL after 12 hours and 1029.4 mL after 24 hours. Total blood loss after surgery was 1257.9 mL. No statistically significant differences in blood loss were noted depending on body weight. In consequence, the percentage of blood lost in relation to total blood volume was determined. This indicator was found to be the only objective measure of blood loss in hip arthroplasty patients. Postoperative bleeding was smaller in patients with higher systolic blood pressure intraoperatively, reduced bone density in the femoral neck and spine, and in females. A tendency to reduced bleeding was observed in the elderly and for shorter surgery times. Blood group and hip replacement technique had no effect on blood loss.

Adult↗
PubMed1984

Factors modifying 3-aminobenzamide cytotoxicity in normal and repair-deficient human fibroblasts.

3-Aminobenzamide (3-AB), an inhibitor of poly(ADP-ribosylation), is lethal to human fibroblasts with damaged DNA. Its cytotoxicity was determined relative to a number of factors including the types of lesions, the kinetics of repair, and the availability of alternative repair systems. A variety of alkylating agents, UV or gamma irradiation, or antimetabolites were used to create DNA lesions. 3-AB enhanced lethality with monofunctional alkylating agents only. Within this class of compounds, methylmethanesulfonate (MMS) treatments made cells more sensitive to 3-AB than did treatment with methylnitrosourea (MNU) or methylnitronitrosoguanidine (MNNG). 3-AB interfered with a dynamic repair process lasting several days, since human fibroblasts remained sensitive to 3-AB for 36-48 hours following MMS treatment. During this same interval, 3-AB caused these cells to arrest in G2 phase. Alkaline elution analysis also revealed that this slow repair was delayed further by 3-AB. Human mutant cells defective in DNA repair differed in their responses to 3-AB. Among mutants sensitive to monofunctional alkylating agents, ataxia telangiectasia cells were slightly more sensitive to 3-AB than control cells, while Huntington's disease cells had a near-normal response. Among UV-sensitive strains, xeroderma pigmentosum variant (XPV) cells were more sensitive to 3-AB after MMS than were XP complementation group A (A) cells, which responded normally. Greater lethality with 3-AB could be dependent on inability of the mutant cells to repair damage by other processes.

Benzamides↗
PubMed1998

[Spiral CT angiography in diagnosis of acute pulmonary embolism. What factors modify implementation of standard algorithms?].

PURPOSE: Debate about the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism are often focussed on sensitivity and specificity in the context of comparative methodologic studies. We intend to investigate whether additional factors might influence this debate. MATERIALS AND METHODS: On the basis of the current literature and of own experience we study the influence of factors such as availability, acceptance, patient-outcome, and cost effectiveness-studies on the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism. This information is analyzed together with data from comparative methodologic studies. RESULTS: The factors availability, acceptance, patient-outcome, and cost-effectiveness-studies do have substantial influence on the implementation of Spiral-CT in the diagnostic algorithms of pulmonary embolism. Incorporation of these factors into the discussion might lead to more flexible and more patient-oriented algorithms for the diagnosis of pulmonary embolism. CONCLUSION: Availability of equipment, acceptance among clinicians, patient-outcome, and cost-effectiveness evaluations should be implemented into the debate about potential implementation of Spiral-CT in routine diagnostic imaging algorithms of pulmonary embolism.

Acute Disease↗
PubMed1994

Key modifiable factors in weight maintenance: fat intake, exercise, and weight cycling.

OBJECTIVE: This 6- to 42-month follow-up study of a 6-month worksite weight control intervention examined predictors of weight maintenance, with a focus on those that could be modified. SUBJECTS: Twenty-nine participants, 14 men and 15 women, from a behavior modification program completed follow-up measurements. MAIN OUTCOME MEASURES: Height, weight, waist-to-hip ratio, food and beverage intake from a 3-day food record, weight history, social support and physical activity were the main outcome measures. RESULTS: One third of the participants maintained their weight losses within 2 kg at follow-up, although all had higher relative weights at follow-up than immediately after the program. High daily fat consumption (r = .40) and reduced time in physical activity (r = .34) correlated with increased relative weight at follow-up (P < .05). APPLICATION: Because previous weight cycling was so strongly related to weight loss maintenance (r = .55), potential weight program participants should learn and practice the weight maintenance behaviors of reduced dietary fat and regular exercise, independently of and before weight reduction attempts.

Adult↗
PubMed1980

Serum factors modify the cellular requirement for Ca2+, K+, Mg2+, phosphate ions, and 2-oxocarboxylic acids for multiplication of normal human fibroblasts.

The rate of multiplication of a population of cultured human lung fibroblasts is determined by the level of common nutrients and serum factors in the medium. By application of the principles of Henri--Michaelis--Menten kinetic analysis to cell growth in vitro, the relationship between the level of a macromolecular fraction of serum that contains growth factors and the concentration of individual nutrient that is required to support a half-maximal rate of cell multiplication was explored. The requirement for the majority of individual nutrients is independent of the level of serum factors in the medium. This includes all 20 amino acids, glucose, purines, pyrimidines, polyamines, choline, and inositol. In contrast, serum factors determine the cellular requirement for Ca2+, K+, Mg2+, Pi, and 2-oxocarboxylic acids. These nutrients are most likely involved in cellular processes related to the mechanism by which growth factors in serum control the cell multiplication rate.

Animals↗
PubMed1993

Short-term heart rate variability and factors modifying the risk of coronary artery disease in a population sample.

Heart rate (HR) variability is impaired in chronic coronary artery disease (CAD), but the mechanism is not fully resolved. This study was aimed at assessing whether HR variability is influenced by the risk factors of CAD. Of a random sample of 120 subjects born in 1954, 88 (41 men and 47 women) could be included in the analyses. No subject had clinical heart disease. The subjects' physical activity, alcohol consumption and smoking were quantified by 2-month diary follow-up. Serum lipids and insulin were measured. The tests of HR variability included power spectral analysis and calculation of the root-mean-square difference of RR intervals at rest under controlled respiration. HR variability indexes were asymmetrically distributed and strongly HR-dependent, and therefore, all statistical tests were performed on log-transformed data adjusted to the population mean HR. Multiple regression analyses showed independent inverse relations between the root-mean-square RR difference and low-density lipoprotein (LDL) cholesterol (beta = -0.22; p = 0.008), and between the total RR-interval power and LDL cholesterol (beta = -0.25; p = 0.007), as well as smoking (beta = -0.19; p = 0.035). In women, alcohol use influenced the RR-interval root-mean-square difference (beta = 0.31; p = 0.015), total power (beta = 0.33; p = 0.017) and high-frequency power (beta = 0.26; p = 0.056). It is concluded that short-term HR variability is related inversely to LDL cholesterol and smoking in the population, and directly to alcohol use in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1983

Factors modifying the early nondiuretic vascular effects of furosemide in man. The possible role of renal prostaglandins.

Animal experiments have suggested that salt-balance, prostaglandin synthesis, and renal function are important determinants of the nondiuretic vascular effects of furosemide. To investigate the influence of these factors in humans, we studied 10 normal volunteers and five anephric patients. The volunteers were studied on three occasions: when on a 10 mEq/day sodium diet, on a 250 mEq/day sodium diet, and on a 10 mEq/day sodium diet with indomethacin, 200 mg/day. The anephric patients were studied immediately after dialysis. Plethysmographic methods were used to measure venous capacitance and blood flow in the calf before, and at 5, 10, and 15 minutes after furosemide, 80 mg, iv. Blood was obtained before and 15 minutes after furosemide for determination of plasma renin activity by radioimmunoassay and of plasma 6-keto-prostaglandin F1 alpha by chromatography-mass spectrometry. We found that furosemide significantly increased venous capacitance in the calf of the normal volunteers on a low salt diet. Indomethacin, high salt intake, or lack of renal function was sufficient to inhibit this effect. Plasma renin activity increased only in the group that had the increase in venous capacitance. Limb blood flow decreased gradually in the 15 minutes following administration of furosemide in the normal volunteers, regardless of salt balance or indomethacin, but remained unchanged in the anephric patients. Plasma 6-keto-prostaglandin F1 alpha was less than 30 pg/ml in all samples. Indomethacin concentration averaged 1.3 micrograms/ml in volunteers on the drug. To determine whether indomethacin, salt intake or renal function affected another venodilator, we studied an additional group of normal and uremic volunteers who received 0.6 mg nitroglycerin sublingually.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Interaction of factors modifying the radiosensitivity of dormant seeds: a review.

A review is presented on modification of radiation-induced effects in dormant plant seeds. Possible sources of discrepancy of data in the earlier literature are analysed. Approaches to the correct experimental study of mechanisms of interaction of environmental factors in the modification of radiobiological reactions are discussed. Progress in the radiation biology of plant seeds, achieved by precise control of experimental conditions, is considered.

Oxygen↗