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Biomedical subjects

A Khalil

Publications and source records attributed to A Khalil.

At least 91 records · Page 5Linked to original sources
PubMed1998

The relationship between serum levels of erythropoietin (EPO) and insulin-like growth factor-1 (ILGF-1) and hematocrit (HCT) in breast cancer patients receiving non-nephrotoxic chemotherapy.

OBJECTIVE: To evaluate the relationship between the hematocrit (HCT), serum erythropoietin (EPO) and insulin-like growth factor-1 (ILGF-1) levels in breast cancer patients receiving non-nephrotoxic chemotherapy. METHODS: Seventeen patients with stage II breast cancer were included. All received 6 cycles of non-nephrotoxic chemotherapy (cyclophosphamide, 5-fluorouracil and doxorubicin or methotrexate with or without tamoxifen). Insulin-like growth factor-1 and EPO levels were determined before and at the end of therapy. Serum EPO levels were determined by Enzyme linked- immunosorbant assay (ELISA) while those of ILGF- I by radioimmunoassay (RIA). RESULTS: A significant drop in mean HCT from 37.41%+/-0.77% to 35.18%+/-0.70%, associated with a significant decline in ILGF-1 levels from 92.1+/-15.48 ng/ml to 52.75+/-10.5 ng/ml at the end of the treatment was noted. This association became significant when patients receiving tamoxifen were excluded (r=0.69, p=0.02). The mean serum EPO levels increased significantly from 13.64+/-0.55 U/l to 19.44+/-3.18 U/l and correlated negatively with ILGF-1 level (r=-0.46, p=0.05). There was no significant relation between the serum EPO levels and HCT (r=-0.26, p=0.32). CONCLUSION: The current data show that ILGF-1 may play an important role in erythropoiesis and it correlates better than EPO with HCT in breast cancer patients receiving non-nephrotoxic chemotherapy.

Adenocarcinoma↗
PubMed1998

Metabolic monitoring during continuous warm- and cold-blood cardioplegia by means of myocardial tissue pH and PO2.

OBJECTIVES: To study the changes in myocardial tissue pH and PO2 during cold- and warm-blood cardioplegic arrests. DESIGN: An experimental study in dogs. METHODS: Nine dogs underwent the following procedures: 30 minutes with an empty heart beating under cardiopulmonary bypass (control period); 30 minutes of warm (33 degrees C) cardioplegic arrest with a 1:4 mix of crystalloid in blood solution administered continuously at 150 mL/min; 30 minutes of cold (15 degrees C) cardioplegic arrest; and 30 minutes of myocardial reperfusion. The cardioplegic blood solution was administered antegradely through the ascending aorta. MAIN OUTCOME MEASURES: Tissue pH and PO2. Arterial and coronary sinus oxygen content and myocardial consumption calculated. RESULTS: There was a modest but significant increase in the left anterior descending (LAD) and circumflex (Cx) tissue pH throughout the experiment. PmO2 in the LAD territory averaged 44 (7) mm Hg (mean and standard error of the mean) during the bypass period, 123 (23) mm Hg at the termination of warm cardioplegic arrest, 146 (28) mm Hg at the end of cold arrest and 66 (17) mm Hg after reperfusion. Oxygen consumption averaged 0.65 (0.15) mL/min during the bypass period, 0.3 (0.18) mL/min at the end of warm arrest, 0.25 (0.16) mL/min at the end of cold arrest and 0.45 (0.08) mL/min after reperfusion (p < 0.05). Oxygen delivery to the LAD territory was greater than myocardial oxygen consumption by an average of 2.02 (0.4) mL/min during bypass, 2.02 (0.62) mL/min after warm arrest, 2.12 (0.5) mL/min after cold arrest and 1.55 (0.25) mL/min after reperfusion (p > 0.05). CONCLUSIONS: During cardioplegic arrest, tissue PO2 increased and oxygen consumption decreased significantly, whereas tissue pH remained normal, suggesting that continuous warm- and cold-blood cardioplegia maintained aerobic glycolysis during myocardial arrest. Thus, the increase in myocardial tissue PmO2 during cardioplegic arrest reflects the decrease in myocardial oxygen consumption while maintaining oxygen supply.

Animals↗
PubMed1998

[Intramedullary metastases of bronchogenic carcinoma. Two cases].

Intramedullary metastases are uncommon. We report two cases in patients with small cell bronchogenic cancer. The clinical diagnosis was supported by T1 magnetic resonance imaging after gadolinium injection. A unique medullary metastasis associated with other metastatic localizations was observed in the first patient and multiple intramedullary metastases alone in the second. These secondary intramedullary localizations were highly sensitive to chemotherapy after the first monthly cure in the first patient and after the third in the second patient. We emphasize the importance of chemotherapy in such cases, usually associated with focal radiotherapy.

Aged↗
PubMed1998

Biological effects of elastin peptides.

Atherosclerosis is clearly one of the most life-threatening diseases and a major cause of morbidity and mortality in industrialized countries. Typical arterial lesions contain both cells originating from the blood (monocytes/macrophages) and locally-recruited smooth muscle cells. The structure of the artery is profoundly disrupted. Degradation of arterial elastin fibers results in loss of elasticity, and several elastin peptides are released that can interact with various cells via an increasingly well-characterized elastin receptor. Elastin receptor-mediated reactions that are of obvious physiologic importance include vasodilating effects and induction of mesenchymal cell adhesion to elastin fibers. Other effects are potentially harmful, such as increased elastase production, free radical release, induction of LDL oxidation, and stimulation of endogenous cholesterol production. These deleterious effects become predominant during aging as a result of chronic exposure of the elastin receptor to circulating elastin peptides. This review describes the results of recent investigations into the biological effects of elastin peptides.

Animals↗
PubMed1998

Artificial endometrial preparation for oocyte donation using synthetic estrogen and progestogen.

OBJECTIVE: To evaluate the outcome of an oocyte donation program using synthetic estrogen and progestational agents for uterine preparation. METHODS: Conjugated estrogen, 1.25 mg per day at increasing doses and dydrogesterone, a synthetic progestogen, 30 mg per day were used for uterine priming. All embryo transfers were done on day 2 of progestogen supplementation. RESULTS: The pregnancy rates were 38% per embryo transfer. The ongoing pregnancy rate was 31% with an abortion rate of 20%. CONCLUSION: Endometrial preparation in an oocyte donation program using orally administered synthetic estrogen and progestogen gives pregnancy rates comparable to those reported with natural products.

Adult↗
PubMed1998

Is there a safe anticoagulation protocol for pregnant women with prosthetic valves?

We studied the outcome of 41 pregnancies in an attempt to identify an appropriate and safe anticoagulant regimen for pregnant women with cardiac valve prosthesis. The cumulative number of events: (neonatal death, premature deliveries, intrauterine fetal death and spontaneous abortion) was 66.6%, 20%, 12.5% and 20% in the Coumadin, Fraxiparine, Heparin and porcine valve groups, respectively. We conclude that in pregnant women with mechanical heart valves, low molecular weight heparin therapy is a superior strategy compared to warfarin.

Adult↗
PubMed1998

Intrauterine insemination IUI: the effect of ovarian stimulation and infertility diagnosis on pregnancy outcome.

We determined the intrauterine insemination (IUI) pregnancy outcome in the same group of patients when applying different methods of ovulation induction. A group of patients with unexplained (no. 46) and male factor infertility (no. 101) consented to have the following treatment protocol at the American University of Beirut-Infertility Center: IUI to be performed in three natural ovulatory cycles in all patients, then in three clomiphene citrate (CC) stimulated cycles in the remaining non-pregnant patients, and then three cycles with controlled ovarian hyperstimulation (COH) in the remaining group. Of the total 147 patients 130, 138 and 123 underwent 273 natural, 278 CC and 266 COH IUI cycles, respectively. Semen processing for IUI was done by washing the sperm twice and using the swim-up technique. The chi-square test was used for statistical analysis. Pregnancy rate per cycle of IUI with COH (9.8%) was significantly higher than that of IUI in natural cycles (3.3%) but approached significance when compared to IUI with CC cycles (5.4%). Also unexplained infertility cases had a significantly higher pregnancy rate (58.7%) when compared to that of male factor cases (22.8%). IUI still has a place in the treatment of infertility due to selective causes. Combined with COH, IUI gives the best pregnancy rate although its benefit with natural or CC cycles remains obvious.

Adult↗
PubMed1998

Clomiphene citrate challenge test: cycle to cycle variability of cycle day 10 follicle stimulating hormone level.

The clomiphene citrate challenge test (CCCT), a means of assessing ovarian reserve, was shown by several studies to have an excellent predictive value for achieving conception in natural cycles, during ovulation induction and in-vitro fertilization cycles. Accordingly we elected to study the cycle to cycle variability of CCCT so as to determine the reliability of a single CCCT result. Two groups of patients were studied, the first (n = 40) were those patients who were performing the test because it was indicated, and the second (n = 24) were those who were receiving clomiphene citrate for ovulation induction. In both groups CCCT intercycle variability was significant in 75% of the cases, but this variability altered the prognostic values of the test in only 40% of the first group. In conclusion, our study showed a high percentage of intercycle variability of CCCT but further studies are needed to evaluate the influence of this variability on potential conception.

Adult↗
PubMed1997

Reciprocal protection of LDL and HDL oxidised by .OH free radicals in the presence of oxygen.

The aim of this work was to compare the behaviour of HDL oxidised by .OH or .OH/O2.- free radicals produced by gamma radiolysis in the absence or in the presence of LDL at the same concentration of 3 g x l(-1), in order to specify the possibility of reciprocal protection of HDL and LDL towards lipid peroxidation. This oxidation was quantitatively evaluated by the decrease of endogenous alpha-tocopherol and the formation of oxidation products (thiobarbituric acid-reactive substances and conjugated dienes) and by the determination of initial radiation yields. Our results demonstrated that HDL could be protected by LDL against in vitro radical oxidation only in the presence of oxygen (action of .OH/O2.- free radicals). This observation addresses new questions about the interaction between HDL and LDL, especially the possibility of a reciprocal protection.

Dose-Response Relationship, Radiation↗
PubMed1997

Changes in apoptosis of human polymorphonuclear granulocytes with aging.

Many alterations with aging occur at the cellular and organic levels in the immune system ultimately leading to a decrease in the immune response. Our aim in the present work was to study apoptosis of polymorphonuclear granulocytes (PMN) with aging under various stimulations since apoptosis might play an important role in several pathologies encountered with aging. The PMN of healthy young (20-25 years) and elderly (65-85 years) subjects were examined after 24 h of sterile culture with and without stimulation. The stimulating agents included: phorbol myristate acetate (PMA), hydrogen peroxide (H2O2), N-formyl-methionyl-leucyl phenylalanine (FMLP), granulocyte-macrophage colony stimulating factor (GM-CSF), reduced glutathione (GSH), lipopolysaccharide (LPS) and interleukin 2 (IL-2). Apoptosis was assessed by traditional staining of the plates, by flow cytometric staining and DNA gel electrophoresis. It was found that without stimulation the susceptibility of PMN to apoptosis was slightly increased with aging. Under various stimulations, such as PMA. H2O2, apoptosis was almost 100%, while the treatment by FMLP, oxLDL and GSH did not change its extent in PMN obtained either from young or elderly subjects. Marked age-related changes were observed in the extent of apoptosis under stimulation with GM-CSF, IL-2 and LPS. These agents were able to significantly prevent apoptosis in PMN of young subjects, while only the GM-CSF was able to slightly modulate it in neutrophils of elderly subjects. From these results, we suggest that changes in apoptosis of PMN with aging could play a role in the increased incidence of certain immune system related pathologies of aging, such as cancer, infections and autoimmune disorders.

Adult↗
PubMed1997

Ecological determinants of intestinal parasitic infections among pre-school children in an urban squatter settlement of Egypt.

Population growth in Egypt has led to the creation of several urban squatter settlements. The aim of the present work was to study the prevalence and some potential risk factors of intestinal parasitic infections among preschool children in a randomly chosen urban squatter settlement in Alexandria, Egypt. A house to house cross-sectional survey was conducted during late 1995. Data were collected through questionnaire interview regarding socio-demographic and environmental conditions from 1324 families residing in the settlement. Stool samples were collected from 658 preschool children below 5 years of age and examined for intestinal parasites. Overall, the prevalence rates of infections with the intestinal Helminths and Protozoa were 47.3 and 31.5 per cent, respectively, which were very high compared to previously reported figures for this age group in Egypt. Multiple logistic regression analysis showed that certain groups of preschool children were much more likely to develop the infection with both groups of intestinal parasites. They included children over 2 years of age (OR = 2.75, 95 per cent CI = 1.23-4.12 and OR = 2.65, 95 per cent CI = 1.70-3.45 for Helminths and Protozoa, respectively), whose families had pools of sewage around houses (OR = 2.13, 95 per cent CI = 1.22-3.19 and OR = 2.83, 95 per cent CI = 1.45-3.95 for helminths and protozoa, respectively) and shared toilets with another family (OR = 1.95, 95 per cent CI = 1.38-2.75 and OR = 1.65, 95 per cent CI = 1.06-2.58 for Helminths and Protozoa, respectively). In addition, certain groups of children were much likely to develop protozoal infections including children whose families lacked tap water inside dwelling (OR = 1.85, 95 per cent CI = 1.26-2.77) and disposed human excreta in septic tank very close to the dwelling (OR = 2.17, 95 per cent CI = 1.43-3.75). Efforts to reduce intestinal parasites should focus on reducing exposures. Improvement in domestic water supplies with the introduction of piped sewerage system is likely to have a marked decreasing effect on the prevalence of infection among this age group.

Age Distribution↗
PubMed1997

Helicobacter pylori and uremic gastritis: a histopathologic study and a correlation with endoscopic and bacteriologic findings.

In this work 70 asymptomatic uremic patients under maintenance hemodialysis in our institution underwent upper-gastrointestinal endoscopy as part of a routine investigation prior to kidney transplantation. Their endoscopic findings were scored and antral mucosal biopsies were obtained and subjected to histopathologic and bacteriologic assessment. Bacteriologic examination included culture, rapid urease test, and microscopic examination for detection of Helicobacter pylori. Histopathologic examination of the gastric mucosa showed chronic superficial gastritis in 52%, atrophic gastritis in 5.7% and intestinal metaplasia in 37% of the cases. Of the cases with superficial gastritis, 5 showed in addition gastric mucosal dysplastic changes. There was no correlation between the histopathologic and endoscopic findings. Nevertheless, there was a significant association between histopathologic changes and H. pylori infection (p = 0.0001). All cases with atrophic gastritis showed H. pylori, and of 24 cases with chronic active superficial gastritis. H. pylori was detected in 18, while it was detected in only 2 of 13 cases with chronic inactive superficial gastritis and in 4 of 29 cases with normal antral mucosal biopsies. Among different variables in dialysis patients, only patients' ages were found to have significant association with H. pylori infection (p < 0.03). We have concluded that in asymptomatic uremic patients under maintenance hemodialysis, relying only on endoscopy for critical assessment of the upper gastrointestinal tract is unsatisfactory and histopathologic examination of the antral mucosal biopsies is mandatory. Chronic superficial gastritis and atrophic gastritis should be expected in up to 60% of the patients, and there is a strong association between H. pylori infection and gastritis.

Adult↗
PubMed1997

Myocardial distribution of cardioplegia administered by antegrade and retrograde routes to ischemic myocardium.

OBJECTIVE: To study the distribution of a cardioplegic solution delivered by antegrade and retrograde routes to ischemic myocardium. Retrograde administration has been suggested to improve protection of the ischemic myocardium. However, there are insufficient data on perfusion of ischemic and necrotic zones by the retrograde route. DESIGN: A laboratory study in dogs. METHOD: In 12 dogs, 500 mL of hyperkalemic crystalloid cardioplegia containing 0.5 mCi of thallium-201 was injected antegradely or retrogradely through the coronary sinus after 3 hours of occlusion and 2 hours of reperfusion of the left anterior descending coronary artery. Myocardial distribution of the cardioplegic solution was measured by computer planimetry in the normally perfused zone, in the ischemic area and in the necrotic zone. RESULTS: The mean (and standard deviation) area at risk of ischemia (% of the left ventricle) delimited by Evans blue perfusion was smaller in dogs receiving a retrograde injection than in those receiving an antegrade injection (34% [3%] v. 42% [4%], p = 0.15). The infarct size (% of the area at risk indicated by triphenyltetrazolium dye) averaged 25% (11%) and 20% (7%) respectively (p = 0.36). The ratio of thallium-201 activity in ischemic to normal myocardium averaged 76% (13%) in the retrograde and 89 (12%) in the antegrade groups (p = 0.75). The ratio of thallium activity of infarct to normal myocardium averaged 56% (8%) in the retrograde group and 93% (19%) in the antegrade group (p = 0.18). Large areas of hypoactivity in the left ventricular myocardium were noted on scintigraphic imaging in all dogs that received retrograde perfusion. CONCLUSIONS: The retrograde injection of cardioplegia through the coronary sinus does not improve the distribution of cardioplegic solution in the acutely ischemic myocardial area nor in the zone of acute infarction in the dog. Because some cells may remain viable in the border zone and into the necrotic area, retrograde cardioplegia may result in suboptimal protection and incomplete prevention of further damage to the myocardium.

Animals↗
PubMed1997

Oxidation of human high-density lipoproteins by .OH and .OH/O(.-)2 free radicals.

The aim of this work was to specify the mechanisms involved in the radical oxidation of human high-density lipoprotein (HDL) and to compare these mechanisms with those described previously for the oxidation of low-density lipoprotein (LDL) under the same experimental conditions (Bonnefont-Rousselot et al., Radiat, Res. 134, 271-282, 1993). The oxidation of HDL, initiated by .OH or .OH/O(.-)2 free radicals from gamma radiolysis of water, was evaluated as a function of increasing radiation dose by analyzing quantitatively the decrease of endogenous alpha-tocopherol and the formation of oxidation products (thiobarbituric acid-reactive substances and conjugated dienes). All qualitative conclusions were supported by quantitative data (radiation yields and concentrations of the oxidation markers at high radiation doses) and by the mechanisms of the kinetics, .OH free radicals in the absence of oxygen were less efficient in initiating HDL oxidation than in the presence of oxygen (action of .OH/O(.-)2 free radicals), which was in agreement with the enhancement of the action of .OH free radicals by oxygen. The remaining significant level of vitamin E in HDLs at high radiation doses in the absence of oxygen could be explained by a regeneration of vitamin E by an oxidation product that was able to reduce the alpha-tocopheroxyl radical. The yields related to the decrease in the vitamin E content of HDLs after exposure to radiation with .OH or .OH/O(.-)2 free radicals were slightly higher than those obtained previously in LDLs under similar experimental conditions. Moreover, in the presence of oxygen, .OH free radicals led to a lower formation of thiobarbituric acid-reactive substances in HDLs than in LDLs. Such discrepancies in the behavior of these two lipoprotein fractions could be related to the differences in the chemical composition of HDLs and LDLs.

Free Radicals↗
PubMed1997

Urinary estrogen metabolites and breast cancer: a case-control study.

Preliminary studies suggest that the estrogen metabolite 16 alpha-hydroxyestrone is associated with breast cancer, whereas 2-hydroxyestrone is not. However, epidemiological studies evaluating this relationship and taking established risk factors for breast cancer into account are lacking. The purpose of this study was to examine the association of the ratio of the urinary estrogen metabolites (2-hydroxyestrone and 16 alpha-hydroxyestrone) and of the individual metabolites with breast cancer. A spot urine sample, a brief history, and clinical data were collected from breast cancer cases (n = 42) and from women coming to the hospital for a routine mammogram or attending a free breast cancer screening (n = 64). 2-Hydroxyestrone and 16 alpha-hydroxyestrone were measured by enzyme immunoassay, and the estrogen metabolite ratio (EMR; 2-hydroxyestrone:16 alpha-hydroxyestrone) was computed. Cases and controls were similar in terms of age (mean age of cases, 53.8 +/- 15.1 years, versus 54.2 +/- 10.4 years for controls; P = 0.9) and demographics. Mean EMR was not associated with breast cancer overall (1.67 +/- 0.80 versus 1.72 +/- 0.66; P = 0.7). However, in postmenopausal women, the mean EMR was significantly lower in cases compared to controls (1.41 +/- 0.73 versus 1.81 +/- 0.71; P = 0.05). The multivariate adjusted odds ratios for the intermediate and lowest tertiles of the EMR relative to the highest among postmenopausal women were 9.73 (95% confidence interval, 1.27-74.84) and 32.74 (95% confidence interval, 3.36-319.09), respectively. The test for trend was highly significant (P = 0.003). Analyses of the individual metabolites indicated that 16 alpha-hydroxyestrone was a strong risk factor. The EMR did not show any consistent associations with age, race/ethnicity, age at first birth, parity, body mass index, family history of breast cancer, smoking, or alcohol intake. These data suggest a strong, inverse association of the EMR and a strong positive association of 16 alpha-hydroxyestrone with breast cancer in postmenopausal women. Larger studies are needed to confirm these results and to assess the relationship of the EMR and of the individual metabolites with breast cancer, with attention to menopausal status and clinical factors and with adjustment for known breast cancer risk factors.

Adult↗