Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Effect of chitosan nanoparticles on microtensile bond strength of resin composite to dentin: an in vitro study / Efeito de nanopartículas de quitosana na resistência a união por microtração da resina composta à dentina: um estudo in vitro

Objective: The purpose of this study was to evaluate the effect of chitosan nanoparticles on microtensile bond strength of resin composite to dentin using self etch adhesive after aging. Material and Methods: A total number of 90 freshly extracted, sound human molar teeth. Flat tooth surface was gained after cut of the occlusal surface. Three main groups according to pretreatment of dentin before adhesive application; 0.2 % chitosan, 2.5 % chitosan and no treatment control group. Universal self etch adhesive were applied according to manufacture instruction and 4 mm of Feltik Z250 xt composite. Storage of specimens for 1 day, 3 months and 6 months in 37O C distilled water. After that, the tooth was sectioned to beams of 1 mm x8 mm sticks for microtensile bond strength test using universal testing machine. Scanning electron microscope (SEM) was used to evalute the effect of chitosan nanoparticles on dentin and smear layer. Kruskal-Wallis test was used to compare between the three groups as well as the three aging periods. Dunn's test was used for pair-wise comparisons. The significance level was set at P ≤ 0.05. Results: chitosan 0.2% is statistically significant increase in bond strength than chitosan 2.5% and control in one day group. Three months chitosan 0.2 % groups have statistically significant increase in bond strength than chitosan 2.5%. It was found in 6 months that control and chitosan 0.2 % have statistically significant increase in bond strength than chitosan 2.5%. There was statistically significant difference found between the three studied groups regarding bond strength at different storage times . Conclusion: Microtensile bond strength was influenced by different chitosan concentration. Different aging periods had no effect on the microtensile bond strength without application of chitosan and with application of 2.5% chitosan concentration. (AU)

Introdução: O objetivo deste estudo foi avaliar o efeito das nanopartículas de quitosana na resistência da microtração de união do compósito de resina à dentina usando adesivo autocondicionante após o envelhecimento. Material e Métodos: Foram utilizados um total de 90 dentes molares humanos extraídos e sadios. A superfície plana do dente foi obtida após o corte da superfície oclusal. Os dentes foram divididos em três grupos principais de acordo com o pré-tratamento da dentina e antes da aplicação do adesivo: 0,2% de quitosana, 2,5% de quitosana e nenhum tratamento foi utilizado no grupo controle. O adesivo autocondicionante universal foi aplicado de acordo com as instruções do fabricante e 4 mm de composito Feltik Z250 xt foi inserido. O armazenamento de amostras foi realizado por 1 dia, 3 meses e 6 meses em água destilada a 37 °C. Depois disso, o dente foi seccionado em peças de 1 mm x 8 mm para teste de resistência de união por microtração, utilizando máquina de teste universal. Microscópio eletrônico de varredura (MEV) foi usado para avaliar o efeito das nanopartículas de quitosana na dentina e na camada de smear layer. O teste de Kruskal-Wallis foi utilizado para comparar os três grupos e os três períodos de envelhecimento. O teste de Dunn foi usado para comparação pareada dos grupos. O nível de significância foi estabelecido em P ≤ 0,05. (AU)

Molecular and Biochemical Study of Superoxide Dismutase Gene Polymorphisms in Egyptian Patients with Type 2 Diabetes Mellitus with and without Retinopathy.

Aims: This study aims to determine the antioxidant enzyme EC-SOD polymorphisms in Egyptian patients with type 2 diabetes mellitus with and without retinopathy, and its association with other biochemical changes to assess whether decreased SOD activity is associated with the development of diabetic complications. Study Design: Cross-sectional study. Place and Duration of Study: Department of Medicine Al-Hussein University Hospital, Cairo, Egypt, between May 2010 and April 2011. Methodology: The present study investigated the relationship among diabetes mellitus, lipid profiles, SOD activity, ESR, and CRP in the blood of 40 patients with type 2 diabetes with and without retinopathy and 20 healthy control subjects. The mean age of the diabetic patients was similar to that of control. The mean duration of the disease was 3.53 ± 1.17 years (1–5 years) in patients with type 2 diabetes without retinopathy and 18.7 ± 3.1 with retinopathy. Also we studied Arg213Gly dimorphism of the EC-SOD gene in type 2 diabetic patients with and without retinopathy and control persons using the PCR technique. Results: Superoxide dismutase (SOD) level was significantly decreased in diabetics and more markedly decrease in those with retinopathy. Total cholesterol (CHOL), triglyceride (TG) and low-density lipoprotein-cholesterol (LDL-c) levels were significantly increased in diabetics and more markedly increased in those with retinopathy compared with the control level. Genotype distribution of the EC-SOD in diabetic patients with and without retinopathy differed from normal individuals, as the argentines-to-glycine amino acid substitution was higher in diabetic patients compared with the normal individuals. Conclusion: The present study revealed that hyperglycemia produced marked oxidation impact as evidenced by a significant increase in lipid profile, lipid per oxidation products, as well as a significant decrease in the total SOD activity. Moreover, it showed that the genotype distribution of the EC-SOD was differed as the arginine-to-glycine amino acid substitution was higher in diabetic patients with and without retinopathy compared with the control individuals. This report emphasizes the important role of superoxide dismutase and its genotype distribution in diabetic patients with and without retinopathy, and hence the need for antioxidant supplements to delay the severity of diabetic retinopathy.

Effects of tranexamic acid during endoscopic sinus surgery in children

This study was conducted to evaluate the effect of tranexamic acid [TA] on the intra-operative bleeding during the functional endoscopic sinus surgery [FESS] in children. A total of 100 children recruited to undergo FESS were randomized into two groups. Group I: Was given just after induction, intra-venous 25 mg/kg TA diluted in 10 ml of normal saline. Group II: Was given 10 ml of normal saline. Non-invasive blood pressure, heart rate, and quality of the surgical field were estimated every 15 min. Volume of bleeding and duration of the surgical procedure were recorded. Surgical field quality after 15 min revealed that seven patients in group I had minimal bleeding versus no one in group II, P=0.006. Meanwhile, 35 patients in group I had mild bleeding versus 26 patients in group II, P=0.064. Higher number of patients in group II than in group I had moderate bleeding, P=0006. Also, at 30 min, revealed that 10 patients in group I had minimal bleeding versus one patient in group II, P=0.004. Meanwhile, 37 patients in group I had mild bleeding versus 28 patients in group II, P=0.059. Higher number of patients in group II than in group I had moderate bleeding, P<0001. Duration of the surgeries and volume of bleeding were significantly less in tranexamic group than the placebo group, P<0.0001. Single intra-venous bolus dose of tranexamic in children during the FESS improves quality of surgical field, reduces intra-operative bleeding, and duration of surgery

Effects of preoperative beta-blocker on blood loss and blood transfusion during spinal surgeries with sodium nitroprusside-controlled hypotension

The present study sought to determine whether premedication with oral beta-blocker before hypotensive anesthesia with sodium nitroprusside could improve the quality of surgical field, decrease the blood loss, and decrease the need for homologous blood transfusion and duration of surgery. Eighty patients scheduled for spinal fixation surgery were included in a prospective, randomized, double-blinded study. Patients were classified into two groups: Group I received oral atenolol 50 mg twice one day before surgery; and Group II received placebo tablets identical in appearance to atenolol tablets for the same period and interval. All patients in both the groups received intraoperative sodium nitroprusside [SNP] as a hypotensive agent. Hemodynamic variables, amount of sodium nitroprusside used, quality of surgical field, and the amount of homologous blood transfusion and blood loss were compared between groups. Heart rate and amount of SNP used were significantly less [P < 0.0001] in the atenolol group, but no significant difference was found in intraoperative mean arterial blood pressure [MABP] between the two groups. The time of surgeries was significantly shorter in Group I than in Group II [185 +/- 15.21 vs 225 +/- 12.61 min], P < 0.0001. The quality of surgical field was better in Group I than in Group II in all times of measurements, P < 0.0001. The amount of blood loss and the amount of packed red blood cells transfused were significantly less in Group I than in Group II, P < 0.0001. No clinically significant complications were observed in either group. Premedication with oral atenolol 50 mg twice/day for one day before hypotensive anesthesia with SNP during spinal surgeries seems to be clinically safe and effective to reduce heart rate, amount of SNP used, amount of blood loss, and amount of blood transfused with better quality of surgical field

A Pilot Study For Evaluating Egyptian Health Websites: Technical And Ethical Perspectives.

Background: The growing popularity of the Internet has made it easier and faster to find health information. Much of this information is valuable; however, the Internet also allows rapid and widespread distribution of false and misleading information. Aim of the work: To evaluate some of the Egyptian health websites from the Technical and Ethical perspectives and to compare the reliability of the different types of Egyptian health websites. Materials and Methods: This is a descriptive study. Search engines (eg. Google.com and Yahoo.com) were thoroughly searched for Egyptian health websites. Some of these websites were not accessible. Out of thirty two health websites, thirteen internet health websites were randomly selected and evaluated twice in this study. They were classified into 4 categories, official, professional, educational and private. The tool used in this study was a questionnaire developed by the research team depending on EHealth code of ethics, 2000 and international technical guidelines. The questionnaire consists of two main categories (technical and ethical). The technical evaluation includes (authority, objectivity, coverage, currency, design, privacy and security). The ethical evaluation includes (quality of information, informed consent and professionalism). A score for the questionnaire was developed by the research team to assess the websites. All statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 11.0. Comparisons between ethical and technical categories were done using the student’s t-test and ANOVA test for continuous variables and Pearson’s Chi square test for categorical variables. Results: On evaluating the quality of information of the health websites, it is noticed that in 92.3% of the sample, medical care is provided by professionals and their information based on scientific studies. Around forty six percent (46.2%) of the health websites do not mention the date of publication, date of recent update and the source of the information. Concerning the professionalism, 100% of the sample obeys laws and regulation in identifying themselves and mentioning the limitation of online consultation. 76.95% of the sample states clearly the purpose of the health website. Only 38.5% of them were recently updated. Privacy policy evaluation shows that 33.3% mentions if the system prevents unauthorized access to personal data while only 16.7% states how the user's personal data is stored and for how long. There is a statistically a significant change (p<0.05) on comparing the quality of information between the different types of websites. Both of the official and professional websites are better than educational and private websites. Conclusion: Some of the Egyptian health websites are reliable and up-to-date; some are not. Most of them are technically satisfactory. Evaluation of the health websites faces difficulties due to continuous updating. Recommendations: we should teach the health seekers to trust what they see or read on the Internet only if they can validate the source of the information and the authors and contributors should always be identified. It is necessary to establish mechanisms of Accreditation of Egyptian Health Websites. E-Health Ethics Training is very essential for the health professionals.

Acute normovolemic hemodilution versus controlled hypotensive anesthesia in major orthopedic surgery

The purpose of this study was to investigate the efficacy and safety of controlled hypotension versus ANH as blood conservation methods during major orthopedic surgery. Forty patients, assigned to receive either ANH [HT= 30%] or controlled hypotension. General anesthesia was induced by fentanyl 2micro gm/kg intravenously, thiopental Na 5mg/kg intravenously and atracurim 0.5mg/kg. After induction of anesthesia but before surgery, the patients were classified into two groups according to the technique of blood conservation used: group I [20 patients] acute normovolemic hemodilution. The volume of blood withdrawn has been replaced simultaneously by infusion of identical volume of hydroxyethyl starch 6% in order to maintain normovolemia. Group II [20patients]: controlled hypotensive anesthesia. A mean of 1000 ml blood was predonated [20% of the total blood volume] in hemodilutio group. Blood loss was, significantly higher in ANH group. The total loss was 1500mL [ANH] vs. 1200 mL [in hypotensive group], [p < 0.05]. The average amount of blood transfusion was 262.5 ml [ANH group] vs. 187.5 ml [hypotensive group]. 50% went through surgery without receiving blood [ANH] vs. 60% [hypotensive group]. No renal, neurological or cardiopulmonary complications were registered. Also there was slight but significant metabolic acidosis. The acidosis was metabolic in origin because PaCO2 was kept constant and [Bic] and [BE] decreased significantly and it was not lactic acidosis as serum lactate remains within normal limit. It is considered as hyperchloermic metabolic acidosis as serum chloride significantly increased. Both ANH and hypotensive anesthesia can be used safely in patients undergo major orthopedic surgery however, Deliberate hypotension was the most effective means of reducing intraoperative bleeding and the time for this procedure was shorter than for normovolaemic haemodilution combined with autotransfusion. Also there was slight but significant metabolic acidosis

Prevalence of malnutrition among patients on admission to a pediatric hospital

At the time of admission to the pediatric hospital of Cairo University 150 Children whose age ranged form birth to 12 years; 106 males and 44 females complaining of acute or chronic medical illness, were examined to assess their nutrition status. The aim was to know the extent of malnutrition problem among them. Their weight and length/ height were obtained as well as blood hemoglobin, serum albumin and total lymphocyte count. Most of the patients were coming from families of low socioeconomic class. The study revealed high prevalence of malnutrition and anemia together with low blood lymphocytic count. This may have predisposed to their medical illness. Hence, it is recommended to supply proper nutrition care to help limiting the period of hospital stay

Nutrition status and serum uric acid levels in adult men and its relation to atherosclerosis

The study aimed to investigate the relationship between serum uric acid [SUA] concentration and atherosclerosis. Forty five adult men aged 40-60 years were volunteers from three different institutions in Cairo. They were divided into 3 equal groups: one group being clinically healthy and normal serum uric acid was taken as control. The second group suffered from hyperlipidemia and hyperuricemia. The third group sufferred from hyperuricemia only. All groups were subjected to socioeconomic data collection, dietary and anthropometric [weights and heights] assessment, chemical analysis included serum levels of uric acid, lipid profile and platelets count. The results showed that all groups had their requirements from total calories and total proteins but low in carbohydrates. Group II had high fat and purine intake. It also showed positive correlation between serum uric acid and each of protein, fat and purine intake and the highest atherogenic index. Also there was positive correlation between serum uric acid and blood levels of triglycerides and cholesterol and negative correlation with blood platelets. Hence, it is recommended to have balanced diet with reasonable amount of foods rich in purine as prophylactic measure against atherosclerosis

Study of the mechanism underlying the prokinetic action of erythromycin on lower esophageal sphincter pressure in dogs

Erythromycin [EM] and a number of its derivatives exhibit prokinetic properties. In particular, the drug increases the contractile activity of smooth muscles of esophagus and promotes gastric emptying in both health and disease. The drug enhances esophageal and gastric motility by acting as a motilin agonist. The aim of the study was to evaluate the effect of low dose of EM, as a prokinetic agent, on the lower esophageal sphincter pressure [LESP] and to study the receptors involved in the mediation of the prokinetic action of EM. The study was carried out on 30 adult healthy dogs [10-15 kg] divided into five groups, each group consisted of 6 dogs. The studied groups were: I: a control group [placebo treated], II: an erythromycin treated group [EM gp] [7 mg/kg b.w. by i.v.i], and three groups III, IV, V that were treated with EM [7 mg/kg b.w. i.v.L preceded by either atropine [a muscarinic blocker] in a dose of 40 micro ag/kg b.w. i.v.i., ondansetrone [5 HT3 antagonist] in a dose of 0.1 mg/kg b.w. i.v.i or metoclopramide [dopamine receptor type 2 antagonist] in a dose of 150 micro g/kg b.w. i.v.i. respectively. After an over night fasting, basal recording of LESP was carried out in each group by an esophageal manometer connected to a pressure transducer. LESP was recorded for all animals in all groups fifteen minutes after the end of the predescribed treatments. Data obtained showed that EM significantly increased the resting LESP. Pretreatment with either atropine or ondansetrone totally prevented the increase in LESP induced by EM. However, pretreatment with metoclopramide failed to prevent the increase in LESP induced by EM. The findings suggest that EM in a low, subantimicrobial dose has a prokinetic action on the lower esophageal sphincter. It was found that this prokinetic action is exerted most probably by stimulating cholinergic pathway and strongly suggested that 5 HT3 receptors are involved in this process. Meanwhile, the dopaminergic receptors seem to have no role in the mediation of this prokinetic action of EM. It is hoped that this prokinetic action of EM could be of a particular benefit in the improvement of GIT motility disorders. However this warrants further investigation to help more understanding of cellular mechanisms regarding that effect of EM

Serum leptin elevation in obese women with polycystic ovary syndrome: a continuing controversy

The full pathogenesis of the polycystic ovary syndrome is not yet known. Heterogeneity is a confounding factor and several links between the diverse abnormalities seen in these cases are still missing. Obesity was one of the triad mentioned in the original description, and is an important differentiating factor between the two phenotypes of the syndrome namely obese and non-obese. Leptin is suggested to contribute to the pathogenesis of PCOS in obese subjects. In this study leptin levels were significantly different between obese and non-obese subjects, and were significantly different between insulin resistant and non-insulin resistant PCOS suggesting that body mass index and insulin resistance were the two main factors governing serum leptin levels

Systemic arterial compliance and cardiac function in young patients with type 1 diabetes mellitus

Arterial elastic properties are altered with increasing age and in various disease states, including non-insulin-dependent diabetes mellitus [NIDDM]. Whether young patients with insulin-dependent diabetes mellitus [IDDM] have reduced arterial compliance before developing endothelial dysfunction or overt micro-and macrovacular disease is unclear. A total of 30 young patients with IDDM and 20 healthy subjects underwent [1] systemic arterial compliance determination by vessel wall movement detector system [complior], [2] common carotid artery-intimal medial thickness [IMT] by B-mode ultrasound, [3] echocardiographic assessment of systolic and diastolic left ventricular function, [4] brachial artery responses to reactive hyperemia [with increased flow causing endothelium-dependent dilatation] and sublingual isosorbide dinitrate [causing endothelium-independent dilatation], [5] lipid profile and hemoglobin A1c, and [6] 24-h urine collection for albumin excretion rate [AER] Arterial compliance was 23.1% lower in IDDM subjects compared with control subjects [4.86 +/- 0.445 vs. 6.32 +/- 0.889 cm4/dyn. 10[-7], P = 0.000]. IMT and all indexes of systolic and diastolic ventricular function were similar in both groups. Flow-mediated dilatation [FMD] was significantly impaired in diabetic patients. The ratio of FMD to isosorbide dinitrate induced dilatation was significantly lower in the diabetic subjects indicating that impaired dilatation to increased flow was out of the proportion to the impairment of the isosorbide dinitrate response in these subjects. The median AER was 5.98 micro g/min in the DM group and 2.92 micro g/min in the control group [P = 0.005]. Hemoglobin A1c correlated inversely with compliance [r = -0.993, P = 0.000], FMD [r = -0.929, P = 0.000] and isosorbide dinitrate -induced dilatation [r = -0.938, P = 0.000] in diabetic patients A significant positive correlation was found between arterial compliance and both FMD [r = 0.900, P = 0.000] and isosorbide dinitrate-mediated dilatation [r = 0.911, P= 0.000]. This study indicates that early changes in macrovascular function namely impaired arterial compliance and reactivity, may precede abnormalities in cardiac function or in arterial IMT in young individuals with short duration type 1 DM. Arterial compliance and reactivity may prove to be predictive of future atherosclerotic complications in patients with diabetes; therefore the noninvasive long-term assessment of arterial physiology and its relationship to the progression of cardiovascular risk factors is required. The present study also supports a relationship between metabolic control, arterial compliance and endothelial function

Evaluation of some haemostatic markers in normal pregnancies and pregnancies complicated by preeclampsia or eclampsia

To establish the plasma evolution of P-selectin, plateletfactor4 [Pf4], prothrombin fragments 1+2 [F1+2], thrombin antithrombin complex [TAT], von Willebrand factor [vWF] and blood platelet count during normal pregnancy, preeclampsia and eclampsia and to determine which are the most relevant and accurate to perform in clinical practice for estimating the severity of preeclampsia. Twenty patients with mild preeclampsia, twenty patients with severe preeclampsia, ten eclamptic cases and ten normotensive pregnant women were included in the study. All cases and controls were with gestational age ranging between 28 and 38 weeks. All five markers increased and platelet count decreased in the severe preeclampsia and eclampsia groups. A highly significant negative correlation was found between platelet count and both P-selectin and Pf4 in the three studied hypertensive groups. Moving from mild to severe preeclampsia to eclampsia, vWF and Pf4 showed an increasingly abnormal results. Pf4 was the only haemostatic marker elevated in the mild preeclampsia group as compared with the normal pregnant group [P=0.000]. [1] Platelet activation may play an important role in the pathogenesis of preeclampsia; [2] Plasma levels of vWF and Pf4 could reflect the severity of this disease, [3] Pf4 appears to be an interesting marker for detecting early alterations in the haemostatic system in pregnancies complicated by preeclampsia. It seems that measurements of haemostatic markers in patients with preeclampsia may have prognostic value in determining the outcome of pregnancy in this pregnancy disorder. They offer possibilities of early assessment of therapeutic approaches aimed at limiting vascular endothelial damage and platelet activation

Clinical significance of measurements of serum and urinary thrombomodulin and serum e-selectin in diabetic patients with and without complications

Serum and urinary levels of soluble thrombomodulin [TM] and the serum levels of the soluble leucocyte adhesion molecule E-selectin, were measured in 80 diabelic patients. Fourty patients with insulm-dependent diabetes mellitus [IDDM] were divided into 20 non-complicated patients [group I] and 20 complicated patients [group II]. Ten age-matched healthy subjects were used as a control [group III] for the IDDM patients. Another 40 patients with non-insulin-dependent diabetes mellitus [NIDDM] comprised 20 non-complicated patients [group IV] and 20 complicated patients [group V]. Ten more age-matched healthy subjects were selected as a control [group VI] for the NIDDM patients. Serum and urinary concentrations of TM were significantly higher in diabetic patients compared with controls. Moreover, serum and urinary TM levels were significantly increased in complicated IDDM and NIDDM patients compared with the non-complicaied patients and the control subjects. Similarly, serum concentrations of E-selectin were found to be significantly higher in complicated diabetic patients versus the non-complicated patients and the control groups. In all diabetic patients of the four studied groups and in each separale group, serum and urinary levels of TM and serum E-selectin concentrations correlated positively with the duration of diabetes, fasting and postprandial blood glucose, HbA[IC] and urinary albumin excretion. A significant positive correlation was also found between urinary and serum levels of TM in the four studied groups of patients. Furthermore, serum and urinary levels of TM together with serum E-selectin concentrations correlated positively with the frequency of complications in complicated IDDM and NIDDM patients. The results suggest that serum and urinary TM levels could be a sensitive and predictive marker for the generalized vascular endothelial mjury induced by hyperglycemia and/or premicroangiopathy in diabetic patients. The present data point to a functional role for the soluble leucocyte adhesion molecule E-selectin in the development and progressions! complications in diabetic patients. The results also indicate that the concentrations of TM and E-selectin may be retated to metabolic control

Central versus peripheral actions of adrenomedullin in a hypertensive rat model

Adrenomedullin [AM] is a peptide with potent vasorelaxing and natriuretic properties originally isolated from human pheochromocytoma. It may function as a circulating hormone that is involved in the regulation of cardiovascular system, renal function and hormone secretion. It has been observed that the hypotensive effect of AM in the periphery is not matched by a similar effect when injected centrally. The mechanisms involved in the peripheral hypotensive and central hypertensive actions of AM in normal rats are controversial and diverse; moreover in hypertension the underlying mechanisms are not tackled till now. 120 male albino rats were used in this study to assess the mechanisms involved in the peripheral versus the central actions of AM in the rat model. Hypertension was induced in 90 rats using NG-nitro-L-arginine ester [L-NAME] and ten normal rats were used as a control group. The peripheral and central actions of AM were tested in the hypertensive rats and in another 20 normal rats. The 90 hypertensive rats were divided into nine equal groups. Peripherally, AM was either injected alone [group I-A] or following a two-weeks of oral administration of prazosin [0.55 mg/kg/day], propranolol [14.4 mg/kg/day], valsartan [14.4 mg/kg/day] or isosorbide dinitrate [10.4 mg/kg/day] [groups II-A to V-A respectively]. Centrally, AM was either injected intracerebroventricularly [icv] alone [group I-B] or following a bolus icv injection of saralain [10 micro g] [group II-B] or after a two-weeks of oral administration of prazosin [0.55 mg/kg/day] or clonidine [18 micro g/kg/day] [group III-B and IV-B respectively]. Mean arterial blood pressure [MABP], plasma renin activity [PRA] and aldosterone level values were compared before and after AM injection in the same rate of each group. A 40.6% drop in MABP was elicited in normal rats injected peripherally with AM. This drop was attenuated to 18.6% in L-NAME hypertensive rats. The percent age drop in MABP in hypertensive rats pretreated with isosorbide dinitrate [43.3%] was comparable to that observed in normal rats when AM was injected intravenously to both groups [p=0.999]. A significant decrease in PRA and aldosterone level was produced in hypertensive rats pretreated with various drugs following the peripheral administration of AM as compared to their pre-injection values. On the other hand, a significant further increase in MABP was obtained following the icv injection of AM to L-NAME hypertensive rats pretreated with saralazin [P=0.000]. The changes observed in MABP, PRA and aldosterone level after the central administration of AM to hyptertensive rats pretreated with either clonidine or prazosin were insignificant as compared to their pre-injection values. This study suggests that the peripheral vasodilator effect of AM is mediated partially via nitric oxide release or probably by other mechanisms. The central hypertensive response to AM in the L-NAME rat model is probably not mediated by angiotensin-II receptors. It could be through enhancing the central sympathetic discharge via an action on either alpha 1, alpha 2 or the suggested imidazoline receptors located centrally. Finally, AM is supposed to be involved in the physiological resetting of renin-angiotensin-aldosterone system possibly secondary to changes in either catecholamines discharge or nitric oxide level. These results were discussed

Interrelationship between nitric oxide synthase and myocardial tumor necrosis factor-alpha effect on cardiac contractile function in preconditioned anesthetized dogs

Brief periods of myocardial ischemia and reperfusion render the myocardium tolerant to a subsequent sustained ischemia. This phenomenon has been known as ischemic preconditioning [PC]. It has recently become apparent that ischemic PC consists of two phases: an early phase, which occurs within minutes and disappears within 2 to 4 hours from the PC ischemia, and a late phase, which becomes manifest 24 hours later. The purpose of the present study was to test the hypothesis that the protective effect of ischemic PC is mediated by augmented nitric oxide [NO] formation. This study also aims at examining the effect of ischemic PC on postischemic myocardial tumor necrosis factor-alpha [TNF-alpha] production. This study was carried out on 38 healthy adult dogs of either sex. Six dogs were sacrificed and left ventricular myocardium was excised, homogenized and cardiac TNF-alpha homogenate was determined by chemiluminescence. Thirty-two dogs were randomized into 4 equal groups; Group I [preconditioned group], Group II [ischemic control group], Group III [preconditioned N-nitro-L-arginine methyl-ester [L-NA] treated group] and Group IV [ischemic L-NA treated group]. All groups were allowed 3 hours of reperfusion thereafter. Left ventricular systolic pressure [LVSP] and cardiac output [COP] were measured before and after left anterior descending coronary artery [LAD] occlusion reperfusion [O/R] in the four studied groups. After the three hours of reperfusion, TNF-alpha was measured in the cardiac homogenate of all groups. There was no statistically significant difference in LVSP and COP when comparing the four groups after LAD O/R However, there was a significant drop in both parameters in each of the four studied groups after LAD O/R. The absent short-term beneficial role of PC on myocardial contractility following O/R could be attributed to stunning of the myocardium: Furthermore, inhibition of NO synthesis did not attenuate myocardial stunning in preconditioned and ischemic anesthetized dogs. The present study also demonstrated that O/R increases cardiac TNF-alpha levels and that ischemic PC decreases ischemia-induced cardiac TNF-alpha production, which is still significantly higher in the preconditioned groups, compared with control group. This drop in myocardial TNF-alpha following ischemic PC did not improve postischemic functional recovery in anesthetized dogs. The absent short-term beneficial role of pretreatment with a NOS inhibitor could be explained by the fact that inducible NO synthase [iNOS] mediated only the late dysfunction induced by TNF-alpha

Effect of cholecystectomy on sphincter of oddi motility in dogs

Gallbladder and sphincter of Oddi [SO] function are controlled by a balance of both hormonal and neuronal factors. Neuronal connections pass between the gallbladder and the SO via the cystic duct. It is therefore possible that cholecystectomy may alter SO motility. The present study investigated the effect of cholecystectomy on SO function in anesthetized dogs. Biliary manometry was performed in a group of anesthetized dogs undergoing cholecystectomy and compared with a control group of matched weight and sex. The cholecystectomized dogs compared with the controls showed a significant increase in mean common bile duct [CBD] pressure together with a significant decrease in mean basal SO pressure and SO phasic frequency. There was also a significant increase in the duration of phasic contractions in the cholecystectomy group compared with the control group. No significant change was noticed in the amplitude of phasic contractions and in the duodenal pressure when comparing both groups. These findings show that the gallbladder serves as a reservoir dampening increases in common duct pressure. The increase in intraductal tension following cholecystectomy in the canine model could overcome the choledochoduodenal sphincter resistance resulting in a drop in SO basal pressure associated with a decrease in the frequency of phasic contractions. It is also possible that ductal distension inhibits SO function by local reflexes. Removal of the gallbladder itself may eliminate a significant component of the neural circuity modulating biliary function. Such effects may ultimately lead to the SO manometric abnormalities, which have been described for SO dysfunction

influence of experimentally induce, non-insulin dependent diabetes on the extent of myocardial injury in a canine ischaemia-reperfusion model

Diabetes mellitus is a well known risk factor for coronary artery disease and subsequent myocardial infarction. The present study evaluated the effect of short term [12 weeks] experimentally induced non-insulin-requiring diabetes on the extent of myocardial injury in a canine ischaemia-reperfusion model and investigated the underlying biochemical mechanisms. Non-insulin-dependent diabetes was induced in 10 dogs by the streptozotocin-alloxan method and another 10 dogs were used as controls. On the day of the experiment, dogs of either group were weighted and blood samples were withdrawn from the anticubital vein for biochemical and lipid determinations. Dogs were then anaesthetised and myocardial infarction was provoked by occluding the left anterior descending coronary artery [LAD] for 1 hour followed by 3 hours reperfusion. Biopsies were taken from the center of the LAD bed before and then after the 4 hours of the whole occlusion/reperfusion technique. Twelve weeks following diabetes induction, diabetic dogs had higher fasting blood glucose, fructosamine, cholesterol, triglycerides, and apo B concentrations than control dogs. Plasma insulin level was significantly lower in diabetic dogs than controls. Also, plasma antioxidants vitamin E and A were significantly lower in diabetics than in controls on the day of the surgical procedure. Capillaries of the diabetic myocardium showed thickening of basal lamina. The diabetic cardiocytes revealed scalloping of sarcolemma and changes in the Z line in the form of thickening, irregularity and loss of alignment. Light bands were seen in many areas along the myofibrils. After ischaemia-reperfusion, severe ultrastructural changes were observed in the diabetic cardiocytes. Myofilaments showed disruption, lysis and fragmentation. Mitochondrial changes and widening of intercalated discs were also noticed. From the previous study, we cannot identify exactly the mechanism[s] by which diabetes aggravated myocardial injury. The results nevertheless suggest that one reason why myocardial ischaemia is less well tolerated in diabetics than in non-diabetics is likely to be by inducing myocardial ultrastructural changes. This may partly explain the poor prognosis of myocardial infarction in diabetic persons

Subclavian catheters and the late development of subclavian vein stenosis

Subclavian catheterization has become one of the most popular methods of access for temporary dialysis and intravenous hyperalimentation. But there is risk of late Subclavian vein stenosis. In this study 18 patients, age 40-65 years old, of both sexes. All are coming for insertion of double-lumen catheter for haemodialysis through the Subclavian route. They had no history of previous ipsilateral Subclavian catheterization, no history of diabetes mellitus. The duration of catheterization was 3-6 weeks, and venograms were performed on the patients within more than 6 months after catheter removal. Eight catheters [44%] had to be removed because of catheter related infection, the other 10 catheters [55%] were removed electively. 3 venograms were abnormal, 2 in patients who had catheter site infection [25%], and one patient who had no evidence of infection [15%]. Two venograms showed. Subclavian vein stenosis [50% 90%], one venogram showed total occlusion of the vein with marked collaterals. Catheter infection is a major risk for late development of Subclavian vein stenosis. The Subclavian route should be used only for acute situations, or better to use the internal jugular route which better preserves the vein integrity