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Biomedical subjects

Mahmoud Huleihel

Publications and source records attributed to Mahmoud Huleihel.

At least 37 records · Page 2Linked to original sources

Distinct expression and distribution of vesicular proteins in the hippocampus of TNFa-deficient mice during development.

Tumor necrosis factor alpha (TNFa) is a cytokine produced mainly by cells of the immune system. It is also expressed by brain neurons and glia. In the brain, TNFa governs synaptic plasticity, such as long-term potentiation and learning. Using TNFa-deficient mice (TNFa-KO) and immunohistochemical techniques, we resolved the spatio-temporal effect of TNFa on the expression of vesicular soluble N-ethylmaleimide-sensitive factor attachment protein receptor (v-SNARE) in the presynaptic terminals of the hippocampus during the first month of development. During postnatal days 1-14, the levels of Synaptotagmin I and VAMP II were similar in the hippocampus of TNFa-KO and wild type (wt) mice. However, the levels of Syntaptotagmin II were reduced in the pyramidal cell layer of the CA1 region in TNFa-KO. At postnatal day 21, both proteins accomplished comparable levels in the hippocampus of TNFa-KO and wt mice. In addition, TNFa deficiency impairs the correlation of expression of Synaptotagmin I and II in CA1 region. The expression of those proteins in the CA1 stratum radiatum was uniform during development and similar in both mice groups. Higher expression of all examined proteins was demonstrated in dendritic fields of the CA3 region in TNFa-KO as compared to wt mice. We suggest that the impairment of synaptic plasticity by TNFa may be related to its modulation of synaptic vesicle proteins.

Animals↗

The use of FTIR microscopy for evaluation of herpes viruses infection development kinetics.

The kinetics of Herpes simplex infection development was studied using an FTIR microscopy (FTIR-M) method. The family of herpes viruses includes several members like H. simplex types I and II (HSV I, II), Varicella zoster (VZV) viruses which are involved in various human and animal infections of different parts of the body. In our previous study, we found significant spectral differences between normal uninfected cells in cultures and cells infected with herpes viruses at early stages of the infection. In the present study, cells in cultures were infected with either HSV-I or VZV and at various times post-infection they were examined either by optical microscopy or by advanced FTIR-M. Spectroscopic measurements show a consistent decrease in the intensity of the carbohydrate peak in correlation with the viral infection development, observed by optical microscopy. This decrease in cellular carbohydrate level was used as indicator for herpes viruses infection kinetics. This parameter could be used as a basis for applying a spectroscopic method for the evaluation of herpes virus infection development. Our results show also that the development kinetics of viral infection has an exponential character for these viruses.

Animals↗

Selective vasodilator effect of magnesium sulfate in human placenta.

PROBLEMS: To determine if magnesium sulfate (MgSO4) attenuates the vasoconstrictor effect of angiotensin II (Ag II), endothelin-1 (ET-1) and thromboxane mimetic (TX) in the human fetal placental vasculature and if interleukin-1 beta (IL-1beta) is involved in this process. STUDY DESIGN: Isolated placental cotyledons (n = 18) were dually perfused with fetal perfusion pressure used as an index of vascular response. The vasoconstriction effect of bolus injection of various concentrations of Ag II (10(-1)) 10(-6) M) or ET-1 (10-(10)-10(-4) M) or TX (10(-10)) 10(-5) M) was established in the absence or presence of MgSO4 (7 mg% constant infusion during 10 hr). Statistical significance was determined by paired t-test and ANOVA. RESULTS: MgSO4 significantly attenuates the vasoconstrictor effect of Ag II in the fetal placental vasculature in the human placenta (P = 0.02). Moreover, significant attenuation of vasoconstrictor response to ET-1(10(-10))10(-5) M) was observed in the presence of MgSO4 (P = 0.02). However, no attenuation of the vasoconstrictor response to TX was noted in the presence of MgSO4 (P > 0.5). Ag II and TX were shown to induce IL-1beta secretion by placental tissue. This effect was completely reduced by perfusion of MgSO4 (7 mg%; constant infusion). CONCLUSIONS: MgSO4 significantly attenuates the vasoconstrictor effect of Ag II and ET-1 in the fetal-placental vasculature in the human placenta, but not that of TX. Inhibition of local production of IL-1beta could be one of the mechanisms used by MgSO4 to reduce the vasoconstrictory effect of Ag II and TX in human placental cotyledone.

Angiotensin II↗

Regulation of spermatogenesis by paracrine/autocrine testicular factors.

Spermatogenesis is a complex process regulated by endocrine and testicular paracrine/autocrine factors. Gonadotropins are involved in the regulation of several testicular paracrine factors, mainly of the IL-1 family and testicular hormones. Testicular cytokines and growth factors (such as IL-1, IL-6, TNF, IFN-gamma, LIF and SCF) were shown to affect both the germ cell proliferation and the Leydig and Sertoli cells functions and secretion. Cytokines and growth factors are produced by immune cells and in the interstitial and seminiferous tubular compartments by various testicular cells, including Sertoli, Leydig, peritubular cells, spermatogonia, differentiated spermatogonia and even spermatozoa. Corresponding cytokine and growth factor receptors were demonstrated on some of the testicular cells. These cytokines also control the secretion of the gonadotropins and testosterone in the testis. Under pathological conditions the levels of pro-inflammatory cytokines are increased and negatively affected spermatogenesis. Thus, the expression levels and the mechanisms involved in the regulation of testicular paracrine/autocrine factors should be considered in future therapeutic strategies for male infertility.

Animals↗

Implications of the evolution pattern of human T-cell leukemia retroviruses on their pathogenic virulence (Review).

Simian retroviruses pose a serious threat to public health, as two human pathogenic retroviruses, HIV and HTLV, have been already proved to originate from such non-human viruses. Therefore, studying their natural prevalence among wild non-human primates is important for planning strategies to prevent the emergence of additional human retroviral pathogens. This article is focused on tracing the origin and evolution of the human T-cell leukemia viruses HTLV-I and HTLV-II in comparison to that of the simian lymphotropic viruses STLV-I, STLV-II and STLV-L, which are phylo-genically classified into a common group called primate T-lymphotropic viruses (PTLV). Thus, HTLV-I and STLV-I are referred to as PTLV-I and HTLV-II and STLV-II as PTLV-II, whereas STLV-L, which is highly divergent from both HTLV types, comprises a third subgroup called PTLV-L. The phylogeny of PTLV indicates that both, HTLV-I and HTLV-II emerged from a simian origin, but their subsequent evolution continued in different patterns. HTLV-I includes 6 subtypes which evolved from STLV-I through several times of different geographic interspecies transmission between simian and human hosts. These repeated invasions to new primate species are likely to give rise to viral strains with increasing pathogenic potential. On the other hand, HTLV-II includes 4 subtypes which appear to originate from a common human ancestor virus that emerged from only one simian to human transmission, whereas the subsequent evolution of HTLV-II and STLV-II strains continued separately only within the Homo sapiens and Pan paniscus species respectively, without repeated interspecies jumps. Such evolution pattern likely involves less genetic changes and selection of viral strains with low pathogenic virulence that could co-exist with their hosts for long time. These different evolution patterns can explain the much wider implication of HTLV-I with human clinical disorders than HTLV-II. Of note, however, more recently HTLV-II started spreading much more rapidly through intravenous drug users to many geographical regions, with a 150-350 fold higher mutation rate than that of its previous strictly endemic strains. This change in the mode of the virus spread creates a serious risk for emergence of HTLV-II strains with higher virulence.

Animals↗

Lack of interaction of digoxin and P-glycoprotein inhibitors, quinidine and verapamil in human placenta in vitro.

OBJECTIVE: To determine the effect of quinidine and verapamil, known antiarrhythmic agents and P-glycoprotein (Pgp) inhibitors, on digoxin transport from the maternal to the fetal compartment in the isolated perfused human placenta. STUDY DESIGN: Isolated placental cotyledons from normal human placentae (n=20) were dually perfused with M199 medium enriched with albumin (0.3%) and glucose (0.1%). The maternal and the fetal circulation flow rates were 12 and 6 ml/min, respectively. Closed circulations were used to evaluate steady state transplacental gradient formation. In six placentae quinindine was added to the maternal circuit; after 45 min of perfusion, digoxin was added to the maternal circulation. The effect of verapamil on digoxin transfer from the maternal to the fetal compartments was explored in five placentae. In six additional placentae the transfer of digoxin was studied in the absence of quinidine. Transplacental passage of digoxin was calculated from repeated fetal and maternal perfusate samples. Digoxin levels were determined in perfusate samples by fluorescence polarization immunoassay. Antipyrine was added to the maternal reservoir of all placentae as reference substance. RESULTS: The transfer of digoxin (alone) and in the presence of quinidine or verapamil was 10.93+/-3.71, 9.00+/-5.2 and 12.94+/-4.86%, respectively. The levels of digoxin in the fetal compartment, 0.62+/-0.20, 0.48+/-0.29 and 0.60+/-0.26 ng/ml, respectively, were not significantly affected by quinidine and verapamil. These Pgp modulators, also did not influence significantly the steady state levels of digoxin in the maternal compartment. CONCLUSION: Neither quinidine nor verapamil affected the transplacental transfer of digoxin in vitro in normal human placentae. In contrast to the other tissues, they do not inhibit Pgp activity in term human placentae.

ATP Binding Cassette Transporter, Subfamily B↗

Role of protein kinase C and the Sp1-p53 complex in activation of p21(WAF-1) expression by 12-O-tetradecanoylphorbol-13-acetate in human T cells.

Previous reports have shown that, in certain cell types, p21(WAF-1), which plays a central role in cell proliferation, can be activated by HTLV-I Tax protein and by TPA. Tax and TPA are also known to stimulate HTLV-I gene expression. Since cell proliferation has a major impact on HTLV-I replication, it was of interest to investigate their effect on p21(WAF-1) in human T cells, which are the main target of HTLV-I in human infection. This study demonstrates that p21(WAF-1) is activated in such cells by both factors, each acting through a different mechanism that does not influence the other. The effect of TPA is shown to require PKC activity. Notably, however, examination of different PKC isoforms revealed that PKC-alpha and PKC-epsilon stimulated p21(WAF-1) expression, whereas PKC-eta was rather inhibitory and PKC-beta1 and beta2 were ineffective. All these isoforms were found to be activated by TPA in the employed T cells, but this apparent paradox was resolved by the observation that when coexpressed together in these cells, the stimulatory PKCs override the inhibitory isoform. Further experiments demonstrated that the PKC-induced p21(WAF-1) activation was mediated by binding of Sp1-p53 complex to the second most upstream of the six Sp1 recognition sites present in its promoter and that this effect did not require the cooperation of an p53-binding site.

Cyclin-Dependent Kinase Inhibitor p21↗

FTIR microspectroscopy of malignant fibroblasts transformed by mouse sarcoma virus.

Fourier transform infrared microspectroscopy (FTIR-MSP), which is based on the characteristic molecular vibrational spectra of cells, was used to investigate spectral differences between normal primary rabbit bone marrow (BM) cells and bone marrow cells transformed (BMT) by murine sarcoma virus (MuSV). Primary cells, rather than cell lines, were used for this research because primary cells are similar to normal tissue cells in most of their characteristics. Our results showed dramatic changes in absorbance between the control cells and MuSV124-transformed cells. Various biological markers, such as the phosphate level and the RNA/DNA obtained, based on the analysis of the FTIR-MSP spectra, also displayed significant differences between the control and transformed cells. Preliminary results suggested that the cluster analysis performed on the FTIR-MSP spectra yielded 100% accuracy in classifying both types of cells.

Amides↗

Preliminary results of evaluation of progress in chemotherapy for childhood leukemia patients employing Fourier-transform infrared microspectroscopy and cluster analysis.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, but remarkable progress in methods of chemotherapy has increased the cure rate to 80%. The leukemic cells called blasts are eliminated within 7 days of chemotherapy. Clinically, the blast count is monitored directly with the use of blood smears on the basis of specific genetic markers and immunophenotyping methods such as flow cytometry. In this article, we present preliminary results, obtained with the use of Fourier-transform infrared microspectroscopy and cluster analysis, of an approach to monitoring the progress made with chemotherapy in 1 B-cell and 2 T-cell pediatric ALL patients. Our results indicated that the biological marker derived from the spectra did not provide accurate prediction of the progress made with chemotherapy. However, cluster analysis of FTIR-MSP spectra provided good classification of the samples with and without blasts, which correlate satisfactorily with clinical data. Extensive studies are required to substantiate our findings statistically which may have potential application of FTIM in the diagnosis and follow-up of various types of malignancies.

Algorithms↗

Psychological factors correlate meaningfully with percent-monocytes among acute coronary syndrome patients.

Recent research demonstrates the importance of inflammatory parameters in the etiology and prognosis of the acute coronary syndrome (ACS). This study explored relations between psychological factors and immunological parameters routinely measured among ACS patients. Forty-two ACS patients completed questionnaires assessing perceived-control, emotional support, hostility, and life-events 2-4 days after hospitalization. Data on total leukocytes and percentages (%) of monocytes, %neutrophils, and %lymphocytes upon admission to hospital were collected from computerized medical charts as well as various biomedical information and risk-factors (e.g., diagnosis, left-ventricle-LV functioning, smoking, and hypertension). Of all significant biomedical variables, LV-function and arrival-time correlated uniquely with total leukocytes. Controlling for LV-function and arrival-time, hostility and life-events positively correlated with %monocytes, and perceived-control and emotional-support inversely correlated with %monocytes. Emotional-support was positively correlated and life-events were negatively correlated with %neutrophils. Macrophages play a pivotal role in plaque instability, the trigger of an ACS. This initiating role, and our finding of a relationship between recruitment of monocytes and a poor psychosocial profile, predictive of ACS, are consistent with a PNI component in the pathophysiology of ACS.

Acute Disease↗

Spectroscopic evaluation of the effect of a red microalgal polysaccharide on herpes-infected Vero cells.

The sulfated polysaccharide obtained from a species of red microalga has proved to be a potent antiviral agent against various members of the herpes family. In the present study, we used microscopic Fourier transform infrared spectroscopy (FT-IR) to investigate differences between normal cells, those infected with herpes viruses, and infected cells treated with red microalgal polysaccharide. FT-IR enables the characterization of cell or tissue pathology based on characteristic molecular vibrational spectra of the cells. The advantage of microscopic FT-IR spectroscopy over conventional FT-IR spectroscopy is that it facilitates inspection of restricted regions of cell cultures or tissue. Our results showed significant spectral differences at early stages of infection between infected and noninfected cells, and between infected cells treated with the polysaccharide and those not treated. In infected cells, there was an impressive decrease in sugar content and a considerable increase in phosphate levels in conjunction with the infection progress. Our results also proved that sugars penetrated and accumulated inside cells treated with the red microalgal polysaccharide. These could have been sugar fragments of low molecular weight present in the polysaccharide solution, despite purification by dialysis. Such sugar accumulation might be responsible for a breakdown in the internal steps of the viral replication cycle.

Animals↗

Activation of HTLV-I long terminal repeat by apoptosis inducing agents: mechanism and implications for HTLV-I pathogenicity (review).

HTLV-I is the etiological agent of adult T-cell leukemia (ATL), tropical spastic paraparesis/HTLV-I associated myelopathy (TSP/HAM) and certain other clinical disorders. After infection in human the virus enters into a latent state, in which very low viral gene expression can be detected. On the other hand several major characteristics of ATL and TSP/HAM indicate that their genesis requires activation of the dormant virus. TSP/HAM is characterized by high virus expression, which accounts for most of its immunopathological manifestations, whereas the process leading to ATL is believed to be initiated by the viral Tax protein, implying that it requires, at least, a temporary activation of the latent virus. Data from our and other laboratories suggest that this activation may likely be induced by environmental or/and intrinsic apoptosis-inducing factors. Moreover, we have demonstrated a mechanistic linkage between the activation of the viral promoter and the early stage of the apoptotic cascade. However, we have also shown that Tax rescues virus-expressing T-cells from apoptotic death. This suggests that Tax protein, emerging after activation of the latent virus, can rescue the host cells of the activated virus from the ultimate apoptotic death. Since the development of both TSP/HAM and ATL seems to depend on the viral Tax protein, we describe a possible system for anti Tax gene-therapy approach based on a negative transdominant mutant Tax gene.

Adult↗

New aspects in placental drug transfer.

The human placenta is the interface between the mother and fetus in the uterus. Until recently it was generally believed that the uterus provides a protective environment for the fetus. It is now accepted that any chemical substance, including any therapeutic agent, administered to a mother is able to permeate across the placental barrier. Unfortunately, the placental transfer of substances and their distribution in the placenta is not well established. Understanding the structure of placental transporters and their function may serve as the ideal tool for drug development and the cure of mother and fetus during pregnancy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Vasoconstrictive activity of oxytocin in meconium impregnated human placentas.

OBJECTIVE: The aim of our study is to determine whether oxytocin acts differently on the fetal-placental vascular bed of normal and meconium impregnated placentas. STUDY DESIGN: Isolated placental cotyledons (n=10) were dually perfused with fetal perfusion pressure used as an index of vascular resistance. As perfusion medium we used lactated Ringer salt solution, containing polyvinylpyrolidone (25 g/l), bovine serum albumin (0.1 mg/ml), glucose (1.0 g/l), heparin (20 IU/ml) and gentamycin (48 microg/ml). The pH of the medium was adjusted to 7.4 with bicarbonate. The maternal site was gassed with 95% O(2):5% CO(2) and in the fetal site with 95% N(2):5% CO(2) at 37 degree C. Perfusion rates were 4-6 and 10-12 ml/min in the fetal and maternal circulation, respectively. TNF-alpha and IL-beta1 levels in the fetal-placental perfusate were evaluated using specific commercial ELISA kits. RESULTS: No significant changes in the amount of TNF-alpha release were observed after injection of oxytocin into the fetal circulation (31+3pg/ml; P=0.5). No IL-beta1 activity was observed in the fetal perfusate of normal and meconium impregnated placentas during the experiments. No significant difference was seen in basal perfusion pressure in normal and meconium impregnated placentas, however, a bolus injection of oxytocin (10U/ml) resulted in a significant increase in perfusion pressure in meconium impregnated placentas from basal pressure of s45+5 to 88+4 mm Hg after injection of oxytocin, (P=0.004, ANOVA). CONCLUSION: Vasoconstrictive effect of oxytocin was observed only in meconium impregnated placentas and no vascular effect of oxytocin was documented in normal placentas. The clinical implication of our findings is that one should use oxytocin for stimulation of labor with caution in the presence of meconium stained amniotic fluid.

Case-Control Studies↗

Involvement of intratesticular IL-1 system in the regulation of Sertoli cell functions.

The Interleukin-1 (IL-1) system has been suggested to be involved in the cell-cell cross talk within the testis. To investigate the testicular autocrine, paracrine and endocrine factors involved in the regulation of Sertoli cell functions, we have examined the capacity of Sertoli cell cultures, from immature mice, to produce IL-1alpha, IL-1beta and IL-1 receptor antagonist (IL-1ra) under in vitro cultures and in the presence of testicular physiological and pathological factors. Our investigation revealed that Sertoli cells produce large amounts of IL-1alpha, IL-1ra but not IL-1beta under basal culture conditions, as examined by ELISA and immunohistochemical staining. Liposaccharides (LPS), as well as IL-1alpha and IL-1beta were found to stimulate IL-1alpha and IL-1ra, but not IL-1beta production, in Sertoli cells from immature mice. Maximum concentration of IL-1alpha and of IL-1ra was observed after 2 and 8 h after the stimulation, respectively. The addition of IL-1ra to Sertoli cells did not alter their capacity to constitutively produce IL-1alpha. However, the stimulatory effects of recombinant IL-1alpha on IL-1alpha production by Sertoli cells were reversed by the concomitant addition of recombinant IL-1ra. FSH is capable to induce IL-1ra production in Sertoli cells in a dose-dependent manner but not IL-1alpha or IL-1beta. As expected, Sertoli cell cultures were also shown to constitutively secrete transferrin. Stimulation of these cultures with IL-1alpha, IL-1beta significantly increased their capacity to secrete transferrin. Addition of IL-1ra to unstimulated Sertoli cell cultures did not affect their capacity to secrete transferrin. Stimulation of Sertoli cell cultures with a combination of both IL-1alpha and FSH or IL-1beta and FSH showed additive effect between IL-1 and FSH in their capacity to induce transferrin secretion by these cells. However, stimulation of Sertoli cells with a combination of both IL-1ra and FSH did not affect their capacity to secrete transferrin as compared with FSH-stimulated cultures. Our results with Sertoli cells, in addition to previous data on Lydig cell and germ cells, may suggest the involvement of the IL-1 system in testicular paracrine/autocrine regulation, which could be involved in the regulation of spermatogenesis and spermiogenesis processes and male fertility.

Animals↗

A comparative study of gallstones from children and adults using FTIR spectroscopy and fluorescence microscopy.

BACKGROUND: Cholelithiasis is the gallstone disease (GSD) where stones are formed in the gallbladder. The main function of the gallbladder is to concentrate bile by the absorption of water and sodium. GSD has high prevalence among elderly adults. There are three major types of gallstones found in patients, White, Black and Brown. The major chemical component of white stones is cholesterol. Black and brown stones contain different proportions of cholesterol and bilirubin. The pathogenesis of gallstones is not clearly understood. Analysis of the chemical composition of gallstones using various spectroscopic techniques offers clues to the pathogenesis of gallstones. Recent years has seen an increasing trend in the number of cases involving children. The focus of this study is on the analysis of the chemical composition of gallstones from child and adult patients using spectroscopic methods. METHODS: In this report, we present FTIR spectroscopic studies and fluorescence microscopic analysis of gallstones obtained from 67 adult and 21 child patients. The gallstones were removed during surgical operations at Soroka University Medical Center. RESULTS: Our results show that black stones from adults and children are rich in bilirubin. Brown stones are composed of varying amounts of bilirubin and cholesterol. Green stones removed from an adult, which is rare, was found to be composed mainly of cholesterol. Our results also indicated that cholesterol and bilirubin could be the risk factors for gallstone formation in adults and children respectively. Fluorescence micrographs showed that the Ca-bilirubinate was present in all stones in different quantities and however, Cu-bilirubinate was present only in the mixed and black stones. CONCLUSIONS: Analysis based on FTIR suggest that the composition of black and brown stones from both children and adults are similar. Various layers of the brown stone from adults differ by having varying quantities of cholesterol and calcium carbonate. Ring patterns observed mainly in the green stone using fluorescence microscopy have relevance to the mechanism of the stone formation. Our preliminary study suggests that bilirubin and cholesterol are the main risk factors of gallstone disease.

Adult↗

Novel spectral method for the study of viral carcinogenesis in vitro.

Fourier transform infrared (FTIR) spectroscopy is a unique technique for the laboratory diagnosis of cellular variations based on the characteristic molecular vibrational spectra of the cells. Microscopic FTIR was used to investigate spectral differences between normal and malignant fibroblasts transformed by retrovirus infection. A detailed analysis showed significant differences between cancerous and normal cells. The contents of vital cellular metabolites were significantly lower in the transformed cells than in the normal cells. In an attempt to identify the cellular components responsible for the observed spectral differences between normal and cancerous cells, we found significant differences between DNA of normal and cancerous cells.

3T3 Cells↗

FTIR spectroscopic method for detection of cells infected with herpes viruses.

Microscopic FTIR spectroscopy was used to investigate the spectral differences between normal cells in culture and cells infected with various members of the herpes family of viruses [Herpes simplex (HSV) and Varicella zoster (VZV)]. The main objective of this study is to evaluate the possibility of developing microscopic FTIR spectroscopy as a sensitive assay for the detection of herpetic infections at their early stages. The advantage of this method over conventional FTIR spectroscopy is that it facilitates inspection of restricted regions of tissue. Our results showed significant and consistent differences between all normal and HSV or VZV infected cells that were tested. Detectable and significant spectral differences between normal and infected cells are seen as early as 24 h postinfection, but the damage of the cells (cytopathic effect), caused by the infecting virus, can be seen by optical microscope observations at only 3 days postinfection. An impressive increase in the levels of vital cellular metabolites was seen in the herpes virus infected cells compared to normal cells. It seems that this spectral behavior is unique for infection with herpes viruses, because when these cells were infected with other viruses from different families like retroviruses, a considerable decrease in the levels of vital cellular metabolites was seen in infected cells compared to normal cells. Cluster analysis performed on FTIR mass chromatography yielded 100% accuracy in classifying control uninfected and VZV or HSV infected cells. Our data strongly support the possibility of developing FTIR microscopy as a diagnostic method for early detection of herpetic infections.

Animals↗