bluuebunny/crossref_metadata_2025 huggingface dataset:
A PAR domain transcription factor is involved in the expression from a hematopoietic-specific promoter for the human LMO2 gene
Authors: Crable Scott C. , Anderson Kathleen P.
Published: March 2003

The transcription factor LMO2 is believed to exert its effect through the formation of protein-protein interactions with other DNA-binding factors such as GATA-1 and TAL1. Although LMO2 has been shown to be critical for the formation of the erythroid cell lineage, the gene is also expressed in a number of nonerythroid tissues. In this report, we demonstrate that the more distal of the 2 promoters for the LMO2 gene is highly restricted in its pattern of expression, directing the hematopoietic-specific expression of this gene. Deletion and mutation analyses have identified a critical cis element in the first untranslated exon of the gene. This element is a consensus-binding site for a small family of basic leucine zipper proteins containing a proline and acidic amino acid–rich (PAR) domain. Although all 3 members of this family are produced in erythroid cells, only 2 of these proteins, thyrotroph embryonic factor and hepatic leukemia factor, can activate transcription from this LMO2 promoter element. These findings represent a novel mechanism in erythroid gene regulation because PAR proteins have not previously been implicated in this process.
Evidence for a role for Gαi1 in mediating weak agonist-induced platelet aggregation in human platelets: reduced Gαi1 expression and defective Gi signaling in the platelets of a patient with a chronic bleeding disorder
Authors: Patel Yatin M. , Patel Kirti , Rahman Salman , Smith Mark P. , Spooner Gillian , Sumathipala Rushika , Mitchell Michael , Flynn Geraldine , Aitken Alexandra , Savidge Geoffrey
Published: March 2003

We have examined platelet functional responses and characterized a novel signaling defect in the platelets of a patient suffering from a chronic bleeding disorder. Platelet aggregation responses stimulated by weak agonists such as adenosine diphosphate (ADP) and adrenaline were severely impaired. In comparison, both aggregation and dense granule secretion were normal following activation with high doses of collagen, thrombin, or phorbol-12 myristate-13 acetate (PMA). ADP, thrombin, or thromboxane A2 (TxA2) signaling through their respective Gq-coupled receptors was normal as assessed by measuring either mobilization of intracellular calcium, diacylglycerol (DAG) generation, or pleckstrin phosphorylation. In comparison, Gi-mediated signaling induced by either thrombin, ADP, or adrenaline, examined by suppression of forskolin-stimulated rise in cyclic AMP (cAMP) was impaired, indicating dysfunctional Gαi signaling. Immunoblot analysis of platelet membranes with specific antiserum against different Gα subunits indicated normal levels of Gαi2,Gαi3,Gαz, and Gαq in patient platelets. However, the Gαi1level was reduced to 25% of that found in normal platelets. Analysis of platelet cDNA and gDNA revealed no abnormality in either the Gαi1 or Gαi2 gene sequences. Our studies implicate the minor expressed Gαi subtype Gαi1 as having an important role in regulating signaling pathways associated with the activation of αIIbβ3 and subsequent platelet aggregation by weak agonists.
Aggravation of endotoxin-induced disseminated intravascular coagulation and cytokine activation in heterozygous protein-C–deficient mice
Authors: Levi Marcel , Dörffler-Melly Janine , Reitsma Pieter , Büller Harry , Florquin Sandrine , van der Poll Tom , Carmeliet Peter
Published: March 2003

In the pathogenesis of sepsis and disseminated intravascular coagulation (DIC), dysfunctional anticoagulant pathways are important. The function of the protein C system in DIC is impaired because of low levels of protein C and down-regulation of thrombomodulin. The administration of (activated) protein C results in an improved outcome in experimental and clinical studies of DIC. It is unknown whether congenital deficiencies in the protein C system are associated with more severe DIC. The aim of the present study was to investigate the effect of a heterozygous deficiency of protein C on experimental DIC in mice. Mice with single-allele targeted disruption of the protein C gene (PC+/–) mice and wild-type littermates (PC+/+) were injected with Escherichia coli endotoxin (50 mg/kg) intraperitoneally. PC+/–mice had more severe DIC, as evidenced by a greater decrease in fibrinogen level and a larger drop in platelet count. Histologic examination showed more fibrin deposition in lungs, kidneys, and liver in mice with a heterozygous deficiency of protein C. Interestingly, PC+/– mice had significantly higher levels of proinflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β, indicating an interaction between the protein C system and the inflammatory response. Survival was lower at 12 and 24 hours after endotoxin in the PC+/– mice. These results confirm the important role of the protein C system in the coagulative-inflammatory response on endotoxemia and may suggest that congenital deficiencies in the protein C system are associated with more severe DIC and adverse outcome in sepsis.
Adhesion of normal and Plasmodium falciparum ring–infected erythrocytes to endothelial cells and the placenta involves the rhoptry-derived ring surface protein-2
Authors: Douki Jean-Bernard Lekana , Sterkers Yvon , Lépolard Catherine , Traoré Boubacar , Costa Fabio T. M. , Scherf Artur , Gysin Jürg
Published: March 2003

Recent findings have challenged the current view of Plasmodium falciparum (P falciparum) blood-stage biology by demonstrating the cytoadhesion of early ring-stage–infected erythrocytes (rIEs) to host endothelial cells and placental syncytiotrophoblasts. The adhesion of rIEs was observed only in parasites that bind to the placenta via chondroitin sulfate A (CSA). In this work, a panel of mouse monoclonal antibodies (mAbs) that specifically inhibit cytoadhesion of rIEs but not of mature IEs was generated The previously described ring surface protein 2 (RSP-2), a 42-kDa protein, was identified as the target of the ring-stage–specific mAbs. Time course surface fluorescence experiments revealed a short overlap (approximately 4 hours) of expression between RSP-2 and P falciparum erythrocyte membrane protein 1 (PfEMP1). Their consecutive expression enables IEs to adhere to endothelial cells during the entire blood-stage cycle. During this study, a new phenotype was detected in parasite cultures, the adhesion of normal erythrocytes (nEs) to endothelial cells. All adherent nEs were coated with RSP-2. Immunolocalization studies show that RSP-2 is a rhoptry-derived protein that is discharged onto the erythrocyte membrane during contact with merozoites. Our results identify RSP-2 as a key molecule in sequestration of young blood-stage forms and nEs to endothelial cells.
Prognostic value of pretransplantation positron emission tomography using fluorine 18-fluorodeoxyglucose in patients with aggressive lymphoma treated with high-dose chemotherapy and stem cell transplantation
Authors: Spaepen Karoline , Stroobants Sigrid , Dupont Patrick , Vandenberghe Peter , Maertens Johan , Bormans Guy , Thomas José , Balzarini Jan , De Wolf-Peeters Christine , Mortelmans Luc , Verhoef Gregor
Published: March 2003

The study assessed the prognostic value of fluorine 18-fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) after salvage chemotherapy before high-dose chemotherapy with stem cell transplantation (HDT/SCT) in patients with induction failure or relapsing chemosensitive lymphoma. Retrospective analysis of the clinical and conventional imaging data of 60 patients scheduled for HDT/SCT was performed in parallel with the analysis of the [18F]FDG-PET results. To determine the ability of [18F]FDG-PET to predict clinical outcome, PET images were reread without knowledge of conventional imaging and clinical history. Presence or absence of abnormal [18F]FDG uptake was related to progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier survival analysis. Thirty patients showed a negative [18F]FDG-PET scan before HDT/SCT; 25 of those remained in complete remission, with a median follow-up of 1510 days. Two patients died due to a treatment-related mortality but without evidence of recurrent disease at that time (228-462 days). Only 3 patients had a relapse (median PFS, 1083 days) after a negative [18F]FDG-PET scan. Persistent abnormal [18F]FDG uptake was seen in 30 patients and 26 progressed (median PFS, 402 days); of these 26, 16 died from progressive disease (median OS, 408 days). Four patients are still in complete remission after a positive scan. Comparison between groups indicated a statistically significant association between [18F]FDG-PET findings and PFS (P < .000001) and OS (P < .00002). [18F]FDG-PET has an important prognostic role in the pretransplantation evaluation of patients with lymphoma and enlarges the concept of chemosensitivity used to select patients for HDT/SCT. (Blood. 2003;102:53-59)
Pancreatitis leading to thrombotic thrombocytopenic purpura in systemic lupus erythematosus: a case report and review of literature
Authors: Singh R , Saunders B , Scopelitis E
Published: March 2003

Pancreatitis is a well-establishedbut unusual complicationof thrombotic thrombocytopenicpurpura (TTP). It is also an unusual complication of systemic lupus erythematosus (SLE). However, TTP occurring as a consequence of acute pancreatitis in a patient with SLE has never been reported. We report a 24-year-old African American woman with active systemic lupus (SLE) who developed thrombotic thrombocytopenic purpura (TTP) following an episode of acute pancreatitis. The TTP was manifested by low-grade fever, microangiopathic hemolytic anemia, renal insufficiency, altered mental status, seizures and thrombocytopenia. The patient was initially treated with pulse corticosteroids with inadequate response and subsequentlywith daily plasmaphresis, leading to full remission. This case represents first report of pancreatitis leading to TTP in a patient with systemic lupus erythematosus.
Catastrophic antiphospholipid syndrome complicating orthotopic liver transplantation
Authors: Villamil A , Sorkin E , Basta M C , Mysler E , Macias S , Pekolj J , Ciardullo M , Eleta F , de Santibañes E , Allievi A , Gadano A
Published: March 2003

Catastrophic antiphospholipid syndrome (CAPS) is an acutely devastating situation characterized by widespread thrombotic microangiopathy in the presence of elevated titers of antiphospholipid antibodies. We describe a 57-year old woman who underwent liver transplantation for primary sclerosing cholangitis and developed this malignant variant of the antiphospholipid syndrome.
DNA methylation in systemic lupus erythematosus
Authors: Sekigawa I , Okada M , Ogasawara H , Kaneko H , Hishikawa T , Hashimoto H
Published: March 2003

Recent studies on epigenetics, including DNA methylation and its regulatory enzymes, seem likely to contribute to elucidation of the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE), although the relationship between DNA methylation and SLE has long been the subject of investigation.To obtain a deeper understandingof the role of DNA methylation in the induction of SLE, we reviewed the relationship between DNA methylation and SLE based on findings reported in the literature and our own data. Various studies, including ours, have indicated the possible importance of DNA methylation, especially hypomethylation, in the etiology of SLE. These epigenetic studies may give us clues towards elucidation of the pathogenesis of SLE and development of new therapeutic strategies for this disease.
Detection and clinical significance of Ba2+- and Sr2+-dependent antiprothrombin antibodies in patients with systemic lupus erythematosus and antiphospholipid syndrome
Authors: Sanaka T , Matsuda J , Teramoto T
Published: March 2003

We conducted this study to confirm whether or not Ca2+-dependent antiprothrombinantibody (aPT) in patients’sera with systemic lupuserythematosusand=or primary antiphospholipidsyndromewould react to prothrombin=phosphatidylserinein the presenceof Sr2+, Mn2+ or Ba2+, or divalentmetal ions like Ca2+, utilizingELISA, and to analyze the clinical significance of these metal-dependentaPT. We found the presence of Ba2+- and Sr2+-dependent IgG, IgM and IgA-aPT in up to 65% of patients negative for Ca2+-dependent IgG-, IgM and IgA-aPT. Maximally 69% of them were complicated by antiphospholipidsyndrome-relatedsymptoms. These data suggest that the measurementof Ba2+- and Sr2+- along with Ca2+-dependentaPT may become a clinicallyuseful tool to correctly detect patients with antiphospholipid-related complications. However, further study is needed to clarify the clinicopathologicaldifferences among these aPTs in the future.
Lack of association between hyperprolactinemia and soluble IL-2 receptor levels in systemic lupus erythematosus
Authors: Daza L , Lavalle C , Duarte C , Huerta R , Moreno J
Published: March 2003

The aim of the study was to evaluate the associationbetween hyperprolactinemiaand T lymphocyte activation through the soluble IL-2 receptor (sIL-2R) in systemic lupus erythematosus (SLE) patients. Seventy SLE patients, 18 of them with hyperprolactinemia (HPRL), were compared with 18 normoprolactinemic (NPRL) patients and 10 age-matched healthy blood-bank donor women. Patients were evaluated by means of the SLE activity index (SLEDAI). Total serum IgG and sIL-2R levels were determined by an ELISA assay. Differences between sIL-2R and IgG serum levels in patients and controls were examined by Kruskal-Wallis analysis and a Spearman r correlation to determine the association between sIL-2R, IgG and prolactin (PRL) levels. IgG and sIL-2R serum levels did not differ significantly between HPRL and NPRL patients: 1827.3 (1428- 2226) vs 2028.8 (1586- 2467) mg=dl and 882.2 (511-1254) vs 740.1 (534-946.4) U=ml, respectively (confidence interval 95%). In the total SLE group, sIL-2R and IgG serum levels were positively associated (P = 0.0009), however, this was not the case for sIL-2R and PRL (P > 0.49). We did not demonstrate an associationbetween HPRL and lymphocyte activation measured through serum sIL- 2R in female patients with SLE.
Homozygous single nucleotide polymorphism of the complement C1QA gene is associated with decreased levels of C1q in patients with subacute cutaneous lupus erythematosus
Authors: Racila D M , Sontheimer C J , Sheffield A , Wisnieski J J , Racila E , Sontheimer R D
Published: March 2003

We report an association between a non-familial form of photosensitive Lupus-specific skin disease, subacute cutaneous lupus erythematosus (SCLE), and a new single nucleotide polymorphism (SNP) in the C1QA gene. We also describe an association between this SNP and lower levels of serum C1q. This SNP consists of adenine replacing the third guanine in the codon for amino acid residue Gly70 (position excludes the 22 amino acid leading peptide) that is located in the second exon of the C1QA gene. We have designated this SNP C1qA - Gly70GGA (the GenBank sequence at this location is C1qA - Gly70GGG). A survey of 19 SCLE patients showed that 11 (58%) were homozygous for C1qA - Gly70GGA SNP, seven (37%) were heterozygous, and only one patient (5%) was homozygous for the GenBank sequence. In contrast, only 13 of 62 (21%) normal controls were homozygous for the C1qA - Gly70GGA SNP, 41 (66%) controls were heterozygous and eight (13%) controls were homozygous for the GenBank sequence. Thus, the C1qA - Gly70GGA SNP is strongly associated with SCLE (P-value = 0.005 by chi-square analysis with Yates correction). This SNP would traditionally be classified as clinically silent as it does not encode a different amino acid. However, our studies have suggested that this SNP appears to be associated with a functional abnormality of C1q expression since its presence correlates inversely with serum levels of C1q antigenic protein in both SCLE patients and normal controls. The mechanism by which this phenotypic change is associated with the translationally silent (synonymous) C1qA - Gly70GGA genetic variation is currently unknown.
Rapid clinical progression to diagnosis among African-American men with systemic lupus erythematosus
Authors: Arbuckle M R , James J A , Dennis G J , Rubertone M V , McClain M T , Kim X R , Harley J B
Published: March 2003

The initial clinical course of systemic lupus erythematosus (SLE) is variable, ranging from relatively minor manifestations progressing over years to rapid onset of fulminate disease. We sought to identify factors associated with the rapid manifestation of SLE. Chart review of military medical records was used to identify 130 patients who met the American College of Rheumatology classification criteria for SLE. Demographics, clinical criteria date of occurrence, and the date of SLE classification (at least four clinical criteria) met were documented. Prospectively stored serum samples prior to the diagnosis were evaluated for SLE autoantibodies. Median time from the first recorded criteria to diagnosis was significantly shorter in African-American (AA) males compared with AA females and European American (EA) females and males combined. AA males were more likely to have nephritis as their first clinical symptom. Also, less time transpired between the first clinical criterion and SLE diagnosis in AA males with nephritis than in other groups presenting with nephritis. Even when cases presenting with nephritis were excluded, a diagnosis of SLE was made more rapidly in AA males. African-American men progress from initial clinical manifestations to SLE diagnosis more rapidly than other ethnic or gender groups.
The transforming growth factor-β1 gene polymorphism (G915C) is not associated with systemic lupus erythematosus
Authors: Schotte H , Willeke P , Rust S , Assmann G , Domschke W , Gaubitz M , Schlüter B
Published: March 2003

Lymphocyte production of transforming growth factor (TGF)-β1 is decreased in systemic lupus erythematosus (SLE). The lack of this immunoregulatory cytokine may contribute to the characteristic T cell disregulation and aberrant B cell stimulation in SLE patients. The less common C allele of the TGFB1 polymorphism (G915C) is associated with a lower TGF-β1 production capacity. We performed a population-basedcase - control study to analyse the impact of this polymorphism on disease susceptibility, on clinical SLE manifestations and autoantibody production. A total of 203 German Caucasian SLE patients (fulfilling the 1982 ACR criteria, disease duration 11.5±7.0 years) and 158 ethnically, age- and sex-matched healthy controls were genotyped with a mutagenically separated polymerase chain reaction. There were no significant differences in the genotype distribution and allele frequencies between patients (915 C = 0.08) and healthy controls (915 C = 0.10). Comparing subgroups of patients, we found no association of major disease manifestations or specific autoantibodies with TGFB1 genotypes or alleles. The TGFB1 polymorphism (G915C) neither significantly contributes to the disease susceptibility, nor predisposes to clinical and immunological manifestations typical of SLE. Further studies are needed to corroborate the pathogenic role of TGF-β1 in SLE patients and to identify the precise genetic elements controlling its production.
Endothelial dysfunction and atherothrombosis in mild hyperhomocysteinemia
Authors: Weiss Norbert , Keller Christiane , Hoffmann Ulrich , Loscalzo Joseph
Published: March 2003

Mildly elevated plasma homocysteine levels are an independent risk factor for atherothrombotic vascular disease in the coronary, cerebrovascular, and peripheral arterial circulation. Endothelial dysfunction as manifested by impaired endothelium-dependent regulation of vascular tone and blood flow, by increased recruitment and adhesion of circulating inflammatory cells to the endothelium, and by a loss of endothelial cell antithrombotic function contributes to the vascular disorders linked to hyperhomocysteinemia. Increased vascular oxidant stress through imbalanced thiol redox status and inhibition of important antioxidant enzymes by homocysteine results in decreased bioavailability of the endothelium-derived signaling molecule nitric oxide via oxidative inactivation. This plays a central role in the molecular mechanisms underlying the effects of homocysteine on endothelial function. Supplementation of folic acid and vitamin B12 has been demonstrated to be efficient in lowering mildly elevated plasma homocysteine levels and in reversing homocysteine-induced impairment of endothelium-dependent vasoreactivity. Results from ongoing intervention trials will determine whether homocysteine-lowering therapies contribute to the prevention and reduction of atherothrombotic vascular disease and may thereby provide support for the causal relationship between hyperhomocysteinemia and atherothrombosis.
The pathophysiology of erectile dysfunction related to endothelial dysfunction and mediators of vascular function
Authors: Maas Renke , Schwedhelm Edzard , Albsmeier Jennifer , Böger Rainer H
Published: March 2003

The incidence of erectile dysfunction increases with diabetes, hypertension, hypercholesterolaemia, cardiovascular disease and renal failure. All these conditions are associated with endothelial dysfunction. This review addresses the pathophysiology of erectile dysfunction with a special focus on new insights into nitric oxide (NO)-mediated pathways, oxidative stress and parallels to endothelial dysfunction. NO appears to be the key mediator promoting endothelium-derived vasodilation and penile erection. The possibility is discussed that elevated plasma concentrations of asymmetrical dimethylarginine (ADMA), an endogenous NO synthase inhibitor, may provide an additional pathomechanism for various forms of erectile dysfunction associated with cardiovascular risk factors and disease. Likewise, the role of endothelium-derived factors mediating NO-independent pathways is evaluated.
A novel ultrasound method for evaluation of collateral development in limb ischemia
Authors: Mohler Emile R , Sehgal Chandra M , Ferrari Victor A , Parmacek Michael , Shih Anthony , Wilensky Robert L
Published: March 2003

Although clinical studies are underway to evaluate the effectiveness of angiogenesis, there are no validated, non-invasive methods to assess peripheral collateral development. This study was performed to validate a novel ultrasound-based method of assessing collateral formation in a pig model of hindlimb ischemia.

Ultrasonography of predefined ultrasound planes was performed on 12 pigs immediately after ligation of the right common femoral artery, and 7, 14, 28 and 42 days thereafter. A custom software program was used to evaluate both color Doppler (CD) and power Doppler (PD) images to generate flow indices.

Collateral development was observed with ultrasound as early as 7 days post-arteriectomy and increased dramatically by 28 days. Areas of persistent ischemia resulting from inadequate collateral formation were easily quantified in all images. Collaterals detected on ultrasound were confirmed by angiography and histology, and tissue perfusion by a fluorescent microsphere method.

As demonstrated with color and power Doppler measurements, collateral formation is initiated early after ischemic injury in this large juvenile animal model of angiogenesis. This non-invasive method is useful to quantify blood flow, visualize angiogenesis and determine areas of persistent lower limb ischemia, and may have an important role in evaluating new approaches to modulate angiogenesis.
Isolated internal jugular vein thrombosis: risk factors and natural history
Authors: Sheikh Mobeen A , Topoulos Arthur P , Deitcher Steven R
Published: March 2003

Deep venous thrombosis (DVT) involving the upper extremities, chest, and neck has become appreciated as a significant cause of morbidity, especially in individuals with central venous access devices (CVAD). Like DVT involving the leg and pelvic veins, axillo-subclavian vein thrombosis can result in pulmonary embolism, post-thrombotic syndrome, and venous limb gangrene. Data relating to the natural history of internal jugular vein thrombosis (IJVT) is lacking. Risk factors, treatment patterns, and clinically relevant outcomes were retrospectively assessed in 74 consecutive patients with isolated IJVT. All patients (median age 66 years; range 36-80) had CVAD-associated IJVT, 22 (29.7%) had a history of cancer, and 14 (18.9%) had a history of prior DVT. Thirty-two (43.2%) were treated with systemic anticoagulation, 2 (2.7%) received a superior vena cava filter, and 40 (54.1%) received no specific therapy. Of the patients who underwent serial imaging, 7/40 (17.5%) had thrombus propagation. Two (2.7%) patients were diagnosed with pulmonary embolism, 8 (10.8%) were diagnosed with malignancy during a median follow-up of 20 months (range 18-24), and 3/53 (5.7%) suffered a recurrent DVT. Outcomes similar to those seen in leg DVT were observed. The most effective treatment strategy remains to be determined, but anticoagulant treatment was associated with a trend towards reduced all-cause mortality.
Massive pulmonary embolism: a remarkable case and review of treatment
Authors: Cooper Joshua M , Beckman Joshua A
Published: March 2003

Although the clinical syndrome following pulmonary embolism (PE) may be subtle, in the case of massive PE the severity of the clinical presentation typically makes the picture more obvious. If more than two lobar pulmonary arteries become obstructed, the hemodynamic and respiratory consequences are severe, and may be life threatening. We present an unusual case where a patient experienced transient hemodynamic collapse during valsalva, and a massive saddle pulmonary embolus was discovered incidentally. Current treatment options for massive PE are then discussed.
Vascular viewpoint
Authors: Merali Fatima S , Anand Sonia S
Published: March 2003

Objectives: To determine if immediate surgical repair or regular radiologic surveillance improves survival in patients with small aortic aneurysms.

Methods: A total of 1136 people with asymptomatic infrarenal aortic aneurysms (4.0-5.4 cm) with minimal co-morbidities were randomized to standard surgical repair with interposition of a synthetic graft (n = 569) versus radiological surveillance (n = 567). Patients were followed up every 6 months, and those in the surveillance group had CT scan or ultrasound imaging studies. If the aneurysm reached at least 5.5 cm in diameter, or enlarged by 0.7 cm in 6 months, or 1 cm in 1 year, patients in the surveillance group were referred for surgery. The mean duration of follow-up was 4.9 years.

Outcomes: The primary outcome was death from any cause, and the primary analysis was by intention to treat.

Results: In all, 92.6% patients underwent repair in the immediate surgery group compared with 61.6% repairs in the surveillance group. No significant difference in death from any cause was observed between the immediate repair group (25.1%) and the surveillance group (21.5%) (RR 1.21; 95% CI: 0.95-1.54). Immediate repair did not benefit any of the prespecified groups.

Conclusion: No survival benefit is associated with immediate repair of asymptomatic abdominal aortic aneurysms which are less than 5.5 cm.
In-vitro evaluation of bioadhesion in particulate systems and possible improvement using interactive mixtures
Authors: Bredenberg Susanne , Nyström Christer
Published: March 2003

The bioadhesion of tablet components was tested using the fracture method (maximum tensile stress in detaching the sample from mucus membrane) and comparing traditional tablet specimens with powder monolayers. Both nonadhesive excipients and established mucoadhesive materials were investigated. Some nonadhesive materials showed unexpectedly good adhesive properties when tested as tablets but not as powders. Conversely, some bioadhesive materials had unexpectedly low adhesive properties when tested as tablets. Thus, powder specimens of some materials appear to give more realistic results than tablet specimens in this respect. The use of powder specimens seems particularly applicable for testing dispersible tablets intended fortransmucosal absorption. Potential for increasing the bioadhesive properties of coarse, nonadhesive carrier particles by coating them with fine particles of bioadhesive materials during dry mixing (forming interactive mixtures) was also studied. The tensile strength of the adhesive bond between the mucosa and the nonadhesive excipients was improved when fine cross-linked carboxymethyl cellulose sodium (Ac-Di-Sol) particles were added. The addition of increased proportions of Ac-Di-Sol initially improved the bioadhesive properties until a plateau was reached. A standardised test of bioadhesive capacity could therefore involve the addition of fine bioadhesive powders to coarse carriers in proportions close to those providing monoparticulate surface coverage. Interactive mixtures such as these may also offer potential as a tool for use in the development of bioadhesive drug formulations.
Therapeutic equivalence of a low dose artemisinin formulation in falciparum malaria patients
Authors: Wong J W , Yuen K H , Nagappan S , Shahul W S , Ho S S David , Gan E K , Toh W T
Published: March 2003

We have evaluated the therapeutic equivalence of a β-cyclodextrin–artemisinin complex at an artemisinin dose of 150 mg, with a commercial reference preparation, Artemisinin 250 at a recommended dose of 250 mg. One hundred uncomplicated falciparum malarial patients were randomly assigned to orally receive either β-cyclo-extrin–artemisinin complex (containing 150 mg artemisinin) twice daily for five days or the active comparator (containing 250 mg artemisinin) twice daily for five days. The patients were hospitalized for seven days and were required to attend follow up assessments on days 14, 21, 28 and 35. All patients in both treatment groups were cured of the infection and achieved therapeutic success. At day seven of treatment, all patient blood was clear of the parasites and the sublingual temperature of all patients was less than 37.5°C. Moreover, the parasite clearance time in both treatment groups was similar, being approximately three days after initiation of treatment. Comparable plasma artemisinin concentrations were observed between patients in both treatment groups at 1.5 and 3.0 h, although slightly higher levels were obtained with patients in the β-cyclodextrin–artemisinin complex-treated group. The β-cyclodextrin–artemisinin complex at a dose of 150 mg artemisinin was therapeutically equivalent to 250 mg Artemisinin 250. Additionally, patients receiving β-cyclodextrin–artemisinin complex showed less variability in their plasma artemisinin concentrations at 1.5 h post-dosing, which suggested a more consistent rate of drug absorption.
Therapeutic usefulness of Keishi-bukuryo-gan for diabetic nephropathy
Authors: Nakagawa Takako , Yokozawa Takako , Terasawa Katsutoshi , Nakanishi Kazuo
Published: March 2003

Keishi-bukuryo-gan is a traditional herbal medicine, which is used clinically as a vascular system disorder-eliminating drug. In this study, its effect on the progression of diabetic nephropathy in experimental rats was investigated. The diabetic nephropathy model used in this study shows functional and morphological changes of the kidney resembling those seen in patients with diabetic nephropathy. Increased proteinuria and serum urea nitrogen and creatinine levels and decreased creatinine clearance, which are important parameters of renal function, were observed in rats with diabetic nephropathy. Pathological examination of the kidney revealed diffuse, nodular and exudative lesions and arteriolar hyalinosis. The deterioration of renal function was ameliorated in rats treated with Keishi-bukuryo-gan for 15 weeks and these results agreed with the renal histological findings. In addition, metabolic abnormalities mediated by persistent hyperglycaemia (the glycation reaction, excessive polyol pathway activity, oxidative stress and lipid metabolic abnormalities) were also observed. However, Keishi-bukuryo-gan reduced accumulation of advanced glycation end products, determined by measuring fluorescence, and serum lipid peroxidation, triglyceride and total cholesterol levels dose-dependently. Thus, this study indicates the potential therapeutic usefulness of Keishi-bukuryogan for retarding the progression of renal damage and suggests that its beneficial effects were due to its ability to improve metabolic abnormalities associated with diabetes.
Erythromycin, an inhibitor of mitoribosomal protein biosynthesis, alters the amphotericin B susceptibility of Candida albicans
Authors: Geraghty Patrick , Kavanagh Kevin
Published: March 2003

Exposure of the yeast Candida albicans to the macrolide antibiotic erythromycin (C37H67NO13) results in elevated tolerance to the polyene antifungal amphotericin B. Erythromycin displays no fungistatic activity against C. albicans but inhibits the synthesis of cytochromes, particularly cytochrome aa3. Consequently there is a reduction in aerobic respiration by up to 90% when cells are exposed to 10 mg mL−1 erythromycin. Cellular ergosterol levels are also severely reduced. Erythromycin inhibits protein biosynthesis in ribosomes (mitoribosomes) located within the mitochondrion of the yeast cell, which results in a disruption of cytochrome biosynthesis with an adverse effect on respiration. The synthesis of ergosterol is oxygen dependent and consequently ergosterol levels are depleted in erythromycin-treated C. albicans. Ergosterol is the target for amphotericin B and since there is less of this sterol in erythromycin-treated cells, there is an increase in tolerance of the antifungal agent. Our work indicates that co-administration of erythromycin and amphotericin B to control bacterial and fungal infections, respectively, may inadvertently lead to an elevation in the tolerance of C. albicans for this antifungal agent.
Non-steroidal anti-inflammatory drug, nabumetone, prevents indometacin-induced gastric damage via inhibition of neutrophil functions
Authors: Ishiwata Yoshiro , Okamoto Masayuki , Yokochi Shoji , Hashimoto Hiroyuki , Nakamura Takashi , Miyachi Atsushi , Naito Yuji , Yoshikawa Toshikazu
Published: March 2003

Nabumetone is a non-steroidal anti-inflammatory drug (NSAID). It works as a prodrug and is extensively metabolized to an active metabolite, 6-methoxy-2-naphthylacetic acid (6MNA). It is well known that neutrophil infiltration and activation are critical in the pathogenesis of NSAID-induced gastric injury, and nabumetone shows less incidence of gastrointestinal irritancy. We examined the effects of nabumetone on neutrophil activation and on indometacin-induced gastric damage. In the indometacin-induced gastric mucosal injury, rats were treated with indometacin and then nabumetone or 6MNA was orally administered. Nabumetone prevented gastric damage accompanied by the reduction of neutrophil infiltration into gastric mucosa, but such an effect was not observed with 6MNA. Nabumetone reduced the formyl methionyl leucyl phenylalanine (fMLP)-induced respiratory burst of human neutrophils to 30% of the control level in-vitro, but 6MNA did not. In addition, nabumetone prevented the fMLP-induced migration of neutrophils. Nabumetone did not inhibit O−2 generation in the xanthine-xanthine oxidase system. These results suggest that nabumetone prevents gastric damage induced by the active metabolite, 6MNA, via the suppression of neutrophil activation in gastric mucosa.
Possible involvement of peripheral serotonin 5-HT3 receptors in fluvoxamine-induced emesis in Suncus murinus
Authors: Fujiwara-Sawada Mina , Imanishi Taiichiro , Yoshida Akiko , Baba Jun
Published: March 2003

Selective serotonin reuptake inhibitors fluvoxamine and fluoxetine, as well as serotonin (5-HT), induced vomiting in Suncus murinus (a house musk shrew). Fluvoxamine- and fluoxetine-induced vomiting gradually decreased with their repeated administration. Vomiting induced by serotonin also decreased with repeated treatment with serotonin. In these shrews, fluvoxamine-induced vomiting was partially inhibited. Fluvoxamine might induce vomiting, at least partially, by indirectly activating peripheral 5-HT3 receptors, since serotonin has been reported to induce vomiting by activating peripheral 5-HT3 receptors and granisetron, a 5-HT3 antagonist, partially suppressed fluvoxamine-induced vomiting in our previous finding. In addition, fluvoxamine-induced vomiting was impaired more effectively using a step-wise dose-up schedule of fluvoxamine than a fixed high-dose schedule. Therefore, a careful dosing strategy starting with a low dose might be effective for avoiding emesis associated with the clinical use of fluvoxamine.
Supercritical fluid processing of proteins: lysozyme precipitation from aqueous solution
Authors: Moshashaée Saeed , Bisrat Mikael , Forbes Robert T , Quinn éilís Á , Nyqvist Håkan , York Peter
Published: March 2003

Aqueous solutions of hen egg lysozyme (3% w/v) were dispersed and precipitated by a homogenous mixture of supercritical carbon dioxide–ethanol using the Solution Enhanced Dispersion by Supercritical fluid (SEDS) process. The effects of different working conditions, such as temperature, pressure and the flow rates of the solution and ethanol, on the particle-formation process were studied. The morphology, particle size and size distribution and biological activity of the protein were determined. The precipitates were examined with high-sensitivity differential scanning calorimetry (HSDSC) and high-performance cation-exchange chromatography. Particle size measurements showed the precipitates to be aggregates with primary particles of size 1–5 μm. The similarity of HSDSC data for unprocessed and processed samples indicated that the different physical forces that stabilise the native form of lysozyme are unchanged after SEDS processing. From FT-Raman spectroscopic studies secondary structural changes were observed in certain SEDS-produced lysozyme, with most processed samples displaying a slightly more disordered secondary structure than the unprocessed sample. However, SEDS samples produced at 200 bar and 40 °C exhibited negligible disturbance. Thus the SEDS process utilising aqueous solution was able to bring about size reduction of lysozyme with minimal loss of biological activity.
Comparison of metabolic pharmacokinetics of baicalin and baicalein in rats
Authors: Lai Miao-Ying , Hsiu Su-Lan , Tsai Shang-Yuan , Hou Yu-Chi , Chao Pei-Dawn Lee
Published: March 2003

Baicalin and baicalein, a flavone glucuronide and its aglycone, are bioactive constituents of Scutellariae Radix with various beneficial activities. We have characterized and compared the metabolic pharmacokinetics of baicalin and baicalein in rats. Baicalein was administered intravenously and orally to rats, and baicalin was orally administered. An HPLC method was used to determine the concentration of baicalein before and after hydrolysis using β-glucuronidase/sulfatase. The pharmacokinetic parameters were calculated by using WINNONUN. Unpaired Student's t-test was used for statistical comparison. The result showed that after intravenous administration of baicalein, 75.7% of the dose was circulating as its conjugated metabolites. After oral administration of baicalein, absorption of baicalein itself was negligible, whereas the glucuronides/ sulfates of baicalein were predominant in the plasma. When compared with intravenous bolus administration with dose correction, the absolute absorption was 40%. When baicalin was administered orally, glucuronides and sulfates of baicalein were exclusively circulating in the plasma. The relative absorption for baicalin was 65% when compared with baicalein. Profound differences of serum profile and pharmacokinetics were observed between oral baicalein and baicalin. Baicalin demonstrated significantly later time to peak concentration (tmax) and lower peak serum concentration (Cmax) of baicalein conjugated metabolites than baicalein, indicating baicalin was absorbed more slowly and to a lesser extent than baicalein.
Sensitivity to β-adrenoceptor agonists of adipocytes from rats treated with an aqueous extract of Croton cajucara Benth
Authors: Grassi-Kassisse Dora Maria , Wolf-Nunes Valéria , Miotto Alexandre Marcucci , Farias-Silva Elisângela , Brito Alba Regina Monteiro Souza , Nunes Domingos Savio , Spadari-Bratfisch Regina Célia
Published: March 2003

Aqueous extracts of Croton cajucara bark are used in folk medicine to treat hepatic and gastrointestinal disorders and as a coadjuvant in weight-loss programs. We examined the effect of treating rats for 15 days with a 5% aqueous extract of C. cajucara on body weight and food intake. The epididymal adipose pads were removed and the lipolytic responses of isolated adipocytes to isoprenaline, noradrenaline (norepinephrine), BRL37344 and adrenaline (epinephrine) were analysed in the absence or presence of metoprolol or ICI118,551. Treated rats had a significantly lower weight gain than control rats, with no difference in food and liquid intake, epididymal fat-pad weight or basal glycerol release. The sensitivity of the lipolytic response to isoprenaline and adrenaline was significantly higher in adipocytes from treated rats. The sensitivity to noradrenaline or BRL37344 was unaltered. Metoprolol shifted the dose-response curves to noradrenaline to the right in adipocytes from control and treated rats; the dose-response curve to isoprenaline in adipocytes from control rats was also shifted to the right. In adipocytes from treated rats, the dose-response curve to isoprenaline was unaltered by metoprolol but was shifted to the right by ICI118,551, a β2-adrenoceptor antagonist. We conclude that in adipocytes from treated rats there is an increase in the lipolytic response to non-selective agonists (isoprenaline and adrenaline) mediated by β2-adrenoceptors, with no alteration in the responses mediated by β1-adrenoceptors (noradrenaline) or β3-adrenoceptors (BRL37344). This effect could increase the role of adrenaline as an endogenous stimulator of lipolysis.
The effect of food components on the absorption of P-gp substrates: a review
Authors: Deferme Sven , Augustijns Patrick
Published: March 2003

P-glycoprotein (P-gp), a well characterized efflux mechanism which is functionally expressed in the intestinal epithelium, constitutes, along with intestinal metabolism, an important part of the biochemical barrier function of the intestinal mucosa. This efflux carrier may be responsible for limiting the bioavailability of several drugs after oral intake. Recently, increasing attention is being paid to the interaction of dietary components with the intestinal absorption of drugs. This review focuses on the modulating capacity of food components on the intestinal absorption of P-gp substrates. The possible P-gp inhibitory effects of several dietary constituents are discussed. In addition, this review will also focus on the effect of several bioflavonoids on the P-gp-mediated efflux of drugs. As the role of P-gp (and other efflux carriers, including multidrug resistance-associated proteins and breast cancer resistance protein) in limiting the bioavailability of drugs becomes more clear, more research is required firstly to identify the effect of dietary compounds on these efflux carriers and secondly to reveal the clinical relevance of this interaction.
Intracellular calcium measurements of single human skin cells after stimulation with corticotropin-releasing factor and urocortin using confocal laser scanning microscopy
Authors: Wiesner Burkhard , Roloff Birgit , Fechner Klaus , Slominski Andrzej
Published: March 2003

Using confocal laser scanning microscopy we investigated the Ca2+ distribution in single corticotropin releasing factor- and urocortin-stimulated human skin cells. The models tested included melanoma cells, neonatal melanocytes and keratinocytes, and immortalized HaCaT keratinocytes. The changes in intracellular Ca2+ signal intensities observed after stimulation of different cell types with corticotropin releasing factor and urocortin showed that: (1) the increase of intracellular Ca2+ concentration was caused by a Ca2+ influx(inhibition by EGTA); (2) this Ca2+ influx took place through voltage-activated Ca2+ ion channels (inhibition by d-cis-diltiazem,verapamil) and (3) cyclic nucleotide-gated ion channels were not involved in this process (no effect of Mg2+). The effects were also observed at very low peptide concentrations (10-13 M) with no apparent linear correlation between peptide dosage and increase of fluorescence intensity,which implied co-expression of different corticotropin releasing factor receptor forms in the same cell. Immortalized (HaCaT) keratinocytes exhibited the strongest differential increases of a Ca2+ fluorescence after peptide-stimulation. Corticotropin releasing factor induced Ca2+flux into the cytoplasm, while urocortin Ca2+ flux into the nucleus with a remarkable oscillatory effect. The latter indicated the presence of an intracellular urocortin-induced signal transduction pathway that is unique to keratinocytes.
Junctional protein MAGI-3 interacts with receptor tyrosine phosphataseβ (RPTPβ) and tyrosine-phosphorylated proteins
Authors: Adamsky Konstantin , Arnold Katya , Sabanay Helena , Peles Elior
Published: March 2003

Receptor protein tyrosine phosphatase β (RPTPβ) mediates cell-cell and cell-matrix interactions. By searching for intracellular proteins that interact with the cytoplasmic region of this phosphatase using the two-hybrid method, we identified several proteins containing PDZ domains. One of these proteins, MAGI-3, contains a guanylate-kinase-like region, six PDZ and two WW domains. The interaction between RPTPβ and MAGI-3 was confirmed by co-immunoprecipitation and pulldown experiments in transfected cells. Immunofluorescence and immunoelectron microscopy revealed that MAGI-3 is concentrated in specific sites at the plasma membrane and in the nucleus. In epithelial cells, MAGI-3 was localized with ZO-1 and cingulin at tight junctions, whereas in primary cultured astrocytes it was found in E-cadherin-based cell-cell contacts and in focal adhesion sites. Although MAGI-3 itself was not phosphorylated on tyrosine residues, it became associated with tyrosine-phosphorylated proteins following a short treatment of the cells with vanadate. In glioblastoma SF763T cells MAGI-3 was associated with a tyrosine-phosphorylated protein with the apparent molecular weight of 130 kDa, whereas in Caco2 cells it was associated with a 90 kDa protein. Finally, we show that p130 served as a substrate for RPTPβ and that its dephosphorylation required the C-terminal sequence of the phosphatase, which mediated the interaction with MAGI-3. These findings suggest a possible role for MAGI-3 as a scaffolding molecule that links receptor tyrosine phosphatase with its substrates at the plasma membrane.