Anomalous Zemplén deacylation reactions of alpha- and beta-D-mannopyranoside derivatives

Reaction of mono-, di-, and trisaccharide derivatives of methyl beta-D- and octyl beta-D-mannopyranosides bearing ester groups at isolated and non-isolated positions on the same molecule, under Zemplén conditions (catalytic amount of sodium methoxide in methanol) gave partially deacylated compounds, in which the O-acyl groups were retained at isolated sites. In the case of one disaccharide, all the benzoyl groups remained intact at the reducing end, while all the acetyl functions were removable from the nonreducing end. In another case, both isolated ester groups at positions 2 and 4 were retained at the reducing end. The isolated 2-O-acyl groups on methyl alpha-D-mannopyranoside compounds were more labile than on the corresponding beta-mannosides under the same conditions. The mechanism of the reaction may be different for ester groups at isolated or non-isolated positions. In the latter case, acyl migration may take place and carry acyl groups into a less hindered position.     

Therapy of multiple myeloma

Multiple myeloma (MM) is a haematological malignancy characterised by the clonal expansion of malignant plasma cells within the bone marrow. It accounts for 10% of all haematological malignant diseases and 1% of all malignancies. The median age of patients at the time of the diagnosis is 70 years. The characteristic clinical features of MM are bone marrow failure, susceptibility to infections, bone pain, pathological bone fractures, hypercalcaemia, and renal failure. Though MM is currently incurable, the important progress in chemotherapy has resulted in an improvement in survival from a median of 7 months in the 1950-ies to about 3 years today. Advances in the diagnosis and in supportive treatment of infections, hypercalcaemia, and renal failure also contributed to the prolongation of survival. For decades, the gold standard of treatment had been oral melphalan alone or in combination with prednisolone. Combination chemotherapy has not improved overall survival (OS), but these regimens have led to the prolongation of event-free survival (EFS) and also to a better quality of life. High-dose chemotherapy with haemopoietic stem cell rescue resulted in a great improvement in EFS as well as OS. For those very few who have an HLA-compatible donor and are under 55, allogeneic bone marrow transplantation offers the best hope of survival but comes at a greatly increased risk of toxicity. There are conflicting data in the literature concerning the role of interferon-alpha; it seems to be able to prolong the duration of the plateau phase. Current treatment is moving towards an approach using sequential therapy. This involves induction therapy proceeding to high-dose chemotherapy with some form of stem-cell rescue. Bisphosphonates reduce hypercalcaemia, bone pain and can inhibit bone destruction. They also possess a direct antitumor activity. The better understanding of the pathomechanism of the disease gives the opportunity of the application of new therapeutic modalities such as antagonising the effect of interleukin-6 (IL-6), or idiotypic vaccination.     

Ovarian carcinoma of low malignant potential treated at the 1(st) Department of Obstetrics and Gynecology Semmelweis University Faculty of Medicine,between 1990 and 2000

The authors analyzed the epidemiologic and histological characteristics and the management of ovarian carcinoma of low malignant potential (LMP) at a university hospital between 1990 and 2000. The authors carried out a retrospective study reviewing hospital charts. Based on the records experience with 29 such tumors is peresented. Of these 20 (74%) were of the serous variety, 7 (26%) were mucinous. LMP tumors accounted for 16% of proliferating epithelial ovarian tumors. They occured at a mean age of 45 years. The LMP tumors were bilateral in 12% of the cases. The majority of patients (87%) with LMP tumors presented with early stage disease. Tumor markers such as CA-125 were not always elevated as in invasive ovarian carcinoma. Laboratory investigations have not demonstrated that these tumors represent an intermediate step between benign ovarian tumors and carcinoma. The recommended therapy is surgical, consisting of total abdominal hysterectomy, bilateral salpingo-oophorectomy, peritoneal washings, and tumor debulking. Conservative surgery consisting of unilateral salpingo-oophorectomy is considered to be an appropriate treatment for young women with early stage LMP ovarian tumors who wish to retain their fertility potential. 50 percent of women who underwent conservative surgery subsequently conceived in this study. There were no recurrences in the study group, so the authors conclude that the long term outcome of LMP tumors is extremely favorable.     

Radiotherapy of benign disorders

The radiation oncologist's primary concern is treatment of patients with malignant tumors but sometimes faces on occasion rare, non malignant disorders. The scarcity of disease incidence is reflected by the paucity of references for these diseases in the literature. This minimal exchange of information may make research and analysis difficult, tedious and not easily directed. Even with recognition of the risks of late skin injury, carcinogenesis, leukemogenesis and genetic damage from all ionizing radiation, radiation therapy also continues to be accepted treatment for benign diseases that do not respond to other methods of therapy. The purpose of this paper is to provide a short overview of the radiotherapy of most frequent benign disorders.     

Effects of pituitary adenylate cyclase-activating polypeptide on the cyclooxygenase pathway of rat platelets and on platelet aggregation

Several data suggest that pituitary adenylate cyclase-activating polypeptide (PACAP) is involved in the regulation of local circulation. One possible role of PACAP in the regulation of circulation is that, it may modify the cyclooxygenase pathway of the arachidonate cascade in platelets. Our study was designed to study the effect of PACAP on the cyclooxygenase pathway of rat platelets and on platelet aggregation. PACAP (10(-7) and 10(-6) M) significantly inhibited the cyclooxygenase pathway of platelets, mostly the thromboxane synthesis. Pretreatment with a PACAP receptor antagonist, PACAP(6-38), or with an inhibitor of protein kinase A, H-89, shows that the effects of PACAP on the cyclooxygenase pathway were diminished. In the aggregation studies, PACAP inhibited both the arachidonic acid-induced and the thrombin-induced platelet aggregation. It can be concluded that PACAP inhibits the cyclooxygenase pathway of rat platelets via a specific PACAP receptor-activated, cAMP-dependent pathway, and these effects of PACAP are involved in the inhibition of platelet aggregation.     

Influence of temperature and pH on the in vitro adherence of Candida albicans.

Yeast adherence to epithelial cells is a very important step in colonization and infection caused by these opportunistic pathogens. This phenomenon may be modified in vitro by many factors. The aim of this work was to find out how variations in pH and temperature modify the in vitro adherence of Candida albicans to epithelial cells. We worked with epithelial buccal cells and a yeast strain according to Gibbons and Van Houte technique with slight modifications. In the first assay, adherence at 28 degrees C and 37 degrees C, and three pH values, 6, 7.2 and 8.4 were simultaneously studied. We did not find significant variations in adherente capacity, but a slight increase was detected at pH 7.2 and 37 degrees C. In the second assay, temperature was fixed at 37 degrees C and four pH values were studied: 3, 4, 5, and 7.2. We find a highly significant difference (p < 0.001) between adherente at pH = 7.2 with respect to the other pH values. According to these results C. albicans adherence to epithelial buccal cells, in vitro, is produced at 37 degrees C and pH 7.2 in optimal conditions.     

Conus venoms: a source of toxins which interact with membrane- potential-dependent sodium channels

Marine snails of the genus Conus, as they are carnivorous predators, have a venom apparatus used to capture their prey. The toxins contained in the venoms of Conidae, called conotoxins, are of a particular high degree of diversity and represent powerful tools in the neuroscience field. Indeed, these toxins specifically bind with a high affinity to receptors and ionic channels. Therefore, they provide original pharmacological tools which receive increasing investigation both to identify and study some functions of the nervous systems and to characterize new types and closely related subtypes of receptors or ionic channels. The voltage-gated sodium channel, because of its fundamental role in cell membrane excitability, is the specific target of a large number of animal and vegetal toxins. Actually, at least seven toxin receptor sites have been identified on this channel-protein. These toxins, and in particular conotoxins, are used to precise the role of different types and/or closely related subtypes of sodium channels in the peripheral and central nervous systems. The focus of the present review is to summarize our current knowledge of the consequences of physiological interactions between different conotoxin families and sodium channels.     

Preparation of N2, N2,7-trimethylguanosine affinity columns

2,2,7-trimethylguanosine (TMG) binding proteins from human cells were purified through TMG-affinity columns. TMG synthesis was improved and the TMG obtained was shown to be similar to the TMG in the 5' cap of the UsnRNAs. The eluates obtained with TMG-affinity chromatographies were very different from those isolated with m7G-affinity columns, thus suggesting that specific TMG-binding proteins were obtained. The fraction may be enriched with factors associated with import and/or hypermethylation of UsnRNPs.     

Phosphatidylinositol 3-kinase contributes to Erk1/Erk2 MAP kinase activation associated with hepatocyte growth factor-induced cell scattering

MAP kinase cascade-dependent responses were investigated during scattering of HepG2 human hepatoma cells stimulated by HGF or phorbol ester. Inhibition of phosphatidylinositol 3-kinase with LY294002 prevented completely the dissociation of cells. Inhibition of MAP kinase kinase (MEK) with PD98059 prevented the development of characteristic morphological changes associated with cell migration. EGF, which failed to induce cell scattering, caused a short-term increase in the phosphorylation of Erk1/Erk2 MAP kinases. On the contrary, HGF or phorbol ester stimulated the phosphorylation of MAP kinases for a long time. Experiments performed with LY294002 indicated that phosphatidylinositol 3-kinase contributed to the HGF-stimulated phosphorylation of Erk1/Erk2. This finding was confirmed by the demonstration that the MAP kinase cascade-dependent expression of a high-Mr (>300 kDa) protein pair appearing in the course of cell scattering was inhibited by LY294002 in HGF-induced cells but was not inhibited in phorbol ester-treated cells.     

Essential oil of Lepechinia schiedeana (Lamiaceae) from Costa Rica

The composition of the essential oil isolated by steam distillation from aerial parts of the Costa Rican herb Lepechinia schiedeana (Schlecht) Vatke (Lamiaceae) collected in El Empalme, Costa Rica, was determined by capillary gas chromatography (GC) and coupled gas chromatography-mass spectrometry (GC-MS) analyses. Fifty-one components were identified corresponding ca. 93% of the oil. The major components were beta-pinene (26.6%), cis-pinocamphone (25.1%), delta-3-carene (6.1%), trans-pinocamphone (4.0%), camphor (3.8%) and beta-caryophyllene (3.7%).