Architecture of the yeast origin recognition complex bound to origins of DNA replication

In many organisms, the replication of DNA requires the binding of a protein called the initiator to DNA sites referred to as origins of replication. Analyses of multiple initiator proteins bound to their cognate origins have provided important insights into the mechanism by which DNA replication is initiated. To extend this level of analysis to the study of eukaryotic chromosomal replication, we have investigated the architecture of the Saccharomyces cerevisiae origin recognition complex (ORC) bound to yeast origins of replication. Determination of DNA residues important for ORC-origin association indicated that ORC interacts preferentially with one strand of the ARS1 origin of replication. DNA binding assays using ORC complexes lacking one of the six subunits demonstrated that the DNA binding domain of ORC requires the coordinate action of five of the six ORC subunits. Protein-DNA cross-linking studies suggested that recognition of origin sequences is mediated primarily by two different groups of ORC subunits that make sequence-specific contacts with two distinct regions of the DNA. Implications of these findings for ORC function and the mechanism of initiation of eukaryotic DNA replication are discussed.

Involvement of nuclear factor-kappa B in platelet-activating factor-mediated tumor necrosis factor-alpha expression

Tumor necrosis factor (TNF)-alpha and platelet-activating factor (PAF) are important mediators of inflammatory reactions, and their release is controlled by a positive feedback network. However, the regulatory mechanisms underlying the interaction of these two molecules are unknown. Within 10 min of the injection of lipopolysaccharide (LPS) into C57BL/6 mice, effects inducible by PAF such as anaphylactic shock-like symptoms, disseminated intravascular coagulation, and hemorrhage in renal medullae were observed, and all these pathological changes were prevented by the PAF antagonist, BN 50739. The plasma level of PAF after LPS injection reached a peak at 5 min. TNF-alpha gene expression was evident 20 min after LPS injection and was maximal at 40 min, and the level of serum TNF-alpha reached a peak at 1 h. Pretreatment with BN 50739 inhibited LPS-induced TNF-alpha gene expression and protein synthesis in a dose-dependent manner. Injection of PAF or treatment of the macrophage cell line, J774A.1, with PAF activated the transcription factor, nuclear factor (NF)-kappa B, which is essential for inducible TNF-alpha transcription. The activation of NF-kappa B by PAF preceded the LPS-mediated TNF-alpha gene expression. Pretreatment with BN 50739 inhibited LPS-induced mobilization of NF-kappa B in a dose-dependent manner in vivo as well as in vitro. These data suggest that PAF, which is released immediately or shortly after LPS injection, induces the expression of TNF-alpha through the activation of NF-kappa B.

Design of novel analogue peptides with potent fungicidal but low hemolytic activity based on the cecropin A-melittin hybrid structure

In order to design synthetic peptides with potent antifungal activity but low cytotoxic activity under physiological conditions, several analogues of the previously reported cecropin A (CA)-melittin (ME) hybrid peptide, CA(1-8)-ME(1-12), were synthesized. These analogues were designed by analysis of the alpha-helical wheel diagram of CA(1-8)-ME(1-12). Antifungal activities were measured by growth inhibition of the yeast Trichosporon beigelii and by hemolytic assay with human red blood cells, respectively. Substitution of Thr for Lys at position 18 and 19 of CA(1-8)-ME(1-12) caused a dramatic reduction in hemolytic activity. Two analogue peptides (analogue I and III) showed more potent antifungal and lower hemolytic activity than the original peptide. To study the antifungal mechanism of these peptides, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed with the most powerful antifungal analogue I peptide designed in the present study. As determined by propidium iodide staining, fungal cells treated with analogue I or melittin showed higher fluorescence intensity than those treated with the weak antifungal peptide, cecropin A. By confocal microscopy the analogue I was detected in the intracellular region as well as the in cell membrane. These facts suggested that the antifungal function of this novel peptide analogue acts by pore formation in the cell membrane.

Anti-IL-4 monoclonal antibody prevents antibiotics-induced active fatal anaphylaxis

We previously reported that anti-IL-4 mAb (11B11) failed to prevent protein-induced fatal murine anaphylaxis. To investigate the effect of anti-IL-4 on hapten-induced anaphylaxis, a model of murine anaphylaxis induced by antibiotics, penicillin V (Pen V) and cephalothin (CET), was developed, and the effect of anti-IL-4 on the anaphylaxis was observed. Pen V and CET induced 100 and 70 to 90% fatal reactions, respectively, when C57BL/6 mice were sensitized i.p. with 500 microg of antibiotic-OVA conjugate with 2 x 10(9) Bordetella pertussis and 1.0 mg of alum and challenged i.v. with 100 microg of antibiotic-BSA conjugate 14 days later. Serum taken from mice sensitized to Pen V passively sensitized normal mice to develop systemic anaphylaxis, and this ability of the serum was abrogated by heating at 56 degrees C for 2 h or depletion of IgE, but not IgG, Abs. Thus, the antibiotic-induced fatal reaction was an IgE-dependent anaphylactic reaction. Administration of anti-IL-4 at the beginning of sensitization completely prevented the fatal anaphylactic reactions to both Pen V and CET. This effect of anti-IL-4 was associated with its suppressive activity on antibiotic-specific serum IgE, but not IgG, levels. More importantly, anti-IL-4 therapy in previously sensitized mice was also effective in preventing the fatal reactions and rapidly reduced the established IgE levels. This study provides a new animal model of hapten-induced anaphylaxis and indicates that blocking of IL-4 activity may be beneficial in allergic diseases caused by a variety of haptens in which IgE Abs play a major role.

Anti-IL-4 monoclonal antibody prevents antibiotics-induced active fatal anaphylaxis

We previously reported that anti-IL-4 mAb (11B11) failed to prevent protein-induced fatal murine anaphylaxis. To investigate the effect of anti-IL-4 on hapten-induced anaphylaxis, a model of murine anaphylaxis induced by antibiotics, penicillin V (Pen V) and cephalothin (CET), was developed, and the effect of anti-IL-4 on the anaphylaxis was observed. Pen V and CET induced 100 and 70 to 90% fatal reactions, respectively, when C57BL/6 mice were sensitized i.p. with 500 microg of antibiotic-OVA conjugate with 2 x 10(9) Bordetella pertussis and 1.0 mg of alum and challenged i.v. with 100 microg of antibiotic-BSA conjugate 14 days later. Serum taken from mice sensitized to Pen V passively sensitized normal mice to develop systemic anaphylaxis, and this ability of the serum was abrogated by heating at 56 degrees C for 2 h or depletion of IgE, but not IgG, Abs. Thus, the antibiotic-induced fatal reaction was an IgE-dependent anaphylactic reaction. Administration of anti-IL-4 at the beginning of sensitization completely prevented the fatal anaphylactic reactions to both Pen V and CET. This effect of anti-IL-4 was associated with its suppressive activity on antibiotic-specific serum IgE, but not IgG, levels. More importantly, anti-IL-4 therapy in previously sensitized mice was also effective in preventing the fatal reactions and rapidly reduced the established IgE levels. This study provides a new animal model of hapten-induced anaphylaxis and indicates that blocking of IL-4 activity may be beneficial in allergic diseases caused by a variety of haptens in which IgE Abs play a major role.

The use of P31 magnetic resonance spectroscopy to evaluate the effect of ATP-MgCl2 perfusion on the metabolism of rat skin island flaps

Depleted levels of adenosine triphosphate (ATP) are described as one of the important causes of skin flap failure. This study evaluated the beneficial effects of intra-arterial perfusion of ATP-magnesium chloride (MgCl2) in ischemic neurovascular skin island flaps in the rat and observed the changes of the highenergy phosphate metabolite using phosphorus 31-(P31) magnetic resonance spectroscopy (MRS). The changes of ATP, phosphocreatine (PCr), and inorganic phosphate (Pi) were observed from P31 MRS and the ratios of each metabolite were compared. The extent of skin flap survival was assessed 7 days after operation using an image analyzer. The PCr/Pi ratio of the experimental group (ATP-MgCl2) was significantly different from the control group (balanced salt solution; p < 0.05). Furthermore, the infusion of ATP-MgCl2 (40.3%) significantly improved the area of flap survival compared to the control group (14.2%; p < 0.05). The ratios of PCr/Pi PCr/(PCr + Pi) correlated with the extent of flap survival, and correlation coefficients were 0.59 and 0.60, respectively. In conclusion, ATP-MgCl2 improved skin flap survival. We were able to assess the metabolic state of the ATP-MgCl2-perfused skin flap and found that PCr/Pi ratios correlated with flap survival.

Cloning and sequencing of an alpha-glucosidase gene from Aspergillus niger and its expression in A. nidulans

We have cloned an extracellular alpha-glucosidase gene from Aspergillus niger with oligonucleotide probes synthesized on the basis of the determined peptide sequences. The nucleotide sequence revealed an open reading frame of 985 amino acids split with three introns, and the deduced amino acid sequence was nearly identical to that of the alpha-glucosidase previously determined. The cloned gene was introduced into Aspergillus nidulans, and its expression in the transformants was shown to be regulated by the carbon sources in the medium, suggesting that a common regulatory expression system is shared by these two species as is the case of other starch-degrading enzymes of Aspergillus species.

Rotational instability of the mid-thoracic spine: assessment and management

SUMMARY. Recent research has enhanced the understanding of instability of the spine. The principles of this research have been incorporated into the evaluation and treatment of the unstable thorax. Rotational instability of the midthorax is commonly seen following trauma to the chest. Specific mobility and stability tests have been developed to detect this instability. The tests are derived from a biomechanical model of evaluation. Treatment is based on sound stabilization principles and although the segment will remain unstable on passive testing, the patient can be trained to control the biomechanics of the thorax and return to a high level of function. Copyright 1996 Harcourt Publishers Ltd.

Immunohistochemical localization of NAD glycohydrolase in human and rabbit tissues

NAD glycohydrolase (NADase) is present in many organisms from bacteria to mammals. In any given organism, this enzyme is ubiquitous in many tissues. However, its precise localization and its physiological significance have not been defined. We have determined the distribution of NADase in normal human and rabbit tissues by immunoblotting and immunohistochemistry, using a polyclonal antibody raised in goats. Immunoblot analyses revealed that NADase was highly expressed in the heart, lung, stomach, and liver tissues of the rabbit. From immunohistochemical studies of NADase, high concentrations in both human and rabbit tissues were found in hepatocytes and sinusoidal lining cells, sinus histiocytes of the lymph node, spleen and thymus, glomerular capillary endothelial cells of the kidney, cardiac muscle, endothelium of blood vessels, and erythrocytes.

Occurrence of disseminated intravascular coagulation (DIC) in active systemic anaphylaxis: role of platelet-activating factor

The possible occurrence of DIC in active systemic anaphylaxis was investigated in mice. Induction of active systemic anaphylaxis resulted in the development of DIC symptoms such as thrombocytopenia, prolongation of prothrombin time, hypofibrinogaemia, and elevated level of fibrinogen/fibrin degradation products. In addition, in histological examinations, massive congestion and cellular infiltration in pulmonary interstitia, and considerable haemorrhage in renal medullae were observed. All these changes were nearly completely prevented by pretreatment with platelet-activating factor (PAF) antagonist (BN 50739). Moreover, the same haematological and morphological changes were produced by a bolus injection of PAF. These data strongly suggest that DIC occurs in active systemic anaphylaxis and PAF plays a pivotal role in the development of DIC in anaphylaxis.

Expression of c-kit ligand in human keratinocytes

The c-kit ligand is expressed on tissue-anchored stromal cells. It plays an important role in the development of c-kit-bearing cells, such as haematopoietic cells, germ cells, mast cells and melanocytes. In the present study, we used the reverse transcriptase-mediated polymerase chain reaction (PCR) technique to investigate whether human keratinocytes are able to express c-kit ligand mRNA. Two sets of primers were designed to distinguish two types of c-kit ligand mRNA (full-length type and spliced type). One set was used to amplify an 882-bp DNA fragment from the full-length type, and a 798-bp DNA fragment from the spliced type. Another set was used to amplify a 375-bp DNA fragment from the full-length type only. A cDNA fragment corresponding to the full-length type mRNA was amplified from a cDNA preparation of cultured human keratinocytes as well as from epidermis obtained by the suction blister technique. This result indicates the spontaneous transcription of full-length type mRNA of the c-kit ligand in human keratinocytes.

Clinicopathologic and immunophenotypic study of non-Hodgkin's lymphoma in Korea. Lymphoreticular Study Group of the Korean Society of Pathologists

This study sponsored by the Lymphoreticular Study Group of the Korean Society of Pathologists was carried out to provide nationwide data about the histopathologic-immunophenotypic features of malignant lymphomas in Korea. Two hundred and ninety Non-Hodgkin's lymphoma (NHL) among 312 malignant lymphomas collected from three representative areas in Korea were histologically reclassified. Two hundred and fifty three cases were immunohistochemically studied. T-cell lymphoma comprised 35.2% of NHL in this study and showed a quite comparable incidence to that of Japan and China, but it was much higher than in Western countries. A very low prevalence rate of the follicular variety (4.0%) and a higher propensity of primary extranodal involvement (60%) are additional characteristics of NHL in Korea. The most common histologic subtype of B cell lymphoma was diffuse large cell type, whereas the most common subtype of T cell lymphoma was diffuse mixed small and large cell type.

Cross-cultural study of alcoholism: comparison between Kangwha, Korea and Yanbian, China

A cross-cultural comparison study of alcohol use disorder between Kangwha and Yanbian was conducted using the Korean version of the Diagnostic Interview Schedule (DIS). The subjects of the two areas studied were all native Koreans but lived in different sociocultural environments. A significant difference in lifetime prevalence rate of alcohol abuse (Kangwha 16.48%, Yanbian 6.95%; p less than 0.05) and similarity of alcohol dependence (Kangwha 10.23%, Yanbian 11.50%; p less than 0.05) were found. Among a total of 21 items of alcoholic symptoms, 14 items showed significant differences in frequencies between the two areas. The authors have suggested that alcohol abuse and alcohol dependence are two different diagnostic categories in origin, alcohol abuse is more related to socio-cultural environment and alcohol dependence to biogenetic background. The authors have discussed the possible reasons for a higher prevalence rate of alcohol abuse in Kangwha compared to Yanbian.

Dual effects of pertussis toxin on murine neutrophils in vivo. I. Pertussis toxin inhibits extravasation potential of mature neutrophils while simultaneously stimulating granulopoiesis

Pertussis toxin (Ptx) has been employed as an adjuvant by many investigators to augment various types of cell-mediated and humoral immune responses. Recent work from our laboratory indicates that the exacerbation of delayed-type hypersensitivity (DTH) and contact hypersensitivity (CH) responses observed in Ptx-treated mice may be mediated by an absolute increase in the number of circulating neutrophils capable of migrating into tissue sites of antigen challenge. The purpose of the present study was to analyze the effects of Ptx on neutrophils and neutrophil function in vivo. Evidence is presented here suggesting that Ptx has both direct and indirect effects on neutrophils following its in vivo administration to normal mice. Mature neutrophils that are directly exposed to the actions of Ptx in vivo exhibit a marked reduction in their ability to extravasate into tissue sites of inflammation. These findings are consistent with those that have been reported following the exposure of isolated neutrophils to the effects of Ptx in vitro (i.e., that Ptx has an inhibitory effect on many of the functional capabilities of isolated neutrophils). Moreover, we have also determined that Ptx can affect the kinetics of neutrophil production indirectly through its ability to stimulate granulopoiesis. Ptx-exposed mice develop a protracted peripheral blood neutrophilia following toxin administration. Although the mechanism(s) involved in stimulating increased neutrophil production is presently unclear, both dexamethasone and indomethacin (cyclooxygenase pathway inhibitors) are able to function synergistically with Ptx to produce a markedly enhanced neutrophilia in exposed mice. We propose that the capacity of Ptx to augment CH and DTH responses and act as a potent adjuvant may relate, in part, to its ability to alter the rate of neutrophil production in vivo.

The role of neutrophils in tissue localized cell-mediated immunologic responses: I. The intensity of contact-type and delayed-type hypersensitivity responses may be influenced by the extent of extracellular matrix degradation by neutrophil proteases

Studies were undertaken to evaluate factors capable of influencing the intensity of contact hypersensitivity (CH) and delayed-type hypersensitivity (DTH) responses in mice. It is well known that the exposure of animals to ultraviolet radiation (UVR) causes a depression of CH and DTH responses whereas the injection of mice with nanogram quantities of pertussis toxin (PT) before sensitization results in greatly augmented CH responses following hapten challenge. Histopathology and biochemical quantitation of myeloperoxidase (MPO) activity in biopsies obtained from the challenged ears from normal, UVR-exposed, or PT-treated animals determined that a direct correlation existed between the intensity of the ear-swelling response and the degree of neutrophil infiltrate into the challenge site. Few neutrophils were observed to infiltrate into the ears of UVR-exposed animals when compared to normal animals, whereas a pronounced neutrophil infiltration was observed in the challenged ears of PT-pretreated animals. These observations led us to question whether tissue-infiltrating neutrophils, or their products, might be involved in controlling the intensity of CH and DTH responses. The direct injection of murine neutrophils, neutrophil homogenates, and a neutrophil granular fraction into the ear pinnae of normal mice resulted in a dosage-dependent ear-swelling reaction after 24 hours that was histologically similar to antigen-induced CH or DTH responses (primarily mononuclear cell infiltrate). Additional studies determined that an injection of elastase, collagenase, or peptides of elastin or collagen generated by elastase or collagenase treatment of insoluble elastin or collagen also caused a pronounced ear-swelling accompanied by a mononuclear cell infiltration. On the basis of these studies, coupled to experiments that demonstrated an inhibitory influence of alpha-1-antitrypsin (alpha 1-AT) on CH and DTH responses, we propose that neutrophil proteases may play an important role in regulating the intensity of CH and DTH responses in mice through their capacity to degrade extracellular matrix proteins whose peptide fragments are chemotactic for mononuclear cells and fibroblasts.

Modulation of luteinizing hormone immunoreactivity and bioactivity by dopamine but not norepinephrine in women

It has been suggested that changes in bioactive luteinizing hormone in women occur toward midcycle and may result in increased bioactive/immunoreactive luteinizing hormone ratios. To determine whether dopamine or norepinephrine modulate immunoreactive and bioactive luteinizing hormone secretion, 15 ovulatory women were studied in the mid to late follicular phase. Dopamine in two doses (0.5 micrograms/kg/min and 4 micrograms/kg/min) and norepinephrine, 0.1 microgram/kg/min, were infused for 4 hours, and metoclopramide, 10 mg intravenously, was also given to determine whether dopamine receptor antagonism results in changes. Bioactive luteinizing hormone and the bioactive/immunoreactive luteinizing hormone ratio increased in women from the early to late follicular phase (p less than 0.05). Both intravenous doses of dopamine resulted in significant decrements in immunoreactive luteinizing hormone (20 +/- 2 and 20 +/- 3%, p less than 0.02) and bioactive luteinizing hormone (36.7% and 43.2%, p less than 0.05). With dopamine there was also a significant decrease in the bioactive/immunoreactive luteinizing hormone ratio (p less than 0.02). Intravenous norepinephrine, however, resulted in no changes in either immunoreactive or bioactive luteinizing hormone levels. Metoclopramide also did not change immunoreactive or bioactive luteinizing hormone levels. These data suggest that although endogenous dopaminergic blockade may not play a significant role in determining basal levels of luteinizing hormone, decreases in dopamine at the pituitary level may increase the bioactive/immunoreactive luteinizing hormone ratio. Norepinephrine does not appear to exert major changes in immunoreactive or bioactive luteinizing hormone.

A new dasycladacean alga associated with the 'Arctic Ordovician' fauna on Cornwallis Island

A new species of dasycladacean alga is present in the upper Thumb Mountain and in the overlying Irene Bay Formations of the Cornwallis Group on Cornwallis Island, Northwest Territories. The alga is associated with the 'Arctic Ordovician' fauna, which is of considerable biogeographical and biostratigraphical importance. This fauna is believed to be of early Late Ordovician (Caradocian) age.The new alga is a member of the cyclocrinitid tribe and clearly is to be referred to the genus Cyclocrinites. It is distinguished from all other cyclocrinitid species by the exceptionally small size, the unusual bilobate form, and the mode of calcification of its thallus. It is believed to have lived in tropical waters which were quiet and shallow, to have been anchored to the seabed by means of rhizoids. and to have grown only in areas in which fine-grained carbonate sediment was accumulating.

An Experimental Study of Thermal Aspects of Cylindrical Plunge Grinding

The workpiece temperature in cylindrical plunge grinding is considered as a superposition of a base temperature and an interference zone temperature. A solution for the transient base temperature distribution is derived. A two-part experiment for determining thermal effects is described. The heat transfer coefficient at the workpiece surface is measured in the first part, and specific grinding energy and workpiece temperature are measured in the second part. The energy entering the workpiece during grinding is determined from the base temperature solution and experimental data. Results obtained with several grinding fluids and application systems are presented. The energy entering the workpiece was found to be 75 to 85 percent of the total grinding energy during dry grinding and 25 to 35 percent during wet grinding.

REARRANGEMENT STUDIES WITH C14. X. ETHANOL-2-C14 FROM THE IRRADIATION OF ETHANOL-1-C 14 WITH Co60 GAMMA RAYS

The irradiation of aqueous solutions of ethanol-1-C14, containing about 2% ethanol by weight, with up to 58.0 million rads of Co60 γ-rays led to the formation of up to 0.49% ethanol-2-C14 in the alcohol recovered after irradiation. The G value of this isotope position rearrangement was about 0.04 and amounted to approximately 2% of the G value for the total amount of ethanol decomposed. Possible mechanisms for the rearrangement are discussed.