bluuebunny/crossref_metadata_2025 huggingface dataset:
Smoke data from the Cone Calorimeter for comparison with the room fire test
Authors: ÖOstman Birgit A.‐L. , Tsantaridis Lazaros D.
Published: May 2005

Smoke production in the full–scale room fire test ISO 9705 (Commonly referred to as the Room Corner Test) and in the Cone Calorimeter ISO 5660 has been analysed for three sets of building products comprising a total of 28 products. The smoke production may be critical for the fire classification of surface products since some products produce large amounts of smoke in the room fire test even if they do not reach flashover within 20 min. Several smoke parameters in the Cone Calorimeter and the room fire test have been analysed. Good correlations have been obtained when the products are divided into two groups: products with more than 10 min to flashover in the room fire test and those with less than 10 min. These two time categories correspond to the two heat output levels in the room fire test: 100 kW for the first 10 min and then 300 kW up to 20 min. For products with more than 10 min to flashover the average rate of smoke production and the total smoke production seem to be useful parameters for predictions of smoke release in the room fire test. Both parameters have good correlations between data from the Cone Calorimeter and the room fire test. For products with less than 10 min to flashover no parameter seems to give useful predictions. For all products evaluated together, the correlations are not so good, but the same regression lines as for products with more than 10 min might be used as a first rough estimate. In this case the total smoke production in the Cone Calorimeter could be used to estimate the total smoke production in the room fire test for different building products, independent of their estimated time to flashover.

It is suggested that the average rate of smoke production and the total smoke production from the Cone Calorimeter is reported in addition to the mass‐based specific extinction area. This will be helpful in predicting smoke release in the room fire test and will also make the data on smoke release analogous to those on heat release.
A study of spalling behaviour of PAN fibre‐reinforced concrete by thermal analysis
Authors: Sarvaranta Leena , Elomaa Matti , Järvelä Eliisa
Published: May 2005

Comparisons are made between polypropylene (PP) fibres and polyacrylonitrile (PAN) fibres in order to relate the thermal properties of fibres with the respective fibre mortar behaviour under thermal exposure. Thermogravimetry (TG), differential scanning calorimetry (DSC) and thermochromatography (ThGC) are utilized. When a cementitious fibre mortar is being heated, several physical phenomena occur in the temperature range between 100°C and 200°C. There is a significant difference in the thermal behaviour between PP and PAN fibres. PP fibres melt at 160–170°C. The non‐melting behaviour of PAN fibre together with its rapid exothermic degradation reactions at around 300°C may add risk to the spalling of fibre mortar under rapid thermal exposure.
Current Japanese standards for flammability tests on electric cables
Authors: Nakagawa Yuichi , Komai Takeshi
Published: May 2005

This paper outlines the flammability test methods and requirements for electric cables specified in some Japanese standards. Only two different methods of a small‐scale flame test as specified in Clause 28 of JIS C 3005 are applied to electric cables for general use, and whether or not the flammability test should be conducted and which method should be adopted depends on the type of cables, both of which are specified in each separate standard. Cables for electrical equipment of ships have to pass another small‐scale flame test as prescribed in Section 6.7 of JIS C 3410. A flame test method for flame‐retardant telecommunication cables has been introduced in JIS C 3521. This specifies a vertical open tray flame test on grouped cables, almost in accordance with IEEE Standard 383. In addition to the method for a vertical open tray flame test, one for a vertical closed duct flame test on grouped cables is also specified in a Japanese Cable Makers' Association Standard, i.e. JCS 366. Some flame‐retardance requirements for electric cables in Japan are listed and discussed.
Physical modelling fire performance of wall‐covering materials
Authors: Richardson L. R. , Cornelissen A. A. , Dubois R. P.
Published: May 2005

A small‐scale enclosure was constructed for characterizing the contribution of interior finish wall‐lining materials to fire growth in compartments. The enclosure was based upon refinements to a design devised by scientists at the National Institute for Standards and Technology for quarter‐scale modelling of room fire tests on interior‐finish materials. A large volume of evidence is presented demonstrating how this small‐scale enclosure could provide the information about surface flammability, heat release, smoke generation and contribution to fire growth that is required for a reasonable assessment of the fire performance of interior wall‐finish materials.
Performance tests in human psychopharmacology (1): Test reliability and standardization
Authors: Parrott A. C.
Published: May 2005

Reliability, validity and standardization are well‐established principles in most areas of psychometrics, but are rarely mentioned in performance assessment within human psychopharmacology. Test reliability and standardization are examined here, while validity is covered in two succeeding articles. The undocumented reliability of human psychopharmacology performance tests makes the interpretation of findings difficult and ambiguous. Reliability, or consistency within and between test sessions is, however, easy to calculate. Several procedures for calculating reliability are described, with test–retest reliability recommended as the most appropriate single summary measure. Poor test standardization is another major problem, with many research groups using different tests. The extent of this problem is examined, and a set of standardization requirements proposed. They could comprise the basis for test manuals. The problems of undocumented reliability and unstandardized tests have been recognized within the field for many years, yet no moves have been made to remedy the situation. One simple solution would be for psychopharmacology journals to accept only documented tests, and to request test–retest reliability data.
TSH responsiveness to TRH (‘the TRH test’)—of no diagnostic value in depression
Authors: Vaughan J. A. , O'Malley B. P. , Barker S. , Woods K. L. , Palmer R. L. , Rosenthal F. D.
Published: May 2005

Serum free T4, free T3 and TSH (IRMA), along with TSH responsiveness to TRH (500 μg i.v.), were investigated in 12 patients, initially when severely depressed and again upon recovery, and in a group of age‐matched controls. The TSH response to TRH did not differ significantly between patients and controls, nor did it alter with treatment of depression. There were no significant differences in basal TSH levels. Free T3 levels were very significantly lower in untreated patients than in controls (p = 0·004), as were free T4 levels (p = 0·02), and had not improved significantly at recovery. Basal TSH levels showed a strong association with the integrated TSH response to TRH (p < 0·001) in both patients and controls. Thus in depression, as in thyoid dysfunction, the TRH test can be abandoned in favour of sensitive basal TSH measurement but, more importantly, the TRH test has no value in the diagnosis of endogenous depression or in monitoring treatment response. However, there is a reduction in free thyroid hormone levels in depression which has not been rectified by the time of clinical recovery.
Effect of clonazepam on tardive akathisia
Authors: Kuniyoshi Masahiro , Arikawa Katsuyoshi , Miura Chishin , Inanaga Kazutoyo
Published: May 2005

Clonazepam was administered to nine patients with tardive akathisia which could not be controlled by antiparkinsonian drugs, and a good response was obtained in all cases. The daily dose of clonazepam given was only 1.0–3.0 mg. In two of the nine patients, akathisia recurred when the dose of clonazepam was reduced, but disappeared again after the dose was increased again. Clonazepam appears to be worth trying in patients with tardive akathisia, and is effective at relatively low doses. However, a dose reduction should be performed with caution, since there is the possibility that akathisia will recur.
Irritability in panic disorder: Effects of imipramine treatment
Authors: Nutt D. J. , Glue P.
Published: May 2005

To establish the presence and magnitude of irritability in panic disorder, and its relationship with anxiety and depression, ratings of each variable were monitored in 18 patients with panic disorder before and during imipramine treatment. Pretreatment ratings of inward‐and outward‐directed irritability demonstrated borderline levels of morbidity. Over the duration of treatment, irritability ratings fell, and there were substantial reductions in ratings of depression, but only small reductions in ratings of state anxiety. There were a number of significant correlations between pre‐ and post‐treatment ratings of irritability and depression, but little association between these and ratings of anxiety.
Mouse strain‐dependent hepatic interaction of psychoactive agents with ethanol and biogenic aldehydes metabolizing enzymes
Authors: Messiha F. S.
Published: May 2005

The effect of multiple dose regimens of amantadine, reserpine, chlorpromazine alone or combined on liver alcohol (L‐ADH) and aldehyde dehydrogenase (L‐ALDH) was studied in three strains of mice. A strain‐dependent difference between endogenous specific activity of these enzymes and their sensitivity to the agents studied was determined. The C57BL/6 mice showed most resistance to drug effect and possessed greater activity of mitochondrial L‐ALDH isoenzymes and L‐ADH than either ICR or BALB/C mouse strains, respectively. Amantadine induced both L‐ADH and mitochondrial L‐ALDH while reserpine inhibited them also as a function of mouse strain. Both reserpine‐and chlorpromazine‐mediated inhibition of albino ICR mouse L‐ADH and BALB/C mitochondrial L‐ALDH was alleviated by pretreatment with amantadine. This indicates antagonism between amantadine and these agents. The results suggest a genotypic sensitivity to drug action which may explain the individual sensitivity to the development of chlorpromazine and reserpine‐produced side‐effects, and the potency of amantadine in management of such drug‐induced adverse reactions.
PATENT NEWS
Authors: Solamon Donald D.
Published: May 2005

The patent literature can be a morass of confusion. It is complicated by legalese, often uncommunicative titles, and difficult, as well as cryptic, categorization. To kiip current with the broad arena of patents on biomaterials and medical devices is much more difficult than keeping current with the scientific literature of the international journals.

It is the goal of my column to provide readers with techniques and tools to better utilize this rich source of scientific information. Also, I intend to provide focused surveys of recent patents in specific areas relating to biomaterials and medical devices. Finally, I will try to include discussion of what constitures patentable material and educate those of us who are new to patent literature and new to the requirements of applying for patents for our discoveries.

I appeal to the readership to submit requests for specific areas to be addressed in this column. The interaction will enrich us all.
Research and development report: Production of fine particulate ultra high molecular weight poly(ethylene) for biological response studies
Authors: Leigh H. D. , Taylor P. , Swaney A. , Black Jonathan
Published: May 2005

Interest in biological responses to particulate biomaterials has produced a need for well‐characterized submicron ultra high molecular weight poly(ethylene) (UHMWPE) debris. A new technique, cryogenic attrition, is described as well as a characterization of an initial ca. 65% submicron preparation of UHMWPE, termed grind S. Production of submicron particles from a common commercial medical grade of primary UHMWPE “grain” produces fractions with different densities, apparently reflecting the presence of crystalline and amorphous phases. Further process optimization and debris characterization is planned with eventual distribution of material as an interlaboratory comparison material for biological response experiments.
Pulsed laser deposition of hydroxylapatite thin films on Ti‐6Al‐4V
Authors: Cotell Catherine M. , Chrisey Douglas B. , Grabowski Kenneth S. , Sprague James A. , Gossett Charles R.
Published: May 2005

Pulsed laser deposition was used to deposit thin films of calcium hydroxylapatite (Ca10(PO4)6(OH)2), or HA, on polished substrates of Ti‐6Al‐4V. Thin films of pure, crystalline HA, uncontaminated by other calcium phosphate phases, were deposited over a range of temperatures between 400 and 800°C. The HA films were polycrystalline with a preferred (001) crystallographic orientation, as determined by transmission electron microscopy and x‐ray diffraction. Adhesion of the HA films to the Ti‐6Al‐4V substrates was excellent when films were deposited at temperatures ≤600°C; in a scratch test, mean pressures of ca. 1010 Nm−2 produced conformational cracking in a film deposited at 600°C, but no decohesion from the substrates.
Bioactive ceramics for periodontal treatment: Comparative studies in the patus monkey
Authors: Wilson June , Low Samuel B.
Published: May 2005

Four bioactive ceramic materials currently recommended for regeneration of osseous tissues in treatment of periodontal disease have been compared with Bioglass® particulates, of equivalent size in two compositions, in a monkey model. Both Bioglass® materials were found to be easily manipulated, were haemostatic and osteoproductive allowing restoration of both alveolar bone and periodontal ligament. Epithelial downgrowth was inhibited and epithelial attachment was close to the preimplantation level. The other materials were slower to act and epithelial downgrowth was to the same level as in unfilled control defects.
Plasma surface modification of synthetic absorbable sutures
Authors: Loh Ih‐Houng , Lin Hui‐Ling , Chu C. C.
Published: May 2005

The aim of the study was to examine the feasibility of using plasma surface modification technology to alter the hydrolytic degradation rate of commercial synthetic absorbable sutures. Size 2‐0 Dexon, Vicryl, PDSII, and Maxon sutures were tested. They were treated by two different surface modification techniques: parylene deposition and plasma gases (Methane, trimethylsilane, and tetrafluoroethene). The thickness of surface treatment ranges from 200 to 1000°AR. The treated sutures were subject toin vitrohydrolytic degradation in phosphate buffer of pH = 7.4 at 37°C for up to 120 days. The tensile breaking strength, weight loss, surface wettability, bending stiffness, and surface morphology were evaluated. The results indicated that the concept of plasma surface treatment for altering the hydrolytic degradation of synthetic absorbable sutures was feasible, and the level of improvement depended on the type of sutures, the treatment conditions, and the duration of hydrolysis. Vicryl and PDSII sutures showed overall the best improvement in tensile strength retention among the four commercial sutures. Dexon and Maxon sutures, however, exhibited only marginal improvement. The observed improvement in tensile strength retention appeared to be related to the increasing hydrophobicity of the sutures. The surface treatments did not adversely affect the bending stiffness of the sutures and no visible surface morphological changes were observed. Refinements and optimization of the surface treatment conditions are needed for achieving the maximum advantage of the proposed concept, particularly shielding the harmful effect of uv during plasma treatment.
Preparation of fibrin glue: A study of chemical and physical methods
Authors: Silver Frederick H. , Wang Ming‐Che , Pins George D.
Published: May 2005

Concentrated fibrinogen was prepared from whole blood by cryoprecipitation or chemical precipitation and combined with thrombin to make fibrin glue (FG). Surgical application of FG include control of bleeding, adhesion of tissues, and sealing of tissue defects. The purpose of this study was to compare cryoprecipitation (cryo) of fibrinogen to precipitation using ethanol, ammonium sulfate (AS), and poly(ethylene glycol) (PEG). Our results suggest that AS precipitation is as effective as cryo in yielding fibrin glues with high bond strengths and is more effective than ethanol and PEG precipitation. In addition, the volume of FG per milliliter of plasma is greater after AS precipitation than after a single freeze‐thaw cycle. It is concluded that AS is an efficient means for preparing FG from autologous blood. © 1995 John Wiley & Sons, Inc.
Foam fractionation of proteins: Concentration of aqueous solutions of bovine serum albumin
Authors: Schnepf Robert W. , Gaden Elmer L.
Published: May 2005

The effects of pH and concentration on foam separation of the protein bovine serum albumin (BSA) from solution has been studied. All results agree, at least qualitatively, with theory. BSA maximum enrichments were observed at the isoelectric pH and enrichment ratio was found to increase with decreasing protein concentrations.
The protection of some baked products against moulds by chemical and irradiation techniques
Authors: Axford D. W. E. , Ottaway F. J. H.
Published: May 2005

The nature of the problem of mould growth on baked products is discussed. Existing information on the reduction of this source of wastage by chemical and irradiation techniques is briefly reviewed, and new experimental evidence is presented relating to the use of these procedures. The effectiveness of ionizing radiations in preventing mould growth is indicated but there are many problems to be considered before it can be regarded as a satisfactorily established technique.
The course of bacterial population growth in batch and continuous culture according to the theory of Monod
Authors: Northam Jack I.
Published: May 2005

The equations of Monod that describe the course of bacterial population growth and substrate concentration during continuous culturing are usually analysed with reference to steady‐state conditions. These equations are analysed to give information on the course of bacterial population growth from inoculation to the achievement of a steady‐state condition. For common values of certain parameters occurring in Monod's development, growth is well approximated by an exponential law (logarithmic phase) which depends on: (a) the maximum specific growth‐rate constant for the organism and medium concerned, and (b) the constant dilution rate.
Transient and steady states in continuous fermentaion. Theory and experiment
Authors: Luedeking Robert , Piret Edgar L.
Published: May 2005

Steady‐state and transient equations are derived for continuous‐flow fermentation processes. Analytical as well as graphical methods for predicting from batch data the performance of single‐ or multi‐stage continuous fermentations are developed. The criteria for stability are also examined. Actual experimental measurements of continuous lactic acid fermentations conducted at controlled pH levels agree with the theory developed.
Combined irradiation–heat processing of canned foods: Green peas inoculated with anaerobic bacterial spores
Authors: Kempe Lloyd L. , Graikoski John T. , Bonventre Peter F.
Published: May 2005

Combined irradiation–heat processing is shown to be syner‐gistic for killing anaerobic bacterial spores inoculated into canned green peas. Following 1·2 megarad of gamma irradiation an F0 of 0·5 sterilized green peas inoculated with either 5,000,000 Clostridium botulinum 213 B or 300 PA 3679 spores per can. This processing schedule must be considered a minimum since it is based on a limited number of cans. Because sterilization by either irradiation or heat alone can damage the organoleptic properties of canned foods, the lowered schedules possible with combined processing may prove to be of value for preserving vegetables as well as meats.
The removal of nitrogen and phosphorus from sewage effluents through the use of algal culture
Authors: Witt V. , Borchardt J. A.
Published: May 2005

This study is designed to establish fundamental data which will permit the eventual application of algal culture to the removal of nutrients from sewage plant effluents. A test cell is described which gives reproducible data when environmental parameters are varied. The effect of changes in temperature, light intensity and culture density as reflected in the growth rate, are shown, and the influence of these parameters on the removal of nitrogen and phosphorus under the test conditions indicated. The importance of an adequate carbon source and proper pH control is demonstrated. The organisms used were Scenedesmus and Chlorella in mixed or unialgal cultures.
Sewage sludge conditioning with sulphur oxidizing bacteria
Authors: Johnston Wendye E. , Ives K. J.
Published: May 2005

Previous research has shown that a reduction in pH of digested sewage sludge considerably improves its filtration characteristics. Experiments with sulphur oxidizing bacteria (thiobacilli) have shown that under aerobic conditions with a supply of elemental sulphur the pH can be reduced by microbial sulphuric acid synthesis. A semi‐continuous process of sludge conditioning by this method was evolved, which would continue if the pH did not rise above pH 7 and if sufficient sulphur was supplied. Attempts to substitute sodium thiosulphate, or sulphide‐rich sludge, for elemental sulphur were unsuccessful. A note is appended on a method of enumerating the thiobacilli.
Purification process development using radioactive vitamin B12
Authors: Bungay H. R. , Marsh M. M. , Peterson R. C.
Published: May 2005

The use of low‐level radiotracer techniques permits rapid, precise estimation of yields and material balances for processing steps. This is a great advantage for development work with Vitamin B12 because the conventional methods using microbiological assays are slow and lack precision. Release of the vitamin from S. griseus cells, selection of absorbing resins, and screening of eluting agents were followed using cobalt‐60 cyanocobalamin. The method is most valuable when supplemented by microbiological assays because the yields of radioactivity are misleading in conditions which inactivate the vitamin.
Pilot plant studies on parboiling of rice—III. Effect of hot soaking and mechanical drying on the nutritive value of parboiled rice
Authors: Mazumder A. C. , Bose A. N. , Ganguli N. C. , Guha B. C.
Published: May 2005

Hot soaking of paddy in the parboiling process does not significantly affect the digestibility of rice compared to ‘raw’ rice. Mechanically dried parboiled rice appears to be slightly more digestible in vitro than sun‐dried parboiled rice. It is also significantly superior in thiamine value.
The formation of magnetic iron sulphide by bacterial reduction of iron solutions
Authors: Freke Anthony M. , Tate Donald
Published: May 2005

Laboratory scale experiments have been carried out with sulphate‐reducing bacteria growing under anaerobic conditions to investigate the removal of iron from iron‐containing solutions. The complete removal of iron, as the insoluble sulphide, has been achieved from both ferrous and ferrous–ferric sulphate solutions. It has been found that under certain conditions a magnetic iron sulphide is produced. This aggregates under the influence of a magnetic field and settles at a rate of some 30 in./min. The magnetic sulphide has only been obtained from intermittent continuous cultures. With the system employed, rates of removal of up to 150 mg of iron per litre of culture vessel per hour have been obtained.
Modulation of extracellular‐matrix synthesized by cultured stromal cells from normal human breast tissue by epidermal growth factor
Authors: Baley Patricia , Lützelschwab Irene , Scott‐Burden Timothy , Küng Willy , Eppenberger Urs
Published: May 2005

A routine, reproducible procedure was developed for the preparation and characterization of stromal cells from normal human breast tissue obtained by reduction mammaplasty. Isolates (n = 15) all exhibited enhanced rates of proliferation, even in the presence of 20% fetal calf serum, when exposed to epidermal growth factor or transforming growth factorα (both 10−8 M). Cellular responsiveness to these growth factors was consistent with expression of specific surface receptors for epidermal growth factor (∼104/cell). In cultures, stromal cells elaborated an extensive, crosslinked, insoluble extracellular matrix which remained firmly associated with the plastic surface of tissue culture ware upon lysis of cells. The insoluble matrix material was analyzed using enzymatic digestion procedures following incorporation of radio‐labelled precursors into macromolecular material prior to lysis and preparation. The relative proportion of glycoconjugate (glycopeptides and proteoglycans) and collage‐nous material present in matrix material was ∼45% and ∼55%, respectively, and this was modulated by inclusion of epidermal growth factor into culture medium to ∼60% and ∼40%, respectively. Under similar culture conditions stromal cells synthesized twice as much hyaluronate as was produced by control cultures. By use of specific antibody preparations we identified at least four species of glycopeptide present in stromal matrices (namely, fibronectin, laminin, tenascin, and thrombospon‐din) as well as three types of collagen (types I, III, and IV). The rapid and reproducible procedure for the preparation of radiolabelled insoluble matrix material from normal human breast tissue allows for the study of cellular interaction involving extracellular matrix turnover and degradation.
Suppression of protein kinase C and the stimulation of glucocorticoid receptor synthesis by dexamethasone in human fibroblasts derived from tumor tissue
Authors: Gadson Preston , McCoy Judy , Wikström Ann Charlotte , Gustafsson Jan‐Ake
Published: May 2005

Exposure of fibroblasts derived from keloid tissues, desmoid and dermal tissue from individuals with Gardner's syndrome ‐(GS) to dexamethasone resulted in the suppression of protein kinase C ‐(PKC) activity and [3H] thymidine incorporation into DNA, and a 20°fold induction of glutamine synthetase activity. Treatment of GS and keloid fibroblasts with 0.1 μM dexamethasone for 36 h increased glucocorticoid receptor ‐(GR) synthesis, as determined by [35S] methionine labeling and immunoprecipitation with a monoclonal antibody to the human GR. The suppression of PKC activity by dexmethasone was shown to result from a loss of protein mass as determined by immunoblotting using an antibody to PKC type III. In contrast to these results, exposure of fibroblasts isolated from normal tissues to dexamethasone did not result in the suppression PKC and [3H]thymidine incorporation, there was only a sixfold induction of glutamine synthetase, and a decrease of GR synthesis. As no primary receptor binding defect could be detected, the altered response of tumor cells to steroid‐occupied receptor indicates a partial post‐receptor binding defect in GS and keloid cells.
Growth and protein phosphorylation in the Nb2 lymphoma: Effect of prolactin, cAMP, and agents that activate adenylate cyclase
Authors: Rayhel Elizabeth J. , Hughes James P. , Svihla Doreen A. , Prentice David A.
Published: May 2005

The Nb2 T lymphoma is unique in that these lymphocytes proliferate in response to prolactin as well as in response to interleukin‐2. In this study, we have examined the responsiveness of the adenylate cyclase system in Nb2 cells and the role of this signaling system in regulating proliferation and protein phosphorylation. An analog of cAMP inhibited prolactin‐stimulated proliferation and blocked a prolactin‐induced decrease in protein phosphorylation. Forskolin, a potent activator of adenylate cyclase in T lymphocytes, did not elevate cAMP levels in Nb2 cells and was not an effective inhibitor of prolactin‐induced proliferation. In fact, one preparation of forskolin stimulated proliferation of quiescent Nb2 cells. Like forskolin, prostaglandin E2 did not stimulate cAMP production in Nb2 cells even though, it increased cAMP in a preparation of rat peripheral blood lymphocytes. Cholera toxin appeared to ADP‐ribosylate a stimulatory guanine nucleotide‐binding protein in Nb2 cells, but the toxin did not increase intracellular levels of cAMP nor was it a potent anti‐mitogenic agent. Pertussis toxin, an agent that can increase cAMP production through suppression of the inhibitory guanine nucleotide‐binding protein, exerted only minor anti‐proliferative actions on prolactin‐stimulated Nb2 cells. These data suggest that cAMP inhibits Nb2 cell proliferation and prolactin‐induced changes in protein phosphorylation but that the adenylate cyclase system in our clone of Nb2 cells responds poorly to agents that normally increase cAMP.
Alteration of lacto‐series glycolipid glycosyltransferase activities in human colonic adenocarcinoma DLD‐1 cells after culture in N,N‐dimethylformamide‐containing medium
Authors: Holmes Eric H. , Greene Thomas G.
Published: May 2005

Human colonic adenocarcinoma DLD‐1 cells were grown under conditions which induce characteristics of differentiated cells using medium containing 0.8% N,N‐dimethylformamide in order to study alterations in glycosphingolipid glycosyltransferase activities during this process. Analysis of biosynthetic reactions involved in lacto‐series antigen synthesis revealed no changes in the specific activities of either β1→4galactosyltransferase or α1→3/4fucosyltransferase with N,N‐dimethylformamide treatment. However, a dramatic decrease of from 14‐ to 20‐fold in the β1→3N‐acetylglucosaminyltransferase activity was observed in the treated cells. This enzyme catalyzes the rate‐limiting step in lacto‐series core chain synthesis. This is consistent with the pattern of regulation of lacto‐series antigen expression found to occur during oncogenesis in human colonic mucosa (Holmes EH, Hakomori S, Ostrander GK: J Biol Chem 262:15649, 1987). Total glycolipids from untreated and N,N‐dimethylformamide‐treated cells were isolated and subjected to TLC immunostain analysis and solid phase radioimmunoassay with a series of monoclonal antibodies specific for lacto‐series‐based carbohydrate antigens. A decrease of about 2‐fold or less in the quantity of lacto‐series antigens was observed as a consequence of N,N‐dimethylformamide treatment in both neutral glycolipid and ganglioside fractions. The results suggest that only very low levels of β1→3N‐acetylglucosaminyltransferase activity are required for the steady state expression of significant levels of lacto‐series based glycolipids and that modulation of its activity levels by N,N‐dimethylformamide treatment in DLD‐1 cells represents a convenient in vitro system for studying aspects of regulation of lacto‐series antigen expression.
Stimulation of a histone H4 protein kinase in Triton X‐100 lysates of rabbit peritoneal neutrophils pretreated with chemotactic factors: Lack of requirements of calcium mobilization and protein kinase C activation
Authors: Huang Chi‐Kuang , Laramee Gary R. , Yamazaki Munehiro , Sha'afi Ramadan I.
Published: May 2005

The characteristics of the activation of a histone H4 kinase activity in Triton X‐100 lysates of rabbit peritoneal neutrophils pretreated with fMet‐Leu‐Phe were studied: The activation of the kinase was (a) inhibited by the antagonist of formylpeptide, t‐Boc‐(Phe‐Leu)2−‐Phe, (b) completely inhibited by pertussis toxin pretreatment, (c) not affected by the pretreatment of neutrophils with an activator of protein kinase C, phorbol‐12‐myristate‐13‐acetate, or an inhibitor of protein kinase C, 1‐(5‐isoquinoline‐sulfonyl)‐2‐methyl‐piperazine, and (d) not inhibited in the cells preloaded with the intracellular calcium chelators, bis‐(o‐aminophenoxy)‐ethane‐N,N,N',N'‐tetra acetic acid acetoxymethyl‐ester (BAPTA/AM). These results suggest that the stimulus‐induced activation of H4 kinase requires functional receptor and GTP‐binding protein but neither calcium mobilization nor protein kinase C activation.
p53 Mutations: Gains or losses?
Authors: Michalovitz Dan , Halevy Orna , Oren Moshe
Published: May 2005

Although the case for p53 as a tumor suppressor gene appears very strong, one should still keep an open eye for the possibility that mutations in p53 do not necessarily imply a mere loss of “suppressor” activity. It is still possible that the presence of a p53 mutation in a tumor contributes, in a dominant positive manner, to tumorigenesis. In other words, certain p53 mutants may well be oncogenic in their own right, and carry distinct activities that promote growth deregulation and malignant progression. Elucidating this issue also has practical implications, since the nature of the resident mutations may greatly dictate the consequences of attempts to reintroduce wild‐type (wt) p53 into particular types of tumor cells. There are two major obstacles along the road to meaningful answers: the limitations of the experimental systems used for evaluating the biological activities of Wt and mutant p53 and a fundamental lack of knowledge about the relevant biochemistry of the p53 protein. These two aspects constitute primary experimental challenges for investigators in the field.
Metal ion resistance in fungi: Molecular mechanisms and their regulated expression
Authors: Mehra Rajesh K. , Winge Dennis R.
Published: May 2005

One stress response in cells is the ability to survive in an environment containing excessive concentrations of metal ions. This paper reviews current knowledge about cellular and molecular mechanisms involved in the response and adaptation of various fungal species to metal stress. Most cells contain a repertoire of mechanisms to maintain metal homeostasis and prevent metal toxicity. Roles played by glutathione, related (γ‐EC)nG peptides, metallothionin‐like polypeptides, and sulfide ions are discussed. In response to cellular metal stress, the biosynthesis of some of these molecules are metalloregulated via intracellular metal sensors. The identity of the metal sensors and the role of metal ions in the regulation of biosynthesis of metallothionin and (γ‐EC)nG peptides are subjects of much current attention and are discussed herein.
Constitutively activated neu oncoprotein tyrosine kinase interferes with growth factor‐induced signals for gene activation
Authors: Lehtola Laura , Sistonen Lea , Koskinen Päivi , Lehväslaiho Heikki , Alitalo Kari , Renzo Maria Flavia Di , Comoglio Paolo M.
Published: May 2005

The neu receptor oncoprotein tyrosine kinase, capable of transforming cultured fibroblasts and causing mammary carcinomas in transgenic mice, carries a point mutation in its transmembrane domain and shows a constitutive tyrosine kinase activity. We analyzed the neu tyrosine kinase and its substrates in transfected NIH 3T3 fibroblasts by phosphotyrosine immunoblotting. Tyrosine phosphorylated proteins were similar but not identical in epidermal growth factor (EGF)‐stimulated cells expressing the human EGF receptor (EGFR) or a chimeric EGFR/neu receptor but differed from phosphotyrosyl proteins constitutively expressed in neu oncogene‐transformed cells. The neu oncoprotein in the latter cells was phosphorylated in tyrosine in a ligand‐independent manner and had a shortened half‐life in comparison with the normal neu protein. Tumor promoter pretreatment inhibited ligand‐induced receptor tyrosine phosphorylation and decreased tyrosine phosphorylated neu oncoprotein. Prolonged pretreatment with 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) also prevented the induction of immediate early growth factor‐regulated genes in response to neu activation. Expression of the neu oncogene but not the protooncogene in NIH 3T3 cells was associated with enhanced levels of the jun and fos oncoproteins and loss of serum growth factor induction of immediate early mRNA responses. The constitutively activated neu oncoprotein tyrosine kinase thus deregulates cellular genomic responses to growth factors.
Estrogen‐stimulation of postconfluent cell accumulation and foci formation of human MCF‐7 breast cancer cells
Authors: Gierthy John F. , Lincoln David W. , Roth Karen E. , Bowser Samuel S. , Bradley Laurie , Dickerman Herbert W. , Bennett James A.
Published: May 2005

Foci, nodules of cellular overgrowth, that appear after confluence are an in vitro characteristic of malignant transformation. A well‐studied in vitro model of estrogen‐dependent tumors is the MCF‐7 cell line, derived from a pleural metastasis of a human breast adenocarcinoma. We report that cultivation of MCF‐7 cells, using routine methods, results in extensive estrogen‐stimulated postconfluent cell accumulation characterized by discrete three‐dimensional arrays. Side view Nomarski optical sections revealed these to be principally multicellular foci with occasional domes and pseudoacinar vacuoles. This effect on MCF‐7 cell growth occurs in media containing fetal bovine serum but not with calf serum or charcoal‐dextran‐treated fetal bovine serum unless supplemented with estrogens. Foci formation starts 5–6 days after confluence, and the number of foci generated is a function of the concentration of added estrogens. Foci formation is suppressed by the antiestrogens Tamoxifen and LY 156758. Addition of progesterone, testosterone, or dexamethasone had little or no effect, while various estrogens (ethinyl estradiol, diethylstilbestrol, and moxestrol) induced foci development. Clones derived from single cells of the initial MCF‐7 population revealed a wide variance in estrogen‐induced foci formation, demonstrating heterogeneity of this tumor cell line. The postconfluent cell growth of the estrogen receptor‐deficient cell line, MDA‐MB‐231, contrasted with MCF‐7 by developing an extensive multilayer morphology devoid of discrete structures. The tumorigenic potential of the MCF‐7 cells used in our experiments was confirmed by their estrogen‐dependent growth in immunosuppressed male BDF1 mice.

These data suggest an estrogen receptor‐based mechanism for the development of multicellular foci during postconfluent growth of MCF‐7 cells. After confluence, foci, in contrast to the quiescent surrounding monolayer, retain proliferating cells. Focus formation, therefore, reflects the heterogeneous responsiveness of these cells to estrogens and should provide a model permitting in vitro comparisons between the progenitor cells of multicellular foci and the monolayer population.
Antisense inhibition of c‐myc expression reveals common and distinct mechanisms of growth inhibition by TGFβ and TNFα
Authors: Robinson‐Benion Cheryl , Salhany Kevin E. , Hann Stephen R. , Holt Jeffrey T.
Published: May 2005

Downregulation of the c‐myc gene in HL‐60 cells is associated with growth inhibition and induction of differentiation. Previous studies have reported that the growth inhibitors TGFβ and TNFα downregulate c‐myc mRNA levels, suggesting the possibility that these agents may exert some of their phenotypic effects via c‐myc downregulation. Our study demonstrates that although both growth inhibitors produce a similar decrease in c‐myc protein synthesis, TNFα produces a greater growth inhibition and differentiation induction in HL‐60 cells. Combined addition of anti‐myc oligomer with either growth inhibitor produces no additive effect. In fact, 4 μM anti‐myc oligomer produces the same growth and differentiation effects as does 10 ng/ml TGFβ1. We conclude that downregulation of c‐myc expression represents a common mechanism of growth inhibition by TGFβ and TNFα, but that TNFα possesses an additional effect that is independent of c‐myc expression.
Taurine release associated to volume regulation in rabbit lymphocytes
Authors: García J. Jesús , Olea R. Sánchez , Pasantes‐Morales H.
Published: May 2005

Rabbit lymphocytes exposed to hyposmotic media first swell and then recover their initial volume within 6 min. During volume recovery, free amino acids (FAA) decrease from 451.1 to 208 nmoles/mg protein. Taurine was the dominating FAA, accounting for 70% of the FAA pool. The time course of 3H‐taurine release induced by hyposmolarity followed that of volume recovery. Efflux of 3H‐taurine in an 8 min period was 17.8% (of total labeled taurine accumulated during loading) in an isosmotic medium. Reducing osmolarity to 0.87, 0.75, 0.62, and 0.5 increased this release to 24.8%, 38.1%, 56.4% and 70.9%, respectively. The volume‐sensitive release of 3H‐taurine was unaffected by omission of external Na+ or Ca++ and was reduced by 23% in the absence of Cl−. It was unaffected by agents disrupting the cytoskeleton or by tetraethylammonium, barium, quinidine, and gadolinium, but was 26% reduced by DIDS. Taurine release was inhibited at 4°C, but was unchanged at 15°C or 25°C. An involvement of FAA, particularly taurine, in lymphocyte volume regulation is suggested.
Hepatoma‐associated nuclear matrix nonhistone antigens
Authors: Kilianska Zofia , Krajewska Wanda M. , Xie Ronglin , Klyszejko‐Stefanowicz Leokadia , Chiu Jen‐Fu
Published: May 2005

Polyclonal antibodies generated against a group of high molecular weight nonhistone proteins from Morris hepatoma 7777 were used in immunological studies of hepatoma‐associated nonhistone proteins in rat and hamster. We revealed the presence of cross‐reactive antigens in rat Morris hepatomas 7777 and 8994, and in hamster Kirkman‐Robbins hepatoma, but not in normal rat or hamster livers. These specific nonhistone proteins were found to be preferentially localized in the nuclear matrix of rat Morris hepatoma 7777 as well as hamster Kirkman‐Robbins hepatoma.
Role of platelet‐derived growth factor in wound healing
Authors: Pierce Glenn F. , Mustoe Thomas A. , Altrock Bruce W. , Deuel Thomas F. , Thomason Arlen
Published: May 2005

Platelet‐derived growth factor (PDGF) is a potent activator for cells of mesenchymal origin. PDGF stimulates chemotaxis, proliferation, and new gene expression in monocytes‐macrophages and fibroblasts in vitro, cell types considered essential for tissue repair. Therefore, we analyzed the influence of exogenously administered recombinant B chain homodimers of PDGF (PDGF‐BB) on two experimental tissue repair paradigms, incisional and excisional wounds. In both types of wounds, as little as 20‐200 picomoles applied a single time to wounds significantly augmented the time dependent influx of inflammatory cells and fibroblasts and accelerated provisional extracellular matrix deposition and subsequent collagen formation. In incisional wounds, PDGF‐BB augmented wound breaking strength 50–70% over the first 3 weeks; in excisional wounds, PDGF‐BB accelerated time to closure by 30%. PDGF‐BB exaggerated, but did not alter, the normal course of soft tissue repair, resulting in a significant acceleration of healing. Long term observations established no apparent differences between PDGF‐BB treated and non‐treated wounds. Thus, the vulnerary effects of PDGF‐BB were transient and fully reversible in both wound healing models. Furthermore, analysis of PDGF‐treated and non‐treated wounds has provided important insights into mechanisms of normal and deficient tissue repair processes. PDGF appears to transduce its signal through wound macrophages and may trigger the induction of positive autocrine feedback loops and synthesis of endogenous wound PDGF and other growth factors, thereby enhancing the cascade of tissue repair processes required for a fully‐healed wound. Thus, PDGF and other wound produced polypeptide growth factors may be the critical regulators of extracellular matrix deposition within healing wounds.
Biocompatible controlled release polymers for delivery of polypeptides and growth factors
Authors: Langer Robert , Moses Marsha
Published: May 2005

The development of biocompatible, controlled release systems for macromolecules has provided the opportunity for researchers and clinicians to target and deliver, on site, biologically active factors. This advance has also facilitated the purification and characterization of a number of important biomolecules. These systems include controlled release delivery systems which release proteins through porous polymer matrices, degradable polymeric delivery systems, and modulated polymer release systems. These areas of research will be reviewed with regards to their design, release kinetics, and biocompatibilities. The utilization of these systems to release such biologically important polypeptides as growth factors (e.g., fibroblast growth factor, epidermal growth factor, transforming growth factor‐B) as well as a number of important inhibitory factors (e.g., nitrosoureas, angiogenesis inhibitors) in both in vivo and in vitro studies will be discussed.
EGF and TGF‐α in wound healing and repair
Authors: Schultz Gregory , Clark Warren , Rotatori D. Scott
Published: May 2005

Wound healing is a localized process which involves inflammation, wound cell migration and mitosis, neovascularization, and regeneration of the extracellular matrix. Recent data suggest the actions of wound cells may be regulated by local production of peptide growth factors which influence wound cells through autocrine and paracrine mechanisms. Two peptide growth factors which may play important roles in normal wound healing in tissues such as skin, cornea, and gastrointestinal tract are the structurally related peptides epidermal growth factor (EGF) and transforming growth factor alpha (TGF‐α). EGF/TGF‐α receptors are expressed by many types of cells including skin keratinocytes, fibroblasts, vascular endothelial cells, and epithelial cells of the GI tract. In addition, EGF or TGF‐α are synthesized by several cells involved in wound healing including platelets, keratinocytes, and activated macrophages. Healing of a variety of wounds in animals and patients was enhanced by treatment with EGF or TGF‐α. Epidermal regeneration of partial thickness burns on pigs or dermatome wounds on patients was accelerated with topical application of EGF or TGF‐α, and EGF treatment accelerated healing of gastroduodenal ulcers. EGF also increased tensile strength of skin incisions in rats and corneal incisions in rabbits, cats, and primates. Additional research is needed to better define the roles of EGF, TGF‐α, and their receptor in normal wound healing, to determine if alterations have occurred in the EGF/TGF‐α system in chronic wounds, and to optimize vehicles for effective delivery of peptide growth factors to wounds.
Mammalian hepatocytes as a foundation for treatment in human liver failure
Authors: Jauregui Hugo O. , Gann Kathryn L.
Published: May 2005

Technological advances in the separation and culture of mammalian hepatocytes have facilitated the use of these cells as the foundation for either hepatocyte transplantation or hepatocyte‐seeded hollow fiber liver assist devices (LAD). To fully appreciate the practical applications of these tissue engineering solutions, it is necessary to understand the types of human liver failure as well as the corresponding animal models. The most immediate application of this type of technology is the treatment of hepatic encephalopathy (HE), an acute and highly fatal complication of fulminant hepatic failure. Although the pathogenesis of HE is unknown, failure of the detoxification function of the liver is accepted as playing an important role in this disorder. Consequently, the assaying and preservation of P450 activity in the grafted cells or in the LAD must be among the main targets of this research. This review explores the problems in hepatocyte transplantation and culture that deserve special consideration and emphasizes the conditions contributing to the vitro maintenance of phenotypic expression of these cells.