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PubMed1985

[Relative spacing of the microtubules and intermediate filaments during fibroblast spreading in culture].

Using double immunofluorescence staining, microtubules and intermediate filaments were shown to have similar distribution in the substrate-spread mouse embryo fibroblasts. However, in cells spreading on the substrate, microtubules grow from the centre to the periphery regions quicker than intermediate filaments. We suppose that microtubules may guide the spreading of intermediate filaments from the perinuclear regions to the periphery of the cell during its spreading.

Animals↗

PubMed1989

[Stimulation of spreading and aggregation of platelets on immobilized type V collagen: mechanisms depending on Ca2+ and protein kinase C].

The effects of phorbol ester (PMA) and stable prostaglandin endoperoxide analog (U46619) on platelet interaction with a surface coated with monomeric type V collagen (CV substrate) and free Ca2+ concentration in platelet cytoplasm ([Ca2+]in) have been studied. In the absence of PMA and U46619, the discoid and spherical platelets from suspension are attached to CV substrate but are incapable of spreading and aggregation on the substrate. An addition of PMA (0.15-1.5 nM) or U46619 (1.5 microM) to the reaction mixture stimulates platelet spreading and the formation of multilayer (thrombi-like) aggregates on CV substrate. Using the fluorescent probe Quin 2, it was found that U46619 (0.1 microM) increases [Ca2+]in from the basal level (100-120 mM) to 600 nM. PMA (0.75-15 nM) exerts only a slight effect increasing [Ca2+]in by 30-40 nM. The data obtained suggest that the PMA-induced spreading and aggregation of platelets on CV substrate can occur via activation of protein kinase C at relatively low [Ca2+]in values. These results also testify to the existence of a substrate-independent mechanism of spreading of platelets activated in suspensions by soluble inducers.

Aminoquinolines↗

PubMed1985

Spread of multiresistant gram-negative bacilli among severely immuno-compromised mice during prophylactic treatment with different oral antimicrobial drugs.

Gram-negative infections are generally regarded as a major cause of severe infections in granulocytopenic patients. To prevent such infections, selective decontamination (SD) of the digestive tract has been introduced. It is assumed that if SD is applied on all patients in an oncologic station it may not only provide protection to patients thus treated, but it may have also epidemiologic consequences. SD may considerably reduce the number of circulating (antibiotic-resistant) strains in the ward and therewith significantly further reduce the chance of severe infection during periods of granulocytopenia. Because the effect which different kinds of antibiotics may have on the accumulation and spread of resistant bacteria cannot be studied in patients, it was investigated experimentally. Groups of 15 conventional mice were lethally irradiated and each group was treated with one antibiotic. On the day of irradiation one mouse per cage was orally contaminated with a multi-resistant strain either of E. coli or Ps. aeruginosa. The spread of these strains among cage mates as well as their effect on mortality was investigated. It appeared that ampicillin promoted spread and enhanced mortality in comparison with a control group, whereas antibiotics currently used for SD did prevent spread of the multi-resistant strain and reduced mortality.

Ampicillin↗

PubMed1986

Interactions of rat hepatocytes with type IV collagen, fibronectin and laminin matrices. Distinct matrix-controlled modes of attachment and spreading.

We have examined the interaction of adult rat hepatocytes in primary culture, to type IV collagen, fibronectin, and laminin, the major basement membrane proteins of normal rat liver. Culture substrata consisted of glass coverslips, which were covalently derivatized with individual purified basement membrane constituents at varying densities of protein. The attachment of freshly prepared hepatocytes was examined after incubation at 37 degrees C for 30 min as a function of the amount of protein on the coverslips. For each of the three types of substratum under study, distinct modes of cell attachment were observed, with the apparent affinity of hepatocytes for type IV collagen being three-fold greater than for fibronectin and ten-fold greater than for laminin. Cell attachment exhibited saturation on all substrata. Hepatocyte spreading was measured by scanning electron microscopy of cells incubated at 37 degrees for 2 h on similarly prepared coverslips. A five-fold greater surface density of type IV collagen was required for maximal spreading compared with attachment. For cells on fibronectin or laminin the maximal cell spreading reached on type IV collagen did not occur even at coverslip protein densities 10 to 20 times those providing for maximal cell attachment. A very similar qualitative pattern of cell proteins was secreted within a few hours of plating on the various substrata and further studies failed to reveal any evidence that attachment and spreading was mediated by endogenously produced matrix molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Spreading of human fibroblasts on pretreated human root dentine.

The spreading of fibroblasts on human dentine and dentine treated with solutions containing fluorides, chlorhexidine or citric acid was determined in vitro. The surface active properties of the test solutions (except for citric acid) with regard to ground and polished dentine were monitored by surface free energy determinations calculated from contact angles. None of the solutions tested drastically altered the surface free energy of dentine, which remained rather high in the range of 73 erg.cm-2. Application of fluoride containing solutions and citric acid decreased the spreading of fibroblasts significantly (p less than 0.05), whereas only chlorhexidine enhanced the spreading of cells (p less than 0.05). This study indicates that the use of fluoride containing solutions should be avoided during and after periodontal surgery and scaling. Chlorhexidine would be recommended however both on the basis of its known antiplaque properties as well as on the basis of its enhancement of cell spreading demonstrated in this study.

Acidulated Phosphate Fluoride↗

PubMed1988

Perineural spread of nasopharyngeal carcinoma: radiological and CT demonstration.

Perineural spread is well known to be the most insidious form of tumour spread of a number of head and neck malignancies. However, perineural extension of nasopharyngeal carcinoma (NC) is a poorly recognized event. Four cases of perineural metastases from NC have been detected with pluridirectional tomography and CT. In 3 cases involvement of the Vidian nerve (nervus canalis pterygoidei) and pterygoid canal was observed. In a fourth patient, invasion of one pterygopalatine fossa and perineural spread along ipsilateral maxillary nerve with enlargement and erosion of the foramen rotundum was demonstrated. Radiological diagnosis of clinically unsuspected perineural tumour spread is important because it markedly influences treatment planning and prognosis of NC.

Carcinoma↗

PubMed1986

Epidemiology of the emergence and spread of drug-resistant falciparum malaria in South-East Asia and Australasia.

A review is presented of the development of drug-resistant malaria in Païlin on the Thai-Kampuchean border and its spread to other parts of the region and beyond. Resistance of P. falciparum to chloroquine appears to have emerged in this area in the early 1960s and evidence of resistance to the combination of sulfadoxine and pyrimethamine and to the combination of diaphenylsulfone and pyrimethamine came from the same area towards the end of the same decade. The factors leading to the emergence and increase of drug resistance appear to have been: the continuous introduction of non-immune migrants to a hyperendemic malaria area, an increase in already intense transmission resulting from the living and working conditions of the migrants and prolonged drug pressure resulting from individual drug consumption and mass drug administration, particularly from the medicated salt project which covered the area in which resistance emerged. These conditions lead to the selection of resistant mutants. Moreover, resistant parasites were exposed to multiple and increasing doses of chloroquine, pyrimethamine and sulfathiazole during repeated passages through non-immune hosts who were being treated for primary attacks, early recrudescences and reinfections. This probably resulted in increasing the degree of resistance and in the selection of parasites resistant to sulfathiazole with cross-resistance to other sulfonamides. In Irian Jaya, Indonesian New Guinea, where there had been a chloroquinized salt project, the level of chloroquine resistance was much lower than in Païlin; this is associated with the absence of a non-immune population and the lower dose of chloroquine base used in the salt. The spread of chloroquine resistance is then discussed. At first resistance was found only in three foci in South-East Asia where A. balabacensis is the vector of malaria. It then spread to all A. balabacensis areas, and finally to areas outside the area of distribution of A. balabacensis. The spread of resistance is found to be favoured by the presence of the vector A. balabacensis and by the introduction of a non-immune population.

Antimalarials↗

PubMed1979

Specificity of the macrophage spreading test with reference to Leishmania antigens and correlation with delayed hypersensitivity.

The inhibition of the macrophage spreading test, claimed to be an in vitro correlate of delayed hypersensitivity, was examined in guinea-pigs immunized with L. enriettii and L. tropica soluble antigens. Cells from peritoneal washings of the guinea-pigs were tested in presence of the homologous and heterologous antigens and also without antigen. Inhibition of macrophage spreading compared to control preparations was noted only in the presence of the homologous antigen when the skin test response of the donor animal was relatively small. The degree of inhibition decreased as the skin test volume increased and when skin test volumes were large there was actual stimulation of macrophage spreading, rather than inhibition. The addition of heterologous antigen to the peritoneal cell preparation always resulted in the augmentation of macrophage spreading above control levels. The possible mechanisms of this in vitro technique and its use as a taxonomic or diagnostic tool are discussed.

Animals↗

PubMed1985

The coordinate organization of vinculin and of actin filaments during the early stages of fibroblast spreading on a substratum.

Cultured normal fibroblasts adhere to their support essentially through the focal adhesion plaques which are greatly enriched with the 130 000 dalton protein, vinculin, along with the newly described 215 000 dalton protein, talin, and at which actin bundles terminate. In order to explore a role for vinculin in the formation of the adhesion plaques and of the actin bundles, we have studied and compared the development of these two cellular structures during the spreading of trypsinized and replated chicken embryonic fibroblasts. The techniques used were double indirect immunofluorescence and interference reflection microscopy. At the earliest stage of cell spreading observed, vinculin distributes into small patches that are located along actin filaments and at the basis of the ruffling membrane. At later spreading stage, vinculin markedly redistributes into larger striations which coincide with focal contacts. Some of these vinculin striations are associated with the ends of microfilaments while the others are not. These observations would suggest that two types of focal contacts can form simultaneously in early cell spreading. Hypotheses are made concerning the role of vinculin in the formation of the adhesive cell structures in the light of these new data and of previous reports on the subject.

Actins↗

PubMed1985

[Upward spread of masking in normal and abnormal ears].

Upward spread of masking was studied for normals and sensorineurally hearing-impaired subjects with high-frequency hearing loss. Hearing-impaired listeners were recruited in such a way as to present normal hearing on the frequency of the masker, that is a narrow band of noise centered at 1 000 Hz. Levels of the masker were set at 70, 80 and 90 dB, respectively. Results first indicated the presence of a relationship between masked and elevated absolute thresholds for a masker level of 70 dB. At masker levels of 80 and 90 dB, hearing-impaired listeners showed excessive upward spread of masking in spite of normal hearing sensitivity at the masker frequency: with 80 and 90 dB of noise, upward spread of masking grew, respectively, 2.6 and 1.6 times faster than in normals. Furthermore, excessive upward spread of masking was shown to progress as a function of hearing loss. Results were interpreted as additional evidence of abnormal frequency selectivity in sensorineurally hearing-impaired listeners.

Adult↗

PubMed1979

[The spreading of Agrobacterium strains in soft-agar (author's transl)].

In a diluted synthetic medium solidified by 0.17% agar populations of Agrobacterium spread with a velocity of 0 to 20 mm/24 hours. This spreading is a consequence of chemotactic movement and cell division. Different bacterial strains spread with a characteristic velocity each. Loss of the TI-plasmid leaves the spreading behaviour unimpaired. It is changed after the introduction of virulence by Kerr transfer or after prolonged culture in D-amino acids.

Agar↗

PubMed1977

Plasma membrane vesiculation: correlation between macrophage spreading and the shedding of cell surface vesicles.

The data presented in this paper establish a correlation between the extent of macrophage spreading and the ability of macrophages to shed plasma membrane vesicles following incubation in a membrane vesiculant. Maximal macrophage spreading was observed following incubation in buffers containing Mn2+ or dithiothreitol. Scanning electron microscopy showed that such macrophages have a uniformly flat surface morphology. Exposure of these macrophage monolayers to a vesiculant containing 25 mM formaldehyde-2 mM dithiothreitol induced plasma membrane vesiculation. Scanning electron microscopy further demonstrated that vesicles were formed and released randomly over the cell surface and that vesicles varied in size from 1 to 15 micrometer. diameter. A variety of chemicals that share the common ability to bind to free sulfhydryl groups have been shown to act as membrane vesiculants as a result of their apparent ability to induce a unique form of cell injury which results in the shedding of cell surface vesicles. The differential effect of vesiculants on cells grown in suspension and as monolayer is interpreted to suggest that reorganization of the cellular cytoskeleton associated with cell spreading may underlie the ability of membrane vesiculants to induce plasma membrane vesiculation in highly spread and adherent macrophage monolayers.

Animals↗

PubMedDate not supplied

[Inflammation and host resistance against tumours. II. -- Antagonism between bradykinin and a fraction isolated from the supernatant of cultured malignant cells on the spreading of macrophages (author's transl)].

When murine peritoneal macrophages are incubated in presence of 10(-6) to 10(-8) M of bradykinin, their spreading is increased. When macrophages are incubated in presence of a low molecular weight fraction of the supernatant from cultured Lewis carcinoma's cells (AP) their spreading is decreased. When macrophages are incuated first with bradykinin and later on with AP, no inhibition of spreading is observed. When macrophages are incubated first with AP and later on with bradykinin, the increase of spreading is not observed.

Bradykinin↗

PubMed1982

Bovid herpesvirus 2: natural spread among breeding bulls.

Sera collected over a seven year period, together with detailed health and management records, were used in a retrospective study of Bovid herpesvirus 2 (BHV-2) spread within a large herd of breeding bulls. Virus spread rapidly throughout the bulls in one barn. Transfer of infected bulls to other barns was followed by further, although sporadic, spread of virus. Spread of BHV-2 from seropositive animals to susceptible bulls in close contact led to the conclusion that reactivation and transmission of latent virus had occurred. Semen from seropositive bulls did not transmit BHV-2 to seronegative calves that were purposefully inoculated by the intranasal or intravenous routes.

Animals↗

PubMed1983

Spreading of a sperm surface antigen within the plasma membrane of the egg after fertilization in the rat.

The rat sperm surface antigen 2D6, located over the entire surface of the spermatozoon, is shown by use of a monoclonal antibody in indirect immunofluorescence experiments to spread laterally over the surface of the egg after fusion of sperm and egg plasma membranes at fertilization. Freshly fertilized eggs, obtained from superovulated rats 14 h after hCG injection, showed the 2D6 antigen to have spread in a gradient over a discrete fan-shaped area of the egg surface anterior to the protruding sperm tail. Eggs at a later stage of sperm incorporation, obtained 20 h after hCG injection, showed that the spread of antigen had extended to cover most or all of their surfaces. By 40 h after hCG injection, the approximate time that fertilized eggs cleaved to form 2-cell embryos, most of the 2D6 antigen had been lost from the cell surface. Fertilized eggs, but not unfertilized eggs or 2-cell embryos, were lysed by 2D6 monoclonal antibody in the presence of guinea pig complement. A model for sperm-egg fusion is presented to account for the observed pattern of spreading shown by the 2D6 antigen. The possible role of sperm antigens on the egg surface is discussed.

Animals↗

PubMed1983

Temporal-spatial-social parameters in the spread of contagious disease.

A conceptual theoretical model was built on the basis of prominent concepts of the generally accepted knowledge on the spread of contagious disease. Subsequently, the model was applied to a real epidemic of variola minor (the mild form of smallpox) and four phases of the epidemic were disclosed. The phases discriminated themselves through their relationships to invasion of certain city subdivisions and rural districts and particularly, through the type of social units involved and the type of persons introducing the disease into these units. Introduction of variola minor into day schools with further spread in classes passed across a threshold which led to a boosting of the number of households affected and of the area involved in the epidemic. The phase of maximal spread corresponded to this operation of day schools as diffusion agencies. The temporal-spatial-social correspondence suggests that phases of the epidemic did occur as a result of periodic variation of the mechanism of spread.

Brazil↗

PubMed1983

Barbotage and spinal anaesthesia. The effect of barbotage on the spread of analgesia during isobaric spinal anaesthesia.

Subarachnoid block was performed with 0.5% plain bupivacaine in 67 patients with patients in the lateral position and the table horizontal. Thirty-six patients had a single injection while in the remaining 31 patients barbotage was used. Injection rates and aspiration rates were constant in both groups at 0.33 ml/second. Mean volumes of bupivacaine used in the two groups were 3.30 and 3.35 ml, respectively. The mean spread of analgesia after 30 minutes was 0.9 dermatomes higher in the group which received a single injection, and this was not statistically significant. The range of spread of analgesia was large in both groups, there was no correlation between spread of analgesia and volume of local anaesthetic used, and there was no correlation between age of patient and spread of analgesia in either group. Control of the level of analgesia during isobaric spinal block is difficult, and is not facilitated by barbotage.

Aged↗

PubMed1981

Morphologic aspects of adhesion and spreading behavior of amphibian blastula and gastrula cells.

By means of SEM we have examined spreading and adhesive behavior of cells isolated from superficial and deep regions of germ layers from blastula to late gastrula in Rana pipiens embryos. Each of the cell populations sampled show adhesive and spreading characteristics distinctive for each region and stage which we interpret as demonstrating the following: (1) From blastula through late gastrula, cells from each region have already acquired the ability to express surface morphologic and adhesive features independently of their association with their neighbors, i.e. autonomously. (2) The distinctive spreading and adhesive characteristics for each tissue sub-population suggest kinetic properties seemingly related to their in vivo morphogenetic movements, epiboly or invagination. (3) The appearance within germ layers of two subpopulations between blastula to mid-gastrula, suggests early intratissue inductive interactions. (4) The outermost, superficial cells from each germ layer show proximal and distal surface differences which may reflect adhesive differentials as postulated by Steinberg (1970) for presumptive ectoderm cells. (5) With the exception of superficial cell proximal and distal differentiation, freshly disaggregated cells do not show morphologic characteristics seen in corresponding cells spreading for one hour.

Animals↗