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At least 757 records · Page 42Linked to original sources
PubMed1980

Ultrastructural changes in cells induced by temperature-sensitive mutants of fowl plague virus at permissive and non-permissive temperature.

Ultrastructural changes developing in chick embryo fibroblast cultures infected with a wild-type strain of fowl plague virus (FPV) or one of six FPV temperature-sensitive (ts) mutants belonging to different complementation groups were studied. Cells infected with wild-type FPV and incubated at optimal (36 degrees C) or nonpermissive temperature (42 degrees C) displayed changes similar to those described for orthomyxoviruses. The same patterns of changes were observed at 36 degrees C in cells infected with ts mutants belonging to five of the complementation groups. Mutant ts 303, possessing mutation-altered haemagglutinin, induced at 36 degrees C the formation of virions carrying a considerably reduced number of spikes on their surfaces. At 42 degrees C, cells infected with ts mutant 131, with a defective primary transcription stage, showed no morphological changes and no formation of electron-dense inclusions. Cells infected with ts mutants with defective secondary transcription or replication displayed nuclear inclusions but no formation of filamentous cytoplasmic structures or virions. Mutant ts 5 with defective late morphogenesis induced formation of considerably enhanced numbers of nuclear inclusions.

Animals↗
PubMed1996

Biological indicators for low temperature steam and formaldehyde sterilization: investigation of the effect of change in temperature and formaldehyde concentration on spores of Bacillus stearothermophilus NCIMB 8224.

Five strains of Bacillus stearothermophilus have been studied to identify a spore strain to be used as a biological indicator organism for low temperature steam and formaldehyde sterilization. Three strains gave poor reproducibility of batch size and growth index and were discarded. The other two strains gave good reproducibility with a high growth index and gave rise to linear survivor curves when exposed to 5% aqueous formaldehyde. However, only NCIMB 8224 sporulates on a simpler medium and as it was the most resistant to formaldehyde, it was further studied. Tests were carried out in a modified miniclave and factors studied included temperature of the steam and formaldehyde concentration. All studies confirmed the suitability of this strain as a biological indicator organism.

Data Interpretation, Statistical↗
PubMed2002

Temperature and flow visualization in a simulation of the Czochralski process using temperature-sensitive liquid crystals.

There is no doubt today that thermal and thermocapillary convection play a dominant role in momentum, heat, and mass transfer in the Czochralski crystal growth method. Because of the complexity of the problems, measurements in one point of the volume are not sufficient to illuminate the flow topography or to compare the experimental results with real or numerically simulated data. Therefore, it is of great interest to measure the temperatures and velocities in the whole field in order to qualitatively analyze thermally driven convection. The new experimental particle image thermometry method, based on computer-aided color analysis of the TLCs reported here, enables the simultaneous determination of the temperature and velocity fields.

Computer Simulation↗
PubMed1976

A comparison of the effects of morphine and pethidine upon body temperature and the reversal of reserpine's effects upon body temperature in the mouse.

The effects of morphine and pethidine upon body temperature and upon the reversal of reserpine hypothermia in the mouse were investigated. Both morphine and pethidine produced a dose-dependent fall in body temperature, that of morphine being totally antagonized by nalorphine and partially by naloxone, while that of pethidine was antagonised by naloxone and enhanced by nalorphine. Both drugs reversed reserpine-induced hypothermia. The reversal by morphine, but not by pethidine, was partially antagonized by naloxone. Adrenalectomy prevented the reversal of reserpine hypothermia by pethidine but morphine produced a partial reversal. Ganglion blockade and alpha-and beta-blockade all prevented reversal of reserpine hypothermia by both drugs. The results are discussed with regard to differences between pethidine and morphine and possible involvement of opiate receptors.

Adrenalectomy↗
PubMed1972

Assessment of the sanitary effectiveness of holding temperatures on beef cooked at low temperature.

Beef cubes cooked at low temperature were surface inoculated and incubated at 43.3 through 53.3 C to establish temperature limits for growth of staphylococci, salmonellae, and Clostridium perfringens. A greater than 99% reduction in staphylococci was achieved after 6 hr at 48.8 C, of salmonellae at 51.1 C, and of C. perfringens at 53.3 C. There were no survivors of a mixed inoculum of Staphylococcus aureus, Salmonella enteritidis, and C. perfringens after 12 hr at 51.1 C.

Animals↗
PubMed1980

Reactivation of temperature-sensitive and non-temperature-sensitive infectious bovine rhinotracheitis vaccine virus with dexamethasone.

Latent infections by a temperature-sensitive (ts) infectious bovine rhinotracheitis virus vaccines was produced as frequently as by non-ts vaccine virus. Thus virus could be reactivated in seven of eight ts vaccinates and six of eight non-ts vaccinates after dexamethasone treatment. Virus excretion could be detectable for 1 to 8 days at a level of 2 x 10(6) to 3 x 10(8) plaque-forming units per ml of nasal secretions. The reactivated virus was shown to be the same as the original virus used for vaccination by its inability to grow at the restrictive temperature (39 degrees C) as well as by its restriction endonuclease cleavage pattern.

Animals↗
PubMed1989

Temperature-sensitive sec mutants of Escherichia coli: inhibition of protein export at the permissive temperature.

Phenotypes of secY and secA temperature-sensitive mutants at permissive (low) temperature have been examined. The secY24 mutant was found to be extremely susceptible to export inhibition by a basal-level synthesis of the MalE-LacZ 72-47 hybrid protein or to overproduction of a normal secretory protein such as maltose-binding protein or beta-lactamase. Comparison of this phenotype of secY24 with those of the secY100 and secA51 mutants under similar conditions suggested that MalE-LacZ protein and overproduced secretory protein do not nonspecifically enhance the partial secretion defect but act synergistically with secY24 to inhibit protein export.

Bacterial Outer Membrane Proteins↗
PubMed2001

Experimental evolution of enzyme temperature activity profile: selection in vivo and characterization of low-temperature-adapted mutants of Pyrococcus furiosus ornithine carbamoyltransferase.

We have obtained mutants of Pyrococcus furiosus ornithine carbamoyltransferase active at low temperatures by selecting for complementation of an appropriate yeast mutant after in vivo mutagenesis. The mutants were double ones, still complementing at 15 degrees C, a temperature already in the psychrophilic range. Their kinetic analysis is reported.

Adaptation, Biological↗
PubMed1976

DNA-negative temperature-sensitive mutants of herpes simplex virus type 1: patterns of viral DNA synthesis after temperature shift-up.

Temperature-sensitive mutants of herpes simplex virus type 1 belonging to four DNA- complementation groups exhibited two distinct patterns of viral DNA synthesis after shift-up to the nonpermissive temperature. In cultures infected with mutants belonging to complementation groups A, C, and D, little or no viral DNA was synthesized after shift-up. In cultures infected with a mutant in complementation group B, nearly normal amounts of viral DNA were synthesized after shift-up.

Cell Line↗
PubMed1980

Integration of the simian virus 40 genome into cellular DNA in temperature-sensitive (N) and temperature-insensitive (A) transformants of 3T3 rat and Chinese hamster lung cells.

We studied the pattern of integration of the simian virus 40 (SV40) genome into the cellular DNA of N-transformants (temperature sensitive) and A-transformants (temperature insensitive) derived from 3T3-Fisher rat and Chinese hamster lung cells. The SV40 DNA was covalently linked to the cellular DNA in both types of transformants. In the rat cells, most N-transformants contained SV40 sequences integrated at a single site; most A-transformants contained SV40 sequences integrated at two to five sites. In the Chinese hamster cells, no significant correlation between the number of integration sites and the phenotype of the transformant was found; one of three integration sites were observed for both the N- and A-transformants. Single copies and tandem repeats of SV40 sequences were observed in A- and N-transformants derived from rat cells. A-transformants arise neither by amplification of the SV40 genome nor by integration at a unique site.

Animals↗
PubMed1994

Mutations in v-Src SH3 and catalytic domains that jointly confer temperature-sensitive transformation with minimal temperature-dependent changes in cellular tyrosine phosphorylation.

We have analyzed two functionally significant amino acid alterations encoded by the temperature-sensitive (ts) v-src mutant of Rous sarcoma virus, LA32. The G-to-V change at residue 300 in the catalytic domain nonconditionally impairs morphological transformation, in vitro kinase activity, in vivo tyrosine phosphorylation, and the cytoskeletal association of v-Src while rendering anchorage- and serum-independent growth ts. The R-to-P mutation in the SH3 domain subtly enhances morphological transformation but has no phenotype if the catalytic domain is inactivated. In the presence of the G-300-to-V mutation, this SH3 domain lesion does not affect v-Src in vitro kinase activity and cytoskeletal association, but it nonconditionally enhances cellular tyrosine phosphorylation and restores morphological transformation at the permissive temperature only. This ability to induce a ts transformed morphology, in concert with nonconditional elevations of cellular phosphotyrosine, suggest that a subset of v-Src targets that are crucial to transformation may be affected in ts fashion by the SH3 mutation. Consistent with this, we find that the R-107-to-P mutation confers ts activity and tyrosine phosphorylation on the SH3-binding enzyme phosphatidylinositol 3'-kinase. Thus, both the SH3 and catalytic domain mutations in LA32 have some ts attributes and they cooperate in determining the mutant's behavior. The ts SH3 mutation is unique and offers the potential for deeper understanding of the function of this domain.

Animals↗
PubMed1983

Observations on temperature and temperature patterns of the gingiva. II. Estimations of the error in measurement.

The diagnostician may expect an error associated with the measurements of clinical parameters. It is important to know how precise these measurements are. The purpose of this study was to make an estimation of the measurement error by comparing repeated measures of the same site. Six dental hygiene students were examined for gingival and were recorded twice. The maximum error associated with 95% of the temperature data and the average error were calculated as 1.3 degrees C and 0.65 degrees C, respectively. The probabilities of making a correct assessment of pocket depth and of sulcular bleeding were computed to be 0.864 and 0.840, respectively. The need for repeated measures was statistically analyzed. It can be concluded from our data that the thermocouple thermometer used in this study is a suitable instrument for measuring the gingival temperature. However, it is necessary to acquire a higher level of precision for the assessment of pocket depth and sulcular bleeding. This can be accomplished by increasing the number of clinical measures on each point.

Adolescent↗
PubMed1985

Role of suggestions in digital skin temperature: implications for temperature biofeedback research.

The purpose of the present experiment was to explore the role suggestions and assessment procedures play in affecting digital skin temperature. Four different types of suggestions were given subjects (warm, cool, pseudo (electronic terms), and no suggestions). Twenty-five subjects were randomly assigned to the four experimental conditions. The data were analyzed by three popular assessment procedures typically found in the literature. As predicted, subjects displayed significant decreases in skin temperature each day regardless of the training condition they were in. The assessment procedures produced differential results.

Biofeedback, Psychology↗
PubMed1982

Dietary energy requirements of broilers reared in low and moderate environmental temperatures. 1. Adjusting dietary energy to compensate for abnormal environmental temperatures.

Four trials were conducted to determine the feasibility of replacing fossil fuel energy with dietary energy to meet the 23- to 48-day-old broiler chicken's energy requirements during abnormal cold exposure. Sexed broilers were fed 3250 or 3500 kcal metabolizable energy (ME)/kg in a 21.1 C environment (a normal management situation), and 3250 or 3125 kal ME/kg in a 26.7 C environment. Body weights and feed utilizations increased when broilers were exposed to a 15.6 C environmental temperature and fed 3375 kcal ME/kg dietary energy as compared to feeding a 3250 kcal ME/kg dietary energy in the same environment. When broilers were reared in a 10.0 C environment, maximum body weights were not obtained by increasing the dietary energy from 3250 to 3500 kcal/kg dietary energy. Broiler males, fed 3250 kcal ME/kg and reared in either a 21.1 or a 26.7 C environment, were larger than males reared in 10.0 C environment. No significant differences were found in broiler female weights reared in a 10.0, 15.6, or 21.1 C environment and fed 3250 kcal ME/kg in each temperature regimen. Feed utilizations were the same broilers were reared in a 15.6 C environment and fed 3375 kcal ME/kg compared to broilers reared in a 21.1 C environment and fed 3250 kcal ME/kg. These results indicate that maximum performance of 23- to 48-day-old broilers may be achieved in a 15.6 C environment by feeding a high energy diet (3375 kcal/kg). Results also showed that dietary energy may replace fossil fuel energy that would normally be supplied in a 21.1 C environment.

Adipose Tissue↗
PubMed1976

[Studies on high temperature oxidation of noble metal alloys for dental use. (III) On high temperature oxidation resistance of noble metal alloys by adding small amounts of alloying elements. (author's transl)].

The previous report pointed out the undesirable effects of high temperature oxidation on the casting. The influence of small separate additions of Zn, Mg, Si, Be and Al on the high temperature oxidation of the noble metal alloys was examined. These alloying elements were chosen because their oxide have a high electrical resistivity and they have much higher affinity for oxygen than Cu. The casting were oxidized at 700 degrees C for 1 hour in air. The results obtained were as follows: 1. The Cu oxides are not observed on the as-cast surface of noble metal alloys containing small amounts of Zn, Mg, Si, Be, and Al. The castings have gold- or silver-colored surface. 2. After heating of the unpolished and polished castings, the additions of Si, Be and Al are effective in preventing oxidation of Cu in the 18 carats gold alloys. Especially the golden surface is obtained by adding Be and Al. But there is no oxidation-resistance on the polished castings in the alloys containing Zn and Mg. 3. The zinc oxide film formed on the as-cast specimen is effective in preventing of oxidation Cu in 18 carats gold alloys. 4. It seems that the addition of Al is most available in dental application.

Aluminum↗
PubMed1992

Human placental cells transformed with temperature-sensitive simian virus 40 are immortalized and mimic the phenotype of invasive cytotrophoblasts at both permissive and nonpermissive temperatures.

Establishment of the human placenta is essential for subsequent development of the embryo. Previous studies from our laboratories have demonstrated that chorionic villus cytotrophoblast stem cells undergo a stepwise differentiation process in vivo that results in their ability to invade the uterine wall. This process can be mimicked by isolated primary first-trimester cytotrophoblasts in vitro. Efforts to study the regulation of this differentiation pathway have been hampered by the inability of the isolated cytotrophoblast to replicate in culture. We therefore performed experiments to determine the suitability of the temperature-sensitive simian virus 40-transformed cell line SPA 255-26 (SPA-26), derived from early-gestation cytotrophoblasts, for studying the cytotrophoblast differentiation pathway that results in uterine invasion. Our results show that this cell line exhibits many properties of differentiated early-gestation cytotrophoblasts at both permissive and nonpermissive temperature. These cells were invasive in vitro and expressed the repertoire of hormones, adhesion molecules, and proteinases characteristic of an advanced stage of cytotrophoblast differentiation in vivo. Thus, these cells should be useful in studying the regulation of the adhesive and invasive behavior of human cytotrophoblasts.

Cell Adhesion Molecules↗
PubMedDate not supplied

[The temperature dependence of receptor structures and temperature-related reception].

In acute experiments on rats, studies have been made on impulse activity of single fibres of n. ischiadicus evoked by stimulation of the receptive fields of the sole by focused ultrasound. Mechanical effects were produced by rectangular ultrasonic stimuli, thermal ones--by trapezoid ones. With respect to the magnitude of a threshold response to a rectangular stimuli, the receptor structures were divided into three groups, i.e. low, mean and high threshold ones. Low and mean threshold receptor units responded to local thermal stimulation. Mean threshold units exhibited an increase of the threshold to mechanical stimulation after local thermal one. In human subjects, the structures which are functionally similar to mean threshold units, evoke thermal sensations, and may be classified not only as temperature dependent, but also as temperature sensitive.

Acoustic Stimulation↗