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At least 811 records · Page 45Linked to original sources
PubMed1992

An appraisal of low-temperature embedding by progressive lowering of temperature into Lowicryl HM20 for immunocytochemical studies.

The progressive lowering of temperature (PLT) method of embedding for electron microscope immunolabelling has been examined with the objective of formulating a standardized protocol which can be applied to a wide variety of samples. The methods described cover fixation, processing of samples by the PLT method, embedding in Lowicryl HM20 and subsequent immunolabelling. Each of the steps in the fixation and embedding protocol has been assessed for its potential to retain both morphology and antigenicity. Comparison of samples embedded in Lowicryl K4M and HM20 at -25 degrees C indicate an increased membrane contrast in HM20 sections, and a further improvement in morphology when samples were embedded in HM20 at -50 degrees C rather than at -25 degrees C. The results of applying the methods described are demonstrated in a range of samples of both mammalian and botanical origin, which includes solid tissues, cells in suspension, and cells grown in vitro as a monolayer culture and embedded in situ. Samples processed by this method have been immunolabelled using a wide range of antibodies recognizing nuclear, cytoplasmic, cell membrane and extracellular matrix antigens.

Acrylic Resins↗
PubMed1979

Temperature-sensitive Chlamydomonas mutants manifesting flagellar regression at a restrictive temperature.

The regeneration kinetics of Chlamydomonas reinhardtii mutants TS-6 and TS-79, whose flagella were mechanically amputated, indicated that the flagellar precursor in cytoplasm was used for regeneration when cycloheximide was present. The TS-6 cells rendered nonflagellate by regression at 35 C did not regenerate in the presence of cycloheximide, indicating that the precursor was inactivated by the high temperature. Neither mutant was able to use the absorbed flagellar components for regeneration in the presence of cycloheximide.

Animals↗
PubMed1996

Cold stress proteins induced in Listeria monocytogenes in response to temperature downshock and growth at low temperatures.

Listeria monocytogenes is a food-borne pathogen with the ability to grow at refrigerator temperatures. Twelve cold shock proteins (Csps) with apparent M(r)s of 48,600, 41,000, 21,800, 21,100, 19,700, 19,200, 18,800, 18,800, 17,200, 15,500, 14,500, and 14,400 were induced by cold shocking L. monocytogenes 10403S from 37 to 5 degrees C, as revealed by labeling with L-[35S]methionine followed by two-dimensional gel electrophoresis. Strain SLCC53 showed a similar response. Cold acclimation proteins were observed in cultures of strain 10403S growing at 5 degrees C, and four of these proteins, with apparent M(r)s 48,000, 21,100, 19,700, and 18,800, were also Csps. Two cold-sensitive transposon-induced mutants were labeled less efficiently than the parent strain, but the Csp response of the mutant examined was very similar to that of the parent strain.

Bacterial Proteins↗
PubMed1976

Chemically induced temperature-sensitive mutants of dengue virus type 2: comparison of temperature sensitivity in vitro with infectivity suckling mice, hamsters, and rhesus monkeys.

A series of temperature-sensitive (ts) mutants of dengue virus type 2 (DEN-2, TH-36 isolate) were induced by treatment with 5-azacytidine. These mutants and parental viruses were compared for the ts trait and/or attenuation in four systems: primary hamster kidney cells, suckling mice, golden Syrian hamsters, and rhesus monkeys. Seven clones judged to possess the ts trait in virto demonstrated a variety of patterns in vivo. On initial isolation, five of seven ts mutants exhibited reduced mouse lethality. The remaining two mutants possessed parental levels of mouse lethality. In hamsters, neither ts mutant nor parental viruses replicated very well, and then only when inoculated intracerebrally. Studies in rhesus monkeys indicated that all seven ts clones and parental viruses were capable of inducing abtibody responses; however, ts-1 and ts-2 failed to produce detectable viremia. After challenge with parental virus, all vaccinated monkeys demonstrated rapid secondary-type antibody response. Reversion from ts to ts(+) was confirmed to ts-1 in mice and ts-3 in monkeys, and was strongly suspected in several other instances.

Animals↗
PubMed1979

Temperature-sensitive mutants of influenza A virus: evaluation of the A/Victoria/75-ts-1A2 temperature-sensitive recombinant virus in seronegative adult volunteers.

An influenza A virus recombinant bearing the surface antigens of the A/Victoria/3/75 (H3N2) strain and the two ts genes of the A/Udorn/72-ts-1A2 virus was evaluated for attenuation, antigenicity, and protective effect in 42 doubly seronegative adult volunteers (i.e., individuals who lacked detectable serum antibodies for the hemagglutinin and neuraminidase antigens). This recombinant, which had a 37 degrees C shutoff temperature for plaque formation and ts mutations on the genes thought to code for the P1 and P3 polymerase proteins, infected 90% of the volunteers. Of the volunteers, 5% developed mild coryza or rhinitis but other signs or symptoms were not observed, indicating that the A/Victoria/75-ts-1A2 recombinant was more attenuated than the A/Victoria/75-ts-1[E] recombinant. Vaccinees shed virus for a shorter interval and at a lower titer than did the A/Victoria/75-ts-1[E] vaccinees. Each ts-1A2 isolate retained the ts phenotype indicating that the recombinant was stable genetically in doubly seronegative adults. Finally, the ts-1A2 recombinant induced significant resistance to subsequent challenge with A/Victoria/75 wild-type virus.

Adult↗
PubMed1985

Two independent mutations are required for temperature-sensitive cell transformation by a Rous sarcoma virus temperature-sensitive mutant.

We molecularly cloned the src coding region of tsNY68, a mutant of Rous sarcoma virus temperature sensitive (ts) for transformation, and constructed a series of ts wild-type recombinant src genes. DNA containing the hybrid genes was transfected into chicken cells together with viral vector DNA and helper viral DNA, and infectious transforming viruses were recovered. Characterization of these recombinant viruses indicated that at least two mutations are present in the 3' half of the mutant src gene, both of which are required for ts. Nucleotide sequence analysis revealed three differences in the deduced amino acid sequence compared with the parental virus. Two of these changes, a deletion of amino acids 352 to 354 and an amino acid substitution at position 461, are responsible for the ts phenotype.

Animals↗
PubMed1999

The major attenuating mutations of the respiratory syncytial virus vaccine candidate cpts530/1009 specify temperature-sensitive defects in transcription and replication and a non-temperature-sensitive alteration in mRNA termination.

The live-attenuated respiratory syncytial virus vaccine candidate cpts530/1009 was previously shown to contain two separate amino acid changes in the L protein, mutations 530 and 1009 (Phe-521-->Leu and Met-1169-->Val, respectively, according to the amino acid sequence of the L protein). Each mutation independently specifies temperature-sensitive (ts) and attenuation phenotypes. In this study, we examined the effects of these mutations on transcription and RNA replication, using complete infectious recombinant virus as well as a plasmid-based minireplicon system, the latter under conditions in which effects on replication and transcription are uncoupled. In comparison with recombinant wild-type virus, the 530 and 1009 viruses were partially restricted at 37 degrees C for RNA replication, mRNA synthesis, and virus growth. The 1009 virus was partially restricted for RNA synthesis and virus growth even at 32 degrees C, which suggested that the 1009 mutation has a non-ts component in addition to the ts component. Interestingly, the synthesis of polycistronic readthrough mRNAs was elevated 1.6- to 3.8-fold for the 1009 virus, and this defect was non-ts. Studies with the minigenome system showed that the 530 and 1009 mutations each directly affect both replication and transcription, that the effect on replication was marginally greater than on transcription for the 530 mutation, and that the increase in readthrough mRNA associated with the 1009 mutation also was observed with the minigenome system.

Mutation↗
PubMed1989

Effect of temperature on fixation suppression ability in normal subjects: the need for temperature- and age-dependent normal values.

The purpose of the present investigation was to determine whether temperature has an effect on the magnitude of fixation suppression (FS) in normal subjects. The subject population consisted of 23 patients ranging in age from 35 to 74 years (mean age of 58.13 years). Each subject received a conventional vestibulometric test battery that included bithermal caloric testing and the FS test. The warm caloric media elicited larger nystagmus slow-phase eye velocities than the cool caloric media. Following warm caloric irrigations, FS was significantly smaller than that following cool caloric irrigations. It also worsened as a function of subject age. The results suggest that separate normal upper limits for FS need to be determined for cool and warm caloric testing. They also suggest that FS ability may decrease with age.

Adult↗
PubMed2004

Investigation of temperature-induced phase transitions in DOPC and DPPC phospholipid bilayers using temperature-controlled scanning force microscopy.

Under physiological conditions, multicomponent biological membranes undergo structural changes which help define how the membrane functions. An understanding of biomembrane structure-function relations can be based on knowledge of the physical and chemical properties of pure phospholipid bilayers. Here, we have investigated phase transitions in dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC) bilayers. We demonstrated the existence of several phase transitions in DPPC and DOPC mica-supported bilayers by both atomic force microscopy imaging and force measurements. Supported DPPC bilayers show a broad L(beta)-L(alpha) transition. In addition to the main transition we observed structural changes both above and below main transition temperature, which include increase in bilayer coverage and changes in bilayer height. Force measurements provide valuable information on bilayer thickness and phase transitions and are in good agreement with atomic force microscopy imaging data. A De Gennes model was used to characterize the repulsive steric forces as the origin of supported bilayer elastic properties. Both electrostatic and steric forces contribute to the repulsive part of the force plot.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

Inhibition of temperature-dependent immobilization of fowl spermatozoa at body temperature by an increased intracellular pH.

Fowl sperm motility was measured by altering the extracellular pH (pHe) at 30 degrees C and 40 degrees C. At 30 degrees C, the motility of intact spermatozoa was vigorous in a medium in the wide pHe range of 7.3-10.1. In contrast, intact spermatozoa were almost immotile at 40 degrees C in medium below a pHe of 8.1. However, the motility could be restored by increasing the pHe; maximum motility was obtained in medium at pHe 9.4. Stimulation of the motility of demembranated spermatozoa at 40 degrees C was also observed with an increased pHe. However, demembranated spermatozoa at 40 degrees C that had been stimulated by increasing the pHe lost their motility when 1 mmol CaCl2 l-1 was added. Motility was restored by the subsequent addition of 2 mmol EGTA l-1. At a high pHe at 40 degrees C, the flagellar ATPase activity of crude dynein extract was not affected, regardless of the addition of CaCl2 or EGTA. The intracellular pH (pHi) of intact spermatozoa, estimated by measuring the accumulation of 9-aminoacridine fluorescence, increased with increasing pHe at both 30 degrees C and 40 degrees C. These results demonstrate that the reversible temperature-dependent immobilization of fowl spermatozoa at 40 degrees C is inhibited by an increased pHi. Furthermore, it is possible that the effects of the increased pHi may not act directly on dynein ATPase activity, but are mediated by a Ca(2+)-related substance(s) on the axoneme.

Animals↗
PubMed2000

Genetic sexing strains of mediterranean fruit fly (Diptera: Tephritidae): quality in mass-reared temperature-sensitive lethal strains treated at high temperatures.

The high-temperature treatment of eggs of mass-reared tsl genetic sexing strains in Mediterranean fruit fly, Ceratitis capitata (Wiedemann), during late embryogenesis (the low-high protocol) conserves more male flies than treatment during early embryogenesis. A tsl strain, AUSTRIA 6-97, was constructed to follow the fate of aneuploid individuals during male-only production. Aneuploid individuals are produced following segregation in the translocation heterozygous males, and they can survive to the pupal stage where they compromise quality because they do not eclose as adults. Hatching, emergence, and male fly production were quantified and the heat-treatment protocol was characterized. The low-high egg treatment conserves the number of euploid-balanced males, and there is a very low survival of aneuploid males. After heat treatment of eggs, at least 95% of the male pupae were euploid compared with only 71% from untreated eggs. The quality of euploid male pupae was diminished with successive daily collections, an effect previously attributed to aneuploid survivors. Reduced yield of euploid males from early heat treatments was the result of an emergence effect, in addition to a maternal effect. A third detrimental effect of heat was found, occurring after hatching and before pupation, that reduces the survivorship of euploid males. The low-high treatment protocol yielded more males, with a higher accuracy than other heat treatments. However, although it avoids both the maternal and emergence effects, the production of euploid males was 30% less than the potential production, implying that the low-high heat protocol for killing female embryos in tsl genetic sexing strains can be fine-tuned.

Animals↗
PubMed1999

Temperature management in trauma patients across the continuum of care: the TEMP Group. Temperature Evaluation and Management Project.

Hypothermia is a potentially preventable consequence of injury in the trauma patient. The physiologic aftermath of hypothermia is such that it is regarded as one of the three components in the trauma triad of death. A multidisciplinary group at a Level I trauma center was formed to originate an innovative team approach to managing temperature in trauma patients. This article describes this unique project to combat a preventable cause of significant morbidity and mortality.

Acute Disease↗
PubMed2000

[Immunogenic activity of temperature sensitive mutation of herpes simplex virus type-1 in mono- and polyvalent conditions with different attenuated strains of virus. I. Analysis of humoral immunity induced by mutant temperature sensitive herpes simplex virus type-1 in monovalent systems].

The aim of the present study was the analysis of the immunogenic activity of temperature sensitive mutant of HSV-1 with significantly decreased pathogenicity for mice. The stability of immunogenic potency was also tested. The level of antibody-mediated response in guinea pigs after two doses of mutant ts HSV-1 or native strain was compared. Antibodies to HSV were measured using ELISA and CFM. Seroconversion rates in tested groups were high, from 80% to 100%. The level of antibody response at 4 week after inoculation measured by ELISA and CFM showed no significant differences between 4 passages of mutant ts HSV-1. Significant higher increase of antibodies level after two doses of viruses was observed for mutant ts HSV-1 as compared to native strain, both in ELISA and CFM.

Animals↗
PubMed2003

Heated socks maintain toe temperature but not always skin blood flow as mean skin temperature falls.

INTRODUCTION: This study was conducted to examine whether toe skin blood flow (Q(toe)) could be maintained in subjects exposed to cold air by warming the foot using a heated sock. METHODS: Four male subjects were exposed to air at 4 degrees C. They wore aramid shirt and trousers, a coverall made from metalized spun bonded polyethylene ("space blanket" fabric), arctic mittens, a 4-ply aramid balaclava, and loose fitting padded boot liners. The subjects rested recumbent on a couch with a pair of heated socks turned on for 120 min and with socks turned off for a further 60 min. Q(toe) was measured using laser Doppler flowmetry. RSULTS: Although the heated socks maintained the skin temperature of the feet above 37 degrees C, Q(toe) was not maintained in two of the four male subjects for the 120 min that the socks were turned on. DISCUSSION: Heated socks cannot be relied on to maintain Q(toe) or to prevent non-freezing cold injuries during prolonged exposure to cold conditions.

Adult↗
PubMed1998

[Phenomena of supramolecular assembly fluid room temperature phosphorescence (II)--effects of alcohols on room temperature phosphorescence of cyclodextrin/4-iodo-4'-ethyl-biphenyl/bromocyclohexane system].

Beta-cyclodextrin( beta/-CD)can induce 4-iodo-4'-ethyl-biphenyl(IEBP)to emit room temperature phosphorescence(RTP) in the presence of bromocyclohexane (BCH). If butyl alcohol (BuOH) is presented as a fourth component at the same time, RTP intensity of the system is enhanced obviously. Effects of different alcohols, CDs and derivatives of beta-CD on RTP emission of the system are studied. The results show that a ternary host-guest inclusion complex is formed among beta-CD, IEBP and BCH, but the alcohol hydroxyl bonds to the rim of the CD cavities by hydrogen-bonding and the alkyl end of alcohol flips over the two tops of the CD due to hydrophobic interaction force. Accordingly, the alcohol acts as a lid for CD cup, thereby shielding IEBP from oxygen and decreasing the collision quenching of oxygen, and decreasing the micro polarity of the CD cavity and the formation constant of ternary inclusion complex increases. As a result, the RTP of the system is enhanced. As far as we can see that the system studied is a typical supramolecular assembly one and the BuOH acts as a molecular regulation for RTP emitting.

Alcohols↗
PubMed1977

["No-touch" measurement of skin temperature in cerebral ischemia and lesions of the sympathetic trunk. Clinical and technical testing of a new infrared apparatus for measuring skin temperature (Ultrakust Thermophil M 202) (author's transl)].

The clinical test was carried out in extracranial carotid occlusions and acute peripheral paralysis with sympathetic lesions. The measurements obtained were compared with those of the infrared thermovision. Both in the technical and in the clinical tests, the device proved to be very suitable. The practical procedure of temperature measurement (cerebral ischemia and lesions of the sympathetic trunk) is described.

Aged↗
PubMed1981

[Body temperature and fever--body temperature regulation, indications and possibilities of fever reducing therapy. II. Indications and effects of fever-lowering procedures and fever-reducing drug therapy].

Fever should be treated according to the individual situation. Securing a sufficient fluid intake is the most important primary measure. The decrease of body temperature by physical means is efficient only in combination with drug therapy and presumes the control of blood circulation. Aminophenazon is the most efficient drug to lower fever. Metamizol should be prefered in children at risk for convulsive disorders. The combination of aminophenazon with phenothiazines can be recommended , prothazine is the drug of first choice in suitable cases a caudal treatment of fever with antiphlogistic drugs as diclophenacsodium (Voltaren) is indicated.

Acetaminophen↗