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At least 109 records · Page 6Linked to original sources
PubMed2001

Oral mucosal blood flow in patients with burning mouth syndrome.

The pathophysiology of burning mouth syndrome (BMS) is largely unknown. Thus, the aim was to study oral mucosal blood flow in BMS-patients using laser Doppler flowmetry (LDF). Thirteen BMS patients (11 female, two male; mean age+/-SD 64.3+/-7.9 years, mean disease duration 18.9+/-6.2 months) and 13 healthy non-smoking controls matched for age and gender (11 female, two male; mean age 64.7+/-8.1 years) were investigated. Using the LDF technique mucosal blood flow (mBF) was measured at the hard palate, the tip of the tongue, on the midline of the oral vestibule, and on the lip. Measurements were made at rest and over 2 min following dry ice application of 10 s duration using a pencil shaped apparatus. In addition, blood pressure (BP), heart rate (HR), peripheral cutaneous blood flow, and transcutaneous pCO(2) were continuously recorded. Mucosal blood flow (mBF) increased at all measurement sites in response to dry ice application (P<0.001) with peak flow at 0.5--1.5 min after stimulation onset. During the following 1.5--2 min, blood flow decreased at all sites with a tendency to return to baseline towards the end of the observation period. Except for BP and peripheral blood flow, all of the cardiovascular changes exhibited significant changes during the observation period; no differences between groups were detected. When compared to healthy controls BMS patients generally exhibited larger changes in mBF. These changes were significant for recordings made on the hard palate (F[1,24]=13.9, P<0.001). Dry ice stimulation appears to be an effective, non-invasive and reasonably tolerable means to investigate mucosal blood flow at different mucosal sites. In general, vasoreactivity in BMS patients was higher than in healthy controls. BMS patients exhibited a higher response on the hard palate compared to controls. These changes in oral blood flow appear to be specifically related to BMS symptoms indicating a disturbed vasoreactivity.

Aged↗
PubMed1996

Radiochemical purity, at expiry, and radiochemical stability of iodine-131 labelled meta-iodobenzylguanidine concentrates for intravenous infusion.

AIM: The determination of the amount of free [131I]iodide in [131I]metaiodobenzylguanidine ([131I]MIBG) concentrates for intravenous infusion under different storage conditions derived from daily practice. METHOD: The percentage of free [131I]iodide was determined in [131I]MIBG concentrates (1.6-3.9 GBq in 7.5 ml), kept on dry ice (up to expiry, 3 days after production) or, after thawing, at room temperature (up to 24 h). A validated solid phase extraction (SPE) assay was used. RESULTS: Free [131I]iodide increased from 1.9% +/- 0.34% at production to 4.4% +/- 0.67% (mean +/- SD; n = 5) at expiry in 3.7 GBq per 7.5 ml [131I]MIBG infusion concentrates stored on dry ice (-78 degrees C). At room temperature, formation of free [131I]iodide was found to be dependent on the radioactive concentration of the fluid. [131I]iodide levels increased from 3.1%, immediately after thawing, to 6.6% and 16.6% at t = 5 and 24 h, respectively, for a 3.9 GBq per 7.5 ml concentrate. CONCLUSION: The investigated formulation of [131I]MIBG concentrates, stored in its original packing containing dry ice, can generally be used up to expiry. After thawing, the undiluted concentrates should be administered to a patient within 3.5 h.

3-Iodobenzylguanidine↗
PubMed1981

Shape and regional volume in immersed lung lobes.

We froze 10 isolated canine lower lobes by immersing them in chlorothene (sp gr 1.4) at -20 degrees C. In six instances the contralateral lower lobe was frozen over dry ice. The lobes were then sliced horizontally, and the volume and weight of each slice were measured so that expansion (specific volume) and the amount of tissue (weight) could be assessed as a function of distance down the lung. Lobes frozen under chlorothene at low [35% total lung capacity (TLC)] and medium [60% TLC] volumes demonstrated a gradient of regional expansion that was about half that predicted on the basis of pleural surface pressure. Lobes frozen under chlorothene at high volumes [80% TLC] did not demonstrate a significant gradient of regional expansion. These results demonstrated tissue interdependence. When lobes frozen under chlorothene were compared with contralateral lobes frozen over dry ice, substantial differences in shape were evident. Chlorothene-frozen lobes had greater vertical height, and a smaller fraction of their weight was present in dependent regions: lobes frozen in chlorothene had half as much tissue over the lower 40% of their vertical height as did lobes frozen over dry ice. We demonstrated two mechanisms by which relative homogeneity of regional expansion was maintained in response to differences in pleural pressure, tissue interdependence and tissue movement from more compressed to less compressed regions.

Air Pressure↗
PubMed1995

Flight activity and response to carbon dioxide of Culicoides variipennis sonorensis (Diptera: Ceratopogonidae) in southern California.

Adult Culicoides variipennis sonorensis Wirth & Jones were collected using miniature suction traps during 12 nights in October and November at a southern California dairy. Traps were baited with carbon dioxide at a constant release rate of 300, 1,000, or 3,000 ml/min or with 1.3 kg of dry ice. The release rate of CO2 from the dry ice in the laboratory declined from 1,486 ml/min during the first 2 h to 303 ml/min after 10-12 h. Nulliparous and parous females responded in a similar and positive manner to increasing CO2 release rates. An automatic interval suction trap baited with CO2 was used to assess diel host-seeking periodicity. Peak host-seeking activity occurred 0-3 h after sunset, when the trap collected up to 170 females or 103 males per hour. Average peak time of collection during the dusk period was 45 min after sunset. Although numbers were lower, parity was higher in the middle of the night. A smaller, secondary peak of activity occurred near sunrise.

Animals↗
PubMed1993

The role of skin nociceptive afferent nerves in blister healing.

Because sensory neuropeptides improve survival of critical skin and muscle flaps in rats, skin nociceptive sensory nerve function in blister healing was examined. Sensory nerve ablation by unilateral hindlimb denervation or cutaneous axon reflex enhancement by 14 days systemic nicotine treatment (5 mg kg-1 day-1) decreased and increased, respectively, peripheral motor functions of nociceptive (peptidergic) skin nerves. Effects on nociception were measured by a radiant heat tail-flick test. Axon reflex flares were evoked by transdermal iontophoresis of acetylcholine or noxious electrical stimulation under pentobarbitone 40 mg kg-1 anaesthesia. Resultant changes in cutaneous microvascular blood flux were measured non-invasively by laser Doppler flowmetry. In nicotine-treated rats compared with placebo-treated controls, acetylcholine-evoked axon reflex flare was enhanced by 240% (p < 0.01) without enhancement of electrically evoked flare. Thus, nicotine-sensitized nociceptors show stimulus specificity in their enhancement of neurogenic flare responses. No significant changes were seen in other endothelial-dependent or smooth muscle-dependent microvascular dilator responses. Nicotine-treated rats had prolonged tail-flick withdrawal latencies to noxious radiant heat stimuli compared with placebo-treated controls (p < 0.05), suggesting an antinociceptive or analgesic effect of nicotine-treatment. Neurogenic effects on wound healing rate were assessed by measuring the dimensions of standardized blisters twice daily. The blisters were raised on hindpaw glabrous skin using a constant weight and diameter of compressed dry ice pellet applied for 30 secs at constant force. Dry-ice blisters raised on the hindpaw 14 days post-denervation were significantly slower to heal completely (42 days) than controls (30 days: P < 0.05) and the surrounding inflammation was reduced. By contrast, nicotine-treated rats showed more rapid blister healing (25 days) than controls (30 days), seen only in the later phase after day 15. Finally, resting substance P release from blisters, after direct cutaneous nerve stimulation, appears to be enhanced in nicotine-treated rats. Thus nociceptive innervation appears critical for inflammation and rapid healing of blisters in rat skin. The data signal a possible important role for neuropeptides in these processes and question the function of nicotinic receptors on sensory nerves.

Animals↗
PubMed1996

Improved method for rhesus monkey or rat skin preparation and cryosectioning for topical or transdermal skin distribution studies.

A method for preparing skin biopsies for cryosectioning was developed to accurately obtain samples from specific areas of the dermis, while minimizing contamination with epidermal tissue. Routine preparation of 6mm punch biopsies from freshly excised, full-thickness skin produced contraction and folding of the edges of the biopsy prior to mounting for snap-freezing and cryosectioning. Sample orientation was ruined, and cryosections were heterogeneous with respect to dermal structures and/or to dermal and epidermal layers. Biopsy artifacts were prevented by prefreezing skin over dry ice prior to taking biopsies. The biopsies were held frozen on dry ice until they were mounted on cryostat pegs with flattened, frozen OCT surfaces; then they were snap-frozen in chilled OCT in an isopentane bath cooled with liquid nitrogen. The method for determining skin level homogeneity of cryosections consisted of taking 10 mu m cryosections for histology between sections sampled for drug level analysis. The histological sections were fixed in 5% acetic acid in methanol and stained with hematoxylin and eosin to define the skin layers and structures associated with each sample for analysis. Histological sections from prefrozen skin had fewer processing artifacts, and dermal cryosections free of epidermal contamination were dramatically increased compared to the routine procedure.

Animals↗
PubMed1994

Acute effects of perinatal hypoxic insult on concentrations of dopamine, serotonin, and metabolites in fetal monkey brain.

Seven monkeys (Macaca mulatta) were laparotomized under general anesthesia (halothane, nitrous oxide, oxygen). Fetal hypoxia was induced in four monkeys by occlusion of the umbilical cord with a hydraulic occluder for 5-6 min. Three sham-operated fetuses served as controls. After unclamping, the fetuses were allowed to reperfuse for 20-30 min. To monitor hypoxia, the fetal electrocardiogram was recorded continuously. Hypoxic insult was associated with a decrease in fetal heart rate during the occlusion. After reperfusion, fetuses were immediately sacrificed and neocortex regions dissected on ice, frozen on dry ice and stored at -70 degrees C. Dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, serotonin, and 5-hydroxyindoleacetic acid were assayed by high performance liquid chromatography with electrochemical detection (HPLC/EC) in hippocampus, caudate nucleus and cortical regions. In the hippocampus, there was a significant increase in 5-hydroxyindoleacetic acid concentration. In prefrontal cortex, there was a trend toward an increase in serotonin but no effects on dopamine and homovanillic acid concentrations. Dopamine, serotonin and metabolites were not altered in the caudate nucleus. These data demonstrate that fetal hypoxia followed by reperfusion produced an increase in serotonin concentration measured within the hippocampus and selected cortical areas known to be targets of hypoxic injury.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

A mark-release-recapture study on the spatial distribution of host-seeking anophelines in northern Thailand.

A mark-release-recapture experiment was conducted at Mae Taeng, Chiangmai, Thailand, in November 1990 to examine the movement of released host-seeking mosquitoes in a heterogeneous environment. A total of 1,848 mosquitoes of nine anopheline species was field-collected, marked with fluorescent dye, and released. Adult collections were made for four nights after the release at five collection sites surrounding the release site. Three different attractants, dry ice (5 kg/site/night), human, and cow bait were used to collect a large number and a wide variety of adult mosquitoes. The recapture rate of released mosquitoes differed among species, ranging from 0 to 7.5%. The species composition was significantly different among collection sites and collection methods, and samples from dry ice collection showed intermediate species composition between those from human and cow bait collections. The spatial distribution of released mosquitoes was not significantly different from that of unmarked mosquitoes. Different behavioral responses to heterogeneous environments by different species of host-seeking mosquitoes was suggested as the underlying mechanism of species-specific spatial distribution of mosquitoes in the study area.

Animals↗
PubMed2001

Gamma-irradiation stability of saturated and unsaturated aliphatic polyanhydrides--ricinoleic acid based polymers.

The effect of terminal sterilization by gamma-irradiation on several ricinoleic acid based polyanhydrides was investigated. The following polymers were used: poly(ricinoleic acid maleate) [P(RAM)], poly(ricinoleic acid succinate) [P(RAS)], poly(hydroxy stearic acid succinate) [P(HSAS)], poly(hydroxy stearic acid maleate) [P(HSAM)], and their copolymers with sebacic acid. The polymers were irradiated with an absorbed dose of 2.5 or 10 Mrad by means of a 60Co source under dry ice or at room temperature. No differences were found between samples irradiated under dry ice and at room temperature. Polymers prepared from monomers containing maleate residues, which contain double bonds adjusted to the anhydride linkage along the polymer chain, decreased in molecular weight, became insoluble, and showed fast hydrolytic degradation. For example, p(RAM), p(HSAM), and their copolymers with sebacic acid decreased in Mw from about 10,000 to about 2000, and from about 30,000 to about 5000, respectively, while polymers based on RAS and HSAS remained stable. This phenomenon was explained by an anhydride interchange-self-depolymerization process of the unsaturated anhydride bonds induced by gamma-irradiation. This explanation was supported by the depolymerization of another class of polymers having an anhydride bond between two double bonds, fumaric acid anhydride polymers. The anhydride bond that lies between two double bonds was found to be more sensitive to gamma-irradiation. This anhydride bond may be cleaved to form two radicals that further react with aliphatic anhydride bonds along the polymer chain to form inter- and/or intracyclization products.

Anhydrides↗
PubMed2000

Hypothermic insult to the periodontium: a model for the study of aseptic tooth resorption.

The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200-250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The results also indicated that progression of the resorptive process required periodic exposure to the injury, in the absence of which repair to the damaged root occurred.

Animals↗
PubMed2004

The use of potassium dichromate and ethyl alcohol as blood preservatives for analysis of organochlorine contaminants.

The "gold standard" for preserving and shipping of human tissue samples for analysis of organochlorine contaminants is freezing. This method can be difficult, costly if using heavy dry ice for shipping, and often unfeasible, especially in less developed countries where electricity and dry ice are frequently rare or absent. Therefore, it is essential that more convenient and practical methods for preservation of blood samples are found. As an alternative to freezing, there have been studies employing potassium dichromate as a preservative for human or cow's milk or ethyl alcohol preservation of blood for dioxin analysis. In this study, four methods were compared to investigate the effectiveness of ethyl alcohol and potassium dichromate as blood preservatives for analysis of dioxins, dibenzofuran, and polychlorinated biphenyl (PCB) congeners. Samples of whole blood from a Dallas, Texas hospital were collected and pooled. Freezing, ethyl alcohol in two concentrations (20% and 40% per volume of sample), and potassium dichromate were used for blood preservation. The blood samples containing potassium dichromate or ethyl alcohol were stored and sent to ERGO laboratory for dioxin analysis and comparison with results from the frozen sample, which was kept frozen at all times until analyzed. This study suggests that potassium dichromate is a suitable alternative to freezing for preservation of whole blood for dioxin, dibenzofuran, and PCB measurements when either lipid or wet weight based results are reported. Potassium dichromate tablets were very easy and convenient to use--two 100 mg tablets (with a dichromate content of about 33 mg each) were added to each bottle containing 65 ml of blood. However, ethyl alcohol at 20% and 40% concentration under the conditions of this pilot study and the analytical method employed did not appear to provide satisfactory preservation when lipid based results are given or when the fat content has to be determined (wet or whole weight). Further research with a larger number of samples, inclusion also of other groups of persistent organic pollutants such as organochlorine pesticides or brominated flame retardants, a longer duration of storage time, and at temperatures greater than US or German room temperature is indicated in order to recommend the routine use of potassium dichromate as preservative for whole blood intended for dioxin, dibenzofuran, and PCB analysis.

Blood Preservation↗
PubMed2006

Radiosterilisation of indomethacin PLGA/PEG-derivative microspheres: protective effects of low temperature during gamma-irradiation.

Currently, gamma-irradiation seems to be a good method for sterilising drug delivery systems made from biodegradable polymers. The gamma-irradiation of microspheres can cause several physicochemical changes in the polymeric matrix. These modifications are affected by the temperature, irradiation dose and nature of the encapsulated drug and additives. This study has aimed to evaluate the influence of temperature during the sterilisation process by gamma irradiation in indomethacin PLGA microspheres including a PEG-derivative. Microspheres were prepared by the solvent evaporation method from o/w emulsion and were then exposed to gamma-irradiation. A dose of 25 kGy was used to ensure effective sterilisation. Some microspheres were sterilised with dry ice protection that guaranteed a low temperature during the process whilst others were sterilised without such dry ice protection. The effects of gamma-irradiation on the characteristics of non-loaded PLGA/PEG-derivative and indomethacin loaded PLGA/PEG-derivative microspheres with and without protection were studied. Non-protected microspheres showed changes in their morphological surface, polymer glass transition temperature, molecular weight and release rate of indomethacin after sterilisation. However, microspheres sterilised with protection did not show significant differences after gamma-irradiation exposure. The sterilisation method was satisfactory when the indomethacin loaded microspheres including a PEG-derivative were exposed to gamma-irradiation at low temperature.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1981

Comparison of various extenders for freeze-preservation of semen from selective captive wild ungulates.

Semen collected by electroejaculation from selected captive wild ungulates was used to evaluate the cryoprotective ability of 4 semen diluents. Three species of ungulates were used: blesbok (Damaliscus dorcas phillipsi), dorcas gazelle (Gazella dorcas), and onager (Equus hemionus onager). Fresh semen was immediately evaluated for the percentage of motility and the progressive motility, and an aliquot was fixed for evaluation of the acrosomal integrity of spermatozoa. The remaining volume of ejaculate was divided into equal aliquots and either frozen raw on dry ice or extended with each of the 4 diluents. Samples were concurrently equilibrated at 5 C, frozen on dry ice, and stored in liquid nitrogen. Aliquots were thawed for evaluation of motility traits and spermatozoal acrosomes. Each diluent provided cryoprotection in each species. However, spermatozoa varied in ability to survive cryopreservation, and postthaw viability was influenced by the semen diluent used. Although ineffective in the onager, the study of morphologic forms of spermatozoal acrosomes proved useful for assessing the cryoprotective property of semen diluents in the blesbok and dorcas gazelle.

Acrosome↗
PubMed2005

Design of a mosquito trap support pole for use with CDC miniature light traps.

A mosquito trap support pole constructed from polyvinyl chloride and aluminum pipes was designed to hang a Centers for Disease Control and Prevention miniature light trap and dry ice container. Miniature light traps normally hang from tree branches. The trap support pole is designed to hang traps and dry ice bait in areas where no suitable trees exist.

Animals↗
PubMed1994

A reliable transport method for isolating Pasteurella haemolytica from bighorn sheep.

We compared three transport methods for the recovery of Pasteurella haemolytica from pharyngeal swabs collected under field conditions from 42 bighorn sheep (Ovis canadensis) in one captive and three free-ranging populations. Transport methods included: Amies medium with charcoal, transported on ice, and cultured on blood agar within 24 hr; direct plating on blood agar, transported on heating pads, and incubated at 37 C within 8 hr of collection; and phosphate buffered glycerol (PBG), transported on dry ice, and stored at -70 C for 10 days before culture. Isolates of P. haemolytica were recovered from all 42 bighorn sheep with a mean (+/- SE) of 1.2 +/- 0.1 (Amies), 1.3 +/- 0.1 (blood agar), and 1.3 +/- 0.1 (PBG) isolates per swab. No statistical differences (P > 0.05) were observed in the recovery of P. haemolytica isolates among the transport methods. However, based on our experience and results of this study, we recommend that if submission of samples to the laboratory is likely to be delayed, pharyngeal swabs be transported in PBG on dry ice and kept frozen until they are cultured. Viable samples can be maintained in PBG at -70 C for several years.

Animals↗
PubMed1995

Cracks in cryopreserved aortic allografts and rapid thawing.

Cryopreserved aortic allografts are shipped in a frozen state. Cracks in the graft, appearing after thawing, can pose serious problems in the planned operative procedures. Cracks were encountered in approximately 3% of all our shipped cryopreserved human material and were strongly associated with transportation in a "dry shipper." We practice two other modes of transport: on dry ice and directly to our operating room. We studied the temperature behavior during thawing of 17 porcine aortic valves in three groups. The valves were frozen and stored like our human valves. Before thawing, they were subjected to stimulated transport in either a dry shipper, on dry ice, or to the operating room. Differences between the groups were noted in the maximal rate of thawing of the inner as well as the outer wall. The highest maximal thawing rates were observed in the dry shipper group, in which 66% of the valves cracked. We therefore suspended transportation of cryopreserved human valves by means of a dry shipper.

Animals↗
PubMed1977

The effect of freezing and the influence of isolation medium on the recovery of pathogenic fungi from sputum.

The primary objective of this study was to determine whether freezing sputa in dry ice had any effect on the recovery of pathogenic fungi. Sputa seeded with each of five fungi (Histoplasma capsulatum, Blastomyces dermatitidis, Cryptococus neoformans, Coccidioides immitis, and Aspergillus fumigatus) were frozen and stored for 24, 48, and 72 hours on dry ice. H. capsulatum was killed, and only a few colonies of B. dermatitidis and C. neoformans were isolated from these sputa. However, A. fumigatus and C. immitis withstood the effects of freezing. A second objective was to compare the recovery of all five fungi from seeded sputa stored at room temperature for 24, 48, and 72 hours, on yeast extract-phosphate agar with NH4OH and on Sabhi agar. The yeast extract-phosphate agar with NH4OH was superior to Sabhi agar, for the isolation of all fungi studied, except A. fumigatus.

Agar↗
PubMed1989

[Disorders of the sensitivity of the anterior teeth in children and adolescents].

1435 permanent incisors and canines were examined in 134 children and juveniles undergoing orthodontic treatment. Nearly 50% of the subjects had sustained trauma to their anterior teeth with equal numbers of boys and girls. Girls, however, were less often injured by direct contact. Pulp testing with dry ice from liquid CO2 showed disturbed sensitivity mainly of the upper anterior teeth. In the group with trauma the frequency of this phenomenon was increased compared to the group without trauma. The electric pulp tester did not prove suitable for sensitivity tests compared with dry ice testing.

Adolescent↗