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Objective The study aimed to investigate factors contributing to heat development during light curing of a flowable bulk-fill resin-based composite (SDRTM, Lot # 602000876, Dentsply Sirona, Konstanz, Germany) (RBC). Materials and Methods Temperatures were measured with calibrated thermocouples. A multi-wave light-emitting diode (LED) light curing unit (LCU) was used (Ivoclar Vivadent, Schaan, Lichtenstein). In all experiments, the RBC was first cured (cured) for 30 s and, after 5 min of recovery time, received a second LCU irradiation (post-cured) for 30 s. The exothermic reaction was measured by calculating the Δ temperature between cured and post-cured RBC. In a cylinder-shaped polymer mold, temperature was recorded inside of RBC during curing (part 1) and light transmission through RBC during curing was investigated (part 2). Pulpal temperatures were assessed in an extracted third molar during light curing (part 3). Data were statistically analyzed using one-way ANOVA (α=0.05). Results Increased thickness of RBC led to decreased pulp chamber temperatures. Inside RBC, there was a large variation in heat development between the cured and post-cured groups (p

The deep inferior epigastric perforator (DIEP) flap has become the first choice in autologous breast reconstruction, as excellent aesthetic results can be obtained with minimal donor site morbidity. However, rates of fat necrosis for DIEP breast reconstruction may be as high as 35%, which not only reduces the aesthetic result but also causes uncertainty due to lump formation in the reconstructed breast.1,2 Fat necrosis is a result of inadequate flap perfusion. Selection of a suitable perforator is critical for decreasing the rate of postoperative fat necrosis and minimizing perfusion-related flap complications.3 A thorough understanding of the vascular anatomy and flow characteristics of a selected perforator is essential to balance flap design and adequate flap perfusion. The angiosome concept by Taylor and Palmer has greatly contributed to our knowledge on flap perfusion.4 Saint-Cyr et al introduced in 2009 the perforasome theory and defined a perforasome as the territory perfused by a single perforator vessel of a named artery.5 The importance of finding the most suitable perforator is reflected in the large number of studies on the use of preoperative perforator mapping using imaging techniques.6 Still the relationship between the designed flap size and areas of perfusion from the selected perforator is a clinical challenge because this ratio is unknown.7 To our knowledge there are no in vivo studies that evaluate how the reduction of the number of perforators during flap harvest effects the perfusion area of a selected perforator. Indocyanine green fluorescence angiography (ICG-FA) is an invasive technique that allows for direct visualization of tissue perfusion by registration of intravascular fluorescence intensity. Infrared thermography (IRT) is a noninvasive technique that indirectly visualizes skin perfusion by measuring infrared (IR) radiation released from the skin surface. In static infrared thermography (SIRT), a single image is taken from the area of interest. In dynamic infrared thermography (DIRT), the area of interest is exposed to a mild thermal challenge, and the rate and pattern of temperature changes are recorded and analyzed. ICG-FA and IRT are well-established techniques that provide real-time assessment of skin perfusion and have been shown to provide valuable information for perforator mapping.7–12 The primary aim of this study was to evaluate the effect of perforator dissection on the perfusion area of the selected perforator in a hemi-DIEP flap by using ICG-FA and IRT intraoperatively. The secondary aim of this study was to compare the results from ICG-FA with those obtained from IRT with respect to flap perfusion.

This study aimed to investigate pulp chamber and surface temperature development using different LED light curing units (LCUs). Eight brands of LED-LCUs were tested in a laboratory bench model. The pulp chamber and surface temperature were recorded with a type T thermocouple and infrared cameras, respectively. The highest pulp chamber and surface temperature increase was 6.1±0.3°C and 20.1±1.7°C, respectively. Wide-spectrum LED-LCUs produced higher pulp chamber temperature increase at 0 mm and 2 mm but lower at 4 mm. Narrow-spectrum LED-LCUs produced higher surface temperature increase. LED-LCU featuring modulated output mode resulted in lower increase in pulp chamber temperature but higher on surface temperature. LED-LCU with light guide tip delivering an inhomogeneous beam caused higher increase in temperature on the surface and in the pulp chamber. LED-LCUs with different spectral emission, output mode and light guide tip design contributed to different temperature development in the pulp chamber and at the surface of teeth.

Background: Wound healing problems following abdominoplasty may be a result of impaired tissue perfusion. This study evaluated the impact a standard abdominoplasty may have on abdominal skin perfusion. Methods: A standard abdominoplasty was performed in 16 patients. Dynamic infrared thermography (DIRT) using a mild and a stronger cold challenge was performed pre-, intra-, and postoperatively on day 1, 2, and in week 6. The abdomen was divided into Huger’s vascular zones. A two-tailed t test was used to evaluate differences in mean temperature between zones. Statistical significance was defined as P < 0.05. Results: Two patients suffered wound healing problems. Abdominal skin perfusion showed a hyperaemic state on day 1, day 2, and week 6, postoperatively. Hotspots in zones I and II had all disappeared at the end of surgery and on day 1, except in the cranial part of zone I. Hotspots reappeared in zones I and II during day 2. A statistically significant difference between zones I and II was seen on day 1 and 2, with zone II being cooler. This difference had disappeared in week 6 for the mild cold challenge but not for the stronger cold challenge. Conclusions: A standard abdominoplasty has a significant impact on abdominal skin perfusion. The skin perfusion is a dynamic process with a gradual improvement over time. The strongest effect was seen in zone II near the lower transverse incision line, where skin perfusion was the least. Such may contribute to impaired wound healing at this site

Objective The study aimed to investigate factors contributing to heat development during light curing of a flowable bulk-fill resin-based composite (SDRTM, Lot # 602000876, Dentsply Sirona, Konstanz, Germany) (RBC). Materials and Methods Temperatures were measured with calibrated thermocouples. A multi-wave light-emitting diode (LED) light curing unit (LCU) was used (Ivoclar Vivadent, Schaan, Lichtenstein). In all experiments, the RBC was first cured (cured) for 30 s and, after 5 min of recovery time, received a second LCU irradiation (post-cured) for 30 s. The exothermic reaction was measured by calculating the Δ temperature between cured and post-cured RBC. In a cylinder-shaped polymer mold, temperature was recorded inside of RBC during curing (part 1) and light transmission through RBC during curing was investigated (part 2). Pulpal temperatures were assessed in an extracted third molar during light curing (part 3). Data were statistically analyzed using one-way ANOVA (α=0.05). Results Increased thickness of RBC led to decreased pulp chamber temperatures. Inside RBC, there was a large variation in heat development between the cured and post-cured groups (p

The following article, Norheim, A.J., Borud, E., Wilsgaard, T., DeWeerd, L. & Mercer, J.B. (2018). Variability in peripheral rewarming after cold stress among 255 healthy Norwegian army conscripts assessed by dynamic infrared thermography. International Journal of Circumpolar Health, 77(1), can be accessed at https://doi.org/10.1080/22423982.2018.1536250. Exposure to cold climate is an inevitable consequence of military training in Norway. Adequate peripheral microcirculation in the extremities is important to maintain temperature, and to protect against freezing cold injuries. The aim of this study was to investigate the variability in skin rewarming ability. The study subjects consisted of 260 healthy Norwegian army conscripts, following a mild cold provocation test (hands immersed in 20°C water for 1 min) using dynamic infrared thermography (DIRT). Thermal images were obtained to investigate any differences in skin rewarming ability of the hand (fingers). DIRT took place under standardised and stable study conditions. Conscripts were characterised as either slow, intermediate or rapid rewarmers. While 90% could recover, partially or completely, within 4 min to the skin temperature values before the provocation test, 10% showed a slow rewarming pattern. In the slow rewarmers, the rewarming ability was correlated with a low average temperature of the hands prior to the cooling test. The healthy young army conscripts in this study showed a large variability in their rewarming ability following a standardised mild cold provocation test.

While health risks from smoking cigarettes are well known, little is known about the health risks of using smokeless tobacco (ST). The aim of this study was to evaluate the effect that ST in the form of oral use of snus with nicotine and snus without nicotine has on peripheral skin blood circulation. 21 young habitual users of snus with nicotine participated in this study. Under controlled conditions the subjects were exposed to a 30 minute period of oral use of snus with nicotine (SN+) and snus without nicotine (SN-). The peripheral skin blood circulation was indirectly monitored on the hands by measuring skin temperature using infrared thermography. The skin blood circulation in the hands showed a statistical significant decrease in the SN+ experiments, while skin blood circulation was hardly effected in the SN- experiments. It is concluded that the use of smokeless tobacco in the form of oral use of snus containing nicotine causes a decrease in peripheral skin blood circulation while such an effect is not seen in snus without nicotine. This knowledge may be of use when treating patients that require adequate peripheral skin circulation or in the military when soldiers are exposed cold conditions.

Source: doi: 10.1007/s00784-016-1962-5 Objectives:To investigate how heat development in the pulp chamber and coronal surface of natural teeth with and without cusps subjected to irradiance using light-emitting diode (LED)–light-curing units (LCUs) is associated with (i) irradiance, (ii) time, (iii) distance, and (iv) radiant exposure. Materials and methods:Three different LED-LCUs were used. Their irradiance was measured with a calibrated spectrometer (BlueLight Analytics Inc., Halifax, Canada). An experimental rig was constructed to control the thermal environment of the teeth. The LED-LCU tip position was accurately controlled by a gantry system. Tooth surface temperature was measured by thermography (ThermaCAM S65 HS, FLIR Systems, Wilsonville, USA) and pulp chamber temperature with a thermocouple. LED-LCU tip distance and irradiation times tested were 0, 2, and 4 mm and 10, 20, and 30 s, respectively. Ethical permission was not required for the use of extracted teeth. Results:Maximum surface and pulp chamber temperatures were recorded in tooth without cusps (58.1 °C ± 0.9 °C and 43.1 °C ± 0.9 °C, respectively). Radiant exposure explained the largest amount of variance in temperature, being more affected by time than irradiance. Conclusions:At all combinations of variables tested, repeated measurements produced consistent results indicating the reliability of the method used. Increased exposure time seems to be the factor most likely to cause tissue damage. Clinical relevance:Risk of superficial tissue damage at irradiances >1200 mW/cm2 is evident. There is a risk of pulp damage when only thin dentin is left at higher irradiances (>1200 mW/cm2). Clinicians should be aware of LED-LCU settings and possible high temperature generated.

Seasonal variations in mortality occur throughout Europe as well as in other parts of the world, such as Japan, China and the southern hemisphere1–6 with a higher death rate in the winter (excess winter deaths). Mortality from cardiovascular disease (CVD) accounts for the majority of the excess winter deaths (up to 70% in some countries), while up to about half of the remaining may be accounted for by increases in respiratory disease.3,7 The majority of deaths from CVD occur in the elderly. For example, in Norway, CVD, including ischaemic heart disease and cerebrovascular disease, accounts for about 46% of all causes of death. About 90% of all CVD-related deaths occur in people who are ≥65 years. Cold exposure related to winter mortality from ischaemic heart disease, cerebrovascular disease, respiratory disease, and all causes in warm and cold regions of Europe have been previously investigated in a large European Economic Community supported study.7 The main findings of this study was that mortality increased to a greater extent with a given fall in temperature in regions with warm winters, in populations with cooler homes, and among people who wore fewer clothes and were less active outdoors. Similar findings regarding excess winter mortality were found in a comparative study between Norway and the Republic of Ireland, two countries that were not investigated in the Eurowinter study.6,8 A comparison of these two countries is of interest since they are demographically similar with respect to CVD mortality, but have different climates. In 1993, the population of Norway and the Republic of Ireland was 4 312 000 and 3 563 000, respectively and in both countries mortality due to CVD, accounted for approximately the same percent of deaths (1985–93: Norway 45% and Ireland 47%.6 Seasonal variation in …

Background Recalcitrant lateral epicondylitis (elbow tendinosis) is a common cause of elbow pain. There are many forms of treatment, none being superior. Hypothesis The main hypothesis tested in this study is that radiofrequency microtenotomy offers better results than the extensor tendon release and repair operation for elbow tendinosis, especially earlier recovery. Study Design Randomized controlled trial; Level of evidence, 1. Methods Twenty-four patients were randomized into 2 treatment groups, extensor tendon release and repair, and microtenotomy. Dynamic infrared thermography (DIRT) was employed as an objective method to verify the diagnosis as well as to document the outcome 3 months after the surgical procedure. Results Visual analog scale pain scores in the microtenotomy but not in the release group decreased significantly after 3 weeks. There was no statistically significant difference in pain scores between the 2 groups at 3, 6, and 12 weeks, and at 10 to 18 months. At 12 weeks, grip strength had improved significantly in the microtenotomy but not in the release group. The functional score was significantly increased in both groups. The DIRT group showed significant differences in epicondyle skin temperature between diseased and normal elbows both pre- and postoperatively. Abnormal DIRT images correlated well with elevated pain scores. Conclusions Radiofrequency microtenotomy provides a promising alternative to the release operation for elbow tendinosis. Dynamic infrared thermography provides a reliable, noninvasive, objective method for the diagnosis of elbow tendinosis, as well as for evaluation of the outcome following treatment.

Cardiovascular diseases (CVD) are responsible for around 20% of all deaths worldwide (approximately 14 million) and are the principal cause of death in all developed countries, accounting for 50% of all deaths. Variations in the annual per capita death rates in different countries are well documented. Less well known are seasonal variations in death rates, with the highest levels occurring during the colder winter months, which have been described in many countries. This phenomenon is referred to as excess winter mortality. CVD-related deaths account for the majority of excess winter deaths (up to 70% in some countries), while about half of the remaining are due to increases in respiratory diseases. Paradoxically, CVD mortality increases to a greater extent with a given fall in temperature in regions with warm winters. While much of the indirect evidence points to the notion that cold is somehow involved in explaining excess winter deaths, the mechanism by which seemingly mild exposure to cold ambient conditions can increase the risk of death remains unclear. The strong indirect epidemiological evidence coupling cold climate to mortality may be related to indoor rather than outdoor climatic conditions (e.g., cold/damp houses versus warm/dry houses) coupled with a plethora of factors including health status, ageing-related deterioration in physiological and behavioral thermoregulation, toxicology, and socioeconomic factors.

Twelve captive wild-caught adult arctic foxes (Alopex lagopus) were anesthetized a total of 24 times for an equal number of surgical procedures involving implantation of heart rate (HR) and core body temperature transmitters (Tb) between October 1995 and April 1997. Xylazine–ketamine and medetomidine–ketamine anesthesia was used, resulting in an unacceptably high death rate. One out of four foxes anesthetized with xylazine–ketamine died, whereas two of nine foxes anesthetized with medetomidine–ketamine died out of a total of 20 surgical procedures. Durations of the surgeries for implantation of Tb transmitters and HR transmitters were 73 ± 7 min and 95 ± 13 min, respectively.

Source at https://doi.org/10.1080/22423982.2016.1273677. Frostbite sequelae are a relevant occupational injury outcome for soldiers in arctic environments. A Caucasian male soldier suffered frostbite to both hands during a military winter exercise. He developed sensory-motor disturbances and cold hypersensitivity. Angiography and thermography revealed impaired blood flow while Quantitative Sensory Testing indicated impaired somato-sensory nerve function. Two years after the initial event, he received an off label treatment with Botulinum toxin distributed around the neurovascular bundles of each finger. After treatment, cold sensitivity was reduced while blood flow and somato-sensory nerve function improved. The successful treatment enabled the soldier to successfully pursue his career in the army.

The central portion of chronic wounds is often hypoxic and relatively hypothermic, representing a deficient energy supply of the tissue, which impedes wound healing or even makes it impossible. Water-filtered infrared-A (wIRA) is a special form of heat radiation with a high tissue penetration and a low thermal load to the skin surface. wIRA produces a therapeutically usable field of heat and increases temperature, oxygen partial pressure and perfusion of the tissue. These three factors are decisive for a sufficient tissue supply with energy and oxygen and consequently as well for wound healing, especially in chronic wounds, and infection defense. wIRA acts both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA can advance wound healing or improve an impaired wound healing process and can especially enable wound healing in non-healing chronic wounds. wIRA can considerably alleviate the pain and diminish wound exudation and inflammation and can show positive immunomodulatory effects.In a prospective, randomized, controlled study of 40 patients with chronic venous stasis ulcers of the lower legs irradiation with wIRA and visible light (VIS) accelerated the wound healing process (on average 18 vs. 42 days until complete wound closure, residual ulcer area after 42 days 0.4 cm(2) vs. 2.8 cm(2)) and led to a reduction of the required dose of pain medication in comparison to the control group of patients treated with the same standard care (wound cleansing, wound dressing with antibacterial gauze, and compression garment therapy) without the concomitant irradiation. Another prospective study of 10 patients with non-healing chronic venous stasis ulcers of the lower legs included extensive thermographic investigation. Therapy with wIRA(+VIS) resulted in a complete or almost complete wound healing in 7 patients and a marked reduction of the ulcer size in another 2 of the 10 patients, a clear reduction of pain and required dose of pain medication, and a normalization of the thermographic image. In a current prospective, randomized, controlled, blinded study patients with non-healing chronic venous stasis ulcers of the lower legs are treated with compression garment therapy, wound cleansing, wound dressings and 30 minutes irradiation five times per week over 9 weeks. A preliminary analysis of the first 23 patients of this study has shown in the group with wIRA(+VIS) compared to a control group with VIS an advanced wound healing, an improved granulation and in the later phase of treatment a decrease of the bacterial burden. Some case reports have demonstrated that wIRA can also be used for mixed arterial-venous ulcers or arterial ulcers, if irradiation intensity is chosen appropriately low and if irradiation is monitored carefully. wIRA can be used concerning decubital ulcers both in a preventive and in a therapeutic indication. wIRA can improve the resorption of topically applied substances also on wounds. An irradiation with VIS and wIRA presumably acts with endogenous protoporphyrin IX (or protoporphyrin IX of bacteria) virtually similar as a mild photodynamic therapy (endogenous PDT-like effect). This could lead to improved cell regeneration and wound healing and to antibacterial effects. In conclusion, these results indicate that wIRA generally should be considered for the treatment of chronic wounds.

Background: Water-filtered infrared-A (wIRA) is a special form of heat radiation with a high tissue-penetration and with a low thermal burden to the surface of the skin. wIRA is able to improve essential and energetically meaningful factors of wound healing by thermal and non-thermal effects. Aim of the study: prospective study (primarily planned randomised, controlled, blinded, de facto with one exception only one cohort possible) using wIRA in the treatment of patients with recalcitrant chronic venous stasis ulcers of the lower legs with thermographic follow-up. Methods: 10 patients (5 males, 5 females, median age 62 years) with 11 recalcitrant chronic venous stasis ulcers of the lower legs were treated with water-filtered infrared-A and visible light irradiation (wIRA(+VIS), Hydrosun® radiator type 501, 10 mm water cuvette, water-filtered spectrum 550–1400 nm) or visible light irradiation (VIS; only possible in one patient). The uncovered wounds of the patients were irradiated two to five times per week for 30 minutes at a standard distance of 25 cm (approximately 140 mW/cm2 wIRA and approximately 45 mW/cm2 VIS). Treatment continued for a period of up to 2 months (typically until closure or nearly closure of the ulcer). The main variable of interest was “percent change of ulcer size over time” including complete wound closure. Additional variables of interest were thermographic image analysis, patient’s feeling of pain in the wound, amount of pain medication, assessment of the effect of the irradiation (by patient and by clinical investigator), assessment of feeling of the wound area (by patient), assessment of wound healing (by clinical investigator) and assessment of the cosmetic state (by patient and by clinical investigator). For these assessments visual analogue scales (VAS) were used. Results: The study showed a complete or nearly complete healing of lower leg ulcers in 7 patients and a clear reduction of ulcer size in another 2 of 10 patients, a clear reduction of pain and pain medication consumption (e.g. from 15 to 0 pain tablets per day), and a normalization of the thermographic image (before the beginning of the therapy typically hyperthermic rim of the ulcer with relative hypothermic ulcer base, up to 4.5°C temperature difference). In one patient the therapy of an ulcer of one leg was performed with the fully active radiator (wIRA(+VIS)), while the therapy of an ulcer of the other leg was made with a control group radiator (only VIS without wIRA), showing a clear difference in favour of the wIRA treatment. All mentioned VAS ratings improved remarkably during the period of irradiation treatment, representing an increased quality of life. Failures of complete or nearly complete wound healing were seen only in patients with arterial insufficiency, in smokers or in patients who did not have venous compression garment therapy. Discussion and conclusions: wIRA can alleviate pain considerably (with an impressive decrease of the consumption of analgesics) and accelerate wound healing or improve a stagnating wound healing process and diminish an elevated wound exudation and inflammation both in acute and in chronic wounds (in this study shown in chronic venous stasis ulcers of the lower legs) and in problem wounds including infected wounds. In chronic recalcitrant wounds complete healing is achieved, which was not reached before. Other studies have shown that even without a disturbance of wound healing an acute wound healing process can be improved (e.g. reduced pain) by wIRA. wIRA is a contact-free, easily used and pleasantly felt procedure without consumption of material with a good penetration effect, which is similar to solar heat radiation on the surface of the earth in moderate climatic zones. Wound healing and infection defence (e.g. granulocyte function including antibacterial oxygen radical formation of the granulocytes) are critically dependent on a sufficient energy supply (and on sufficient oxygen). The good clinical effect of wIRA on wounds and also on problem wounds and wound infections can be explained by the improvement of both the energy supply and the oxygen supply (e.g. for the granulocyte function). wIRA causes as a thermal effect in the tissue an improvement in three decisive factors: tissue oxygen partial pressure, tissue temperature and tissue blood flow. Besides this non-thermal effects of infrared-A by direct stimulation of cells and cellular structures with reactions of the cells have also been described. It is concluded that wIRA can be used to improve wound healing, to reduce pain, exudation, and inflammation and to increase quality of life.

Background. In this study we have investigated the effect of cold exposure on young healthy subjects, with particular emphasis on the hematological system. Study design. The lightly clothed subjects were seated in a thermally controlled climatic chamber for three hours. Methods. One group (control) was exposed to three hours at 28 °C, while the other group was first exposed to one hour at 28 °C, and then two hours of decreasing temperature, ending at 6 °C. Mean body temperature decreased, blood pressure increased, and metabolism increased by 60 % in the cold exposure group compared to the control group. Blood samples were taken through an arterial catheter every hour during the exposure, one hour before and 1.5, 3 and 25 hours after the exposure. Results. Red blood cell counts increased, due to hemo-concentration. In the cold neutrophil counts did not increase during the day, but were stable at a lower level compared to the controls. Conclusions. It is suggested that the cold induced decrease in neutrophil count is caused by an activation and increased adhesion of the neutrophils to the endothelial wall. This finding is supported by the cold exposure-induced increases in IL-8 and Thromboxane B2 in LPS-stimulated blood, and an increase in the plasma concentration of P-selectin. (Int J Circumpolar Health 2004; 63(2):115-128) Keywords: blood factors, cell counting, cold exposure, P-selectin

Cineangiographic examination of reindeer exposed to local (hypothalamic) or general heating and cooling revealed that the angular oculi veins are constricted during cold stress but dilated during heat stress. Moreover, during heat stress a segment of the facial vein appeared to be occluded, causing the cold venous return from the nasal mucosa to be routed directly to the cavernous sinus for selective cooling of the brain. Histological examination of the vasoactive segment of the facial vein showed unusually thick longitudinal and circular layers of smooth muscle cells. Obstruction of angular oculi blood flow by clamping of the veins in the heat-stressed animal resulted in an immediate rise in brain temperature. When reindeer under heat stress shift from closed- to open-mouth panting, only the expiratory phase of the respiratory cycle takes place through the mouth, whereas inspiration through the nose is continued. In this way, cooling of the nasal mucosa and, hence, cooling of the brain, is maintained.

1. Extrahypothalamic thermosensitivity at normal (39 degrees C) and lowered (33.8 degrees C) hypothalamic clamp temperatures has been measured in cold exposed rabbits equipped with chronically implanted hypothalamic perfusion thermodes. The animals were subjected to body core cooling by means of cold perfused thermodes placed in the colon. 2. At lowered hypothalamic temperature the threshold core temperature for increased metabolic heat production due to body core cooling was significantly increased as compared to that at normal hypothalamic temperature. However, the slope of the response relating increased metabolic rate to body core temperature was significantly reduced. 3. The experimental results compare well with those predicted from a mathematical model, which takes into account the effect of temperature on synaptic transmission of afferent information in the hypothalamus.

A method is described whereby it is possible to alter total body core temperature independently of environmetal temperature and/or exercise in conscious reindeer. The method employs the use of a simple heat exchanger introduced through a permanent rumen fistula. The heat exchanger consists of a 7 m long coil of flexible plastic tubing (OD, 10.0 mm, ID, 8.0 mm). By perfusing the tubing with thermostatically controlled water, heat can be added to or subtracted from the body core at rates equalling several times resting heat production. It is suggested that the method could be used in any large ruminant species.En intra-rumenal varmeveksler til bruk i større, uanesteserte dyr.Abstract in Norwegian / Sammendrag: Vi har i denne undersøkelsen beskrevet en metode for hvordan kroppstemperatur hos uanesteserte reinsdyr kan endres uavhengig av omgivelsestemperatur og om dyret løper eller ikke. Metoden innebærer bruk av en enkel varmeveksler som plasseres i dyrets vom gjennom en permanent vom-fistel. Varmeveksleren består av en 7 m lang kveil av fleksibel plastslange (ytre diameter 10.0 mm, indre diameter 8.0 mm). Ved å perfundere slangen med vann av en bestemt temperatur er det mulig å fjerne eller tilføre kroppen en varmemengde som tilsvarer flere ganger dyrets varmeproduksjon. Vi mener at denne metoden kan tilpasses alle store drøvtyggere.Potsiin asetettavan låmpotilan muuttajan kåytto suurilla nukkumattomilla elåimillå.Abstract in Finnish / Yhteenveto: Tutkimuksessa olemme kuvanneet menetelman, jolla voidaan muuttaa nukuttamattoman poron ruumiinlåmpotilaa riippumatta ulkolampotilasta tai siita juokseeko elåin vai ei. Menetelmassa kåytaan yksinkertaista låmpotilan muuttajaa, joka asetetaan elaimeen pysyyan potsifistulan kautta. Låmpotilan muuttaja kasittåa 7 m pitkan muoviletkurullan (letkun halkaisija 10.6 mm, reian halkaisija" 8.0 mmJTTayttåmålla letku tietyn lampoisellå vedella on mahdollista joko laskea tai nostaa ruumiin lampomååråa niin, etta se vastaa moninkertaisesti elaimen omaa låmmontuottoa. Oletamme, etta menetelmåa voidaan kayttaå kaikille suurille mårehtijoille.

Previous studies have shown that reindeer are able to restrict respiratory heat loss by use of nasal heat exchange (Blix and Johnson, 1983). This mode of heat conservation, which is based on cooling of the expired air, and thereby condensation of water, particularly at low ambient temperatures, is possible because of the existence of a temperature gradient along the length of the nasal passages (Johnsen et ai, 1985a). Furthermore, Blix and Johnsen (1983) have shown that there is a summer to winter difference of about 12°C in exhaled air temperature at, for instance, —10°C ambient temperature, in these animals. At this ambient temperature respiratory minute volume and frequency were the same in summer and winter. This therefore indicates that the temperature gradient along the nasal mucosa in reindeer must be under physiological control. We have recently investigated the vascular anatomy of the reindeer head with particular emphasis on the nasal mucosa. Based on ideas which emanated from this work we have put forward a hypothesis for the operation and control of nasal heat exchange in reindeer (Johnsen et aL, 1985a). In order to visualize the vascular system of the reindeer head we have made use of uni-lateral plastic casts. These casts revealed that the nasal mucosa in reindeer consists of a network of frequently anastomosing arteries running the full length of the nasal turbinates in the anterior direction. This rete runs adjacent to and in close contact with a venous rete of similar complexity with which it communicates by way of capillaries and arterio-venous anastomoses. It was also evident from the plastic casts that the effluent from the venous rete can be drained through the deep sphenopalatine group of veins at the posterior end, and through the superficial dorsal nasal vein at the anterior end of the nasal cavity. The dorsal nasal vein in turn has a possibility to drain either directly into the jugular vein via the facial vein, or to the carotid rete for selective cooling of the brain. In situations of extreme heat conservation in the cold we suggest that the blood runs in opposite directions in the arterial and the venous rete of the nasal mucosa, whereby the temperature gradient along the nasal mucosa, which is necessary for cooling of the expired air, is maintained due to counter-current heat exchange. In this situation arterial inflow to the rete is low, and the dorsal nasal vein and the vessels of the anterior end of the venous rete are constricted. Accordingly, the venous effluent from the nasal mucosa is primarily drained through the sphenopalatine group of veins at a temperature close to that of the arterial blood. On the other hand, when the animal is in a state of extreme heat dissipation (in a hot environment, or during running), respiratory minute volume will increase substantially (Blix and Johnsen, 1983). However, an increase in respiratory minute volume without circulatory adjustments, will result in a substantial decrease of nasal mucosal temperature and a subsequent reduction in expired air temperature, which would compromise the dissipation of heat bv way of the respiratory tract. Under such heat

© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Background: The current gold standard for preoperative perforator mapping in breast reconstruction with a DIEP flap is CT angiography (CTA). Dynamic infrared thermography (DIRT) is an imaging method that does not require ionizing radiation or contrast injection. We evaluated if DIRT could be an alternative to CTA in perforator mapping. Methods: Twenty-five patients scheduled for secondary breast reconstruction with a DIEP flap were included. Preoperatively, the lower abdomen was examined with hand-held Doppler, DIRT and CTA. Arterial Doppler sound locations were marked on the skin. DIRT examination involved rewarming of the abdominal skin after a mild cold challenge. The locations of hot spots on DIRT were compared with the arterial Doppler sound locations. The rate and pattern of rewarming of the hot spots were analyzed. Multiplanar CT reconstructions were used to see if hot spots were related to perforators on CTA. All flaps were based on the perforator selected with DIRT and the surgical outcome was analyzed. Results: First appearing hot spots were always associated with arterial Doppler sounds and clearly visible perforators on CTA. The hot spots on DIRT images were always slightly laterally located in relation to the exit points of the associated perforators through the rectus abdominis fascia on CTA. Some periumbilical perforators were not associated with hot spots and showed communication with the superficial inferior epigastric vein on CTA. The selected perforators adequately perfused all flaps. Conclusion: This study confirms that perforators selected with DIRT have arterial Doppler sound, are clearly visible on CTA and provide adequate perfusion for DIEP breast reconstruction.