Thermo- and photoelectric current in hornet cuticle

Thermoelectric and photoelectric currents were measured in the cuticle of hornets. The spontaneous current in the studied specimens ranged between 30-40 nAmp under conditions of darkness whereas under illumination the current drops to near zero. Upon warming up to 28-29 degrees C, the current rises to 50-200 nAmp but subsequently, after a while, it declines, regardless of whether the temperature is held steady, continues to rise or is lowered. In light, the current values are lower than in darkness and this under all conditions. When the specimen is charged with an electric current under fixed temperature, the current attains several microAmp in darkness but is usually less than that under illumination by about one order of magnitude. The capacitance values range between 1-7 mFarad both in light and in the dark. Possible mechanisms for creating this cuticular current and the changes which it undergoes under the various experimental conditions are discussed, and so also the properties of hornet cuticle as a semiconductor and possible applications of the described phenomena in everyday life of hornets.     

Observation of ultrastructural changes in cultured retinal pigment epithelium following exposure to blue light

BACKGROUND: The retina can be damaged by light even when levels of energy are well below the threshold for thermal damage, and the experimental damage of the retinal pigment epithelium (RPE) may be induced more easily by blue light than by longer wavelengths of visible light. The present study demonstrates the ultrastructural damage produced by exposure to blue light in cultured RPE. METHODS: Long-Evans rats were enucleated 8-10 days after birth for primary culture. One week after seeding, the monolayer culture of RPE cells was exposed to a cool blue light (wavelength = 440 +/- 10 nm) for 36 h (12 h/day, 3 days) at 2.0 mW/cm2. Transmission electron microscopy was used to compare the exposed RPE with the control. The entire experiment was repeated 3 times independently. RESULTS: The cytoplasm of the exposed RPE exhibited degenerative changes, such as large whorls of membrane, lamellar whorls and whorled inclusions. CONCLUSION: The RPE cells can be damaged directly by blue light after excluding the possible influence of phagosomes. This primary culture of RPE can also serve as an in vitro model for the study of light damage to the RPE.     

Illumination partly reverses the postsynaptic blockade of the frog neuromuscular junction by the styryl pyridinium dye RH414

The styryl pyridinium dye RH414, which we have used recently for optical monitoring of synaptic vesicle membrane trafficking in frog motor nerve terminals, reversibly inhibited contractions in the frog nerve-muscle preparations used for those studies. We report here the results of experiments into the basis of this inhibition and how the blocking effects can be modulated by incident light, by using conventional intracellular recording and iontophoretic techniques. Bath application of 5-42.5 microM RH414 blocked nerve-evoked twitches in frog cutaneus pectoris muscles, although subthreshold endplate potentials and miniature endplate potentials could still be recorded. In the presence of the dye, illumination of the recording area with light from a mercury arc lamp over a wide range of wavelengths (340-560 nm) potentiated the amplitude of endplate potentials, miniature endplate potentials, and depolarizations resulting from iontophoretic application of acetylcholine. The magnitude of both the light-induced disinhibition of endplate and iontophoretic potentials increased with the intensity of the illumination and developed exponentially with a time constant of several hundred milliseconds. Both the dye-induced inhibition and the light-induced disinhibition disappeared after washing in dye-free physiological saline. Muscle fibre resting membrane potential, input conductance and miniature endplate potential frequency, however, were not affected by these manipulations. These data are consistent with a specific, curare-like interaction of the dye with acetylcholine receptors which can be modulated by light.     

Incidence of leukemia in Krakow in the period 1980-1990]

OBJECTIVE: This study was done to compare costs, operating and recovery times, safety, and patient acceptance between (a) minimally invasive laparoscopic tubal ligation under sedation and local anesthesia and (b) conventional laparoscopic operating-room-based tubal ligations under general anesthesia. METHODS: Fourteen women desiring sterilization were randomized between tubal ligation under sedation/local analgesia versus general anesthesia. Procedures were performed by supervised residents previously unfamiliar with the minimally invasive technique. Hospital charges were used as a surrogate for cost. Operating or procedure room times, surgical complications, and recovery times were recorded. Patient acceptance was assessed using satisfaction surveys administered in the recovery room and again 1 week postoperatively. RESULTS: The cost of minimally invasive tubal ligation was significantly lower than for the conventional technique ($1,615+/-$134 vs $2,820+/-$110, p < 0.001). Surgical times were not different between the two procedures: 40.4+/-15 min for the conventional technique versus 32.9+/-10 min for minimally invasive surgery. However, the total in-room time required in the operating room significantly exceeded that for the procedure room technique (84+/-10 min vs 60+/-2 min, p < 0.05). Likewise, recovery time for the general anesthesia technique was longer (48+/-6 min vs 14+/-7 min, p < 0.03). No complications were encountered with either surgical method. Patient satisfaction for pain, fatigue, and days of missed work was similar between the two groups. CONCLUSIONS: The use of minimally invasive surgery to perform tubal ligation is advantageous over conventional laparoscopic tubal ligation under general anesthesia with regard to cost and time utilization. The minimally invasive technique appears to be easy to learn, safe, and well tolerated.     

Type A fibril of the mouse tectorial membrane shows D-periodicity: an atomic force microscopic examination

This study demonstrated that type A fibrils of the mouse tectorial membrane showed a morphology characteristic of collagen, as demonstrated using an atomic force microscope. In the topographical imaging mode, the surface of the type A fibrils showed a periodic pattern, consisting of alternating grooves and ridges. The periodicity of the type A fibrils was 69.1 +/- 0.6 nm, which is in accordance with characteristic collagen D-periodicity. The difference in height between grooves and ridges was 1.6 +/- 0.3 nm. In the variable deflection imaging mode, the type A fibrils showed a clear banding pattern, which consisted of alternating light and dark zones, with D-periodicity. In addition, the type A fibrils exhibited one minor dark band in the light zone and one minor light band in the dark zone.     

Dark adaptation in the American red squirrel (Tamiosciurus hudsonicus).

Used a behavioral tracking technique to investigate dark adaptation in 3 American red squirrels. Dark adaptation was fully completed within 30 min after the offset of the longest light-adaptation duration. An increase in visual sensitivity of more than 3 log units had taken place, and the final threshold (10-5 ml) was about 1 log unit above the scotopic threshold of a human tested in the same apparatus. A discontinuity occurred about 4 min after the start of dark adaptation when the Ss were light adapted for 4 min. No rod-cone break occurred when the Ss were not light adapted above room illumination. When colored test stimuli (red, yellow, and blue) were used after 4 min of light adaptation, rod-cone breaks occurred for each test stimulus. It is concluded that the tree squirrel possesses a functional duplex retina. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chronic fatigue syndrome

The hepatoprotective activity of crude extract of artemisia scoparia (aerial parts) was investigated against experimentally produced hepatic damage using carbon tetrachloride (CCl4) as a model hepatotoxin. CCl4 at the dose of 1.5 ml/kg, produced liver damage in rats as manifested by the rise in serum levels of AST and ALT to 395 +/- 110 and 258 +/- 61 IU/l (mean +/- SEM; n = 10) respectively, compared to control values of 106 +/- 15 and 26 +/- 04. Pretreatment of rats with plant extract (150 mg/kg) significantly lowered (P < 0.01), the respective serum GOT and GPT levels to 93 +/- 05 and 27 +/- 03 IU/l, indicating hepatoprotective action. Pentobarbital sodium (75 mg/kg)-induced sleeping time in mice was found to be 140.8 +/- 1.5 min (n = 10) which was similar (P > 0.05) to that obtained in the group of animals pretreated with the plant extract (139.9 +/- 1.8 min). CCl4 treatment extended the pentobarbital sleeping time to 212.2 +/- 19.1 min and pretreatment of animals with plant extract reversed the CCl4-induced prolongation in pentobarbital sleeping time to 143.9 +/- 5.5 min (P < 0.001) which further confirms the protective action of the plant extract against CCl4-induced liver damage. These data indicate that the plant artemisia scoparia is hepatoprotective and validate the folkloric use of this plant in liver damage.     

Fluorescence in situ hybridization analysis of chromosome 1p36 deletions in human MYCN amplified neuroblastoma

Artificial illumination is an important factor in the management of layers. In this study, a new monochromatic light system was developed for egg layers. Prelaying pullets (Lohmann) were marked and housed in nine light and temperature control rooms (15 battery cages, 3 hens per cage; n = 45), divided into three light treatments: 0.1 and 0.01 W/m2 light intensity using light emitting diode (LED) lamps and 0.1 W/m2 using mini-fluorescent bulbs (PL) (control). In each of the LED rooms, three wavelengths were tested: 560 (n = 9), 660 (n = 9), 880 (n = 6), and 660 intermitted lighting (15 min light 45 min dark, 660IN) (n = 9). Birds were exposed to 12 h light and 12 h of darkness using PL lamps. At 21 wk of age, the light period was increased to 12.75 h by using 5.5 h of LED lamps and 7.25 of PL light source for Groups 1 and 2, the third group received 12.75 h of PL light. Until 28 wk of age, light hours increased by 0.5 h/w using LED light for Groups 1 and 2 and PL source for the third group, reaching 16 h of light at 28 wk of age. Egg production and feed consumption were recorded daily; egg components were recorded weekly for 10 mo. A significant reduction in egg production was observed in all 880nm groups; no differences in egg production and quality were found in the other groups. Feed consumption was significantly lower by 7% in all 0.01 W/m2 groups. We suggest that an important reduction in rearing costs of laying hens may be obtained by using this system.     

Light-dependent changes in outer segment free-Ca2+ concentration in salamander cone photoreceptors

Simultaneous measurements of photocurrent and outer segment Ca2+ were made from isolated salamander cone photoreceptors. While recording the photocurrent from the inner segment, which was drawn into a suction pipette, a laser spot confocal technique was employed to evoke fluorescence from the outer segment of a cone loaded with the Ca2+ indicator fluo-3. When a dark-adapted cone was exposed to the intense illumination of the laser, the circulating current was completely suppressed and fluo-3 fluorescence rapidly declined. In the more numerous red-sensitive cones this light-induced decay in fluo-3 fluorescence was best fitted as the sum of two decaying exponentials with time constants of 43 +/- 2.4 and 640 +/- 55 ms (mean +/- SEM, n = 25) and unequal amplitudes: the faster component was 1.7-fold larger than the slower. In blue-sensitive cones, the decay in fluorescence was slower, with time constants of 140 +/- 30 and 1,400 +/- 300 ms, and nearly equal amplitudes. Calibration of fluo-3 fluorescence in situ from red-sensitive cones allowed the calculation of the free-Ca2+ concentration, yielding values of 410 +/- 37 nM in the dark-adapted outer segment and 5.5 +/- 2.4 nM after saturating illumination (mean +/- SEM, n = 8). Photopigment bleaching by the laser resulted in a considerable reduction in light sensitivity and a maintained decrease in outer segment Ca2+ concentration. When the photopigment was regenerated by applying exogenous 11-cis-retinal, both the light sensitivity and fluo-3 fluorescence recovered rapidly to near dark-adapted levels. Regeneration of the photopigment allowed repeated measurements of fluo-3 fluorescence to be made from a single red-sensitive cone during adaptation to steady light over a range of intensities. These measurements demonstrated that the outer segment Ca2+ concentration declines in a graded manner during adaptation to background light, varying linearly with the magnitude of the circulating current.     

In situ comparison of 665 nm and 633 nm wavelength light penetration in the human prostate gland

The depth of treatment in photodynamic therapy (PDT) of tumors varies with the wavelength of light activating the photosensitizer. New generation photosensitizers that are excited at longer wavelengths have the potential for increasing treatment depths. Tin ethyl etiopurpurin (SnET2), a promising second-generation photosensitizer is maximally activated at 665 nm, which may be significantly more penetrating than 633 nm light currently used with porphyrins in PDT. The penetration of 665 nm and 633 nm wavelength red light in the prostate gland was compared in 11 patients undergoing prostatic biopsies for suspected prostatic cancer. Interstitial optical fibers determined the light attenuation within the prostate gland. Of the 11 patients, 7 had dual wavelength and 4 had single wavelength studies. The mean attenuation coefficients, mueff, for 665 nm and 633 nm wavelength light were 0.32 +/- 0.05 mm-1 and 0.39 +/- 0.05 mm-1, respectively, showing a statistically significant difference (P = 0.0003). This represented a 22% increase in the mean penetration depth and at 10 mm from the delivery fiber there was 1.8 times as much 665 nm light fluence than 633 nm. The mean mueff at 665 nm for benign and malignant prostate tissue were similar (P = 0.42), however, there was significant interpatient variation (mueff ranging from 0.24 to 0.42 mm-1) reflecting biological differences of therapeutic importance. The enhanced light fluence and penetration depth with 665 nm light should allow significantly larger volumes of prostatic tissue to be treated with SnET2-mediated PDT.     

Spinal anesthesia with 2% plain lidocaine for ultrasonically guided vaginal oocyte retrieval]

Spinal anesthesia with 3 ml of 2% plain lidocaine was administered to 10 women for ultrasonically guided vaginal oocyte retrieval. Spread of anesthesia was assessed by skin vasodilatation, change of skin texture, loss of goose flesh reflex, and loss of cold as well as pin-prick sensation, and we studied time to complete motor block, time to two-segment regression, time to full motor and sensory recovery, ambulation time, haemodynamic parameters, and postoperative complications. The highest sensory block assessed by pin-prick was up to Th 8.3 +/- 3.4 10 min following spinal anesthesia. All patients had complete motor block and this was achieved at 9.0 +/- 1.7 min. Times to two-segment regression, full motor and sensory recovery, and ambulation were 84.5 +/- 31.0, 147.5 +/- 24.7, 176.5 +/- 23.2, and 203.3 +/- 50.0 min, respectively. No serious side effects were observed during the operation and postoperatively. We concluded that 3 ml of 2% plain lidocaine provided adequate spinal anesthesia for ultrasonically guided vaginal oocyte retrieval.     

Fluorescence with Wood's light. Current applications in dermatologic diagnosis, therapy follow-up and prevention

The invisible long-wave ultraviolet radiation (340-450 nm, max.365 nm) produced by a Wood lamp can help to diagnose dermatoses with a characteristic fluorescence (tinea capitis, erythrasma, tinea versicolor, Pseudomonas infections, porphyrians, and pigmentary alterations). It is also used in the detection of medications that are taken systemically (tetracycline) or that are applied to the skin. Recently, a fluorescence technique with Wood light has been used as a preventive measure to monitor and quantify skin protection at the workplace and to teach workers in high-risk occupations the proper use of protective creams.     

Infrared imaging of sub-retinal structures in the human ocular fundus

The interaction of infrared light with the human ocular fundus, particularly sub-retinal structures, was studied in vivo. Visible and infra-red wavelengths and a scanning laser ophthalmoscope were used to acquire digital images of the human fundus. The contrast and reflectance of selected retinal and sub-retinal features were computed for a series of wavelengths or modes of imaging. Near infrared light provides better visibility than visible light for sub-retinal features. Sub-retinal deposits appear light and thickened; the optic nerve head, retinal vessels, and choroidal vessels appear dark. Contrast and visibility of features increases with increasing wavelength from 795 to 895 nm. Optimizing the mode of imaging improves the visibility of some structures. This new quantitative basis for near infrared imaging techniques can be applied to a wide range of imaging modalities for the study of pathophysiology and treatment in diseases affecting the retinal pigment epithelium and Bruch's membrane, such as age-related macular degeneration.     

Seasonal changes in pituitary function: amplification of midfollicular luteinizing hormone secretion during the dark season

OBJECTIVE: To analyze the effect of season on the pulsatility of gonadotropin secretion in women living in an area with a large annual variability in daylight length. DESIGN: A prospective study. Pulse studies were carried out in each subject during both the dark and light season. SETTING: The gynecologic endocrine research unit of the University Central Hospital of Oulu. PARTICIPANTS: Eleven ovulatory, healthy women volunteering for the study. INTERVENTIONS: Serum samples were collected at 10-minute intervals for 6 hours on days 7 to 9 of the cycle. MAIN OUTCOME MEASURES: Serum LH and FSH concentrations were measured and the data were analyzed with an algorithm computer-based program. RESULTS: The mean area of LH pulses analyzed was significantly higher during the dark season than the light season (49.1 +/- 3.1 versus 38.5 +/- 1.7 mIU/mL; conversion factor to SI unit, 1.00), while in the amplitude (1.9 +/- 0.1 versus 1.8 +/- 0.1 mIU/mL), number of pulses (5.2 +/- 0.3 versus 4.4 +/- 0.6), and the mean level (9.6 +/- 0.5 versus 9.4 +/- 0.9 mIU/mL) the difference did not reach statistical significance. The number (5.2 +/- 0.5 versus 5.2 +/- 0.4,), amplitude (1.0 +/- 0.05 versus 1.1 +/- 0.07 mIU/mL; conversion factor to SI unit, 1.00), area (29.9 +/- 2.4 versus 29.6 +/- 3.1 mIU/mL), and the mean level of FSH (5.4 +/- 0.6 versus 6.0 +/- 0.8 mIU/mL) during the dark and light seasons were identical, showing no seasonal variability. CONCLUSIONS: The results indicate increased pituitary LH secretion in the midfollicular phase during the dark season that may be related to increased melatonin secretion and decreased ovarian activity at this time of the year.     

Protection against photodynamic therapy (PDT)-induced photosensitivity by fabric materials

"Special" highly protective fabrics are now available that offer broad-spectrum protection in preventing sunburn, and possibly other types of photodamage. It is important to know to what extent these fabrics are capable of protecting the wearer against skin cancer, photosensitivity disorders, and inadvertent phototoxic reactions from photodynamic therapy (PDT). We assess the ability of one such special (Solumbra) fabric and one "typical" summer fabric to provide protection against PDT phototoxicity produced in tape-stripped Sk-1 hairless mice by topical 5-aminolevulinic acid (ALA) and (primarily) visible light (360-800 nm). Since ALA-derived photosensitizers absorb most of the visible spectrum, results from these studies give a good indication of the photoprotective capability of these fabrics throughout this region. Mice were irradiated dorsally with a Kodak slide projector equipped with a 300 W tungsten-halogen lamp (I0 = 48.3 mW/cm2). After determining the minimal phototoxic dose (MPD) to be 1.40 +/- 0.4 J/cm2, we irradiated the tape-stripped ALA-sensitized mice through the stretched test fabrics with appropriate multiples of the MPD. The special fabric provided protection against 25-30 MPD visible light between 360-800 nm in 14/14 mice. The typical fabric failed to provide protection against 2.5 MPD of the same spectrum. No phototoxic or other adverse responses were seen with either the ALA or light control. In conclusion, the Solumbra fabric is much more protective against ALA photosensitization than the typical fabric. Both appear better at blocking UV than visible light.     

Changing from isoflurane to desflurane toward the end of anesthesia does not accelerate recovery in humans

BACKGROUND: In an attempt to combine the advantage of the lower solubilities of new inhaled anesthetics with the lesser cost of older anesthetics, some clinicians substitute the former for the latter toward the end of anesthesia. The authors tried to determine whether substituting desflurane for isoflurane in the last 30 min of a 120-min anesthetic would accelerate recovery. METHODS: Five volunteers were anesthetized three times for 2 h using a fresh gas inflow of 2 l/min: 1.25 minimum alveolar concentration (MAC) desflurane, 1.25 MAC isoflurane, and 1.25 MAC isoflurane for 90 min followed by 30 min of desflurane concentrations sufficient to achieve a total of 1.25 MAC equivalent ("crossover"). Recovery from anesthesia was assessed by the time to respond to commands, by orientation, and by tests of cognitive function. RESULTS: Compared with isoflurane, the crossover technique did not accelerate early or late recovery (P > 0.05). Recovery from isoflurane or the crossover anesthetic was significantly longer than after desflurane (P < 0.05). Times to response to commands for isoflurane, the crossover anesthetic, and desflurane were 23 +/- 5 min (mean +/- SD), 21 +/- 5 min, and 11 +/- 1 min, respectively, and to orientation the times were 27 +/- 7 min, 25 +/- 5 min, and 13 +/- 2 min, respectively. Cognitive test performance returned to reference values 15-30 min sooner after desflurane than after isoflurane or the crossover anesthetic. Isoflurane cognitive test performance did not differ from that with the crossover anesthetic at any time. CONCLUSIONS: Substituting desflurane for isoflurane during the latter part of anesthesia does not improve recovery, in part because partial rebreathing through a semiclosed circuit limits elimination of isoflurane during the crossover period. Although higher fresh gas flow during the crossover period would speed isoflurane elimination, the amount of desflurane used and, therefore, the cost would increase.     

Emergence of elderly patients from prolonged desflurane, isoflurane, or propofol anesthesia

Recovery from prolonged anesthesia might be compromised in elderly patients. Desflurane (DES) may be particularly well suited to achieve a rapid postoperative recovery because of its low lipid solubility. Postoperative recovery was compared in 45 elderly patients randomized to receive either DES, isoflurane (ISO), or propofol (PRO) to maintain anesthesia. Anesthesia was induced with PRO, vecuronium, and fentanyl and maintained with N2O, fentanyl, and the study drug. Times from end of anesthesia to tracheal extubation, eye opening and hand squeezing on command, and ability to state name and date of birth were recorded. Sedation and psychometric evaluation were tested 0.5, 1, 1.5, 2, and 24 h postoperatively. Results are given as means +/- SD. Differences among were analyzed by chi2 or analysis of variance. P < 0.05 compared with DES was considered significant. After a prolonged anesthesia (199 +/- 57 min with DES), immediate recovery times were significantly shorter with DES than with ISO or PRO (times to eye opening: 5.6 +/- 3.4 min, 11.5 +/- 8.4 min, and 11.9 +/- 7.6 min; times to extubation: 6.9 +/- 3 min, 13.1 +/- 8.9 min, 9.9 +/- 6.5 min for DES, ISO, and PRO, respectively). Intermediate recovery, as measured by psychometric testing, sedation levels, and time to discharge from the postanesthesia care unit, was similar in the three groups. In this study, DES provided a transient advantage compared with ISO or PRO with respect to early recovery after prolonged general anesthesia in elderly patients. IMPLICATIONS: Recovery from prolonged anesthesia can sometimes be problematic in elderly patients. We evaluated 45 elderly patients who received either desflurane, isoflurane, or propofol for anesthesia. We found that desflurane provided a transient advantage in terms of postoperative recovery, but whether this difference is clinically important remains to be demonstrated.     

The role of the blood-brain barrier transporter PTS-1 in regulating concentrations of methionine enkephalin in blood and brain

The entrainment of the circadian rhythm of locomotor activity was studied in the field mouse Mus booduga in order to examine the relationship between the free-running period (tau) and minimum tolerable light pulse interval of the skeleton photoperiods. The animals were entrained under three different light/dark (LD) schedules, each out of phase with the other. They were then subjected to various skeleton photoperiods created by two repeated light pulses (LPs) interrupting darkness. Animals that selected the shorter interval between the LPs as their "subjective night" had significantly shorter tau (23.13 +/- 0.38 h) as compared to those that selected the longer dark interval as subjective night (tau = 23.87 +/- 0.18 h). When the longer dark interval was 12 h, animals selecting that interval as their subjective night included both long-tau and short-tau individuals. When both intervals of darkness were of equal duration, no difference in the selection of subjective night was seen between short and long-tau animals. When the "dusk" LP for the animals that selected the longer dark interval as subjective night was advanced by 2 h to create a new skeleton photoperiod, the number of transient cycles appearing before steady-state entrainment was found to depend on the duration of the photoperiods. When the night defined by the two LPs was reduced below 6h, a dramatic "phase jump" in the activity rhythm was observed, and the initial phase relationship was restored after a relaxation in the night duration. We observed considerable interindividual variation in the "minimum tolerable light pulse interval of skeleton photoperiods," which we suggest may be due to the observed variation in tau among individuals.     

Increment-threshold spectral sensitivity in the squirrel monkey.

Measured the spectral sensitivity of 5 adult squirrel monkeys and 2 human males in an increment-threshold context. Under conditions of dark adaptation the spectral sensitivity of the squirrel monkey was closely similar to that of man. For conditions of light adaptation, the squirrel monkey showed maximal sensitivity at 540 nm. with subsidiary peaks at 600 and 440 nm. Relative to man, the squirrel monkey was considerably less sensitive to wavelengths longer than 580 nm. For this species there are substantial differences between the spectral sensitivity functions determined by increment-threshold methods and those obtained using critical flicker frequency (CFF) techniques. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new approach to normalize myocardial temperature in the open-chest pig model

To prevent unphysiological temperature fluctuations in the myocardium in the open-chest model, we constructed a thermocage. Five pigs under pentobarbital sodium anesthesia underwent repetitive left anterior descending (LAD) coronary artery occlusions. Myocardial temperature was measured without any thoracic temperature-controlling device and in the presence of either a heating lamp or the thermocage. Without any thoracic temperature-controlling device, the temperature at 5-mm myocardial depth was 1.28 +/- 0.33 degrees C below the intra-abdominal temperature (P < 0.05). During a proximal 5-min LAD occlusion, myocardial temperature decreased by 1.86 +/- 1.02 degrees C in the ischemic area (P < 0.05). Both the heating lamp and the thermocage abolished the difference between intra-abdominal and myocardial temperatures and prevented the decrease in myocardial temperature during ischemia. Only the thermocage minimized myocardial temperature fluctuations due to air currents and prevented epicardial exsiccation. We conclude that either a thermocage or a heating lamp may be used to normalize myocardial temperature in the open-chest pig model. However, the thermocage is superior to the lamp in minimizing temperature fluctuations and preventing epicardial exsiccation.