Mean Peak Temperature Research Articles

PHENOMENOLOGY OF PROLONGED FEBRILE SEIZURES: RESULTS OF THE FEBSTAT STUDY

Background: Febrile status epilepticus (FSE) has been associated with hippocampal injury and subsequent mesial temporal sclerosis and temporal lobe epilepsy. However, little is known about the semiology of FSE. Methods: A prospective, multicenter study of the consequences of FSE included children, aged 1 month through 5 years, presenting with a febrile seizure lasting 30 minutes or more. Procedures included neurologic history and examination and an MRI and EEG within 72 hours. All information related to seizure semiology was reviewed by three epileptologists blinded to MRI and EEG results and to subsequent outcome. Inter-rater reliability was assessed by the κ statistic. Results: Among 119 children, the median age was 1.3 years, the mean peak temperature was 103.2°F, and seizures lasted a median of 68.0 minutes. Seizure duration followed a Weibull distribution with a shape parameter of 1.68. Seizures were continuous in 52% and behaviorally intermittent (without recovery in between) in 48%; most were partial (67%) and almost all (99%) were convulsive. In one third of cases, FSE was unrecognized in the emergency department. Of the 119 children, 86% had normal development, 24% had prior febrile seizures, and family history of febrile seizures in a first-degree relative was present in 25%. Conclusions: Febrile status epilepticus is usually focal and often not well recognized. It occurs in very young children and is usually the first febrile seizure. Seizures are typically very prolonged and the distribution of seizure durations suggests that the longer a seizure continues, the less likely it is to spontaneously stop. GLOSSARY: ED = emergency department; FS = febrile seizures; FSE = febrile status epilepticus; HHV = human herpesvirus; ILAE = International League Against Epilepsy; IQR = interquartile range; MTLE = mesial temporal lobe epilepsy; MTS = mesial temporal sclerosis.

Burns in Children Caused by Hair Straighteners: Epidemiology and Investigation of Heating/Cooling Curves

We recently encountered a number of burns in young children caused by hair straighteners and decided to study their epidemiology. We carried out a retrospective audit from 1999 to 2006. We also conducted laboratory testing of the thermal profiles of four brands of hair straighteners. Eighteen children (aged 8 months to 13.5 years, mean 2.1 years) sustained hair straightener burns. Most (13/18) affected the upper limbs and six involved the lower limbs. Three (16.6%) children required surgery. The mean peak temperature of the straighteners was 169.5 degrees C (337.1 degrees F). The straighteners that we tested remained at a temperature above 80 degrees C (176 degrees F) for between 6 and 8 minutes. A third of the hair straightener burns occurred when the appliance was switched "OFF" and cooling down. The children affected are very young. Thus, any prevention campaign should target parents. Children should be well supervised and the straighteners should be placed safely out of their reach while they are cooling. Parents should be warned of the risks to young children, even when straighteners have been switched off. Manufacturers should supply suitable cooling bags.

Phenomenology of prolonged febrile seizures

Febrile status epilepticus (FSE) has been associated with hippocampal injury and subsequent mesial temporal sclerosis and temporal lobe epilepsy. However, little is known about the semiology of FSE. A prospective, multicenter study of the consequences of FSE included children, aged 1 month through 5 years, presenting with a febrile seizure lasting 30 minutes or more. Procedures included neurologic history and examination and an MRI and EEG within 72 hours. All information related to seizure semiology was reviewed by three epileptologists blinded to MRI and EEG results and to subsequent outcome. Inter-rater reliability was assessed by the kappa statistic. Among 119 children, the median age was 1.3 years, the mean peak temperature was 103.2 degrees F, and seizures lasted a median of 68.0 minutes. Seizure duration followed a Weibull distribution with a shape parameter of 1.68. Seizures were continuous in 52% and behaviorally intermittent (without recovery in between) in 48%; most were partial (67%) and almost all (99%) were convulsive. In one third of cases, FSE was unrecognized in the emergency department. Of the 119 children, 86% had normal development, 24% had prior febrile seizures, and family history of febrile seizures in a first-degree relative was present in 25%. Febrile status epilepticus is usually focal and often not well recognized. It occurs in very young children and is usually the first febrile seizure. Seizures are typically very prolonged and the distribution of seizure durations suggests that the longer a seizure continues, the less likely it is to spontaneously stop.

Vitrinite-rich coal concentrate intrinsic reactivity index

This work defines a new reactivity coal combustion parameter called intrinsic reactivity index (IRI), combining reactive maceral fraction (vitrinite/liptinite), non-reactive maceral fraction (inertinite/intrinsic mineral matter) and vitirinite reflectance averages. Coal samples from La Yolanda and Guachinte (Valle del Cauca) collieries were used to evaluate the IRI; samples consisted of original and vitrinite concentrated fractions obtained from froth flotation column. This new parameter was compared to three conventional parameters: weighted mean activation energy (WMAE), peak temperature (PT) and final temperature (FT). Results revealed that vitrinite concentrated fractions had higher IRI figures than original coal. This meant that vitrinite concentrated fractions presented higher reactivity to combustion than original coal. Results also showed that EAMP TP and TF decreased with an increase in IRI, suggesting that coal combustion reactivity becomes improved when vitirinite concentration in coal is increased.

A Nationwide Epidemic of Influenza C Virus Infection in Japan in 2004

During the period from January to July 2004, a total of 131 influenza C viruses were detected by cell culture or reverse transcription-PCR (RT-PCR) from specimens that were obtained from children with acute respiratory symptoms in 10 prefectures across Japan. Influenza C virus was identified most frequently in the Miyagi (1.4%, 45 of 3,226 specimens) and Yamagata (2.5%, 31 of 1,263 specimens) prefectures, and the frequency in this year was the highest since 1990. Phylogenetic analysis of the hemagglutinin esterase gene of the 13 strains isolated in nine prefectures revealed that genetically similar strains belonging to the Kanagawa/1/76-related lineage dominantly spread throughout Japan. During the 2004 influenza season, influenza C virus coexisted with epidemics of influenza A virus (H3 strain), and 12 cases were identified from patients who had been diagnosed with influenza-like illness (7 were detected by RT-PCR, and 5 were detected by culture). A comparison of specimens that were found positive by culture with those found positive only by RT-PCR shows that the amount of virus in PCR-positive specimens tended to be lower than in isolation-positive specimens. Although the mean peak temperature in patients in the PCR-positive group was slightly lower, there were no significant differences in characteristics between specimens (i.e., kind of specimen, period from onset to specimen collection, age distribution of patients, and severity of illness). These results suggest that an epidemic of influenza C virus occurred on a national scale during this period and that RT-PCR can be an effective supplemental tool for the evaluation of clinical and epidemiological information.

Thermal Imaging Study Comparing Phacoemulsification With the Sovereign With WhiteStar System to the Legacy With AdvanTec and NeoSoniX System

To assess intraoperative thermal levels at the wound site during divide-and-conquer phacoemulsification with the Sovereign with WhiteStar (SWS) system or the Legacy with AdvanTec and NeoSoniX (LAD) system. Prospective, randomized, parallel-group, comparative study. Twenty-six subjects from a private clinical practice underwent divide-and-conquer phacoemulsification with either the SWS system or the LAD system. CB/CF settings (60%/33% duty cycles) were utilized with SWS and 12 pulses per second with the LAD system. Key criteria assessed were peak wound-site temperature, mean temperature change at the wound site, effective phaco time, average phaco power, procedure time, amount of BSS used, and surgical complications. Mean temperature change at the wound site was greater for the LAD than the SWS group. There was a statistically significant difference (P=.0002) in mean peak wound temperatures, with the LAD group having higher mean peak temperatures (42.47+/-5.33 degrees C) than the SWS group (36.59+/-1.33 degrees C). Highest wound-site temperature was 51 degrees C for the LAD group and 39.3 degrees C for the SWS group. A statistically significant difference (P=.0031) in mean peak temperature was found between the LAD and SWS systems for subjects with a cataract density of 4: higher mean peak temperatures were observed for LAD patients with a cataract density of 4. Our findings show that phacoemulsification using the SWS system results in lower peak temperatures and less temperature change at the phaco wound site compared with the LAD system.

CLINICAL PRESENTATION AND CHARACTERISTICS OF PHARYNGEAL ADENOVIRUS INFECTIONS

We describe the clinical characteristics of 209 children younger than 15 years of age with positive pharyngeal cultures for adenovirus. The mean age of the children was 37 +/- 33 months, and the mean peak temperature was 39.2 +/- 0.76 degrees C. On physical examination, tonsillitis was found for 88% of children; 52% of them had exudative tonsillitis. Forty-eight percent of the patients who had a white blood cell count performed had >15,000 leukocytes per mm, and 25% had >20,000 leukocytes per mm. C-reactive protein concentrations were >7 mg/dL for 22.5% of the patients. Adenovirus pharyngeal infections in young children mimic severe bacterial infections.

Iron Insufficiency as a Risk Factor for Febrile Seizures

Source: Daoud AS, Batieha A, Abu-Ekteish F, et al. Iron status: a possible risk factor for the first febrile seizure. Epilepsia. 2002;43:740–743.The significance of iron status as a possible risk factor for a first febrile seizure (FFS) was investigated at Jordan University and King Hussein Medical Center, Irbid, Jordan. Children admitted with a FFS between January and December 2000 were compared to a reference group of children hospitalized for a febrile illness (eg, upper and lower respiratory tract infection, gastroenteritis) without seizures. The 2 study groups were comparable in all areas. The mean ferritin level of 75 children with FFS was 29.5 +/− 21.3 mcg/L as compared to 53.3 +/− 37.6 mcg/L in 75 matched controls (P=.0001). A plasma ferritin (PF) level of <30 mcg/L was significantly more prevalent among children with FFS than controls (65% vs 32%, P=.000). Mean levels of hemoglobin concentration (Hgb), mean corpuscular volume (MCV ), and mean corpuscular hemoglobin (MCH) were lower in FFS cases than in controls, and a higher proportion of FFS cases had a Hgb <110g/L, MCV <72 fl, and MCH <24 pg (differences not significant). The mean levels of Hgb (97.2), MCV (70.7), MCH (22.9), and PF (22.2) that were seen in children with complex seizures were lower than those seen in children with simple febrile seizures and differences were statistically significant for Hgb (P=.016) and MCH (P=.03). Mean peak temperature on admission and types of febrile illness were not different between cases and controls. Family histories of epilepsy and febrile convulsions were higher among cases, but the differences between cases and controls were not significant. The findings suggest a possible role for iron insufficiency in FFS.Plasma ferritin (PF), an iron containing protein, is used as a measure of iron deficiency and total body iron status. These authors found low PF levels in children admitted for a first febrile seizure (FFS). Previous studies have shown conflicting results. One report suggests that iron-deficiency anemia may raise, not lower, the threshold for febrile seizures, and that ferritin levels increase in response to any febrile illness.1 Another finds a significantly higher rate of iron-deficiency anemia among children with FFS than in controls.2 Lead poisoning, another possible cause of iron-deficiency anemia and febrile convulsions,3 was considered very unlikely in the study population because of preliminary, unpublished data on a similar population which showed this to be a very rare cause. The reason for the decreased levels of PF in children with FFS was undetermined.Other neurologic disorders in which iron-deficiency anemia may play a role include breath-holding spells,4 developmental delay,5 and behavior and cognitive disorders.6 Treatment with iron may reverse developmental delay in iron-deficiency anemia.7 Testing for iron-deficiency anemia is suggested in infants who have experienced febrile seizures, but further studies are needed to confirm a possible role of iron status in FFS.There is still much to be ironed out in trying to understand the pathophysiology underlying this interesting association between low ferritin levels and febrile seizures. A follow-up study of patients found to be iron-deficient at the time of a first febrile seizure to determine the incidence of subsequent febrile seizures after treatment for iron deficiency would be of great interest.

Chronic transmural atrial ablation by using bipolar radiofrequency energy on the beating heart

Background: Recently, there has been renewed interest in the development of minimally invasive procedures to treat atrial fibrillation. Unipolar radiofrequency catheters are plagued by poor results, in part because of their inability to produce transmural lesions. This study tested the ability of bipolar radiofrequency energy to create chronic transmural lesions on the beating heart that isolated atrial myocardium. Methods: Five sheep underwent a right thoracotomy. Baseline pacing was performed from the following targeted areas: right atrial appendage, superior vena cava, inferior vena cava, and right pulmonary veins. A cuff of atrial myocardium around the targeted tissue was clamped between the 2 arms of the device. Radiofrequency energy was delivered at 750 mA and continued until the tissue conductance between the electrodes reached a stable minimum level. After ablation, pacing was used to document tissue isolation. The animals survived for 30 days. Results: Twenty circumferential lesions were produced at the initial operation. The mean ablation time was 9.3 ± 4.0 seconds, and the mean peak temperature was 48.4°C ± 6.4°C. All lesions acutely and chronically isolated the targeted tissue. Trichrome staining showed that all lesions were transmural. There were no instances of pulmonary vein stenosis or thrombosis. Conclusions: Bipolar radiofrequency energy can produce permanent transmural linear lesions on the beating heart. Online measurement of tissue conductance reliably predicted lesion transmurality. This new technology may enable surgeons to perform a curative minimally invasive operation for atrial fibrillation on the beating heart.J Thorac Cardiovasc Surg 2002;124:708-13

Physiological responses in nonheat acclimated horses performing treadmill exercise in cool (20°C/40%RH), hot dry (30°C/40%RH) and hot humid (30°C/80%RH) conditions

SummaryThe aim of the present study was to determine the effect of different environmental conditions on physiological response to exercise. Four winter acclimatised, nonheat acclimated horses of different breeds were exercised at 20°C/40%RH (CD), 30°C/40%RH (HD) and 30°C/80%RH (HH). The exercise test was designed to represent the structure and intensity of a One star Speed and Endurance test (competition exercise test [CET]). All 4 horses were able to complete the full CET (60 min + 30 min active recovery) in CD and HD, but only one horse completed the CET in HH. Two horses were stopped because of pronounced general fatigue and one because of a right atrial temperature (TRA) of 43°C. Oxygen uptake on each phase was not different between CD and HD, but was higher duringPhases B, CandDin HH. Mean peak TRAat the end ofPhase Dwas 40.3 ± 0.2, 41.6 ± 0.4 and 42 ± 0.3°C for CD, HD and HH, respectively. Corresponding, mean peak rectal temperatures (TREC) followingPhase Dwere 39.5 ± 0.1, 40.6 ± 0.1 and 41.5 ± 0.1°C for CD, HD and HH, respectively. Mean time to peak TRECwas 9.3 ± 1.1 (CD), 7.3 ± 1.8 (HD) and 10.8 ± 2.3 (HH) min and was not significantly different between conditions (P&gt;0.05). Heat dissipation amounted to 83 ± 1, 73 ± 2 and 70 ± 1% of heat production in CD, HD and HH, respectively. Weight loss was significantly correlated with both body surface area (CD r = 0.85; HD r = 0.87; HH r = 0.81) and bodyweight (CD r = 0.97; HD r = 0.93; HH r = 0.94). The greatest weight loss recorded was 4.6% bodyweight in one horse in HD. The mean increase in exercise intensity over the whole CET (in terms of V̇O2) of HD and HH compared with CD was 5 ± 3 and 14 ± 3% higher, respectively. The exercise induced hyperthermia and the reduced capacity for heat dissipation produced partial compensatory responses in minute ventilation (V̇E), particularly duringPhase C, when the horses were trotting. In HD, the increase in V̇Ewas achieved mainly through an increase in frequency, whilst in HH it was achieved through an increase in tidal volume (VT). The horses demonstrated a high degree of tolerance to environmental heat load, suggesting a high thermoregulatory capacity. However, for unacclimatised animals exercising in severely hot and humid conditions, performance may be limited.

Reduction of temperatures generated by the triple reamer within the femoral head

The triple reamer is a convenient lool for reaming the proximal femur when using a sliding screw and plate device, but unnecessarily high temperatures may be generated within the femoral head while the lateral cortex is being reamed. Nineteen female patients over 60 years old were randomized to either the standard or a modified reaming technique with the triple reamer during internal fixation of proximal femoral fractures. Temperatures generated within the femoral head were measured. Results showed a mean peak temperature of 51.9° C (range 42–66) using the standard method and 46.3° C (range 40–52) using the modified method (P = 0.07). A significant difference (P < 0.05) was found in the duration of temperature elevation above the critical 44° C (17.4s vs 5.7s), it being prolonged in the standard group. Even in this osteoporotic patient group, damaging temperatures which may contribute to the mechanical failure of fixation, are generated within the femoral head. A simple method to avoid this problem is described.

Reversal by tolazoline hydrochloride of xylazine hydrochloride-ketamine hydrochloride immobilizations in free-ranging desert mule deer.

We captured 10 free-ranging desert mule deer (Odocoileus hemionus crooki) (five males and five females) by net-gun from a helicopter and immobilized them with xylazine hydrochloride (HCl) (100 mg) and ketamine HCl (300 to 400 mg) injected intramuscularly. Arousal and ambulation times were 13.9 +/- 4.2 and 14.3 +/- 4.2 min in eight deer injected intravenously with tolazoline HCl (3.0 mg/kg). We observed a curvilinear relationship (R = 0.50, P less than 0.01) between rectal temperature and time after induction of anesthesia. Mean peak temperature (41.4 C) occurred at 23.7 +/- 3.2 min postinduction and was greater (P less than 0.01) than the mean temperature measured initially (40.8 C). Heart and respiratory rates (108 beats/min and 75 breaths/min) were elevated prior to immobilization. Mean heart rate increased (P less than 0.05) from 90 +/- 9 beats/min in anesthetized deer to 120 +/- 13 beats/min after tolazoline HCl injection. A 20% capture-related mortality rate suggests this combination of physical and chemical capture has serious limitations. Captive deer permitted to recover from xylazine HCl-ketamine HCl immobilization without a reversal agent were able to walk in 290 +/- 79 min.

Measurement of turbulent diffusion field behind a line heat source in a homogeneous shear flow

Turbulent diffusion behind a line heat source immersed in a nearly homogeneous shear flow is investigated. Test section of the wind tunnel is divided into 15 equal width channels equipped with adjustable internal flow resistances for the production of homogeneous shear flow. A combination of X-type hot wire for the measurement of velocity fluctuations and a cold wire for the measurement of temperature fluctuations has been devised to simultaneously obtain the cross correlations between the velocity and temperature fluctuations. The results show that all the distributions of velocity and scalar field are shifted toward the low velocity region of the homogeneous shear flow. The integral scales for velocity and scalar are different from each other in the shape of profiles so that the time scale ratio R does not remain constant. And the distributions of mean and fluctuating temperatures collapsed into a Gaussian curve by normalizing with mean half width and peak temperature.

Comparative therapeutic effect of aerosolized and oral rimantadine HC1 in experimental human influenza A virus infection

Thirty-six adult volunteers were inoculated intranasally with 7.2 log 10 egg infectious doses 50% of an attenuated A/Khabarovsk/77/H1N1 virus. Twenty-four hours later volunteers were begun on both aerosol treatments (rimantadine HC1 25 mg in saline or saline, 10 min exposure twice daily) and oral medications (rimantadine HC1 50 mg or placebo every 6 h, three times daily) which were administered for 5 days. Virus-positive volunteers receiving placebo by both of the two routes had a peak in clinical illness scores on the second treatment day (mean score 5.3), which was not observed in either the aerosol rimantadine (0.6) or oral rimantadine (0.9) treated volunteers. On the second treatment day, the proportion of virus-positive volunteers with elevated axillary temperature measurements and the mean peak temperature measurement were also significantly reduced in both drug groups. No significant effects on the duration of virus shedding were noted. In experimental influenza A virus infection, characterized by mild clinical illness and short duration of virus shedding, low doses of aerosolized rimantadine had a therapeutic effect comparable to that found with larger doses of oral rimantadine.

Correlation of solar microwave and soft X-ray radiation: 2. The burst component

A study of the histories of solar flares observed at 2 cm at the North Liberty Radio Observatory of the University of Iowa and observed at X-ray wavelengths with Mariner 5 (2–9 A) and Explorers 33 and 35 (2–12 A) shows that ‘post-burst increase’ and ‘gradual rise and fall’ events are concurrent microwave and soft X-ray phenomena. The correlation between the X-ray flux and the radio flux is high but nonlinear. The character of the correlation is consistent with a thermal flare theory in which the volume emissivity at X-ray wavelengths is of the spectral form (dE/dν) ∼ exp(-hν/kT) and the radio flux is from the same region that is optically thick with a temperature T. The correlation yields the peak flare temperature, Tp, and the flare solid angle in terms of the fractional increase in temperature relative to the peak temperature, F = δT/Tp. Comparing flare sizes with those obtained by other means (e.g., X-ray telescopes) shows F > 0.2. If free-free emission is assumed responsible for both the X-ray and the radio emissions, an F ∼ 0.5 is consistent with the initial assumptions, whereas an F ∼ 1.0 is not. Thus, temperatures typically double during a flare. Of twenty cases studied, an F = 0.5 yielded a mean peak temperature of 4 million degrees Kelvin and a mean effective diameter of 32 arc seconds.

The diffusion of heat spots in isotropic turbulence

A technique has been developed for the production of small heat spots in the turbulent flow behind bi-plane square-mesh grids, and their distribution downstream of the point of production has been studied using a Wollaston wire-resistance thermometer of response time 0.0002 sec. The transverse spatial distribution function is found to be a Gaussian error function (within the limits of experimental error) at all distances, in agreement with previous results on the temperature wake of a long thin wire. It is possible to determine a mean peak temperature of the spots by measuring the probability that the production of a spot will subsequently raise the temperature at the detector by more than a threshold value as a function of that value. The mean peak temperature is found to decrease with distance downstream more rapidly in turbulent flow than in non-turbulent flow, the observed temperatures being in quantitative agreement with those computed by assuming a spatially uniform rate-of-strain over the volume occupied by the spot. Since the extended spot is too large for this assumption to be literally true, it is concluded that, in the final form, the heat is probably concentrated in a contorted thin layer, and that, following the spot, the shear pattern remains nearly constant in type, decaying aperiodically with the turbulence.