Medical students' distress--quality, continuity and gender differences during a six-year medical programme.

Research observations suggest an increase in distress during the course of medical education, but it is not known whether this distress is chronic and persistent or episodic because follow-ups covering the whole training programme are lacking. We explored stress symptoms among undergraduate medical students (n = 110) at five points during the six-year medical training programme. The quality and continuity of symptoms and gender differences in stress reports were analysed. Questionnaire and interviews were used to assess stress symptoms, perceived health and severity of distress. Stress symptoms, such as fatigue, sleeping problems, anxiety, irritability and depression, were common. No significant gender differences were seen, but there was a consistent increase of stress reports throughout the medical programme in both sexes. Those who were most distressed at the beginning of training also reported more stress later. To conclude, we need interventions that help students to cope with stress, to make a smooth transition from school to medical school, and also to adjust to different learning environments during the different phases of medical education.

The effect of adenoidectomy on occlusal development and nasal cavity volume in children with recurrent middle ear infection.

OBJECTIVES: The aim of the study was to examine the effect of adenoidectomy on occlusal/dentoalveolar development and nasal cavity volume in children who underwent tympanostomy tube insertion with or without adenoidectomy due to recurrent episodes of middle ear infection. METHODS: This prospective controlled study consisted of two randomly allocated treatment groups of children, younger than 2 years, who had underwent more than 3-5 events of middle ear infection during the last 6 months or 4-6 events during the last year. At the mean age of 17 months tympanostomy tube placement without adenoidectomy (Group I, n=63) tympanostomy tube placement with adenoidectomy (Group II, n=74) was performed. At the age of 5 years 41 children of the original Group I (14 females, 27 males, mean age 5.2 yrs, SD 0.17) and 59 children of the original Group II (17 females, 42 males, mean age 5.2 yrs, SD 0.18) participated in the re-examination, which included clinical orthodontic examination defining morphological and functional craniofacial status and occlusal bite index to measure upper dental arch dimensions. Acoustic rhinometry and anterior rhinomanometry was made by otorhinolaryngologist at the same day. RESULTS: No statistically significant differences were found between the groups in the frequencies of morphological or functional characteristics or upper dental arch measurements or in the minimal cross-sectional areas or inspiratory nasal airway resistance measurements. CONCLUSION: Combining adenoidectomy with tympanostomy tube insertion in the treatment of recurrent middle ear infection at an early age (under the age of 2 years) does not seem to make any difference in occlusal development in primary dentition at the age of 5 years as compared to tympanostomy tube insertion only. Since adenoid size was not evaluated, the findings do not allow interpretation that hypertrophic adenoids should not be removed in children with continuous mouth breathing or sleep disordered breathing.

Tissue relaxation enhancement after intravenous administration of (ITCB-DTPA)-gadolinum conjugated albumin, an intravascular magnetic resonance imaging contrast agent.

Gadolinium-isothiocyanato-benzyl-diethylenetriamine pentaacetic acid (ITCB-DTPA-Gd), a derivative of Gd-DTPA, was multiply conjugated to bovine serum albumin (BSA). In the synthesis of BSA-(ITCB-DTPA-Gd) conjugate, none of the five carboxylate groups of DTPA is functionalized for protein-chelate linkage. The rationale for this modification is to improve the affinity for Gd3+. We obtained a high-stability constant for the complex, comparable to unbound Gd-DTPA. Also, the complex had a T1 relaxivity as high as 30.3 seconds-1mmol-1 at 29 MHz (at 24 degrees C). At this field strength, and T1 of rat blood declined 91% after injection of 300 mg/kg of BSA-(ITCB-DTPA-Gd), corresponding to a Gd dose of 0.02 mmol/kg, while at 0.86 MHz it declined 64%. The shortening of T1 in vitro of blood, as well as spleen, lungs, and kidneys, persisted for 60 minutes. Better enhancement on post-contrast magnetic resonance images of rats was obtained at 1.0 T than at 0.04 T. Tissues with rich vascularization and large venous structures were well displayed at the higher field.

Magnetic field dependence of longitudinal relaxation rates of solutions of various protein-gadolinium3+ chelate conjugates.

Bovine serum albumin (BSA) and porcine serum fibrinogen (FIB) were multiply labeled with gadolinium3+ by using three different ligands: DTPA dianhydride, isothio-cyanato-benzyl-DTPA (ITCB-DTPA), in which none of the five coordinating carboxylates is employed for macromolecular linkage, and isothiocyanatobenzyl-TRITA, a macrocyclic ligand. The nuclear magnetic resonance dispersion (NMRD) profiles of the protein-(Gd chelate) conjugates were characteristic to each chelate involved, possessing, as expected, greater longitudinal relaxivities than the corresponding Gd chelates alone and exhibiting prominent peaks at the proton Larmor frequency range of 10 to 40 MHz. Particularly favorable relaxation enhancement was measured in the solutions of BSA-(ITCB-DTPA-Gd) at this field range. When the number of chelates conjugated with protein increased, up to 163 Gd chelates per one fibrinogen, a progressive decrease in relaxivity was observed. This study demonstrates the relaxation properties of novel macromolecular contrast agents designed for magnetic resonance imaging.

Comparative pharmacokinetics of gadolinium DTPA and gadolinium chloride.

An intravenous injection of 153Gd-labeled gadolinium-DTPA or gadolinium chloride was given to 60 rats, which were killed either 15, 40, 120, 300, 900, or 3600 seconds later. Tissue concentrations of gadolinium in the blood, liver, spleen, stomach, pancreas, renal cortex, renal medulla, lungs, heart, adrenals, gluteal muscle, fat, skin, thymus, brain, thyroid, and parathyroids were measured. Five animals were killed at each time interval with gadolinium-DTPA, and at each of the latter four time intervals (15 and 40 seconds excluded) with gadolinium chloride. The pharmacokinetics of gadolinium-DTPA and chloride differ markedly in terms of tissue concentration, distribution volumes, and the time course of these parameters. Gadolinium, when injected as a chloride, evidently forms insoluble carbonate and phosphate precipitates in the blood, which are taken up by the reticuloendothelial system. The distribution of gadolinium-DTPA on dynamic MRI should closely parallel the distribution of iodinated contrast media on dynamic computed tomography.

The utility of contrast media in MRI at 0.02 T. A preliminary report.

The effect of 0.1 mmol gadolinium-DTPA on ultralow field magnetic resonance (MR) images of intracranial neoplasms was studied on 20 patients. Tumors that characteristically were enhanced markedly on computed tomography (CT) (meningiomas, acoustic neuromas) demonstrated moderate to marked contrast enhancement with inversion recovery sequences and with saturation recovery sequences with a short repetition time. Standard spin-echo sequences failed to show any contrast effect. The enhancement of gliomas and metastases was weak and often absent. Contrast enhancement, when present, was helpful in delineating the tumor from surrounding edema but the differentiation of living from necrotic tumor was not successful because of low signal intensity. The low effect of gadolinium-DTPA at 0.02 T may be due to a relatively higher T2 weighting of available pulse sequences. The relaxing effect of macromolecules may also change the proportional effect of paramagnetic substances in an ultralow magnetic field.

The normal faecal microflora does not affect the adhesion of probiotic bacteria in vitro.

Adhesion of probiotic microorganisms to the intestinal mucosa is considered important for many of the reported health effects. The influence of the endogenous microflora on the adhesion of four probiotic lactobacilli to immobilised intestinal mucus was investigated. It was observed that pre-treatment of the immobilised mucus with faecal extract slightly increased the adhesion of Lactobacillus GG. Pre-treatment of the immobilised mucus with faecal bacteria did not affect the adhesion of the tested strains. These results suggest that the normal microflora may not greatly affect the initial adhesion of the probiotic bacteria. This validates the results of earlier reports where the influence of the normal microflora was not taken into account.

MR of intracranial tumors: combined use of gadolinium and magnetization transfer.

PURPOSE: To study the potential combined application of gadolinium and magnetization transfer in the MR imaging of intracranial tumors. METHODS: Twenty-two patients were imaged at low field strength (0.1 T). Corresponding gradient-echo partial saturation images without and with magnetization transfer pulse were produced. Images with intermediate repetition times were obtained in 18 cases; five different sequences were produced in 4 cases. Gadopentetate dimeglumine was used at a dose of 0.1 mmol/kg. RESULTS: Magnetization transfer effect increased the contrast between enhancing lesion and normal brain and the contrast between edema and normal brain; the contrast between enhancing lesion and edema was not significantly changed. On intermediate-repetition-time magnetization transfer images the contrast between enhancing tumor and normal brain and the contrast between edema and normal brain were superior to short-repetition-time magnetization transfer images, but the differentiation between enhancing tumor and edema was poorer. CONCLUSION: Magnetization transfer can be used to improve contrast in Gd-enhanced MR imaging. Combining magnetization transfer with an intermediate-repetition-time image provides the possibility for displaying both enhancing and nonenhancing lesions on a single MR image.

Echo-planar MR determination of relative cerebral blood volume in human brain tumors: T1 versus T2 weighting.

PURPOSE: Maps related to relative cerebral blood volume (rCBV) were generated with the use of the T1 effects produced by a low-dose bolus passage of gadopentetate dimeglumine. The T1 maps were evaluated in a tumor population and compared with rCBV maps obtained with T2-weighted measurements. METHODS: Imaging was performed in 19 patients with suspected intraaxial brain tumors. For the T1 rCBV maps, a low-dose bolus of contrast material was given during T1-weighted interleaved spin-echo echo-planar MR imaging. This was followed by a second injection during serial T2-weighted imaging for generation of the T2 rCBV maps. RESULTS: Among patients with low-grade lesions (n = 9), T1-based and T2-based rCBV maps showed comparably low rCBV in 7 subjects. In the other 2 patients, with confirmed tumor dedifferentiation, elevation of rCBV values was seen on maps obtained with both techniques. Among patients with high-grade tumors (n = 10), 4 had no evidence of recurrence and 6 did have tumor recurrence (confirmed by follow-up and positron emission tomography). In patients with the high-grade lesions exhibiting conventional contrast enhancement, lesions tended to have higher estimated values on T1 rCBV maps than on the T2 rCBV maps. CONCLUSION: Although the T1 rCBV maps showed less contrast as compared with the T2 rCBV maps, they provided diagnostic information that was comparable to the T2 rCBV maps in our series of 19 patients with primary brain tumors.

Reading long words embedded in sentences: informativeness of word halves affects eye movements.

The possibility was explored that the informativeness of a specific region within a word can influence eye movements during reading. In Experiment 1, words containing identifying information either toward the beginning or toward the end were displayed asymmetrically around the point of fixation so that the reader was initially presented with either the informative or noninformative zone. Words were read with shorter summed initial fixation time when the reading was started from the informative zone. In Experiments 2 and 3, the target words were presented in sentences that were to be comprehended. More attention was given to the informative endings of words than to redundant endings. The latter were also skipped more often. The duration of the first fixation was not affected by information distribution within the word, whereas the second fixation duration was. The results of these experiments lend good support to the hypothesis of immediate lexical control over fixation behavior and to the notion of a convenient viewing position.

Neuroticism and the pupillary response to a brief exposure to noise.

'Neurotic' and 'stable' groups (n = 8) were formed by means of the Finnish version of the Eysenck Personality Inventory. Subjects were exposed individually to 80-100 dBA broadband noise. No overt response was made. The dependent variable was the pupil dilation. The louder the noise, the larger the pupil was. At each level of noise intensity, the dilation was largest immediately after the change of intensity. In general, the pupil size decreased in the course of the experiment, indicating habituation. The 'neurotic' subjects displayed the largest relative dilation as a function of noise intensity. Results are discussed in terms of the arousing effects of auditory stimulus intensity.

Event-related brain potentials and the perception of a phonetic continuum.

Competing predictions concerning phoneme discrimination were tested by means of event-related potentials. In research on speech perception, one tradition stems from the physiology of the auditory system whereas another emphasizes categorical perception which involves a marked psychological component. The stimuli were the end points of the Finnish (i)-(y) continuum together with the intermediate boundary sound. Two of these stimuli were presented in each block of trials. One (the 'standard') had a high probability while the other (the 'deviant') was rare. The so-called mismatch negativity (MMN) component of the ERP in response to deviant stimuli showed a large amplitude and short latency when these two stimuli were pure vowels (i) and (y). When the boundary stimulus and one of the pure vowels comprised the stimulus pair, a smaller and more delayed MMN occurred. This result may be taken as support that the discrimination occurs at a basic physiological level. On the other hand, cognitive perception was reflected in the different latencies of the P3 component to (i) and (y). In sum, the results lend support to multilevel hybrid models in the explanation of vowel perception.

Determination of saturation transfer parameters of human tissues in vivo.

In order to study the applicability of magnetization transfer contrast (MTC) to tissue differentiation, the determination of the magnetization transfer (MT) parameters of normal tissues is necessary for the evaluation of pathological conditions. The time-dependent saturation transfer technique was used to investigate the observed magnetization transfer parameters in several human tissues in vivo at 0.1 T. The length of the off-resonance saturation pulse varied from 0 to 750 ms. The magnetization transfer contrast (MTC) was 0.71 in striated muscle, 0.49 in liver, 0.49 in renal cortex, and 0.50 in spleen. The observed magnetization transfer rates (Rwm) were 5.5 s-1 for muscle, 3.1 s-1 for liver, and 1.5 s-1 for both renal cortex and spleen. Our results indicate that measuring Rwm and possibly other relaxation parameters could be useful in tissue differentiation.

Negative gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles at 0.02 Tesla.

Gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles were evaluated in vitro and in rabbits at 0.02 Tesla. Test tubes containing 0.01-1.0 mg particles/ml were imaged in an oil or water bath in order to demonstrate the concentration-dependent signal void and image distortion in vitro at several pulse sequences. The lowest concentration of particles tested clearly decreased the signal intensity. Image distortion was observed when the concentration exceeded 0.07 mg/ml and was more pronounced on the T2-weighted images. The in vitro T2 relaxation time decreased from 122 ms to 56 ms with an increase in the particle concentration from 0.01 to 0.06 mg/ml. A loss of the GI-tract signal was observed in rabbits after the administration of 1 mg particles/kg, given as a 0.03 mg/ml suspension. At a dose of 20 mg/kg (0.6 mg/ml suspension) significant image distortion was observed.

T1rho dispersion of rat tissues in vitro.

The purpose of this study was to demonstrate T1rho dispersion in different rat tissues (liver, brain, spleen, kidney, heart, and skeletal muscle), and to compare the 1/T1rho data to previous 1/T1 data and magnetization transfer of rat tissues at low (0.1 T) B0 field. The 1/T1rho dispersion showed a fairly similar pattern in all tissues. The highest 1/T1rho relaxation rates were seen in liver and muscle followed by heart, whereas the values for spleen, kidney, and brain were quite similar. Compared to 1/T2 relaxation rate, the greatest difference was seen in liver and muscle. The rank order 1/T1rho value at each locking field B1 was the same as the transfer rate of magnetization from the water to the macromolecular pool (Rwm) for liver, muscle, heart, and brain. The potential value T1rho imaging is to combine high T1 contrast of low field imaging with the high signal to noise ratio of high static field imaging. When the T1rho value for a given tissue is known, the contrast between different tissues can be optimized by adjusting the locking time TL. Further studies are encouraged to fully exploit this. Targets for more detailed research include brain infarct, brain and liver tumors.

Imaging perfusion deficits in ischemic heart disease with susceptibility-enhanced T2-weighted MRI: preliminary human studies.

AIM: This feasibility study explores relative myocardial perfusion characterization with an investigational T2/T2 contrast agent. METHODS: Dysprosium-DTPA bis (methylamide) was administered peripherally in six patients with thallium defects. Rest and stress multi-section, gated, T2-weighted images were acquired with a 1.5 T echo-planar imager. Change in transverse relaxation rate was calculated in four segments for each subject. RESULTS: Magnetic resonance (MR) identified five of five instances of ischemia or infarction, at a dose of agent (0.25 mmol/kg) that was comparable to that currently used with clinically approved gadolinium agents. Injection at twice this dose resulted in saturation of the signal change, and the one ischemic segment corresponding to the higher dose was not identified by MR. MR was negative in two segments which, on final diagnosis, were determined to manifest thallium attenuation artifact. CONCLUSION: MR perfusion imaging with high susceptibility agents has the potential to characterize myocardial perfusion deficits.

Secondary otalgia in an adult population.

OBJECTIVE: To analyze the associations of secondary otalgia with general health, stress, insomnia, bruxism, and recurrent head and neck region pains. DESIGN: A population-based survey. SETTING: General community. SUBJECTS: A total of 391 randomly selected subjects (186 men, 205 women) aged 25, 35, 45, 55, or 65 years. METHODS: Standardized interview and self-report questionnaires of general health and stress. RESULTS: Otalgia was statistically significantly associated with all the studied factors. However, in the whole study group, independent predictors of otalgia were the obvious need for temporomandibular disorder treatment, high frequency of stress symptoms, and bruxism. When analyzed in women, the predictors of otalgia were the obvious need for temporomandibular disorder treatment, high frequency of stress symptoms, and age. When analyzed in men, recurrent neck pain was a predictor of otalgia. CONCLUSIONS: We suggest that after ruling out otorhinolaryngologic infectious diseases and temporomandibular disorder in patients with secondary otalgia, the next step is to explore the frequency of stress symptoms, bruxism, and recurrent neck pain. Furthermore, women and men may need a different approach in diagnostics of secondary otalgia. By diagnosing and treating these predictors of otalgia, it may be possible to reach a more successful outcome.

Self-reported symptoms of stress in Finnish patients with craniomandibular disorders.

This study compared the stress reports of Finnish craniomandibular disorder patients and nonpatients by using the Symptoms of Stress Inventory as a screening device. A comparison of Finnish and American craniomandibular disorder patients' stress reports was made in the same manner. The overall stress level of craniomandibular disorder patients was higher than that of nonpatients. The patients had elevated scores on somatic subscales, with muscle tension symptoms being the most characteristic. These results are in accordance with American results. However, statistically significant differences were not found for emotional symptoms.

TMD treatment need in relation to age, gender, stress, and diagnostic subgroup.

Associations between treatment need for temporomandibular disorders (TMD) and age, gender, stress, and diagnostic subgroup were analyzed in an adult Finnish population sample of 506 subjects. When analyzed separately, the association between TMD treatment need and all the studied factors was statistically significant. This finding is in accordance with earlier results. When the studied factors were included into an explanatory model, however, the picture changed. The logistic regression analysis revealed that diagnostic subgroup was the strongest predictor for the TMD treatment need. Total stress score significantly added to the explanatory power of the model, but age and gender did not. The commonplace observation that women show more signs and symptoms of TMD seems to be explainable by their higher stress scores and by the type of symptoms.

Eye movements during repeated reading of a text.

The facilitation of eye movements was studied in two experiments involving a repeated reading paradigm. A text was read three times. Initial reading was immediately followed by the first repetition; the second repetition took place one week later. Recall task instructions were used to encourage a detailed reading of the text. The data were analysed sentence by sentence from the 'first pass' readings not including returns to earlier test locations. A general facilitation for all eye movement parameters was found. Repetition decreased the summed fixation time, the average fixation duration, the number of progressive fixations, and the number of regressions. Additionally, repetition increased saccade lengths. Experiment 2 further qualified the general facilitory effect. The middle section of the text, being the most dense of information, was devoted the most visual attention by the readers. Moreover, it was also found to produce the largest degree of facilitation due to repetition. This was true with all other eye movement parameters except saccade length and average fixation duration. Average fixation durations were longer in the beginning of a text than in the end. This was true in all the three readings. Similarly, for each reading, highly important sentences received more visual attention than unimportant sentences.