Safety assessment of consumption of glabrous canary seed (Phalaris canariensis L.) in rats.

Canary seed is a nutrient-rich cereal grain; however, it has not been used in human food in part due to concerns regarding safety of consumption. Glabrous or hairless canary seed has potential human food use as trichomes are absent. The objective of the oral feeding studies reported here was to assess the safety of yellow and brown glabrous canary seed cultivars as human cereal foods. The first study was a 90-day rat oral toxicity study, which compared the effects of diets containing 50% of either brown dehulled glabrous, brown hulled glabrous, or brown hulled pubescent (hairy) hulled canary seed to a diet containing 50% wheat. No significant adverse effects were observed. In a 28-day and a 90-day study rats were fed yellow or brown glabrous canary seed groats in the AIN-76 diet at concentrations levels of 2.5%, 5% and 10%. The NOAELs in 90-day study were 5.15 g/kg/d and 5.23 g/kg/d for yellow and brown canary seed groats. Consumption of canary seed was associated with reduced incidence and severity of liver lipidosis as compared to controls. The combined results of these studies clearly demonstrate the safety of consumption of glabrous canary seed, and support its use as a human cereal grain.

Ten-year myringoplasty series: does the cause of perforation affect the success rate?

OBJECTIVE: To present the results of primary myringoplasty procedures together with the perforation cause, perforation size and site, surgeon's experience, and surgical method, and to investigate how these factors relate to graft 'take' rates. STUDY DESIGN: Retrospective chart review of 243 consecutive patients undergoing primary myringoplasty with temporalis fascia underlay over a 10-year period from 1994 to 2004. RESULTS: The overall graft take rate was 95 per cent. The retroauricular approach resulted in a 97 per cent graft take rate, whereas a significantly lower rate (77 per cent) was seen for surgery conducted via the endaural approach, or via an ear speculum. There was no relationship between other factors and tympanic membrane healing. CONCLUSION: No association was found between perforation cause and graft take rate. The underlay technique is safe and reliable, and the retroauricular approach is preferable as it enables good surgical access and has better results.

Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies.

Aspartame is a methyl ester of a dipeptide used as a synthetic nonnutritive sweetener in over 90 countries worldwide in over 6000 products. The purpose of this investigation was to review the scientific literature on the absorption and metabolism, the current consumption levels worldwide, the toxicology, and recent epidemiological studies on aspartame. Current use levels of aspartame, even by high users in special subgroups, remains well below the U.S. Food and Drug Administration and European Food Safety Authority established acceptable daily intake levels of 50 and 40 mg/kg bw/day, respectively. Consumption of large doses of aspartame in a single bolus dose will have an effect on some biochemical parameters, including plasma amino acid levels and brain neurotransmitter levels. The rise in plasma levels of phenylalanine and aspartic acid following administration of aspartame at doses less than or equal to 50 mg/kg bw do not exceed those observed postprandially. Acute, subacute and chronic toxicity studies with aspartame, and its decomposition products, conducted in mice, rats, hamsters and dogs have consistently found no adverse effect of aspartame with doses up to at least 4000 mg/kg bw/day. Critical review of all carcinogenicity studies conducted on aspartame found no credible evidence that aspartame is carcinogenic. The data from the extensive investigations into the possibility of neurotoxic effects of aspartame, in general, do not support the hypothesis that aspartame in the human diet will affect nervous system function, learning or behavior. Epidemiological studies on aspartame include several case-control studies and one well-conducted prospective epidemiological study with a large cohort, in which the consumption of aspartame was measured. The studies provide no evidence to support an association between aspartame and cancer in any tissue. The weight of existing evidence is that aspartame is safe at current levels of consumption as a nonnutritive sweetener.

Oral developmental toxicity study of methylsulfonylmethane in rats.

Methylsulfonylmethane (MSM) is a metabolite of dimethyl sulfoxide, and occurs naturally at low levels in many foods. MSM has received wide attention as a dietary supplement to promote joint health. The objective of these studies was to determine the developmental toxicity potential of MSM when administered orally to pregnant rats during the period of major organogenesis and histogenesis. In a preliminary dose-finding study, distilled MSM microprill (i.e., microspherical pellets of MSM) was administered by oral gavage at dose levels of 0 (vehicle control), 50, 250, 500, and 1000 mg/kg/day to 8-9 sperm-positive female Sprague-Dawley rats/group/day on gestation days 6-20. No evidence of maternal or fetal toxicity was observed. For the definitive developmental study, four groups of 24-25 timed-bred primiparous female rats were administered 0, 50, 500, or 1000 mg MSM/kg/day via gavage on gestation days 6-20. Maternal feed consumption, body weight, body weight gain, uterus weight and corrected body weight/body weight gain were unaffected by treatment. No evidence of maternal toxicity, and no significant differences in litter viability, litter size, or litter body weight were detected. Fetal evaluations failed to show any biologically significant increase in the incidence of anomalies in the MSM treated groups, and no malformations were seen in any of the fetuses. No evidence of fetal mortality, alterations to growth, or structural alterations were observed in the fetuses of dams administered 50-1000 mg/kg/day. Therefore, under the conditions of this study, the no-observed-adverse-effect level (NOAEL) for maternal and developmental toxicity was 1000 mg/kg/day.

Enhanced estrogenic responses and sensitivity to azoxymethane following dietary soy isoflavone supplementation in older female rats.

Soy isoflavones are popular supplements among middle-aged and older women based on their potential protection against cancer and their use as alternative hormone replacement therapy. The purpose of this study was to investigate the effects of dietary soy isoflavones on early stage colon cancer in various ages of female rats. Young (1month), mature (11month) and old (22month) female Fisher 344 rats were fed either the control diet or a diet containing 0.4% soy isoflavone isolate for 1week, injected once with 20mg/kg azoxymethane (AOM) and maintained on the diets for another 15weeks. The concentration of isoflavones in the diet was 2g/kgdiet, composed of 1.2g/kg genistin, 0.7g/kg daidzin and 0.1g/kg other isoflavones including glycitin, acetylgenistin, acetyldaidzin, genistein, daidzein, and glycitein. There was no difference over all ages in the development of preneoplastic colonic aberrant crypt foci between rats fed the soy compared to the control diet, indicating that the soy diet did not provide protection against early stage colonic carcinogenesis. On the contrary, several adverse effects of soy supplementation in female AOM-treated rats were observed. Soy-supplemented rats had greater weight loss and a slower recovery of body weight following the AOM injection compared to rats fed the control diet and these changes increased with age. Five of the 21 rats fed the soy supplement died before the end of the experiment while all animals on the control diet survived to term. The density of normal crypts lining the colonic mucosa was reduced in rats fed the soy compared to control diet, indicating gastrointestinal damage. Uterine weights, serum estradiol and serum isoflavone levels were increased in mature and old female rats fed the soy-supplemented diets compared to age-matched controls, suggesting an increasing estrogenic response with age to isoflavone supplementation. These adverse effects of soy isoflavones in aged female animals need further examination because women, and particularly older women, are the prime target population for consumption of soy supplements.

Speech recognition in background noise: monaural versus binaural listening conditions in normal-hearing patients.

HYPOTHESIS: Patients with unilateral conductive hearing impairment often experience a great advantage in improved hearing thresholds after reconstructive ear surgery because the binaural hearing leads to increased speech recognition in competing noise. The aim of this study was to develop a clinical audiometric test to quantify the ability of speech recognition in background noise preoperatively and postoperatively. METHODS: A model consisting of phonetically balanced (PB) monosyllabic words and/or a just-follow-conversation test (JFC) was used in 16 normal-hearing listeners. In 8 of the participants, JFC at two levels of background noise (60 and 40 dB sound pressure level) was used as the only method. The tasks were performed in an anechoic chamber with varying spatial separations of speech and noise sources under free field conditions. The tests were made binaurally and monaurally; the latter condition was achieved by occluding one ear with a hearing protector. In PB word tests, the percent of correctly repeated words was scored. In the JFC task, the speech signal was adjusted by the listener to a level where he or she could just understand what was being said. This was expressed as a signal-to-noise (S/N) ratio. RESULTS: In both types of tests, the subjects achieved significantly better speech recognition scores in the binaural situations. In summary, compared with monaural conditions, the subjects achieved 17% to 18% better speech recognition in PB tests, and in JFC tests a 2-to 3-dB lower S/N ratio in binaural conditions. CONCLUSION: These free field tests can be developed further as a clinical tool preoperatively and postoperatively to evaluate the effect of binaural hearing after ear surgery.

Calmodulin-binding protein detection using a non-radiolabeled calmodulin fusion protein.

Calmodulin-binding proteins are involved in numerous cellular signaling pathways. The biotinylated-calmodulin overlay is a nonradioactive method widely used to detect calmodulin-binding proteins in tissue and cell samples. This method has several limitations; therefore, we developed a nonradioactive calmodulin-binding protein detection overlay using an S-tag-labeled calmodulin fusion protein. An expression system was used to generate a calmodulin fusion protein with an S-tag label, a 15 amino acid sequence that binds to a 105 amino acid S-protein. The S-protein is conjugated to horseradish peroxidase for final detection with a chemiluminescent substrate. The S-tag calmodulin was compared to purified calmodulin and biotinylated calmodulin in a calmodulin-dependent phosphodiesterase assay. The results of the calmodulin-dependent phosphodiesterase assay indicate that S-tag calmodulin induces higher phosphodiesterase activity than biotinylated calmodulin and lower activity than purified calmodulin. A comparison of the biotinylated and S-tag calmodulin overlay assays indicate that S-tag calmodulin is more sensitive than biotinylated calmodulin in the detection of calcineurin, a known calmodulin-binding protein. The overlay assay results also indicate that the S-tag calmodulin and biotinylated calmodulin detect similar calmodulin-binding proteins in colon epithelial cells. In conclusion, the S-tag calmodulin overlay assay is a consistent, sensitive, and rapid nonradioactive method to detect calmodulin-binding proteins.

Effects of indole-3-carbinol on immune responses, aberrant crypt foci, and colonic crypt cell proliferation in rats.

Male Sprague-Dawley rats were treated orally with indole-3-carbinol (13C) for 7 wk at levels of 150, 100, and 50 mg/kg body weight. The rats were injected with 10 mg/kg body weight of the colon carcinogen, azoxymethane (AOM) on d 2 and 9 of 13C treatment. At termination of the study, all rats were assessed for immune function (humoral immunity, specific cell-mediated immunity, and nonspecific cell-mediated immunity). Colonic tissue was collected and examined for the presence of aberrant crypt foci (ACF) and proliferation of crypt cells. Antibody responses to antigen challenge were significantly suppressed in the animals exposed to the high dose of 13C. Delayed-type hypersensitivity responses, natural killer cell activity, the number and multiplicity of ACF, and cell proliferation parameters were not significantly different from those of the controls. Therefore, there was no clear protective or enhancing effect of 13C on ACF numbers or colonic cell proliferation indices. There was no strong correlation between changes in immune responses and the preneoplastic biomarkers of colon cancer.

Eustachian tube function varies over time in children with secretory otitis media.

Impaired opening and closing functions of the Eustachian tube are considered to be pathogenic factors in secretory otitis media (SOM). As the clinical course of SOM is variable, the variability of tubal function is of interest. We aimed to explore the short- and long-term variability of tubal opening and closing functions in SOM. The study comprised 42 ears in 21 children (13 males and 8 females) with tympanostomy tubes due to SOM. The middle ear pressure was recorded during repeated passive forced openings, equalization of + 100 daPa and - 100 daPa by swallowing, Valsalva inflation and forceful sniffing. Test sessions were performed twice (separated by 30 min) on each of 2 days, with a mean interval of 3.7 months in between. In the forced opening test there was a considerable intra-individual variability over time. Expressed as SD of the mean, the variability of the forced opening and closing pressures in individual ears was on average 15% and 23%, respectively, between sessions and 20% and 30% respectively, between test days. In the equalization, Valsalva and sniff tests the rates of responses that changed from positive to negative between sessions and test days ranged from 12% to 33%. Female gender and retraction pockets were related to poorer opening function in the forced opening test. Ears with serous effusion (in contrast to mucoid) showed a similar trend and also a lower occurrence of positive equalization, Valsalva and sniff tests. It was concluded that Eustachian tube opening and closing functions are highly variable in ears with SOM. Consequently, single tubal function tests have low value when used as a prognostic tool in individual ears.

Increased susceptibility of adult rats to azoxymethane-induced aberrant crypt foci.

The purpose of this study was to compare azoxymethane-induced aberrant crypt foci development in the colons of young and adult rats. Young (4 weeks of age) and adult (50 weeks of age) Sprague-Dawley rats were treated with two weekly injections of azoxymethane or saline. Rats were killed either 6 or 14 weeks following the first injection, and the number, size and location of aberrant crypt foci were determined. At both the 6- and 14-week time points, the number of aberrant crypt foci in older rats was significantly greater than in young rats (P<0.01). A higher percentage of aberrant crypt foci were found in the region from the mid-colon to the cecum in older rats as compared to young rats. Colonic cell proliferation was evaluated using bromodeoxyuridine immunohistochemistry. Colonic cell proliferation indices in the rectal, mid-colon and cecal regions of young and older rats were similar in young compared to adult rats. Ten large ACF from each group were screened for mutations in the beta-catenin gene (Ctnnb1) by PCR single strand conformation polymorphism. No mutations were detected. These results demonstrate that older female rats are more susceptible to the induction of aberrant crypt foci by azoxymethane than young female rats. Differences in colonic cell proliferation or beta-catenin mutations in these two age groups do not appear to be responsible for differences in aberrant crypt foci development.

On the physics of the infant feeding bottle and middle ear sequela: ear disease in infants can be associated with bottle feeding.

BACKGROUND: When using conventional feeding bottles, negative pressure is generated in the oral cavity, as well as, in the bottle when fluid is removed by sucking. The negative pressure inside the bottle causes the infant to suck excessively and the intraoral negative pressure may subsequently be transmitted to the middle ear via the eustachian tube. METHODS: in seven infants, simultaneous pressure recordings were performed in the feeding vessel and the middle ear using three types of feeding bottles. RESULTS: with conventional non-ventilated and under-ventilated bottles a negative pressure formed while the infant sucked and negative intratympanic pressure was frequently generated. CONCLUSIONS: it is suggested that this sequence of events may lead to secretory otitis and it's accompanying consequences. In contrast, a fully ventilated bottle showed positive pressure throughout the feeding procedure, which is similar to normal breast-feeding, and negative pressure changes were not recorded in the middle ear.

Variability of Eustachian tube function: comparison of ears with retraction disease and normal middle ears.

OBJECTIVE: To explore the short-term and longterm variability of tubal opening and closing in ears with advanced retractions and in healthy ears. STUDY DESIGN/METHODS: Twenty ears with retraction type middle ear disease (R-MED) and 20 normal ears underwent direct recording of the middle ear pressure during repeated forced openings, equalization of +100 daPa and -100 daPa by swallowing, Valsalva inflation, and forceful sniffing. Tests were performed twice (separated by 30 min) on each of 2 days separated by 3 to 4 months. RESULTS: There was considerable intraindividual variability of the forced opening pressure and the closing pressure in both groups, within as well as between sessions and test days. Although the variability was 1.5 to 2 times higher in ears with retraction than in the normal group, mean Po and Pc did not differ between the groups. Compared with normal ears, ears with retraction changed more frequently from a positive to negative test response, or vice versa, when re-tested after 30 minutes. Rates of positive response in the equalization and Valsalva tests were significantly lower in diseased ears compared with normal ears. CONCLUSIONS: Eustachian tube opening and closing functions vary more in ears with retraction disease than in normal ears, which is consistent with the variable clinical course of R-MED and implies that single tubal function tests have little prognostic value on the individual level.

Ruminant gastrointestinal cell proliferation and clearance of Escherichia coli O157:H7.

Human infections with Escherichia coli O157:H7 cause hemorrhagic colitis that can progress to a life-threatening sequelae. The most common mode of disease transmission is ingestion of contaminated bovine food products, and it is well established that E. coli O157:H7 is a transient member of the bovine microbiota. However, the conditions that induce acquisition and subsequent clearance of this bacterium from the ruminant gastrointestinal tract (GIT) are not understood. Evidence that the rates of epithelial cell proliferation in the lower GIT of cattle are associated with the duration animals remained E. coli O157:H7 culture positive is presented. Cattle with slower rates of intestinal cell proliferation in the cecum and the distal colon were culture positive significantly longer than cohort cattle with faster cell proliferation rates. Cell death rates (apoptotic indices) between the short- and long-term culture-positive animals were not different. Typical grain-based finishing diets and forage-based growing diets did not effect GIT cell proliferation or the duration animals remained E. coli O157:H7 culture positive. To identify a dietary intervention that would effect GIT cell proliferation, we used sheep as a model ruminant. A fasting-refeeding regime that increased the rate of GIT cell proliferation was developed. The fasting-refeeding protocol was used in cattle to test the hypothesis that feeding interventions that increase the rate of GIT cell proliferation induce the clearance of E. coli O157:H7 from the bovine GIT.

Variability of Eustachian tube function in children with secretory otitis media. Evaluations at tube insertion and at follow-up.

OBJECTIVE: Despite the variable clinical course of diseases related to Eustachian tube function, the variability of tubal function has been less focused than outcomes of single tests. This study aimed to compare the passive and active tubal function and its variability in children with secretory otitis media (SOM) at tube insertion and at follow-up. METHOD: Thirty-eight ears in 19 children aged 4-10 years (mean 7.0 years) with long-standing SOM were examined 4-6 h after tube insertion, at 4 months and at 9 months. The pressure in the middle ear and the nasopharynx were recorded while performing (1) forced opening test, (2) equalization of +100 and -100 daPa, (3) Valsalva test, and (4) sniff test. The procedure was repeated after 30 min. Relationships were analyzed by uni- and multi-variate analysis of variance. RESULTS: From tube insertion to 4 months, the mean forced opening pressure increased from 282+/-128 to 355+/-153 daPa (P<0.01), and the mean closing pressure from 91+/-51 to 126+/-82 daPa (P<0.01). There was no further change at 9 months. Female gender, serous effusion (in contrast to mucoid), and more than three previous episodes of acute otitis media were related to higher opening and closing pressures. At tube insertion, 60% and 16% equalized +100 and -100 daPa, respectively, and 28% succeeded in performing Valsalva inflation. The sniff test was positive in 32%, indicating a closing failure. These rates did not change significantly over time. For individual ears, outcomes of all tests varied considerably when retested after 30 min; P(o) changed by +/-12% and P(c) by +/-26%, and 9-29% of the ears changed from a positive to negative response, or vice versa, in the equalization, Valsalva, and sniff tests. CONCLUSIONS: The unexpected finding of weaker closing forces at the day of tube insertion and increased tubal resistance at follow-up might be ascribed to changes in the muco-adhesive forces related to the disease and tube treatment. The pronounced intra-individual variability of test outcomes indicates that tubal function is dynamic and variable in ears prone to SOM, which emphasizes that results of single tubal function tests have very low prognostic value.

MRI screening of the cerebellopontine angle and inner ear with fast spin-echo T2 technique.

In patients with unilateral hearing loss and dizziness it is important to rule out a cerebellopontine angle process. This is often done by audiological and otoneurological investigations. However, in many cases we must rely on the imaging of the temporal bone and the cerebello-brainstem area. The paper has presented the three dimensional (3D) Fast Spin-Echo (FSE) T2 weighted, 0.7 mm thick MR images, which in addition to being quick, does not require the use of expensive contrast material. Between September 1996 and November 1997, 152 patients with unilateral hearing loss and/or balance disorders were investigated. In normal cases the 7th and 8th nerves could be followed accurately from the brainstem to the internal auditory meatus. The found tumors were hypointense compared to the cerebrospinal fluid and could be outlined with reasonable accuracy even without gadolinium contrast. The inner ear had high signal, like cerebrospinal fluid. The patency of the cochlea could be estimated accurately. Thus, 3D FSE T2 weighted images can reliably differentiate between patients with and without pathologies of the cerebellopontine angle. The use of gadolinium contrast could be avoided in most of the cases, but contrast is necessary for differential diagnostic purposes in patients with alterations in the cerebellopontine angle or in doubtful cases.

Determining the geographic origin of potatoes with trace metal analysis using statistical and neural network classifiers.

The objective of this research was to develop a method to confirm the geographical authenticity of Idaho-labeled potatoes as Idaho-grown potatoes. Elemental analysis (K, Mg, Ca, Sr, Ba, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, S, Cd, Pb, and P) of potato samples was performed using ICPAES. Six hundred eight potato samples were collected from known geographic growing sites in the U.S. and Canada. An exhaustive computational evaluation of the 608 x 18 data sets was carried out using statistical (PCA, CDA, discriminant function analysis, and k-nearest neighbors) and neural network techniques. The neural network classification of the samples into two geographic regions (defined as Idaho and non-Idaho) using a bagging technique had the highest percentage of correct classifications, with a nearly 100% degree of accuracy. We report the development of a method combining elemental analysis and neural network classification that may be widely applied to the determination of the geographical origin of unprocessed, fresh commodities.

The character and consequences of disturbing sound sensations in retraction type middle ear disease.

OBJECTIVE: Transient sound disturbances are common but neglected symptoms in retraction type middle ear disease (R-MED). The aim of this study was to explore and describe their character, their individual consequences, and their role in the development of tympanic membrane retractions. METHODS: Fifty-three subjects with manifest retractions and experiences of disturbing sound and ear sensations were interviewed. A qualitative method was used for analysis of the transcribed interviews. RESULTS: Two different patterns emerged from the interviews. 1. Too weak sound was the least common and most tolerable disturbance. It occurred in 45% and was eliminated by Valsalva's inflation. 2. Sudden and transient sensations of too loud and piercing sound, and intermittent autophony frequently caused intense and intolerable discomfort, which might in turn cause loss of control of speech and conversation. These types occurred in 74% and 60%, respectively, and were eliminated by evacuating the middle ear, for example by sniffing. Subjects who described too loud sound or intermittent autophony commonly preferred a retracted tympanic membrane position. This may explain why pressure equalization by swallowing, and inflation by Valsalva's manoeuvre often elicited discomfort. CONCLUSIONS: Transient experiences of too loud sound or intermittent autophony may indicate a shift of sound preference towards the sound experienced at negative middle ear pressure, and an unreliable tubal function in the sense that it fails to stay closed to protect the ear from sounds and pressure variations in the nasopharynx. Such experiences of altered sound may trigger evacuation of the middle ear, which eliminates the sound disturbance. It is crucial to identify, interpret, and explain the disturbances correctly in the therapy and prevention of retractions, since habitual evacuation exposes the tympanic membrane to strong negative pressure loads and a subsequent risk of developing retraction.

Nasal gas composition in humans and its implication on middle ear pressure.

The amount and composition of gas that enters the middle ear by the Eustachian tube is of interest in the study of middle ear pressure regulation. We have studied the gas composition in the nasal cavity through the respiratory cycle in humans by mass spectrometry. The findings were correlated to earlier findings regarding synchronization of swallowing and breathing. The composition of the gas that may pass the Eustachian tube at openings during swallowing seems to be very close to expiratory values: nitrogen 79.19%, oxygen 14.69%, argon 1.00% and carbon dioxide 5.10%.