Frequent feeding delays the gastric emptying of a subsequent meal.

To assess the suitability of the 13C-octanoic acid breath test for measuring gastric emptying in circumstances other than the post-absorptive state, a preliminary study was performed where 6 hourly spaced isoenergetic meals preceded the determination of gastric emptying of a subsequent 2 MJ meal. Emptying was measured in three individuals on four separate occasions, with a reproducibility of 8%. A crossover study was then conducted to test the hypothesis that meal frequency can modulate the gastric emptying of a subsequent meal, with the potential to influence appetite regulation. Sixteen subjects were fed to energy balance, receiving food either as 2 isoenergetic meals 3 h apart or 6 isoenergetic meals fed hourly. Gastric emptying of a subsequent 2 MJ meal was investigated. Visual analogue scales were used throughout to assess appetite. The maximum rate of gastric emptying was unchanged but the onset of emptying was delayed by the more frequent feeding pattern. There was no significant difference in subjective appetite before or after the test meal. In conclusion, short-term increases in feeding frequency delayed the gastric emptying of a subsequent meal, but significant effects on post-meal appetite could not be demonstrated.

Effect of high-fat meals and fatty acid saturation on postprandial levels of the hormones ghrelin and leptin in healthy men.

OBJECTIVE: Ghrelin and leptin play a role in control of food intake and adiposity but mechanisms regulating these hormones in man are poorly defined and evidence that dietary fats may have adverse effects is inconclusive. We investigated whether high-fat meals, which differed in saturated fatty acid (SFA) content acutely modified these hormones. DESIGN: Randomised, double-blind, crossover trial. A high-fat (HF) test meal (59 +/- 4 g fat; 71% of energy as fat) was given for breakfast on two occasions. Meals comprised either high (approximately 70:30) or low (approximately 55:45) saturated:unsaturated fatty acid (SFA:USFA) ratio. Fasting and postprandial measurements of serum total ghrelin (RIA), leptin (enzyme-linked immunosorbent assay (ELISA)) and insulin (RIA) were made over 6 h. Postprandial measurements were also made at 10 and 24 h following a fat-exclusion lunch, snack and dinner. SUBJECTS: A total of 18 lean, healthy men. RESULTS: There was no significant effect of the fatty meal (time, P > 0.05), nor a differential effect of SFA:USFA ratio (treatment*time, P > 0.05) on ghrelin over 6h. Leptin decreased in response to both HF treatments (time, P < 0.001) but increased SFA content did not further inhibit hormone secretion (treatment*time, P > 0.05). There was no significant correlation between ghrelin or leptin and circulating insulin (P>0.05). CONCLUSION: We conclude that HF diets may adversely effect serum leptin, although the circadian decrease may account in part for this response. Increasing dietary SFAs had no deleterious effects on leptin or total ghrelin.

The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults.

CONTEXT: Chitosan, a deacetylated chitin, is a widely available dietary supplement purported to decrease body weight and serum lipids through gastrointestinal fat binding. Although evaluated in a number of trials, its efficacy remains in dispute. OBJECTIVE: To evaluate the efficacy of chitosan for weight loss in overweight and obese adults. DESIGN AND SETTING: A 24-week randomised, double-blind, placebo-controlled trial, conducted at the University of Auckland between November 2001 and December 2002. PARTICIPANTS: A total of 250 participants (82% women; mean (s.d.) body mass index, 35.5 (5.1) kg/m(2); mean age, 48 (12) y) INTERVENTIONS: Participants were randomly assigned to receive 3 g chitosan/day (n=125) or placebo (n=125). All participants received standardised dietary and lifestyle advice for weight loss. Adherence was monitored by capsule counts. MAIN OUTCOME MEASURES: The primary outcome measure was change in body weight. Secondary outcomes included changes in body mass index, waist circumference, body fat percentage, blood pressure, serum lipids, plasma glucose, fat-soluble vitamins, faecal fat, and health-related quality of life. RESULTS: In an intention-to-treat analysis with the last observation carried forward, the chitosan group lost more body weight than the placebo group (mean (s.e.), -0.4 (0.2) kg (0.4% loss) vs +0.2 (0.2) kg (0.2% gain), P=0.03) during the 24-week intervention, but effects were small. Similar small changes occurred in circulating total and LDL cholesterol, and glucose (P<0.01). There were no significant differences between groups for any of the other measured outcomes. CONCLUSION: In this 24-week trial, chitosan treatment did not result in a clinically significant loss of body weight compared with placebo.

Delayed gastric emptying in the obese: an assessment using the non-invasive (13)C-octanoic acid breath test.

AIM: Much of the controversy surrounding the correlation between obesity and gastric emptying lies in the inconsistency of methodology and analysis. This study was designed to overcome some of the discrepancies encountered in previous studies and to test the hypothesis that obese individuals have altered gastric emptying compared to lean individuals. METHODS: Gastric emptying was measured using the (13)C-octanoic acid breath test in 16 lean and 16 obese women pair-matched for age. Following an overnight fast, subjects were given a standard 2 MJ egg meal labelled with 100 microl of [1-(13)C]-octanoic acid. Breath samples were collected at regular intervals over a 6-h period. (13)C-isotopic enrichment in the breath was analysed using isotope ratio mass spectrometry and the data fitted to the established gastric emptying model. The lag times (t(lag)), half excretion times (t(1/2)), latency phase (t(lat)) and ascension times (t(asc)) were calculated. RESULTS: The mean t(1/2)-values (+/-standard error of the mean) were 3.67 +/- 0.14 h and 4.23 +/- 0.18 h for lean and obese respectively, indicating significantly delayed gastric emptying in the obese (p = 0.019). The obese group also showed a significantly slower lag time (t(lag), p = 0.005) and latency phase (t(lat), p = 0.005), but no significant difference was found in the ascension time (t(asc), p = 0.154). Within groups, no correlation was found between half excretion times and body weight or half excretion times and body mass index. CONCLUSIONS: The present study demonstrated a prolonged lag phase and delayed gastric emptying in obese women when compared to lean women. This delay may be as a consequence of high-fat diets, a sedentary lifestyle and increased gastric distension associated with obesity, or a contributing factor in the pathogenesis of obesity resulting from the inactivation of gastrointestinal satiety signals and in an increase in food intake.

Evaluating the cost-effectiveness of orthodontic provision.

The assessment of orthodontic provision is important to determine if treatment was necessary and undertaken appropriately. The ICON objectively quantifies orthodontic treatment need, complexity and outcome and is a valuable occlusal index in the assessment effectiveness of orthodontic care. It is possible to develop cost-effectiveness models by analysing the costs and effectiveness of orthodontic treatment. Several methods are illustrated to compare the orthodontic provision of specialist orthodontists.

Leptin does not respond to 48 h fat deposition or mobilization in women.

OBJECTIVE: To test the hypothesis that acute responses of plasma leptin concentration to energy balance manipulation are mediated by fat flux. DESIGN: Ten healthy women aged 31-63 y, mass 48-113.5 kg, fat mass 8.5-62.5 kg, were studied for 3 days in a whole-body calorimeter on two occasions. After a control day (D1) during which energy balance was maintained, diet was manipulated to induce fat deposition (FD) or mobilization (FM) of 50 g/day for 2 days (D2 & D3). A difference totalling of 194+/-18.6 g fat was achieved between manipulations without significant effects on carbohydrate or protein balance. Fasting plasma leptin was measured on D2 and D4. RESULTS: After the control day plasma leptin concentration averaged 19.01+/-9.8 ng/ml, and was found to be linearly related to body fat mass. After 2 days manipulation of fat balance, leptin concentrations were 21.4+/-10.3 ng/ml (FD) and 21.2+/-11.3 ng/ml (FM). There was no significant difference between treatments in either control day or postmanipulation leptin concentrations, nor did the treatments induce any differences in glucose or insulin concentration responses. CONCLUSION: Although in states of energy balance leptin concentration is linearly related to fat mass, acute modulation of leptin concentration during energy imbalance is not mediated by fat flux.

Effects of inactivity and diet composition on human energy balance.

OBJECTIVES: To investigate the influences of inactivity and dietary macronutrient composition on energy and fat balance and to look for interactions between them. DESIGN: Two-day measurements of energy expenditure and substrate oxidation on five occasions; ad libitum food intake from diets of 35% and 60% energy as fat, with and without imposed activity, and a fixed overfeeding at 35% fat with free activity. SUBJECTS: Eight normal-weight male volunteers. MEASUREMENTS: Energy expenditure and substrate oxidation by indirect whole-body calorimetry, and macronutrient intakes from food consumption on ad libitum regimens. RESULTS: Subjects consumed the same energy, mean 11.6 MJ/d, regardless of activity level, on the 35% diet. Subjects consumed more energy on the 60% than the 35% diet, mean 14 vs. 11.6 MJ/d. Inactivity induced a strong positive energy balance: 5.1 (60% diet), and 2.6 MJ/d (35% diet). Energy balance with activity was not significantly different between diets, nor significantly different from zero: 1.1 MJ/d (60% diet), and -0.2 MJ/d (35% diet). When intentionally overfed, subjects failed to compensate by raising voluntary activity. CONCLUSION: Energy intake was not regulated over a 2-day period in response to either imposition of inactivity or a high-fat diet. Activity proved essential to the avoidance of significant positive energy balance.

Relationship between respiratory muscle strength, nutritional status, and lung volume in cystic fibrosis and asthma.

We measured static inspiratory and expiratory pressures (PImax and PEmax) in 29 patients with asthma for comparison with a previously reported group of 25 patients with cystic fibrosis (CF) and 80 normal control subjects. The purpose of the study was to assess the relationship between respiratory muscle strength, nutritional status, lung volumes, and training effect of the increased work of breathing in patients with chronic air-flow limitation. PEmax was similar in the asthma group, CF group, and normal control subjects despite a significant degree of malnutrition in the CF group (mean body mass percentile (BMP), 78 versus 107% in the asthma group, p less than 0.001). There was no correlation between BMP and PImax or PEmax in either study group. PImax, when corrected for lung volume, was greater than age- and sex-matched control values in 24% of the patients with CF and 48% of the patients with asthma. We conclude that respiratory muscle strength is not related to nutritional status (as measured by BMP) in patients with CF and asthma. Above-normal inspiratory muscle strength may result from a training effect of the increased work of breathing in both CF and asthma, regardless of nutritional status.

Sarcoidosis of the larynx in a child.

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomatous inflammation of various organs, but most frequently involving the lungs of young adults. Sarcoidosis is rare in the pediatric age group, however numerous extensive reviews have been published. The most commonly seen initial manifestations in childhood are non-specific constitutional symptoms such as lethargy, fatigue and malaise, followed by cough, dyspnea, fever, weight loss, and lymphadenopathy in order of decreasing frequency. The diagnosis is one of exclusion and is established when clinical and radiological findings are supported by histological evidence of widespread non-caseating epithelial cell granulomas in more than one organ, or a positive Kveim test. Laryngeal involvement is usually part of the systemic disease, but isolated laryngeal sarcoidosis has been reported in adults. We report here a case of isolated laryngeal sarcoidosis in a 13 year old girl. The differential diagnosis and management are discussed.

The effect of anticholinergic treatment on postexertional wheezing in asthma studied by phonopneumography and spirometry.

Postexertional wheezing is an important clinical sign of nonspecific airway hyperreactivity. We have studied wheezing after exercise in 6 asthmatic subjects, 13 to 20 yr of age, using spectral analysis of recorded tracheal sounds. Automated spectral characterization was used to measure wheezing as a proportion of respiratory time. Anticholinergic treatment with ipratropium bromide (Atrovent) was compared with placebo to investigate effects on postexertional wheezing, and pulmonary function was compared with the result of respiratory sound analysis. Atrovent did not abolish exercise-induced bronchospasm but improved preexercise lung function and thereby caused a parallel upward shift in the response curves. Wheezing after Atrovent was significantly less, later in onset, and mainly expiratory at 20 min after exercise. Wheezing as a percentage of total respiratory time correlated well with FEV1, Vmax50, and SGaw. Analysis of respiratory sounds and automated quantification of wheezing may be a useful complementary test of bronchial obstruction in asthma.

Arterial oxygen desaturation following salbutamol inhalation in acute asthma.

The practicality and accuracy of a new ear oximeter was evaluated. The SaO2 measured with this instrument correlated significantly with simultaneous SaO2 measurements with another ear oximeter in 12 children (age three months to 20 years) with chronic pulmonary or cardiac diseases (r = 0.93, p less than 0.001), and also correlated significantly (r = 0.96, p less than 0.001) with calculated SaO2 based on blood gas measurements of blood from the left side of the heart obtained during cardiac catheterization. The SaO2 was then measured continuously and readings were taken before and five, 15, and 30 minutes after salbutamol inhalation by face mask in 18 children. Following treatment, mean PEFR increased significantly, and mean SaO2 was significantly lower than preinhalation values at five and 15 minutes postinhalation. At 30 minutes, SaO2 had returned to control values. In nine of 18 subjects, SaO2 fell greater than or equal to 5 percent. This response was not predictable on the basis of different parameters (treatment, heart rate, PEFR). The findings suggest that supplemental O2 may be required during the first 30 minutes posttreatment.

Response to cold air hyperventilation in normal and in asthmatic children.

To assess the sensitivity of isocapnic hyperventilation with cold air in detecting airway hyperreactivity in asthmatic children, we studied 13 asthmatic patients (mean age 11.1 years) and 10 normal children. Cold air challenge consisted of 4 minutes of moderate hyperventilation plus another 4 minutes of maximal hyperventilation, both with subfreezing air (-16 degrees to -18 degrees C). Exercise and IHCA tests were done within 5 days and in random sequence. Mean (+/- SE) maximal % delta FEV1 after IHCA was 27 +/- 5.1% in the asthmatic children vs 4.5 +/- 1.2% in the normal subjects (P less than 0.01), even though there were no significant differences in the maximal minute ventilation equivalent between the two groups. Mean maximal % delta FEV1 after exercise was 31.7 +/- 5.6 in the asthmatic group. There was no difference in the sensitivity of the exercise and IHCA tests to detect bronchospasm in asthmatic children. Airway obstruction after IHCA was sharp and brief: maximal at 3 minutes after challenge, and back to 10% of baseline after 11 minutes. In seven asthmatic children the refractoriness to cold air and exercise was studied by repeating each test within 30 minutes; all seven showed significant refractoriness to exercise, and six showed no refractoriness to IHCA. We conclude that exercise and cold air-induced bronchospasm have different physiologic mechanisms, and that cold air testing can be used as a routine challenge to identify airway hyperreactivity in children.

The effects of chronic hyperinflation, nutritional status, and posture on respiratory muscle strength in cystic fibrosis.

We measured maximal static inspiratory and expiratory pressures (PImax and PEmax) in 25 patients with cystic fibrosis (CF) and 80 normal control subjects to determine whether chronic hyperinflation and malnutrition reduce PImax and PImax/PEmax, respectively. In addition, we examined the effect of posture on pressures generated. We used a diminution in PEmax as an index of a malnutrition effect on pressures generated. The patients with CF, although significantly hyperinflated (ratio of residual volume to total lung capacity, 0.49), generated PImax values similar to those of the control subjects (p greater than 0.05). Despite evidence of malnutrition (mean body mass percentile, 78%) the PEmax values of patients with CF and those of control subjects were comparable (p greater than 0.05). There was no postural effect on pressures generated in the normal subjects or the CF group as a whole. We conclude that respiratory muscle strength is normal or supranormal in CF, despite chronic hyperinflation and malnutrition.

Spectral analysis of breath sounds in normal newborn infants.

To determine whether breath sounds in newborns are different from those described in older subjects, fast Fourier transform and power spectra analysis were performed on recorded breath sounds from 14 normal newborns. A respiration-triggered sampling technique was applied to compare early, middle, and late phases of inspiration and expiration, using a thoracic impedance signal. Peak frequencies were found in the range described for normal breath sounds in older subjects, and the frequency range of breath sounds was similar to that reported for older children and adults. The difference in breath sound quality of normal newborns appears to depend on the sound intensity during expiration. In contrast to older subjects, newborns showed only slightly less sound intensity during expiration; in the late phases of inspiration and expiration this intensity was almost equal.

Neonatal pulmonary infarction. A cause of 'cystlike' lucencies on the chest roentgenogram.

Perinatal pulmonary infarction is a difficult and infrequently made diagnosis. A male newborn had infarction of most of the right lung secondary to perinatal pulmonary thromboembolism (PTE). Serial chest roentgenograms initially showed opacity of most of the right lung, followed by the appearance of well-defined radiolucencies resembling pneumatoceles associated with mass effect. By the 25th day of life the localized "cystlike" lucencies were no longer evident and the right lung appeared predominantly hyperlucent. Although the presence of underlying disease makes the diagnosis of PTE in the infant and young child difficult, the clinical features and methods of diagnosis of PTE in this age group are similar to those for the adult. The diagnosis of PTE should be considered in the infant with respiratory distress and unusual findings on chest roentgenography.

Cranial blood volume changes during mechanical ventilation and spontaneous breathing in newborn infants.

We derived a noninvasive method to compare changes in cranial blood volume during mechanical ventilation with changes occurring during spontaneous breathing in newborn infants. In ten infants receiving mechanical ventilation, cranial blood volume increased during inspiration by a mean of 8.3%. We found a consistent relationship between clinical estimation of lung compliance and the amount of cranial volume expansion. During spontaneous breathing in ten infants cranial blood volume decreased during inspiration by a mean of 5.8%. The findings indicate the need for careful monitoring during periods of rapid changes in lung compliance.