The envelope of an oscillatory process and its upcrossings

Let X(t) be a real-valued stochastic process with sample functions which are almost surely continuously differentiable. We say that X(t) has an upcrossing at level u at time t if X(t) = u, X′(t) > 0.

Does the addition of visceral manipulation alter outcomes for patients with low back pain? A randomized placebo controlled trial

BACKGROUND

This study aimed to investigate whether the addition of visceral manipulation, to a standard physiotherapy algorithm, improved outcomes in patients with low back pain.

METHODS

Sixty-four patients with low back pain who presented for treatment at a private physiotherapy clinic were randomized to one of two groups: standard physiotherapy plus visceral manipulation (n = 32) or standard physiotherapy plus placebo visceral manipulation (n = 32). The primary outcome was pain (measured with the 0-10 Numerical Pain Rating Scale) at 6 weeks. Secondary outcomes were pain at 2 and 52 weeks, disability (measured with the Roland-Morris Disability Questionnaire) at 2, 6 and 52 weeks and function (measured with the Patient-Specific Functional Scale) at 2, 6 and 52 weeks. This trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12611000757910).

RESULTS

The addition of visceral manipulation did not affect the primary outcome of pain at 6 weeks (-0.12, 95% CI = -1.45 to 1.21). There were no significant between-group differences for the secondary outcomes of pain at 2 weeks or disability and function at 2, 6 or 52 weeks. The group receiving addition of visceral manipulation had less pain than the placebo group at 52 weeks (mean 1.57, 95% CI = 0.32 to 2.82). Participants were adequately blinded to group status and there were no adverse effects reported in either group.

CONCLUSIONS

Our study suggests that visceral manipulation in addition to standard care is not effective in changing short-term outcomes but may produce clinically worthwhile improvements in pain at 1 year.

Estimating insulin demand for protein-containing foods using the food insulin index

BACKGROUND/OBJECTIVE

The Food Insulin Index (FII) is a novel algorithm for ranking foods on the basis of insulin responses in healthy subjects relative to an isoenergetic reference food. Our aim was to compare postprandial glycemic responses in adults with type 1 diabetes who used both carbohydrate counting and the FII algorithm to estimate the insulin dosage for a variety of protein-containing foods.

SUBJECTS/METHODS

A total of 11 adults on insulin pump therapy consumed six individual foods (steak, battered fish, poached eggs, low-fat yoghurt, baked beans and peanuts) on two occasions in random order, with the insulin dose determined once by the FII algorithm and once with carbohydrate counting. Postprandial glycemia was measured in capillary blood glucose samples at 15-30  min intervals over 3 h. Researchers and participants were blinded to treatment.

RESULTS

Compared with carbohydrate counting, the FII algorithm significantly reduced the mean blood glucose level (5.7±0.2  vs 6.5±0.2 mmol/l, P=0.003) and the mean change in blood glucose level (-0.7±0.2 vs 0.1±0.2 mmol/l, P=0.001). Peak blood glucose was reached earlier using the FII algorithm than using carbohydrate counting (34±5 vs 56±7 min, P=0.007). The risk of hypoglycemia was similar in both treatments (48% vs 33% for FII vs carbohydrate counting, respectively, P=0.155).

CONCLUSIONS

In adults with type 1 diabetes, compared with carbohydrate counting, the novel FII algorithm improved postprandial hyperglycemia after consumption of protein-containing foods.

Higher protein diet for weight management in young overweight women: a 12-month randomized controlled trial

Clinical research on weight management in young women is limited. This randomized controlled trial compared the efficacy of two iso-energetically restricted (5600 kJ) diets [higher protein (HP): 32% protein, 41% carbohydrate, 25% fat or higher carbohydrate (HC): 20, 58, 21%, respectively] in 71 (HP: n = 36; HC: n = 35) young healthy women (18-25 years; body mass index ≥ 27.5 kg/m2) for weight (kg; percent weight loss), body composition, metabolic and iron changes assessed at baseline, 6 and 12 months.

DATA

mean (95% CI). In HP completers at 6 months, percent weight loss was higher [HP: 9.3 (5.6-13.1); HC: 5.1 (2.3-7.9)%; p = 0.06]; although, this did not reach statistical significance. Absolute weight [HP: 8.9 (5.3-12.5); HC: 4.6 (2.2-7.0) kg; p = 0.034] and fat loss [HP: 8.0 (4.4-11.5); HC: 3.4 (1.3-5.6) kg; p = 0.022] were significantly greater. No significant between-diet differences were observed at 12 months. Biochemistry remained within normal ranges with HP showing superior preservation of ferritin at 6 months [HP: 53 (40-66); HC: 46 (30-61) µg/l; p = 0.029]. Both diets supported clinically meaningful weight loss with HP tending to be more effective in the medium-term.

Malnutrition screening and early nutrition intervention in hospitalised patients in acute aged care: a randomised controlled trial

OBJECTIVES

High rates of malnutrition have been reported in the older hospitalized patient population. This is recognised to impact on patient outcomes and health costs. This study aimed to assess the impact of nutrition screening and intervention on these parameters.

DESIGN

Randomised controlled prospective study.

SETTING

The study was performed in the acute geriatric medicine wards of the Prince of Wales Hospital, Sydney Australia.

PARTICIPANTS

All patients admitted to these wards under a geriatrician with an expected length of stay of at least 72 hours were considered for the study.

INTERVENTION

Patients were screened on admission for malnutrition using the Mini Nutritional Assessment (MNA) tool and randomly assigned to control or intervention groups. Intervention patients were immediately commenced on a malnutrition care plan (MCP). Control patients were only commenced on a MCP if referred by clinical staff.

MEASUREMENTS

Length of stay (LOS), weight change and frequency of readmission to hospital were compared between the groups.

RESULTS

143 patients were screened. 119 were identified as malnourished (MN) or at risk of malnutrition (AR). Overall LOS was not different between the two groups (control v. intervention: 13.4 ± 1.3 days v. 12.5 ± 1.2 days, p=0.64). However there was a significant decrease in LOS in the MN (control v. intervention: 19.5 ± 3 days v. 10.6 ± 1.6 days, p=0.013) and a trend to reduced readmissions. There was no difference in weight change over admission between the groups. Without screening, clinical staff identified only a small proportion of malnourished patients (35% of MN and 20% of AR).

CONCLUSIONS

Malnutrition in the older hospital population is common. Malnutrition screening on hospital admission facilitated targeted nutrition intervention, however length of stay and re-presentations were only reduced in older malnourished patients with an MNA score less than 17.

B vitamin status, dietary intake and length of stay in a sample of elderly rehabilitation patients

OBJECTIVES

To investigate the relationships between previous diet, biomarkers of selected B vitamins, nutritional status and length of stay.

DESIGN

Cross sectional study.

SETTING

Geriatric rehabilitation patients, Sydney, Australia.

PARTICIPANTS

Fifty two consenting patients with normal serum creatinine levels and no dementia.

MEASUREMENTS

Serum vitamin B12, plasma vitamin B6, serum and erythrocyte folate, homocysteine and methylmalonic acid (MMA) concentrations; dietary intake using a validated semi-quantitative food frequency questionnaire and nutritional assessment using the Mini Nutritional Assessment (MNA). Length of stay data were collected from medical records after discharge.

RESULTS

The age was 80 ± 8 year (mean ± SD), BMI 26.4 ± 6.8 kg/m2 and MNA score 22 ± 3 indicating some risk of malnutrition. Deficiencies of vitamins B6, B12 and folate were found in 30, 22 and 5 subjects respectively. Length of stay was positively correlated with age and MMA (Spearman's correlation 0.4, p<0.01 and 0.28, p<0.05 respectively) and negatively correlated with albumin, vitamin B6 and MNA score (Spearman's correlation -0.35, -0.33 and -0.29, p<0.05). After adjustment for age and sex, ln vitamin B6 and ln MMA concentrations were significant in predicting ln LOS (p=0.006 and p=0.014 respectively).

CONCLUSION

The study indicates a high risk of vitamin B deficiencies in the elderly and suggests that deficiencies of vitamins B6 and B12 are associated with length of stay. This is concerning as B vitamin status is rarely fully assessed.

Profile of lingual orthodontic users in Australia

BACKGROUND

The use of lingual orthodontic appliances and the training background of orthodontists in Australia using the lingual orthodontic technique are largely unknown. The aim of this study was to investigate the profile of lingual orthodontic users in Australia.

METHODS

Four hundred and fifty questionnaires consisting of 15 questions were sent out to orthodontists in Australia. We obtained a 62 per cent return rate (278) with a 58 per cent rate of completed questionnaires. Statistical analysis using SPSS was performed and various outputs were obtained.

RESULTS

Of the completed returns, 23 per cent were current lingual users; 69 per cent were not and 8 per cent were previous users but have stopped using the appliance. The majority (90 per cent) of the current lingual users were males. The highest percentage of users (35 per cent) was in New South Wales while the smallest percentage was in Tasmania (2 per cent). Around 40 per cent of respondents attended lingual courses as part of their specialist training programme, while 73 per cent had attended lingual courses since graduation and 82 per cent would consider attending a lingual course in the future. Of the 60 per cent current users who did not have a lingual component in their specialist training programme, almost nine-tenths had attended lingual courses since graduation. Of the non-lingual users, 14 per cent attended lingual courses as part of their specialist training programme, 28 per cent attended lingual courses since graduation and 38 per cent would consider attending a lingual course in the future. The main reason cited for being a non-lingual user was that lingual orthodontics could not be an integral part of the practice.

CONCLUSIONS

Most of the orthodontists who graduated more than 16 years ago from their postgraduate training were non-users of the lingual appliance. It seems that around one in four orthodontists currently use the lingual technique, of which NSW orthodontists make up the largest group. Only one-fifth of users had some lingual component in their formal orthodontic training and about half of them have attended lingual courses after graduation. Almost half of orthodontists in Australia would consider attending a lingual course in the future. This survey provides a sound basis for course co-ordinators to plan for continuing lingual orthodontics in the future.

Changes in the physical properties of human premolar cementum after application of 4 weeks of controlled orthodontic forces

This study was performed to assess the relationship between the magnitude of orthodontic force and physical properties of individual human cementum, and to identify the sites that may be predisposed to root resorption. The findings may assist in relating physical properties of dental root cementum and its susceptibility to root resorption. Sixteen maxillary first premolar teeth were selected in eight orthodontic patients (three males and five females), mean age 14.8 years (range 11.2-17.5 years), requiring first premolar extractions. In each patient, a light orthodontic force of 25 cN was applied buccally using a sectional archwire on the first premolar on one side, while a heavy force of 225 cN was applied to the contralateral side. The teeth were extracted 4 weeks after initial force application. Hardness and elastic modulus were measured on the buccal and the lingual surfaces of the cementum at the cervical, middle, and apical third of the root. The results showed that the mean hardness and elastic modulus of cementum in the light force group were greater than in the heavy force group at all positions. There were highly significant differences in both hardness and elastic modulus between the heavy and light force groups (P < 0.01). The mean hardness and elastic modulus of cementum gradually decreased from the cervical to the apical regions for buccal as well as lingual surfaces in both groups. There was, however, an insignificant difference between hardness and elastic modulus on the buccal surface compared with the lingual surface (P < 0.05). It was concluded that the hardness and elastic modulus of cementum were affected by the application of orthodontics forces.

Validation of two-dimensional measurements of root resorption craters on human premolars after 28 days of force application

The aims of this study were to develop a three-dimensional (3D) mathematical model of a typical root resorption crater and to correlate two-dimensional (2D) surface area measurements to 3D volumetric measurements of root resorption craters created under light and heavy orthodontic forces. Data were obtained from a previous study of 36 first premolars from 16 subjects requiring extraction of these teeth as part of their orthodontic treatment. Buccal tipping forces of 25 or 225 g were applied for an experimental period of 28 days. After extraction, the samples were prepared for scanning electron microscopy (SEM) imaging, image processing and analysis. Surface area (2D) and volumetric (3D) measurements of all craters were obtained. A mathematical analysis of the 2D/3D relationship enabled the determination of an appropriate digital model for the shape, type and dimensions of resorption craters, which was also able to distinguish between a 'hemispheric' model versus a 'layered' model of craters. The results demonstrated that 2D and 3D measurements were strongly correlated (r = 0.991**). Within the light and heavy force groups, the measurements were also strongly correlated (r = 0.978** and r = 0.994**, respectively). For a 28 day experimental period, 2D measurements of root resorption craters were found to be as reliable as 3D measurements.

Urinary isoflavonoid excretion is inversely associated with the ratio of protein to dietary fibre intake in young women

OBJECTIVE

To examine the prevalence of excretion of urinary isoflavonoids in women and determine any relationships with accustomed macronutrient intake.

DESIGN

Volunteers in one of two 4-month studies. Study 1 was a randomised crossover study whereby subjects consumed a placebo or isoflavone supplement for 2 months and crossed over. Study 2 was a parallel design in which subjects consumed a placebo for 1 month and an isoflavone supplement for 3 months.

SETTING

All subjects were free-living, healthy volunteers.

SUBJECTS

A total of 25 (study 1, n=14; study 2, n=11) premenopausal women were recruited through advertisements.

INTERVENTIONS

Volunteers were supplemented for 2 months (study 1) or 3 months (study 2) with purified isoflavones (86 mg/day) derived from red clover. Urinary isoflavonoids were measured during the placebo and the second month of isoflavone treatment. Macronutrient intakes were determined from weighed food records.

RESULTS

During isoflavone supplementation, the concentration of urinary total isoflavonoids increased by 15-fold (P<0.0001), with 5.4-fold variation between individuals. Multiple linear regression analysis showed that 24% of this variation could be explained by an interaction between dietary fibre and protein (P=0.047), with a highly significant inverse association between total isoflavonoid concentration and the protein to fibre ratio (r=-0.51, P=0.009).

CONCLUSIONS

Supplementation with purified isoflavones results in an increase in urinary isoflavonoid excretion and part of the individual variation in response is associated with an interaction between intakes of protein and dietary fibre. Whether manipulation of these macronutrients could enhance efficacy of isoflavone supplements remains to be determined.

Root resorption and its association with alterations in physical properties, mineral contents and resorption craters in human premolars following application of light and heavy controlled orthodontic forces

OBJECTIVES

To study the effect of different orthodontic force levels on cementum, investigating from the point of view of its physical properties, alterations in the mineral components, type and location of the resorption craters and the exploration in 3D of space.

DESIGN

In vivo human premolars subjected to heavy and light forces were employed for this study. After a period of movement they were analyzed for hardness and elasticity. Also, the mineral composition measuring Ca, P and F of the cementum root surface was investigated. A new method for volumetric analysis of resorption craters was developed.

RESULTS

There were no significant differences for hardness and elastic modulus between the light and heavy force groups and no significant effects for different tooth positions. Significant inter-individual variation in the Ca, P and F concentrations was noted. Force-related data showed that mean volume of the resorption crater in light-force group was 3.49-fold greater than the control group, and the heavy-force group 11.59-fold more than control group. The heavy force group had 3.31-fold greater total resorption volume then light force group. Buccal cervical and lingual apical regions demonstrated significantly more resorption craters than the other regions. The 2D measurements were strongly correlated to 3D measurements.

CONCLUSION

The application of light and heavy forces did not show any statistically significant differences in hardness and elastic modulus when compared with untreated teeth. The inconsistent increase or decrease of Ca, P and F contents between control and experimental teeth at sites of compression and tension were difficult to explain. There was more resorption by volume in the heavy force group as compared with the light group and controls. Our data also suggested that the high-pressure zones might be more susceptible to resorption after 28 days of force application.

Physiological validation of the concept of glycemic load in lean young adults

Dietary glycemic load, the mathematical product of the glycemic index (GI) of a food and its carbohydrate content, has been proposed as an indicator of the glucose response and insulin demand induced by a serving of food. To validate this concept in vivo, we tested the hypotheses that 1). portions of different foods with the same glycemic load produce similar glycemic responses; and 2). stepwise increases in glycemic load for a range of foods produce proportional increases in glycemia and insulinemia. In the first study, 10 healthy subjects consumed 10 different foods in random order in amounts calculated to have the same glycemic load as one slice of white bread. Capillary blood samples were taken at regular intervals over the next 2 h. The glycemic response as determined by area under the curve was not different from that of white bread for nine foods. However, lentils produced lower than predicted responses (P < 0.05). In the second study, another group of subjects was tested to determine the effects of increasing glycemic load using a balanced 5 x 5 Greco-Latin square design balanced for four variables: subject, dose, food and order. Two sets of five foods were consumed at five different glycemic loads (doses) equivalent to one, two, three, four and six slices of bread. Stepwise increases in glycemic load produced significant and predictable increases in both glycemia (P < 0.001) and insulinemia (P < 0.001). These findings support the concept of dietary glycemic load as a measure of overall glycemic response and insulin demand.

The impact of site specificity and needle manipulation on changes to pain pressure threshold following manual acupuncture: a controlled study

OBJECTIVES

To investigate the contribution of two principal features that underlie traditional Chinese acupuncture: site specificity and application of needle manipulation.

DESIGN

Thirteen volunteers completed a randomised, dual blind (subject and assessor) repeated measures study involving five interventions. Pressure pain threshold (PPT) was measured with an algometer, before and after intervention at 10 sites (acupoints and nonacupoints) across the body.

INTERVENTIONS

Deep needling, with or without manual needle rotation, applied to the acupoint Large Intestine 4 (LI4) or to a nonacupoint located on the medial side of the second metacarpal. Inactive laser to LI4 was used as a control. All interventions were administered for 21 min.

MAIN OUTCOME MEASURES

Percentage change in PPT from preintervention baseline at the 10 sites during the 18 min immediately following intervention.

RESULTS

Statistically significant increases from preintervention PPT means were obtained at all 10 sites following needling of LI4 with manipulation compared with one site after needling LI4 without manipulation. Needling the nonacupoint led to statistically significant increases at six sites when manipulation was present compared with none in the absence of manipulation. No significant changes in mean PPT followed inactive laser. Needling LI4 with manipulation produced mean increases that were statistically significantly greater than those for the other interventions with one exception: needling the nonacupoint with manipulation was as effective as needling LI4 with manipulation at one measurement site only.

CONCLUSIONS

Both manipulation and site of needling contributed significantly to the elevation of PPT following acupuncture. Distribution of effects on PPT did not support either neural segmental or Traditional Chinese Medicine channel theories. Psychological and physiological nonspecific effects appeared to play a minimal role in changes to PPT.

Postprandial hyperglycemia and insulin sensitivity differ among lean young adults of different ethnicities

Both postprandial hyperglycemia and insulin resistance (IR) have implications for the development of cardiovascular disease. The present study was designed to examine differences in postprandial glycemia and insulin sensitivity among young adults of different ethnic origins. Lean, healthy subjects (n = 60) from five ethnic groups [20 European Caucasians, 10 Chinese, 10 South East (SE) Asians, 10 Asian Indians and 10 Arabic Caucasians] were matched for age, body mass index, waist circumference, birth weight and current diet. A 75-g white bread carbohydrate challenge was fed to assess postprandial glycemia and insulinemia. Insulin sensitivity was assessed in three groups by the euglycemic-hyperinsulinemic clamp and in all subjects by homeostasis model assessment (HOMA) modeling. Postprandial hyperglycemia (incremental area under the curve) and insulin sensitivity (M-value) both showed a twofold variation among the groups (P < 0.001) and were significantly related to each other (R(2) = 56%, P < 0.001). Young SE Asians had the highest postprandial glycemia and lowest insulin sensitivity, whereas European and Arabic Caucasian subjects were the most insulin sensitive and carbohydrate tolerant. These findings suggest that IR is evident even in lean, young adults of some ethnic groups and is associated with significant increases in postprandial glycemia and insulinemia in response to a realistic carbohydrate load.

The use of the Box-Behnken experimental design in the optimisation and robustness testing of a capillary electrophoresis method for the analysis of ethambutol hydrochloride in a pharmaceutical formulation

Box-Behnken experimental designs do not appear to be extensively used in optimisation of analytical methods using capillary electrophoresis (CE). This paper describes the use of the Box-Behnken experimental design to optimise the factors affecting the separation of ethambutol hydrochloride (EB), its impurity 2-amino-1-butanol and the internal standard (phenylephrine hydrochloride) in a CE method for a pharmaceutical tablet assay. The three factors studied simultaneously were: buffer pH, buffer concentration and applied electric field, each at three levels. The method was optimised with respect to three responses: resolution between peaks, theoretical plate count and the migration time of the EB peak. A statistical programme, which applies a multiple response optimisation algorithm, was used to calculate and optimise the three responses simultaneously. The optimum conditions were established to be 58.0 mM sodium borate buffer at pH 9.50 and an applied electric field of 412 V/cm. The robustness of the method was also determined and confirmed using a second Box-Behnken design, as part of the validation exercise. System suitability values for the method were derived from the regression surface analysis. The CE method for a pharmaceutical tablet formulation was further validated according to current regulatory requirements, with respect to linearity and range, precision, specificity, accuracy and limit of quantitation. The optimised method gives a fast and efficient separation under 4 min, with complete resolution between the three peaks, and represents an improvement over the existing USP method. It can be concluded that the Box-Behnken experimental design provides a suitable means of optimising and testing the robustness of a CE pharmaceutical method.

The glycaemic index values of Vietnamese foods

OBJECTIVE

To determine and compare the glycaemic index (GI) values of a range of Vietnamese foods in two racial groups.

DESIGN AND SUBJECTS

Twelve healthy subjects (six Asian and six Caucasian) consumed 50 g carbohydrate portions of a reference food (glucose sugar) and nine Vietnamese foods (three rices, three noodle products and three sweet foods) in random order after an overnight fast. The reference food was tested on two separate occasions, and the Vietnamese foods were each tested once. Capillary blood samples were taken at time 0 (fasting), 15, 30, 45, 60, 90 and 120 min from the start of each meal. Samples were analysed for plasma glucose and the incremental areas under the plasma glucose curves (AUC) were used to calculate the GI values of the test foods, using glucose as the reference food (ie GI value of glucose=100). The mean GI value of each food was calculated for the entire group of subjects (n=12) and for both racial groups (n=6).

RESULTS

The three rices had surprisingly high GI values (86-109), whereas the noodle products had relatively low GI values (39-61). The sugar-rich foods produced intermediate GI values (54-79). The GI values for the nine foods calculated separately for the two racial groups were not significantly different from each other (P=0.26).

CONCLUSIONS

The GI values derived from Caucasian subjects are likely to be applicable to Asian populations. Varieties of imported rice from Thailand were found to have high GI values. Alternative low-GI staples, such as rice noodles, may be preferable for Asian/Vietnamese people with diabetes.

SPONSORSHIP

This study was funded by the University of Sydney.

Concentration and distribution of sialic acid in human milk and infant formulas

BACKGROUND

In animal studies, sialic acid supplementation is associated with increases of gangliosides in the brain and improved learning ability. Only limited data are available on the sialic acid content of human milk and infant formulas.

OBJECTIVE

We compared the concentrations of oligosaccharide-bound, protein-bound, and free sialic acid in milk from mothers of full-term and preterm infants and in a range of infant formulas.

DESIGN

The milk from 20 and 14 mothers of full-term and preterm infants (mean gestational age: 31 +/- 3 wk), respectively, was collected at 4 stages of lactation (colostrum, transition, 1 mo, and 3 mo) and compared with 21 different infant formulas.

RESULTS

Total sialic acid concentrations were highest in colostrum (x +/- SEM: 5.04 +/- 0.21 mmol/L in full term) and decreased by nearly 80% over the next 3 mo. Human milk from mothers of preterm infants contained 13-23% more sialic acid than did milk from mothers of full-term infants at 3 of the 4 lactation stages (P < 0.02). The sialic acid content of most formulas was <25% of that found in mature human milk (P < 0.01). Most of the sialic acid in the formulas ( approximately 70%) was bound to glycoproteins, whereas in human milk most sialic acid was bound to free oligosaccharides.

CONCLUSIONS

Human milk, including milk from mothers of preterm infants, is a rich source of oligosaccharide-bound sialic acid, which contrasts with the relatively small amounts found in infant formulas. The nutritional significance of sialic acid is presently unknown, but it is plausible that it is a conditional nutrient that contributes to sialic acid accretion in the brain.

A randomized, controlled study of a mandibular advancement splint for obstructive sleep apnea

Although there is increasing interest in the use of oral appliances to treat obstructive sleep apnea (OSA), the evidence base for this is weak. Furthermore, the precise mechanisms of action are uncertain. We aimed to systematically investigate the efficacy of a novel mandibular advancement splint (MAS) in patients with OSA. The sample consisted of 28 patients with proven OSA. A randomized, controlled three-period (ABB/BAA) crossover study design was used. After an acclimatization period, patients underwent three polysomnographs with either a control oral plate, which did not advance the mandible (A), or MAS (B), 1 wk apart, in either the ABB or BAA sequence. Complete response (CR) was defined as a resolution of symptoms and a reduction in Apnea/Hypopnea Index (AHI) to < 5/h, and partial response (PR) as a > or = 50% reduction in AHI, but remaining > or = 5/h. Twenty-four patients (19 men, 5 women) completed the protocol. Subjective improvements with the MAS were reported by the majority of patients (96%). There were significant improvements in AHI (30 +/- 2/h versus 14 +/- 2/h, p < 0.0001), MinSa(O(2)) (87 +/- 1% versus 91 +/- 1%, p < 0.0001), and arousal index (41 +/- 2/h versus 27 +/- 2/h, p < 0.0001) with MAS, compared with the control. The control plate had no significant effect on AHI and MinSa(O(2)). CR (n = 9) or PR (n = 6) was achieved in 62.5% of patients. The MAS is an effective treatment in some patients with OSA, including those patients with moderate or severe OSA.

A longitudinal study of salivary sialic acid in preterm infants: Comparison of human milk-fed versus formula-fed infants

We found that the saliva of preterm infants fed human milk contains twice the level of sialic acid as that in infants fed commercial formulas. The higher sialic acid level suggests greater viscosity and enhanced protection of the mucosal surfaces in breast-fed infants. Human milk itself is a rich source of sialylated oligosaccharides.

Birth centre or labour ward? A comparison of the clinical outcomes of low-risk women in a NSW hospital

A number of birth centres were established in New South Wales as a result of the Shearman Report (NSW Health Department 1989). The objective of this study was to compare the obstetric outcomes, primarily caesarean section rates, of low-risk women presenting in spontaneous labour to the birth centre with those attending the hospital's conventional labour ward. The study showed that there was no significant difference in the caesarean section rate between the groups (3.5% in the birth centre and 4.3% in the labour ward). We suggest that the site of birthing does not affect clinical outcomes for low-risk women at this hospital. These results are relevant to contemporary clinical practice as they question the basis upon which birth centres have been popularised, that is, the medicalisation of birth in conventional labour wards increases intervention rates.

The effect of supplementation with isoflavones on plasma lipids and oxidisability of low density lipoprotein in premenopausal women

Results of recent clinical studies have lead to the hypothesis that isoflavones are cardioprotective. The aims of this trial were to determine the effect of supplementation with isoflavonoid phytoestrogens on plasma cholesterol concentrations and its distribution among lipoproteins and whether supplementation with isoflavones influences oxidisability of low density lipoprotein (LDL) ex vivo. Fourteen healthy premenopausal women participated in a randomised cross-over trial lasting four menstrual cycles (approximately 4 months). The subjects were asked to consume 86 mg of isoflavones daily for the duration of two menstrual cycles followed by placebo for an equivalent period, or vice versa. Venous blood samples were collected initially and at the end of the second and fourth menstrual cycles for the determination of plasma lipid concentrations and the resistance of LDL to copper-induced oxidation ex vivo. Accustomed dietary intake of isoflavones and lignans during the placebo period were 6.87+/-3.0 and 1.80+/-0.22 mg/day (mean+/-S.E.M.), respectively, and these did not change during the supplementation period. The intake of other dietary components remained constant during the trial. Supplementation resulted in a 5-fold increase in urinary isoflavone excretion (12.2+/-14.2 versus 70.1+/-10.3 micromol/24 h, placebo and isoflavone periods, respectively, P=0.0001). No changes in the oxidisability of LDL (lag time of 32.9+/-3.1 versus 30.4+/-2.9 min) or the plasma concentrations of total cholesterol (4.03+/-0.21 versus 4.11+/-0.18 mmol/l) or triacylglycerol (0.67+/-0.04 versus 0.73+/-0.06 mmol/l) were observed following supplementation. However a significant period effect (P=0.024) was observed and a trend towards a carryover effect (P=0.086) was noted for the concentration of HDL(3) cholesterol. Further studies are required to clarify the potential effect of isoflavones on HDL metabolism and the interaction with plasma steroid hormones during the menstrual cycle.

Comparison of the effects of two low fat diets with different alpha-linolenic:linoleic acid ratios on coagulation and fibrinolysis

Fish oils rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to alter coagulation and fibrinolysis variables. This study compared the effects of a traditional cholesterol-lowering diet and a similar diet, which had 50% of the linoleic acid (LA) replaced with the 18 carbon n-3 fatty acid, alpha-linolenic acid (ALA), on selected hemostatic variables. After a 2-week run-in diet with 39.5% total energy (en) from fat, 29 healthy male subjects consumed a 31.5% en fat diet with approximately 7% en from polyunsaturated fat and an ALA:LA ratio of either 1:1.2 (ALA-rich, n=15) or 1:21 (LA-rich, n=14) for 6 weeks. Blood was collected at the beginning, middle and end of test diets for analysis of Factor VIIc and VIIIc, fibrinogen, von Willebrand factor, activated protein C resistance (APC resistance), tissue plasminogen activator and plasminogen activator inhibitor type-1 activities and/or protein concentrations and platelet fatty acids. The ALA-rich diet tripled the percentage of platelet EPA, (P < 0.0005) but had little effect on coagulation and fibrinolysis. The APC ratio demonstrated increased anticoagulant activity on the ALA-rich diet (P < 0.001) only. Studies in patients with vascular pathologies are indicated to corroborate the current findings. Greater ratios of ALA:LA, achievable only with greater amounts of polyunsaturated fat, may be necessary to produce the effects demonstrated after feeding fish oils.

An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods

The aim of this study was to systematically compare postprandial insulin responses to isoenergetic 1000-kJ (240-kcal) portions of several common foods. Correlations with nutrient content were determined. Thirty-eight foods separated into six food categories (fruit, bakery products, snacks, carbohydrate-rich foods, protein-rich foods, and breakfast cereals) were fed to groups of 11-13 healthy subjects. Finger-prick blood samples were obtained every 15 min over 120 min. An insulin score was calculated from the area under the insulin response curve for each food with use of white bread as the reference food (score = 100%). Significant differences in insulin score were found both within and among the food categories and also among foods containing a similar amount of carbohydrate. Overall, glucose and insulin scores were highly correlated (r = 0.70, P < 0.001, n = 38). However, protein-rich foods and bakery products (rich in fat and refined carbohydrate) elicited insulin responses that were disproportionately higher than their glycemic responses. Total carbohydrate (r = 0.39, P < 0.05, n = 36) and sugar (r = 0.36, P < 0.05, n = 36) contents were positively related to the mean insulin scores, whereas fat (r = -0.27, NS, n = 36) and protein (r = -0.24, NS, n = 38) contents were negatively related. Consideration of insulin scores may be relevant to the dietary management and pathogenesis of non-insulin-dependent diabetes mellitus and hyperlipidemia and may help increase the accuracy of estimating preprandial insulin requirements.

Interrelationships among postprandial satiety, glucose and insulin responses and changes in subsequent food intake

OBJECTIVE

The aim of this study was to investigate whether postprandial glucose and insulin responses were related to concurrent changes in satiety.

DESIGN

Thirty-eight common foods, grouped into six food categories, were tested in total. Each food category was fed to a separate group of subjects. A within-subjects repeated-measures design was used such that within each food category each subject consumed all of the test foods in random order.

SETTING

The study was conducted at the Human Nutrition Research Unit, Sydney University.

SUBJECTS

Separate groups of 11-13 healthy young subjects, who were unrestrained eaters, were recruited for each of the six food categories.

INTERVENTIONS

Isoenergetic 1000 kJ (240 kcal) portions of the test foods were fed to fasting subjects. Fingerprick blood samples and satiety ratings were obtained every 15 min over 120 min after which a standard meal was presented and ad libitum food intake was recorded. A glycaemic score, insulin index and satiety index score was calculated for each food by dividing the area under the 120 min response curve (AUC) for the test food by the AUC for white bread and multiplying by 100. Expressing the results of the test foods relative to those for white bread minimised the confounding influence of inherent differences between the subjects.

RESULTS

Among the 38 test foods, there were no significant relationships between satiety and plasma glucose or insulin responses. However, a negative correlation was found between insulin AUC responses and ad libitum food intake at 120 min which suggests that test foods producing a higher insulin response within 120 min were associated with less food intake and thus indirectly greater satiety. This result is consistent with previous findings that carbohydrate-rich foods are more satiating than fat-rich foods. Thus, total carbohydrate content appears to have been a stronger determinant of short-term satiety, in conjunction with the foods structural characteristics, than the foods glycaemic impact.

CONCLUSIONS

The total amount of carbohydrate consumed at a meal and subsequent insulinaemia may partly determine the degree of hunger arising within the next 2 h.

A satiety index of common foods

OBJECTIVE

The aim of this study was to produce a validated satiety index of common foods.

DESIGN AND SUBJECTS

Isoenergetic 1000 kJ (240 kcal) servings of 38 foods separated into six food categories (fruits, bakery products, snack foods, carbohydrate-rich foods, protein-rich foods, breakfast cereals) were fed to groups of 11-13 subjects. Satiety ratings were obtained every 15 min over 120 min after which subjects were free to eat ad libitum from a standard range of foods and drinks. A satiety index (SI) score was calculated by dividing the area under the satiety response curve (AUC) for the test food by the group mean satiety AUC for white bread and multiplying by 100. Thus, white bread had an SI score of 100% and the SI scores of the other foods were expressed as a percentage of white bread.

RESULTS

There were significant differences in satiety both within and between the six food categories. The highest SI score was produced by boiled potatoes (323 +/- 51%) which was seven-fold higher than the lowest SI score of the croissant (47 +/- 17%). Most foods (76%) had an SI score greater than or equal to white bread. The amount of energy eaten immediately after 120 min correlated negatively with the mean satiety AUC responses (r = -0.37, P < 0.05, n = 43) thereby supporting the subjective satiety ratings. SI scores correlated positively with the serving weight of the foods (r = 0.66, P < 0.001, n = 38) and negatively with palatability ratings (r = -0.64, P < 0.001, n = 38). Protein, fibre, and water contents of the test foods correlated positively with SI scores (r = 0.37, P < 0.05, n = 38; r = 0.46, P < 0.01; and r = 0.64, P < 0.001; respectively) whereas fat content was negatively associated (r = -0.43, P < 0.01).

CONCLUSION

The results show that isoenergetic servings of different foods differ greatly in their satiating capacities. This is relevant to the treatment and prevention of overweight and obesity.

The pharmacokinetics of five pre-mixed combinations of 'short-' and 'intermediate-acting' (NPH) insulins in healthy subjects following subcutaneous administration

The pharmacokinetics of five pre-mixed insulin preparations in the ratio of soluble to NPH insulin of 10:90, 20:80, 30:70, 40:60 and 50:50, were examined in a two part study in fasting healthy subjects. Each received by bolus subcutaneous injection into the anterior abdominal wall, on separate occasions one to two weeks apart, 20U of each of three pre-mixed insulin preparations in random order. In Part 1, nine subjects received Penmix 10:90, Penmix 20:80 and Penmix 30:70 and were observed over a period of 24 hours. In Part 2, eight subjects received Penmix 30:70, Penmix 40:60 and Penmix 50:50 and were observed over an 8 hr post-injection period. Three subjects were common to both parts of the study. Plasma glucose, C-peptide and insulin levels were measured frequently throughout both study periods. Increasing soluble insulin content in the pre-mixtures was reflected in increasing peak plasma insulin concentrations and a greater hypoglycaemic response. There were highly significant differences between the five premixtures and preparations in the 0-4 and 0-8 hours area under the curve (AUC) values for plasma glucose, C-peptide and immunoreactive insulin concentration (p < 0.01). Whereas a gradual difference between the premixtures was seen no two adjacent ones were significantly different, however an overall highly significant difference between the five preparations tested was observed.

Double-blind crossover comparison of human and porcine insulins in patients reporting lack of hypoglycaemia awareness

There has been much debate about reports that some insulin-treated diabetic patients lose awareness of hypoglycaemic symptoms on changing from porcine to human insulin. In a double-blind, crossover study, we sought differences between porcine and human insulin in the frequency and characteristics of hypoglycaemic episodes among patients who reported a reduction of awareness of hypoglycaemia after changing treatment. We studied 50 patients referred by their physicians because of complaints of lack of awareness of hypoglycaemia on human insulin. They had had diabetes for a mean of 20 (SD 12) years and 70% had good or acceptable glycaemic control. Each patient was treated in a double-blind manner for four 1-month periods, two with human and two with porcine insulin, in random order. Only 2 patients correctly identified the sequence of insulin treatments used; 8 or 9 would have been expected to do so by chance alone. The mean percentage of hypoglycaemic episodes associated with reduced or absent awareness was 64% (SD 30%) for human insulin and 69% (31%) for porcine insulin. We could find no statistically significant differences between the insulin species with respect to glycaemic control or the frequency, timing, severity, or awareness of hypoglycaemia. Reduced hypoglycaemia awareness is common with both human and porcine insulins.

Breath hydrogen excretion in infants with colic

Breath hydrogen excretion as an index of incomplete lactose absorption was measured in 118 healthy infants who were either breast fed or given a formula feed containing lactose, some of whom had colic. Infants with colic (n = 65) were selected on the basis of the mother's report of a history of inconsolable crying lasting several hours each day. Infants in the control group (n = 53) were not reported to cry excessively by their mothers. Breath samples were collected using a face mask sampling device preprandially, and 90 and 150 minutes after the start of a feed. Normalised breath hydrogen concentrations were higher in the group with colic than in the control group at each time point. The median maximum breath hydrogen concentration in the colic group was 29 ppm, and in the control group 11 ppm. The percentage of infants with incomplete lactose absorption (breath hydrogen concentration more than 20 ppm) in the colic group was 62% compared with 32% in the control group. The clinical importance of the observed association between increased breath hydrogen excretion and infantile colic remains to be determined. Increased breath hydrogen excretion indicative of incomplete lactose absorption may be either a cause or an effect of colic in infants.