The safety of gum arabic as a food additive and its Energy Value as an ingredient: a brief review

Gum arabic, the natural exudate from Acacia senegal (L.) Willd., has enjoyed the toxicological status 'ADI not specified' for use in minor proportions as a food additive (E414 in the EEC) since 1982, but it is also used as a major ingredient. Manufacturers may therefore be required to make labelling declarations of its Energy Value and of available/non-available carbohydrate. Although gum arabic complies with the definition for soluble dietary fibre, its Energy Value was accepted by the FAO/WHO International Programme of Food Safety to be 4 kcal/gram on the basis of the evidence available in 1982. Subsequently a French claim for a much lower value attracted the attention of manufacturers of low calorie products but a recent precise experiment establishes that the Digestible Energy Value is 3.5 ± 0.12 kilocalories per gram. The physiological mechanism whereby this value arieses is outlined. The more general dietary implications for other complex carbohydrates which conform to the definition for soluble dietary fibre and yet suffer complete degradation in the large bowel are indicated.     

Acetylstrophanthidin does not enhance the reflex pressor response to static muscular contraction

Summary. Cardiac glycosides have been shown to enhance the sensitivity of the reflex cardiovascular responses to stimulation of mechanoreceptors in the heart, carotid sinus and aorta. Little is known, however, about the effect of glycosides on the reflex cardiovascular responses to the contraction-induced stimulation of afferent endings in hindlimb skeletal muscle. We therefore examined the reflex heart rate and arterial pressure responses to static contraction of the hindlimb muscles before and after femoral arterial injection of two doses of acetylstrophanthidin (20 and 80 μ/kg). Neither of the two doses enhanced the reflex cardiovascular responses to contraction, although the larger of the two significantly increased femoral venous potassium concentrations from 3·4±0·2 to 3·8±0·1 mM. Although injection of the two doses as well as injection of a very large dose of acetylstrophanthidin (400 μg/kg) increased baseline mean arterial pressure, these effects were probably caused by the vasoconstrictor action of this agent and not by a chemoreflex, because the increase was not attenuated by denervation of the hindlimb.     

THE EFFECTS OF 4-METHYL-2-THIOURACIL ON FIBRE TYPE AND CROSS-SECTIONAL AREA IN THE SOLEUS MUSCLE OF THE RAT

The effects of 4-methyl-2-thiouracil (MTU, 0.1% in drinking water) on the composition and cross-sectional area of muscle fibres of the rat soleus muscle were studied. The percentage of fast twitch-oxidative-glycolytic (FOG) fibres fell after 2 weeks of treatment with MTU to zero at 8 weeks. In contrast the percentage of FOG fibres in untreated animals fell to 19.2 +/- 2.1% during this period. The mean cross-sectional area of FOG and slow twitch-oxidative (SO) fibres were respectively 39.9% and 23.8% smaller than those of their respective controls 6 weeks after treatment. At 8 weeks the percentage reduction of SO fibre area was 26.8% of the control value. This study indicates that MTU treatment causes atrophy and redistribution of fibre type in the soleus muscle.     

Daily dietary fibre intake of children, 2 to 3 years of age, living in Antwerp, Belgium

Daily dietary fibre intake of toddlers living in Antwerp (Belgium) have been calculated by weighted food records with subsequent conversion using computerised food composition tables. Dietary fibre intakes were also measured by the duplicate portion technique to evaluate the intakes of total, soluble and insoluble dietary fibre. Calculated dietary fibre intake was 10 ± 3 g/d. Measured intakes of total, soluble and insoluble dietary fibre were 14.5 ± 2.8 g/d, 6.0 ± 1.9 g/d, and 8.6 ± 1.6 g/d. Values about the fibre intakes between both methods differed for 31.7%. Bread contributed for more than one third of the total dietary fibre intake. The contributions of the other food groups were 15.1% for fruits, 14.5% for starchy foods and 13.9% for vegetables. The intakes of dietary fibre from bread by the toddlers in this study could be considered as high, whilst intakes from fruits and vegetables might be increased.     

Dietary fibre (non-starch polysaccharides) in cereal products

Dietary fibre, measured as non-starch polysaccharides (NSP) has been determined in 114 cereals and cereal products using the Englyst technique. No diffculties were encountered with the analysis of any food and the results for cooked foods such as bread and breakfast cereals were comparable with the raw materials. The amount of total NSP ranged widely from 0.1% in cornflour to 37% in wheat bran. Detailed analysis of the materials indicated that most of the NSP in wheat and maize was an insoluble arabinoxylan whilst in oats a soluble β-glucan predominated. Barley and rye contained high amounts of both arabinoxylan and β-glucan. The NSP content of cereal products such as breakfast cereals and biscuits reflected the flours and grains from which they were made. When comparing the present data with other published results the importance of complete removal of starch for accurate dietary fibre measurement is stressed.     

分散染料在染色涤纶上固着状态的探讨

利用X-射线衍射、DSC热分析和光学行为的测量,对三个分散染料(C.I.分散红225、167,C.I.分散蓝73)在染色涤纶纤维上的固着状态进行了研究。结果表明:这些染料均不以晶体状态固着在纤维上,所以染色纤维的色光与这些染料晶型的颜色没有关系。     

Disinfection of the Optical Fibre of a Nd-YAP Laser Used in Dental Care

In order to set up a disinfection protocol, the tip of the optical fibre of an Nd-YAP laser, λ=1.34 μm, was contaminated in vitro with: Mycobacterium smegmatis (CIP 7326), Candida albicans (ATCC 2091), Bacillus stearothermophilus (ATCC 7953) or Streptococcus sanguis (ATCC 10556). It was then treated with various biocidal solutions, Septinol^? V, glutaraldehyde 2%, ethanol 95° and NaOCl 6%, using one of two protocols: 10 s of contact, or 5 s of contact followed by 5 s of wiping. The latter technique proved to be the most effective. Whatever the biocidal solution used, all the bacteria adhering to the fibre were eliminated. The protocol was checked in vivo in the canals of 10 teeth presenting root canal infections. No bacteria withstood the treatment with Septinol^? V. This treatment does not alter the qualities and performance of the fibre as far as light transmission is concerned. Paper received 8 February 1997; accepted after revision 17 March 1998.     

Exogen involves gradual release of the hair club fibre in the vibrissa follicle model

Abstract:  Exogen is a distinct phase of the hair cycle describing the process by which the hair club fibre is shed from the follicle. This process is difficult to study in human skin and little is known about the mechanisms involved in the release of club fibres. We sought an alternative model system to study exogen in more detail, and therefore utilised the vibrissa system on the rodent mystacial pad. The time at which a vibrissa club hair will be lost can be predicted, based on the relative lengths of the new growing fibre and old club fibre. This timing phenomenon was exploited to investigate the club fibre within the follicle as it approaches final release, revealing key changes in the adhesive state of the club fibre within the epithelial sac as it approached release. We propose that exogen should be subdivided to represent variations in the club fibre status.     

Lamina-specific changes in hippocampal GABAA/cBZR and mossy fibre sprouting during and following amygdala kindling in the rat

Alterations in hippocampal GABA_A/central benzodiazepine receptor (GABA_A/cBZR) expression and mossy fibre sprouting (MFS) may have aetiological significance in temporal lobe epileptogenesis. Their relationship with each other is also unknown. We utilised [³H]-flumazenil autoradiography to quantify changes in GABA_A/cBZR density and affinity in all hippocampal laminae, and Timm's staining for MFS at different stages of epileptogenesis in the amygdala kindling rat model (after 24 stimulations, 48 stimulations and two weeks post-kindling). During kindling, receptor density was significantly elevated within the dentate stratum moleculare and granulosum, but decreased within the stratum radiatum of CA3 and CA2. Two weeks post-kindling, receptor density remained upregulated in the dentate stratum moleculare and was also upregulated in CA3 stratum oriens and CA1 stratum moleculare. MFS was significantly increased in the dentate stratum moleculare at two weeks post-kindling, with a strong inverse correlation between MFS and GABA_A/cBZR density in this region. No changes in GABA_A/cBZR binding affinity were detected for any hippocampal subregion at any time point. Our results demonstrate that changes in hippocampal GABA_A/cBZR expression are lamina- and time-specific. Within the dentate gyrus, receptor density is upregulated throughout epileptogenesis, whilst within the hippocampus proper, receptor density is downregulated early in epileptogenesis but upregulated at the chronic phase. A novel association between MFS and GABA_A/cBZR density has been demonstrated by this study, which could represent an important compensatory or pathological mechanism associated with epileptogenesis.     

An audit of laxative use and fibre/fluid intakes in a care of the elderly rehabilitation ward

Background: Constipation is a common problem in elderly patients, resulting in considerable discomfort and expenditure on prescribed laxatives. Aims and objectives: This study aimed to audit the use of laxatives on a ward for the rehabilitation of elderly people; to assess the fibre and fluid provided to patients on the basis of hospital menus and to assess the individual, daily intakes of fluid and fibre of three patients. Methods: Pharmacy records were used to audit laxative use on the ward over a 3-month period. Provision of fluid and fibre were assessed by analysis of the regular and soft menus for 3 days, using food composition tables. A weighed intake assessment of three patients for one day was undertaken. Results: Ispaghula husk (Fybogel, Regulan) were the most commonly used laxatives. Although the regular menu appeared to provide adequate amounts of fluid and fibre, results for the soft menu were less satisfactory. All three patients had intakes well below the recommended level of dietary fibre. Conclusion: Despite the limitations of this small study, the findings suggest that improvements in catering and food service could be implemented to increase the intake of dietary fibre by patients in this ward. These should be implemented and the use of laxatives re-audited.