Vitamin D deficiency is common in the elderly, especially in countries where effective sunlight or exposure to sunlight is limited. Two regimes for vitamin D supplementation--low-dose daily oral administration and intermittent high-dose administration--were examined with regard to safety and effectiveness. Eleven papers reporting studies in 449 elderly subjects were reviewed. On low-dose continuous supplementation mean concentration of 25 hydroxyvitamin D (25(OH)D) ranged from 57 to 105 nmol/L compared to 55 to 87 nmol/L following high-dose supplementation. These mean values fall within the physiological range for young adults. Hypercalcemia occurred in only 3 subjects and was associated with a predisposing cause in 2 of 3 subjects. We suggest that low dose continuous supplementation (10 to 20 micrograms daily) is the regime of choice but high-dose intermittent supplementation (2.5 mg six monthly) may be suitable where compliance is poor.

SUMMARYA comparison of the lipid composition of the vegetative and reproductive stages of Agaricus bisporus revealed no major qualitative differences, although quantitative divergences exist. The glycolipids consisted of acylglucoses, acylmannitol, acyltrehalose and a glucosyloxyfatty acid. Two of the acylglucoses corresponded to a tetra-acylglucose and to either a di-or a triacylglucose. The phospholipids were distinctive in that phosphatidylcholine could not be detected. Phosphatidylethanolamine and phosphatidylserine were the major phosphoglycerides. Examination of the neutral lipids revealed the expected array of acylglycerols, free and esterified sterols, and free fatty acids. A substantial amount (26 to 33 %) of the fatty acids of the neutral lipids from both sporophore and mycelium were apparently of chain length greater than CIS. Linoleic acid was a minor component of the total neutral-lipid fatty acids but comprised about one-half of the total free fatty acids.

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Abstracttests, leading to the suggestion that regular Background -Maximal exercise testing is aerobic training may increase life expectancy. 8 used in patients with cystic fibrosis to as-To investigate this important issue, improved sess functional status and prognosis. The methods of quantifying aerobic fitness are relactate threshold is an index of aerobic quired which are not excessively stressful and fitness with significant advantages over are readily acceptable to patients. maximal exercise tests. This study wasVarious techniques have been used to assess undertaken to determine if the lactate fitness in subjects with cystic fibrosis including threshold might be identified, non-in-maximal oxygen consumption, maximum vasively, in adult patients with cystic power output, time to exhaustion during infibrosis and mild lung disease by measure-cremental exercise tests, time to exhaustion at ment of ventilatory and gas exchange para-a fixed work load, or time taken to complete a meters.fixed distance. 5 6 8 9 However, there are many Methods -Ten subjects with mild cystic difficulties associated with their use in this fibrosis (forced vital capacity (FVC) >70% context. 10 In particular, all require the subject predicted) and 10 healthy controls under-to make maximal efforts, rendering such tests took an incremental exercise test on a highly dependent on motivation. bicycle ergometer. Ventilation and gasThe lactate threshold is an alternative index exchange parameters were measured con-of aerobic fitness which has been widely used tinually and arterialised venous blood pH, in athletes. As the workload progressively incarbon dioxide tension (PCO 2 ), and lactate creases during an incremental exercise test, a concentrations were measured at intervals critical exercise intensity is reached above throughout the tests.which blood lactate levels increase proResults -In subjects with cystic fibrosis gressively, reflecting an abrupt rise in lactate there was no significant difference between concentration in the exercising muscles. 10 The the mean gas exchange and lactate thresh-oxygen uptake of the subject at this critical olds (mean difference 1.0 (95% confidence work load is called the lactate threshold (LT), interval (CI) of the mean -1.5 to 3.44) ml/ which is a better indicator of aerobic fitness kg/min). In contrast, there was a sig-than other indices commonly used. It permits nificant difference between the mean identification of the optimum training intensity ventilatory and lactate thresholds (3.8 for an individual and does not require exercise (95% CI 0.9 to 6.7) ml/kg/min). Arterialised to exhaustion for its determination. 10-14 venous PCO 2 increased significantly duringIn healthy subjects the LT may be dethe exercise tests. In healthy subjects the termined non-invasively by identification of the mean differences between these thresholds ventilatory threshold (VenT) which is defined were not significantly different from zero as the point during an incremental exercise test and PCO 2 fell significantly during the...

The glycophosphosphingolipids are a group of sphingolipids characterized by the presence of equimolar amounts of long-chain base and fatty acid (ceramide) and containing either one or two mol of inositol phosphate per mol of lipid. From one to several mol of sugar are also present. Glycophosphosphingolipids have been isolated from both plant and fungal sources. Work in this area had for years been the province of Herbert Carter and colleagues. They showed that such glycolipids occurred in seeds from corn, flax, soya beans and bean leaves