Modification of ion channels and calcium homeostasis of basal forebrain neurons during aging.

In this paper we review the last several years of work from our lab with attention to changes in the properties of basal forebrain neurons during aging. These neurons play a central role in behavioral functions, such as: attention, arousal, cognition and autonomic activity, and these functions can be adversely affected during aging. Therefore, it is fundamental to define the cellular mechanisms of aging in order to understand the basal forebrain and to correct deficits associated with aging. We have examined changes in the physiological properties of basal forebrain neurons during aging with whole-cell and single-channel patch-clamp, as well as, microfluorimetric measurements of intracellular calcium concentrations. These studies contribute to the understanding of integration within the basal forebrain and to the identification of age-related changes within central mammalian neurons. Although extensive functional/behavioral decline is often assumed to occur during aging, our data support an interpretation of compensatory increases in function for excitatory amino acid receptors, GABA(A) receptors, voltage-gated calcium currents and calcium homeostatic mechanisms. We believe that these changes occur to compensate for decrements accruing with age, such as decreased synaptic contacts, ion imbalances or neuronal loss. The basal forebrain must retain functionality into late aging if senescence is to be productive. Thus, it is critical to recognize the potential cellular and subcellular targets for therapeutic interventions intended to correct age-related behavioral deficits.

Foot and hand length for prediction of vital capacity in scoliotic children.

Expected values of vital capacity (VC) and other lung function variables in children are usually predicted from regression equations of the index test on stature. In children with scoliosis, arm span or an "uncoiled" stature derived from the observed stature and the degree of spinal angulation have been used to predict expected values. Stature and hand and foot length were measured and all three anthropometric indices were used as independent variables for the prediction of VC in 489 normal children and adolescents (aged 4-18 years). VC was highly correlated with stature for boys and girls with regression coefficients of 0.93 and 0.91, respectively. For foot length, corresponding coefficients were 0.90 and 0.83, and for hand length 0.90 and 0.80. In 14 scoliotic children, aged 5.9-18.4 years, a close agreement was found for predictions of VC from arm span, uncoiled stature and hand and foot length. When accurate measurements of stature cannot be made, hand or foot length can be used to predict expected VC. This approach may be an alternative to the use of arm span or uncoiled stature to predict VC in children with scoliosis.

Lung function in white children aged 4 to 19 years: II--Single breath analysis and plethysmography.

OBJECTIVE: A study was performed to determine reference ranges for whole body plethysmographic gas volumes and single breath gas transfer in healthy prepubertal and pubertal schoolchildren. METHODS: The study was performed in 772 white London schoolchildren (455 male) who were clinically examined, assessed auxologically and, in 63% of cases, pubertally staged. Regression equations for the calculation of standard deviation scores were derived. RESULTS: Male lung function variables showed a discontinuous pattern of increase with standing height. Linear increases until puberty were followed by a sudden pubertal rise and a further increase with height which was more marked than before puberty. Correction for varying thoracic dimensions eliminated these changes. In females a smoother curvilinear relationship was observed with no correction possible for thoracic size. CONCLUSIONS: Male puberty leads to profound changes in pulmonary function mostly related to thoracic size, an effect not observed in females.

Weight/height2.88 as a screening test for obesity or thinness in schoolage children.

We wished to determine a weight for height measure for use as a simple screening test throughout the schoolage years for obesity or thinness similar to the body mass index in adults but not correlated with either height or age. Single measurements of height, weight, pubertal stage and two site skinfold thickness were collected on 979 healthy London schoolchildren (559 male) aged 4.6-18.8 years from 11 schools by one anthropometrist. Weight/height2.88 was uncorrelated with height or age in either sex. The median (95% confidence interval of the median) value for boys (12.74, 12.58-12.90) did not vary within this age group, height or pubertal stage. In girls the median value 12.46 (12.20-12.61) was valid for all girls less than breast stage 4 but rose sharply to 13.64 (13.21-14.06) thereafter. Percentile charts and nomograms are provided. Conclusion Weight/height2.88 may be a simple screening test for obesity or thinness throughout the schooling years and that its independence of age and height greatly simplifies longitudinal assessment.

Lung function in white children aged 4 to 19 years: I--Spirometry.

OBJECTIVE: A study was performed to produce reference standards for spirometric lung function in white children and to calculate standard deviation scores adjusted for gender and pubertal stage. METHODS: A cross sectional study was made of 772 white children aged 4.6 to 18.8 years (455 male) tested on an OHIO 840 spirometer and assessed anthropometrically and pubertally. RESULTS: Before puberty there was a linear increase in all lung function measurements with height. During puberty a sudden increase occurred, but subsequently the relationship was again linear. No simple single equation described this pattern. Advanced puberty in younger children conferred a respiratory advantage, whilst delayed puberty resulted in the converse. Girls had poorer volumes per unit height, but young girls had superior airflow/unit lung volume. In both sexes lung volumes and flows bore a constant relationship to external thoracic dimensions. CONCLUSIONS: Puberty has a dramatic effect on lung function. Regression equations for predicted values of lung function measurements and for calculation of standard deviation scores are given (with pubertal correction factors) for each gender.