Color categories are not universal: replications and new evidence from a stone-age culture

The authors sought to replicate and extend the work of E. Rosch Heider (1972) on the Dani with a comparable group from Papua, New Guinea, who speak Berinmo, which has 5 basic color terms. Naming and memory for highly saturated focal, non-focal, and low-saturation stimuli from around the color space were investigated. Recognition of desaturated colors was affected by color vocabulary. When response bias was controlled, there was no recognition advantage for focal stimuli. Paired-associate learning also failed to show an advantage for focal stimuli. Categorical Perception effects for both English and Berinmo were found, but only at the boundaries of existing linguistic categories. It is concluded that possession of linguistic categories facilitates recognition and influences perceptual judgments.

Response to dehydration in elderly patients in long-term care

Elderly patients in long-term care have a high plasma osmolality (pOSM) and associated increased mortality. In these patients, we examined pOSM, thirst (visual analogue scale, VAS) and arginine vasopressin (AVP) response to 16-hour dehydration and 2-hour rehydration. Twelve patients were randomly divided into two groups (A & B). Group A had their fluid balance monitored for two weeks, group B did not. Single measurements of VAS, pOSM and AVP were conducted on days 0, 7 and 13. Dehydration tests were conducted in both groups at the start of the study (DAY 1), and at the end of the two-week period (DAY 14). There were no significant differences between group A and B, so the results are presented for the two groups combined. There was a significant increase in both pOSM and VAS during dehydration, and a significant fall in both variables during rehydration [F (9,99) = 18.69, p < 0.001, and F(9,99) = 11.25, p < 0.001, respectively]. Plasma AVP did not change significantly during either dehydration or rehydration [F (9,99) = 0.59, p = 0.8]. There were no significant differences in response for any of the three variables between DAY 1 and DAY 14. We conclude that elderly patients in long-term care exhibit changes in thirst and osmolality during dehydration and rehydration, and that these responses are reproducible. The lack of a significant AVP response requires further investigation.

Production of consistent crush lesions of murine skeletal muscle in vivo using an electromechanical device

The crush model of injury in skeletal muscle is widely used in the investigation of tissue degeneration and regeneration. Previously, such trauma has been induced by using forceps to crush the muscle, commonly applying sufficient pressure to bring the mid-arms of the forceps together. This report introduces a reliable electromechanical device designed to generate reproducible focal lesions in skeletal muscle of mice. The tibialis anterior was crushed in 17 young adult mice. Two days after injury, the muscles were examined microscopically. By morphometric analysis, it was determined that the volumes of the lesions produced were similar (mean 0.499 mm3 +/- 0.098, range 0.278 - 0.601 mm3), and that the full extent of the damaged muscle was easily distinguished and readily quantifiable. This will allow a more precise comparison in future investigations into regenerative differences between age groups, satellite cell activation and the inflammatory response.

A randomised controlled trial and cost analysis of problem-solving treatment for emotional disorders given by community nurses in primary care

BACKGROUND

We set out to investigate whether community nurses could be trained in problem-solving therapy and, once trained, how effective they would be in treating emotional disorders in primary care.

METHOD

Seventy patients with an emotional disorder in primary care were randomly allocated to receive either problem-solving therapy from a trained community nurse or treatment as usual from their general practitioner. Interview and self-rated assessments of clinical and economic outcome were made pretreatment, at eight weeks and at 26 weeks after treatment.

RESULTS

There was no difference in clinical outcome between patients who received problem-solving treatment and patients who received the general practitioner's usual treatment. However, patients who received problem-solving treatment had fewer disability days and fewer days off work. The health care cost of problem-solving was greater than that of the general practitioner's usual treatment but this was more than offset by savings in the cost of days off work.

CONCLUSIONS

Problem-solving treatment can be given by trained community nurses. The clinical effectiveness and cost-benefit of the treatment will depend on the selection of appropriate patients.

Perceptual learning of stereoacuity

It has often been noted that with repeated exposure to random-dot stereograms the time required to perceived depth decreases. Further, with extensive practice, stereoacuity thresholds have been shown to decrease. For both types of learning some researchers have reported specificity of the improvements to retinal location, and have thus suggested that the learning may be localised at early levels of visual processing, such as in primary visual cortex. However, these studies have not adequately ruled out the possibility that the specificity shown may be due to the operation of selective-spatial-attention mechanisms. In the present study this possibility was examined by training observers to judge the relative depth of a pair of stereograms presented equally often in two spatial locations, but stimuli were only presented with one direction of disparity (ie crossed or uncrossed) in any one location. Results indicated that, as expected, observers' judgements improved with practice. However, this improvement transferred completely to stimuli presented with the other direction of disparity in each location. Thus, it is argued that previous findings of retinal-location-specific improvements in stereoacuity may well be due to selective-spatial-attention mechanisms, rather than to learning localised at an early level of visual processing.

Age-related postreceptor mechanisms: changes in adenylate cyclase but not phosphodiesterase in isolated mouse renal medullary collecting ducts

Urine concentrating ability declines with increasing age, partly due to an impaired response of kidney medullary collecting ducts to the antidiuretic hormone, vasopressin. We investigated this change in isolated mouse medullary collecting ducts by measuring the activity of adenylate cyclase and phosphodiesterase, which catalyse the formation and hydrolysis of cAMP, respectively. Adenylate cyclase activity was measured in the presence of vasopressin (which stimulates adenylate cyclase via the receptor) or forskolin (which directly stimulates the catalytic subunit). We showed an age-related decrease in the catalytic subunit of adenylate cyclase, and no difference in the activity of phosphodiesterase, indicating that a reduction in the catalytic subunit of adenylate cyclase contributes towards the age-related decrease in cyclic AMP response of kidney to vasopressin.

Age-associated alterations in thirst and arginine vasopressin in response to a water or sodium load

We have examined simultaneous changes in thirst, plasma osmolality and arginine vasopressin, after oral water loading or hypertonic saline infusion. The studies were carried out in the same subjects, comprising young controls aged 26.8 years (SD 4.8, n = 10) and health status-defined elderly people aged 72.1 years (SD 3.1, n = 10). Water loading caused significant falls in plasma osmolality (p < 0.001) and thirst (p < 0.001), but there was no variation with age. Infusion with 462 mmol/l of sodium chloride increased plasma osmolality significantly (p < 0.001), but there was no variation with age (p = 0.12). The perception of thirst during the osmotic loading experiment was recorded differently by the two age groups (p < 0.0001). However, linear regression analysis showed no age difference in the relationship between thirst and plasma osmolality during osmotic loading. During osmotic loading the relationship between the plasma concentration of arginine vasopressin in response to increasing plasma osmolality varied significantly (slope: p = 0.02; intercept: p = 0.02). Plasma arginine vasopressin rose more rapidly with increasing plasma osmolality in old subjects.

Dual-channel laser scanning microscopy for the identification and quantification of proliferating skeletal muscle satellite cells following synergist ablation

Proliferating skeletal muscle satellite cells are the source of additional myonuclei which allow skeletal muscle to grow and regenerate. Previously, proliferating satellite cells were identified in situ by techniques which were limited either by tissue processing time or inability to observe complete muscle sections, or by errors made in separating these cells from proliferating nonmyogenic cells. To overcome these problems a new method has been devised for the identification and quantification of proliferating satellite cells in situ by light microscopy. The technique involves dual-channel laser scanning imaging of whole muscle sections for the localisation of both the muscle fibre basal lamina and the cell division marker bromodeoxyuridine. Using this technique satellite cell proliferation was quantified in mouse limb muscle following synergist ablation. Dual-channel laser scanning microscopy allowed precise localisation of proliferating satellite cells in the experimental model and, after 4 d, synergist ablation was shown to have produced significant satellite cell proliferation when compared with contralateral and sham-operated controls.

A developmental study of the acquisition of colour terms in Setswana

We report a study of the acquisition of colour terms by speakers of Setswana, the language of Botswana in Southern Africa. This was carried out as a test of Berlin & Kay's theory of colour term universals, on a language with less than the maximum complement of eleven basic colour terms, and in order to document changes in Setswana under the impact of economic development. Seventy-seven five- to nine-year-olds were studied on two colour tasks: elicited lists and colour naming. In general the data were consistent with Berlin & Kay's theory: the rank order of frequency of correct use of colour terms was similar to the order of the Berlin & Kay hierarchy; and primary colour terms were offered more frequently and were more likely to be used correctly than secondary colour terms. The use of English colour terms was prevalent, especially amongst the younger groups, but they functioned as substitutes for Setswana terms, rather than as a means to fill the vacant basic colour term slots.

Fluid balance in elderly patients following acute stroke

We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid input in patients during the acute phase of a first stroke. Fifteen consecutive patients were studied (median age 79) and their blood sampled on days 0, 1, 2, 3, 7 and 14. Plasma osmolality was related to fluid input over days 0-3 (p = 0.0013) and AVP over 14 days (p less than 0.001). Patients with a poor outcome had higher AVP concentrations (p = 0.02). Those on intravenous fluids received a higher volume (p less than 0.01) and had a lower plasma osmolality (p = 0.04). The results of this preliminary study indicate that a standard regime for fluid input is inappropriate.

Influence of age on plasma osmolality: a community study

We have shown an age-associated increase in plasma osmolality (p less than 0.001) in 152 randomly selected subjects, living in the community. In the old [mean age 78.0 (7.5) years] the plasma osmolality was 302.2 (300.6-303.8) mOsmol/kg compared with 291.2 (290.0-292.3) mOsmol/kg in the young [39.2 (11.2) years] (p less than 0.0001). In a further group of 20 screened, health status defined, elderly subjects the plasma osmolality was 298.1 (295.9-300.3) mOsmol/kg, which was significantly higher than the young group (p less than 0.0001) but lower than the unscreened old subjects (p = 0.005). The variance was also significantly lower (p = 0.03). The results may reflect a loosening of homoeostatic control and highlight the need for care in subject selection in studies of ageing.

Age-associated changes in neuroaxonal transport in the hypothalamo-neurohypophysial system of the mouse

In this study, we investigated age-associated changes in neuroaxonal transport of the hormone vasopressin (AVP) and its associated neurophysin (NPII), from the supraoptic nucleus (SON) of the hypothalamus to the neurohypophysis. C57BL/Icrfat male mice of 6 and 28 months of age were injected in the hypothalamus with L-[35S]cysteine. Animals were killed up to 2.25 h after injection and NPII and AVP from the SON and neurohypophysis were separated using HPLC, and the fractions counted for radioactivity. In the SON, radiolabelled NPII and AVP were first detected after 0.50 h in both young and old mice. There was no significant difference between the age-groups in the incorporation of radiolabel over the time course studied. Radiolabelled NPII in the neurohypophysis was significantly above background after 1.25 h in the young, and after 1.50 h in the old mice. The differences between the two age groups was significant (P = 0.05). Radiolabelled AVP followed a similar trend, but was not significantly above background until 1.50 h in the young and 1.75 h in the old. The differences between the two age groups was on the point of significance (P = 0.056). These results indicate a significant reduction of up to 25% in the rate of axonal transport of neurohypophyseal peptides with advancing age.

Cerebral activity prior to motion task performance: an electroencephalographic study

Cerebral activity, as reflected by power in the alpha waveband (8-13 Hz), was examined prior to the performance of three tasks with different effort and accuracy requirements. The study aimed to further investigate changes in activity observed in an earlier study in which expert karate performers exhibited significant increases in alpha band power during preparation for a training task. In contrast to the earlier research, the high effort task produced a significant decrease in 'alpha' power prior to performance. 'Alpha' power prior to the high accuracy task showed significant differences mediated by the outcome. Successful performance was preceded by higher levels of 'alpha' power than unsuccessful attempts. The reported use of a cognitive strategy on the first task produced a significant difference in activity, lower alpha power being associated with the use of such a technique.

Comments on review by Swaab--brain aging and Alzheimer's disease. "Wear and tear" versus "use it or lose it"

This review discusses a new hypothesis about cellular ageing in the context of current experimental observations and other well-known ideas, particularly "wear and tear," the relationship between metabolic rate and life span, and "free radical" reactions. However, even though these concepts are frequently used in the literature it is clear from the data discussed by Swaab that there are fundamental disagreements between the theories and experimental observations.

Stress hormone and blood glucose response following acute stroke in the elderly

We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 consecutive elderly patients (median age 80 [range 75-92] years) following an acute first stroke. The median delay from the onset of the stroke to the first blood sample (day 0) was 9 (range 4-22) hours. Subsequent blood samples were taken, after fasting, for the determination of blood glucose, cortisol, catecholamine, insulin, C-peptide, glucagon, and lactate concentrations on days 1, 2, 3, 7, 14, 30, and 90. For all 23 patients, a significant relation was found between the blood glucose concentration and survival (p = 0.03) and the blood glucose concentration decreased with time (p less than 0.001). There was also a significant relation between blood glucose concentration and outcome (p = 0.02). For the 15 patients with complete data, the major determinants of the blood glucose concentration were the cortisol, insulin, and glucagon concentrations (all p less than 0.001), which accounted for 42% of the variance. When all the indexes were analyzed together by logistic regression, only the cortisol concentration was related to outcome (p = 0.02). Hyperglycemia following a stroke probably reflects the intensity of the stress hormone response. We have confirmed that hyperglycemia is a predictor of outcome in persons with stroke.

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin from Salmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (BCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.